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serafim n nanas
Critical Care Medicine
Medical School, National & Kapodestrian Univercity of Athens, Greece
snanas@cc.uoa.gr

Journal articles

2008
 
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Nanas, Vasileiadis, Dimopoulos, Sakellariou, Kapsimalakou, Papazachou, Tasoulis, Ladis, Pangalis, Aessopos (2008)  New insights into the exercise intolerance of beta-thalassemia major patients.   Scand J Med Sci Sports Feb  
Abstract: The purpose of our study was assessment of the relative contribution of the systems involved in blood gas exchange to the limited exercise capacity in patients with beta-thalassemia major (TM) using integrative cardiopulmonary exercise testing (CPET) with estimation of oxygen kinetics. The study consisted of 15 consecutive TM patients and 15 matched controls who performed spirometric evaluation, measurement of maximum inspiratory pressure (Pimax) and an incremental symptom-limited CPET on a cycle ergometer. Exercise capacity was markedly reduced in TM patients as assessed by peak oxygen uptake (pVO(2), mL/kg/min: 22.1+/-6.6 vs 33.8+/-8.3; P<0.001) and anaerobic threshold (mL/kg/min: 13.0+/-3.0 vs 18.7+/-4.6; P<0.001) compared with controls. No ventilatory limitation to exercise was noted in TM patients (VE/VCO(2) slope: 23.4+/-3.2 vs 27.8+/-2.6; P<0.001 and breathing reserve, %: 42.9+/-17.0 vs 29.5+/-12.0; P<0.005) and no difference in oxygen cost of work (peak VO(2)/WR, mL/min W: 12.2+/-1.7 vs 12.2+/-1.5; P=NS). Delayed recovery oxygen kinetics after exercise was observed in TM patients (VO(2)/t slope, mL/kg/min(2): 0.67+/-0.27 vs 0.93+/-0.23; P<0.05) that was significantly correlated with Pimax at rest (r: 0.81; P<0.001). The latter was also significantly correlated to pVO(2) (r: 0.84; P<0.001) and inversely correlated to ferritin levels (r: -0.6; P<0.02). Exercise capacity is markedly reduced in TM patients and this reduction is highly associated with the limited functional status of peripheral muscles.
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2007
 
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Ourania Papazachou, Maria Anastasiou-Nana, Dimitrios Sakellariou, Antonia Tassiou, Stavros Dimopoulos, John Venetsanakos, George Maroulidis, Stavros Drakos, Charis Roussos, Serafim Nanas (2007)  Pulmonary function at peak exercise in patients with chronic heart failure.   Int J Cardiol 118: 1. 28-35 May  
Abstract: BACKGROUND: Various respiratory abnormalities are associated with chronic heart failure (CHF). However, changes in inspiratory capacity (IC) and breathing pattern from rest to exercise in patients with CHF have not been thoroughly investigated in these patients. MATERIALS AND METHODS: Seventy seven (66 male/11 female) patients with clinical stable CHF (age: 52+/-11 years) were studied. All the patients underwent pulmonary function tests, including measurements of IC and maximal inspiratory pressure (Pimax) at rest and then a maximal cardiopulmonary exercise testing (CPET) on a treadmill. During the CPET, IC was measured every 2 min. Pimax was measured again after the end of CPET. RESULTS: Percent predicted forced expiratory volume in 1 s (FEV1) was 91+/-12, %predicted forced vital capacity (FVC) was 92+/-13, %FEV1/FVC was 81+/-4, and %predicted IC was 85+/-18. Peak exercise IC was lower than resting (2.4+/-0.6 vs. 2.6+/-0.6 l, p<0.001). Analysis of variance between Weber's groups revealed statistically significant differences in peak exercise IC (p<0.001), VE/VCO2slope (p<0.001), resting Pimax (p=0.005) and post-exercise Pimax (p<0.001). At rest, there was a statistically significant difference in end-tidal CO2 (P(ETCO2)) (p=0.002), in breathing frequency (p=0.004), in inspiratory time (Ti) (p=0.04) and in total respiratory time (T(Tot)) (p=0.004) among Weber's groups. At peak exercise there was a statistically significant decrease in minute ventilation (VE) (p<0.001), tidal volume (VT) (p<0.001), respiratory cycle (VT/TI) (p<0.001) and P(ETCO2) (p<0.001). Peak IC was correlated with peak VO2 (r=0.72, p<0.001), anaerobic threshold (r=0.71, p<0.001), VO2/t slope (r=0.54, p<0.0001), and post-exercise Pimax (r=0.62, p<0.001). CONCLUSIONS: In patients with CHF, peak exercise IC is reduced in parallel with disease severity, which is probably due to respiratory muscle dysfunction.
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S Nanas, E Angelopoulos, S Tsikriki, K Kritikos, E Voutsinas, D Zervakis, D Kanaloupiti, M Pratikaki, C Roussos (2007)  Propofol-induced hyperamylasaemia in a general intensive care unit.   Anaesth Intensive Care 35: 6. 920-923 Dec  
Abstract: This study examined the incidence of hyperamylasaemia, in the absence of other plausible causes of pancreatic dysfunction, in intensive care unit (ICU) patients who received propofol. One-hundred-and-seventy-two consecutive patients of a general ICU who stayed for more than 24 hours were studied. Patients with a diagnosis consistent with elevated serum amylase levels at admission were excluded from the study, as were patients who had received medications known to raise serum amylase levels. Forty-four patients 53 +/- 20 years of age and median duration of ICU stay of five days (range two to 55) were eligible. Thirty of those, aged 54 +/- 21 years and median duration of ICU stay of five days (range two to 27) received continuous infusion of propofol for sedation (maximum dose 45 microg/kg/min). Of the 30 patients who received propofol, 16 (53%) developed hyperamylasaemia (125 to 466 IU/l) after two to nine days of continuous infusion. Liver and kidney function remained normal throughout the observation period. Of the 14 patients who did not receive propofol (aged 51 +/- 18 years), only two (14%) developed hyperamylasaemia, a significantly lower incidence (P = 0.021). Propofol infusion is associated with biochemical evidence of pancreatic injury. Amylase levels monitoring of propofol-sedated patients is warranted.
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Eleni E Magira, Dimitrios Zervakis, Christina Routsi, Marina Kontogiorgi, Charis Roussos, Serafim Nanas, Spyros Mentzelopoulos (2007)  Community-acquired methicillin-resistant Staphylococcus aureus carrying Panton-Valentine leukocidin genes: a lethal cause of pneumonia in an adult immunocompetent patient.   Scand J Infect Dis 39: 5. 466-469  
Abstract: Necrotizing pneumonia and fatal septic shock were caused by Panton-Valentine leukocidin-positive, community-acquired, methicillin-resistant Staphylococcus aureus (CA-MRSA) in a previously healthy, 61-y-old female. This patient did not belong to any high-risk group (e.g. homosexuals, military recruits, sports team members, etc.). CA-MRSA infection should be suspected in any adult with severe pneumonia/sepsis.
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Petros Roditis, Stavros Dimopoulos, Dimitrios Sakellariou, Serafim Sarafoglou, Elissavet Kaldara, John Venetsanakos, John Vogiatzis, Maria Anastasiou-Nana, Charis Roussos, Serafim Nanas (2007)  The effects of exercise training on the kinetics of oxygen uptake in patients with chronic heart failure.   Eur J Cardiovasc Prev Rehabil 14: 2. 304-311 Apr  
Abstract: BACKGROUND: Prolonged oxygen uptake kinetics (O2 kinetics), following the onset of a constant workload of exercise has been associated with a poor prognosis in patients with chronic heart failure. This study aimed to determine both continuous and interval training effects on the different O2-kinetics phases in these patients. DESIGN: Twenty-one patients (60+/-8 years) with stable chronic heart failure participated in a 36-session exercise rehabilitation program (three times weekly). Patients were randomly assigned to interval training (n=11; 100% of peak work rate for 30 s, alternating with 30 s-rest) and to continuous training (n=10; 50% of peak work rate). METHODS: Before and after the completion of the program, all patients performed both incremental symptom-limited and constant workload submaximal cardiopulmonary exercise tests. Phase I O2-kinetics was evaluated by time (t), from the start of exercise until the onset of decreased respiratory exchange ratio and phase II by the time constant (tau) of the response from the end of phase I until steady state. RESULTS: After training, there was a significant increase in peak oxygen uptake and peak work rate in both continuous (15.3+/-4.4 vs. 16.6+/-4.5 ml/kg per min; P=0.03 and 81.8+/-40.1 vs. 94.7+/-46.1 W; P=0.03) and interval training groups (14.2+/-3.1 vs. 15.4+/-4.2 ml/kg per min; P=0.03 and 82.5+/-24.1 vs. 93.7+/-30.1 W; P=0.04). Patients who underwent interval training had a significant decrease in t (39.7+/-3.7 to 36.1+/-6.9 s; P=0.05), but not tau (59.6+/-9.4 to 58.9+/-8.5 s; P=ns), whereas those assigned to continuous training had a significant decrease in both t (40.6+/-6.1 to 36.4+/-5.4 s; P=0.01) and tau (63.3+/-23.6 to 42.5+/-16.7 s; P=0.03). CONCLUSIONS: Exercise training improves O2 kinetics in chronic heart failure patients. Both continuous and interval training improve phase I O2-kinetics, but continuous training results in superior improvement of the phase II O2-kinetics, an indirect index of muscle oxidative capacity.
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Spyros D Mentzelopoulos, Maria Pratikaki, Evangelia Platsouka, Helen Kraniotaki, Dimitris Zervakis, Antonia Koutsoukou, Serafim Nanas, Olga Paniara, Charis Roussos, Evangelos Giamarellos-Bourboulis, Christina Routsi, Spyros G Zakynthinos (2007)  Prolonged use of carbapenems and colistin predisposes to ventilator-associated pneumonia by pandrug-resistant Pseudomonas aeruginosa.   Intensive Care Med 33: 9. 1524-1532 Sep  
Abstract: OBJECTIVE: We present our experience with five cases of pandrug-resistant Pseudomonas aeruginosa ventilator-associated pneumonia (VAP) and analysis of risk factors. DESIGN AND SETTING: Case-control study in a 15-bed intensive care unit (ICU). PATIENTS AND PARTICIPANTS: The study included 5 cases and 20 controls. Each case patient was matched to four contemporary controls according to gender, prior hospital admissions, hospitalization duration, ICU admission cause, Acute Physiology and Chronic Health Evaluation (APACHE) II and Sequential Organ Function Assessment (SOFA) scores on ICU admission, and length of ICU stay, and mechanical ventilation duration until first VAP episode by a multidrug-resistant bacterium. MEASUREMENTS AND RESULTS: Recorded variables included age, gender, daily APACHE II and SOFA scores, patient medication, treatment interventions, positive cultures and corresponding antibiograms, occurrence of infection, sepsis, and septic shock, other ICU-associated morbidity, length of ICU stay and mechanical ventilation, and patient outcome. Healthcare worker and environmental cultures, and a hand-disinfection survey were performed. Pandrug-resistant P. aeruginosa isolates belonged to the same genotype and were bla (VIM-1)-like gene positive. The outbreak resolved following reinforcement of infection-control measures (September 27). The sole independent predictor for pandrug-resistant P. aeruginosa VAP was combined use of carbapenem for more than 20 days and colistin use for and more than 13 days (odds ratio 76.0; 95% confidence interval 3.7-1487.6). An additional risk factor was more than 78 open suctioning procedures during 6-26 September (odds ratio 16.0; 95% confidence interval 1.4-185.4). CONCLUSIONS: Prolonged carbapenem-colistin use predisposes to VAP by pandrug-resistant P. aeruginosa. Cross-transmission may be facilitated by open suctioning.
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Angeliki Siafaka, Epameinondas Angelopoulos, Konstantinos Kritikos, Magdalini Poriazi, Neofitos Basios, Vasiliki Gerovasili, Antonios Andreou, Charis Roussos, Serafim Nanas (2007)  Acute effects of smoking on skeletal muscle microcirculation monitored by near-infrared spectroscopy.   Chest 131: 5. 1479-1485 May  
Abstract: BACKGROUND: Cigarette smoking predisposes to vascular disease. Our study aimed to assess the acute effects of cigarette smoking on peripheral microcirculation using near-infrared spectroscopy (NIRS) and to compare microcirculatory function of smokers with that of nonsmokers. METHODS: We examined 65 healthy volunteers: 25 smokers (14 men and 11 women; age range, 20 to 27 years) and 40 nonsmokers (31 men and 9 women; age range, 19 to 38 years). Smokers had refrained from smoking for 2 h prior to the examination. Tissue O(2) saturation (Sto(2)), defined as the percentage of hemoglobin saturation in the microvasculature compartments, was measured with a probe placed on the thenar muscle. Sto(2) baseline values were recorded for 5 min. Subsequently, the brachial artery occlusion technique was applied to evaluate microcirculatory function before, during, and after smoking one cigarette. RESULTS: Sto(2) before smoking was 85 +/- 6% (mean +/- SD), not differing significantly between men and women (84.4 +/- 6.6% vs 85.6 +/- 5.8%, respectively; p = 0.721). Sto(2) did not change significantly during smoking. O(2) consumption rate was significantly greater in women (33.4 +/- 6.7 Sto(2) U/min vs 25.7 +/- 7.1 Sto(2) U/min, p = 0.032) at baseline and throughout the smoking session. O(2) consumption rate was reduced during smoking (p < 0.001) and at 5 min after the smoking session. Smoking had a significant effect on vascular reactivity (p = 0.015), with no significant differences between genders. Five minutes after smoking, vascular reactivity had returned to approximately normal levels. CONCLUSION: Smoking acutely affects microcirculatory function. NIRS is a noninvasive, operator-independent technique that can document these effects. It seems promising for the prospective evaluation of the effects of long-term exposure to cigarette smoke.
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Stavros G Drakos, Efstratios I Charitos, Serafim N Nanas, John N Nanas (2007)  Ventricular-assist devices for the treatment of chronic heart failure.   Expert Rev Cardiovasc Ther 5: 3. 571-584 May  
Abstract: The role of ventricular-assist devices in the management of end-stage heart failure is growing. Initially developed as a 'bridge to transplantation', they are now implanted permanently in patients who need cardiac replacement but are not candidates for cardiac transplantation ('destination therapy'). Furthermore, observations from expert centers indicate that a significant proportion of patients under long-term mechanical assistance can be weaned from mechanical circulatory support after significant functional recovery of their native heart ('bridge to recovery'). This review discusses the emerging roles of mechanical circulatory support and their direct implications in clinical practice. Evolution of devices, important aspects of candidate selection, challenging issues in the management of ventricular-assist device patients (infection, device malfunction, anticoagulation-thromboembolic complications, psychosocial issues and cost) and ongoing research targeting sustained myocardial recovery are discussed.
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2006
 
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John N Nanas, Eleftheria P Tsagalou, Serafim N Nanas, John V Terrovitis, Elias J Tsolakis, Savas Toumanidis, Panagiotis D Papazoglou, George P Alexopoulos, John Kanakakis, Maria I Anastasiou-Nana (2006)  Reverse left ventricular remodeling by intermittent dobutamine infusions and amiodarone in end-stage heart failure due to idiopathic dilated cardiomyopathy.   Int J Cardiol 108: 2. 237-243 Apr  
Abstract: BACKGROUND: The aim of this study was to evaluate the long-term effect of combined intermittent dobutamine infusions (IDI) and oral amiodarone on reverse left ventricular (LV) remodeling and hemodynamics of patients with idiopathic dilated cardiomyopathy (IDC) and end-stage congestive heart failure (CHF). METHODS: This non-randomized, prospective, clinical trial included sixteen consecutive patients suffering from dyspnea for a mean of 76+/-43 months, who presented with acute cardiac decompensation and were weaned from dobutamine therapy after an initial 72-h infusion. They were then placed on a regimen of oral amiodarone, 400 mg/day and weekly IDI, 10 microg/kg/min, for 8 h. The long-term clinical outcomes and the effects of treatment on reverse LV remodeling (echocardiographic parameters) and hemodynamics were evaluated at 3, 6, and 12 months of follow up. RESULTS: A significant degree of reverse LV remodeling, hemodynamic improvements, and survivals >1.5 years were observed in 9 of the 16 patients (56%). In addition, 5 patients (31% of entire cohort) were weaned from IDI after a mean of 61+/-41 weeks, and 4 remained clinically stable for 116+/-66 weeks thereafter. At 12 months of follow-up, LV end-diastolic and end-systolic volume indices had decreased from 231+/-91 to 206+/-80 ml/m2 (P=0.002) and from 137+/-65 to 110+/-50 ml/m2 (P=0.003), respectively, right atrial pressure from 16+/-6 to 5.6+/-4 mm Hg, (P=0.031), and pulmonary capillary wedge pressure from 29+/-4 to 16+/-5.4 mm Hg, P=0.000, while LV ejection fraction had increased from 22+/-6% to 27.3+/-8% (P=0.006). CONCLUSIONS: In end-stage CHF due to IDC, long-term treatment with IDI and oral amiodarone caused reverse LV remodeling, and allowed permanent and successful weaning from IDI in 1/4 of patients.
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Eleftheria P Tsagalou, Maria I Anastasiou-Nana, John V Terrovitis, Serafim N Nanas, George P Alexopoulos, John Kanakakis, John N Nanas (2006)  The long-term survival benefit conferred by intermittent dobutamine infusions and oral amiodarone is greater in patients with idiopathic dilated cardiomyopathy than with ischemic heart disease.   Int J Cardiol 108: 2. 244-250 Apr  
Abstract: BACKGROUND: Intermittent dobutamine infusions (IDI) combined with oral amiodarone improve the survival of patients with end-stage congestive heart failure (CHF). The purpose of the present study was to evaluate whether the response to long-term treatment with IDI+amiodarone is different in patients with ischemic heart disease (IHD) versus idiopathic dilated cardiomyopathy (IDC). METHODS: The prospective study population consisted of 21 patients with IHD (the IHD Group) and 16 patients with IDC (the IDC Group) who presented with decompensated CHF despite optimal medical therapy, and were successfully weaned from an initial 72-h infusion of dobutamine. They were placed on a regimen of oral amiodarone, 400 mg/day and weekly IDI, 10 microg/kg/min, for 8 h. RESULTS: There were no differences in baseline clinical and hemodynamic characteristics between the 2 groups. The probability of 2-year survival was 44% in the IDC Group versus 5% in the IHD Group (long-rank, P=0.004). Patients with IDC had a 77% relative risk reduction in death from all causes compared to patients with IHD (odd ratio 0.27, 95% confidence interval 0.13 to 0.70, P=0.007). In contrast, no underlying disease-related difference in outcomes was observed in a retrospectively analyzed historical Comparison Group of 29 patients with end stage CHF treated by standard methods. CONCLUSIONS: Patients with end stage CHF due to IDC derived a greater survival benefit from IDI and oral amiodarone than patients with IHD.
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Serafim N Nanas, John N Nanas, Dimitrios Ch Sakellariou, Stavros K Dimopoulos, Stavros G Drakos, Smaragdo G Kapsimalakou, Christina A Mpatziou, Ourania G Papazachou, Anargyros S Dalianis, Maria I Anastasiou-Nana, Charis Roussos (2006)  VE/VCO2 slope is associated with abnormal resting haemodynamics and is a predictor of long-term survival in chronic heart failure.   Eur J Heart Fail 8: 4. 420-427 Jun  
Abstract: BACKGROUND: Patients with chronic heart failure (CHF) present with exercise-induced hyperpnea, but its pathophysiological mechanism has not been thoroughly investigated. We aimed to determine the relationship between exercise-induced hyperpnea, resting haemodynamic measurements and the validity of ventilatory response (V(E)/V(CO(2)) slope) as a mortality predictor in CHF patients. METHODS: Ninety-eight CHF patients (90M/8F) underwent a symptom-limited treadmill cardiopulmonary exercise test (CPET). Right heart catheterization and radionuclide ventriculography were performed within 72 h of CPET. RESULTS: Twenty-seven patients died from cardiac causes during 20+/-6 months follow-up. Non-survivors had a lower peak oxygen consumption (V(O(2)p)), (16.5+/-4.9 vs. 20.2+/-6.1, ml/kg/min, p=0.003), a steeper V(E)/V(CO(2)) slope (34.8+/-8.3 vs. 28.9+/-4.8, p<0.001) and a higher pulmonary capillary wedge pressure (PCWP) (19.5+/-8.6 vs. 11.7+/-6.5 mm Hg, p=0.008) than survivors. By multivariate survival analysis, the V(E)/V(CO(2)) slope as a continuous variable was an independent prognostic factor (chi(2): 8.5, relative risk: 1.1, 95% CI: 1.03-1.18, p=0.004). Overall mortality was 52% in patients with V(E)/V(CO(2)) slope > or =34 and 18% in those with V(E)/V(CO(2)) slope <34 (log rank: 18.5, p<0.001). In a subgroup of patients (V(O(2)p): 10-18 ml/kg/min), V(E)/V(CO(2)) slope was a significant predictor of mortality (relative risk: 6.2, 95% CI: 1.7-22.2, p=0.002). Patients with high V(E)/V(CO(2)) slope had higher resting PCWP (19.9+/-9.1 vs. 11.3+/-5.7 mmHg, p<0.001) and V(E)/V(CO(2)) slope correlated significantly with PCWP (r: 0.57, p<0.001). CONCLUSIONS: The V(E)/V(CO(2)) slope, as an index of ventilatory response to exercise, improves the risk stratification of CHF patients. Interstitial pulmonary oedema may be a pathophysiological mechanism of inefficient ventilation during exercise in these patients.
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Christina Routsi, Elisabeth Stamataki, Seraphim Nanas, Christina Psachoulia, Anastasios Stathopoulos, Apostolos Koroneos, Maria Zervou, Gerard Jullien, Charis Roussos (2006)  Increased levels of serum S100B protein in critically ill patients without brain injury.   Shock 26: 1. 20-24 Jul  
Abstract: There is increasing evidence that the release of S100B protein, which is an acknowledged marker of brain injury, is also induced by other causes including hemorrhagic shock. The aim of this study was to investigate the serum concentration of S100B in critically ill mechanically ventilated patients with various degrees of organ dysfunction but without evidence of brain injury or any other neurological disorder and its possible association with tissue perfusion indices. Forty-six critically ill mechanically ventilated patients were studied on intensive care unit admission and until 6 days later. Measurement of serum S100B protein was obtained daily at the time of laboratory sampling and blood gas and lactate analysis. All patients exhibited increased levels of serum S100B levels at least once (median, 0.31 microg/L; interquartile range 25%-75%, 0.17-0.68 microg/L; range 0.04-18 microg/L). There was a significant correlation between S100B and arterial lactate (r, 0.66; P < 0.001), mean arterial pressure (MAP) (r, -0.41; P < 0.001), and pH (r, -0.37; P < 0.001). Serum concentrations of S100B were significantly higher in the presence of hemoglobin (Hb) level of less than 7 mg/dL compared with those measured when Hb level was greater than 7 mg/dL (median, 1.61 mg/dL; interquartile range 25%-75%, 0.66-3.57, vs. median, 0.29; interquartile range 25%-75%, 0.15-0.56, respectively; P < 0.001). Multiple regression analysis with dependent variable S100B and independent variables lactate, Hb, pH, and MAP showed that the only independent variable was the lactate (r, 0.79; r2, 0.62; P < 0.001). Sequential organ failure assessment score was positively associated with S100B values (P < 0.05). In conclusion, serum levels of S100B protein are elevated in critically ill patients, in the absence of an apparent brain damage. Increased S100B values correlated positively with lactate levels and negatively with MAP and pH. Low Hb level is associated with increased S100B levels. These results indicate that serum S100B protein concentration may be related to tissue hypoperfusion.
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Serafim Nanas, Maria Anastasiou-Nana, Stavros Dimopoulos, Dimitrios Sakellariou, George Alexopoulos, Smaragdo Kapsimalakou, Panagiotis Papazoglou, Elias Tsolakis, Ourania Papazachou, Charis Roussos, John Nanas (2006)  Early heart rate recovery after exercise predicts mortality in patients with chronic heart failure.   Int J Cardiol 110: 3. 393-400 Jun  
Abstract: BACKGROUND: Patients with chronic heart failure (CHF) have multiple abnormalities of autonomic regulation that have been associated to their high mortality rate. Heart rate recovery immediately after exercise is an index of parasympathetic activity, but its prognostic role in CHF patients has not been determined yet. METHODS: Ninety-two stable CHF patients (83M/9F, mean age: 51+/-12 years) performed an incremental symptom-limited cardiopulmonary exercise testing. Measurements included peak O2 uptake (VO2p), ventilatory response to exercise (VE/VCO2 slope), the first-degree slope of VO2 for the 1st minute of recovery (VO2/t-slope), heart rate recovery [(HRR1, bpm): HR difference from peak to 1 min after exercise] and chronotropic response to exercise [%chronotropic reserve (CR, %)=(peak HR-resting HR/220-age-resting HR)x100]. Left ventricular ejection fraction (LVEF, %) was also measured by radionuclide ventriculography. RESULTS: Fatal events occurred in 24 patients (26%) during 21+/-6 months of follow-up. HRR1 was lower in non-survivors (11.4+/-6.4 vs. 20.4+/-8.1; p<0.001). All cause-mortality rate was 65% in patients with HRR1<or=12 bpm versus 11% in patients with HRR1>12 bpm (log-rank: 32.6; p<0.001). By multivariate survival analysis, HRR1 resulted as an independent predictor of mortality (chi2=19.2; odds ratio: 0.87; p<0.001) after adjustment for LVEF, VO2p, VE/VCO2 slope, CR and VO2/t-slope. In a subgroup of patients with intermediate exercise capacity (VO2p: 10-18, ml/kg/min), HRR1 was a strong predictor of mortality (chi2: 14.3; odds ratio: 0.8; p<0.001). CONCLUSIONS: Early heart rate recovery is an independent prognostic risk indicator in CHF patients and could be used in CHF risk stratification.
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Stavros Dimopoulos, Maria Anastasiou-Nana, Dimitrios Sakellariou, Stavros Drakos, Smaragdo Kapsimalakou, George Maroulidis, Petros Roditis, Ourania Papazachou, Ioannis Vogiatzis, Charis Roussos, Serafim Nanas (2006)  Effects of exercise rehabilitation program on heart rate recovery in patients with chronic heart failure.   Eur J Cardiovasc Prev Rehabil 13: 1. 67-73 Feb  
Abstract: BACKGROUND: Heart rate recovery (HRR1) immediately after exercise reflects parasympathetic activity, which is markedly attenuated in chronic heart failure (CHF) patients. The aim of our study was to examine both continuous and interval exercise training effects on HRR1 in these patients. DESIGN: The population study consisted of 29 stable CHF patients that participated at a rehabilitation program of 36 sessions, three times per week. Of the 29 patients, 24 completed the program. Patients were randomly assigned to interval {n=10 [100% peak work rate (WRp) for 30 s, alternating with rest for 30 s]} and to continuous training [n=14 (50%WRp)]. METHODS: All patients performed a symptom-limited cardiopulmonary exercise test on a cycle ergometer before and after the completion of the program. Measurements included peak oxygen uptake (VO2p), anaerobic threshold (AT), WRp, first degree slope of VO2 during the first minute of recovery (VO2/t-slope), chronotropic response [% chronotropic reserve (CR)=(peak HR - resting HR)x100/(220 - age - resting HR)], HRR1 (HR difference from peak exercise to one minute after). RESULTS: After the completion of the rehabilitation program there was a significant increase of WRp, VO2p, AT and VO2/t-slope (by 30%, P=0.01; 6%, P=0.01; 10%, P=0.02; and 27%, P=0.03 respectively for continuous training and by 21%, P<0.05; 8%, P=0.01; 6%, P=NS; and 48%, P=0.02 respectively for interval training). However, only patients exercised under the continuous training regime had a significant increase in HRR1 (15.0+/-9.0 to 24.0+/-12 bpm; P=0.02) and CR (57+/-19 to 72+/-21%, P=0.02), in contrast with those assigned to interval training (HRR1: 21+/-11 to 21+/-8 bpm; P=NS and CR: 57+/-18 to 59+/-21%, P=NS). CONCLUSIONS: Both continuous and interval exercise training program improves exercise capacity in CHF patients. However, continuous rather than interval exercise training improves early HRR1, a marker of parasympathetic activity, suggesting a greater contribution to the autonomic nervous system.
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2005
 
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John N Nanas, Panagiotis Papazoglou, Eleftheria P Tsagalou, Argirios Ntalianis, Elias Tsolakis, John V Terrovitis, John Kanakakis, Seraphim N Nanas, George P Alexopoulos, Maria I Anastasiou-Nana (2005)  Efficacy and safety of intermittent, long-term, concomitant dobutamine and levosimendan infusions in severe heart failure refractory to dobutamine alone.   Am J Cardiol 95: 6. 768-771 Mar  
Abstract: Thirty-six consecutive patients in New York Heart Association functional class IV, who were resistant to 24-hour continuous dobutamine infusion, were treated with continuous infusions of dobutamine 10 microg/kg/min for > or =48 hours (group I, n = 18), followed by weekly intermittent 8-hour infusions or more often if needed. In group II (n = 18), after the initial 24-hour infusion of dobutamine, a 24-hour levosimendan infusion was added followed by biweekly 24-hour infusions. The addition of intermittent levosimendan infusions prolonged the survival of patients with advanced heart failure refractory to intermittent dobutamine infusions (45-day survival rates were 6% and 61% in groups I and II, respectively; p = 0.0002, log-rank test).
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I Vogiatzis, O Georgiadou, S Golemati, A Aliverti, E Kosmas, E Kastanakis, N Geladas, A Koutsoukou, S Nanas, S Zakynthinos, C Roussos (2005)  Patterns of dynamic hyperinflation during exercise and recovery in patients with severe chronic obstructive pulmonary disease.   Thorax 60: 9. 723-729 Sep  
Abstract: BACKGROUND: Not all patients with severe chronic obstructive pulmonary disease (COPD) progressively hyperinflate during symptom limited exercise. The pattern of change in chest wall volumes (Vcw) was investigated in patients with severe COPD who progressively hyperinflate during exercise and those who do not. METHODS: Twenty patients with forced expiratory volume in 1 second (FEV(1)) 35 (2)% predicted were studied during a ramp incremental cycling test to the limit of tolerance (Wpeak). Changes in Vcw at the end of expiration (EEVcw), end of inspiration (EIVcw), and at total lung capacity (TLCVcw) were computed by optoelectronic plethysmography (OEP) during exercise and recovery. RESULTS: Two significantly different patterns of change in EEVcw were observed during exercise. Twelve patients had a progressive significant increase in EEVcw during exercise (early hyperinflators, EH) amounting to 750 (90) ml at Wpeak. In contrast, in all eight remaining patients EEVcw remained unchanged up to 66% Wpeak but increased significantly by 210 (80) ml at Wpeak (late hyperinflators, LH). Although at the limit of tolerance the increase in EEVcw was significantly greater in EH, both groups reached similar Wpeak and breathed with a tidal EIVcw that closely approached TLCVcw (EIVcw/TLCVcw 93 (1)% and 93 (3)%, respectively). EEVcw was increased by 254 (130) ml above baseline 3 minutes after exercise only in EH. CONCLUSIONS: Patients with severe COPD exhibit two patterns during exercise: early and late hyperinflation. In those who hyperinflate early, it may take several minutes before the hyperinflation is fully reversed after termination of exercise.
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DOI   
PMID 
Ioannis Vogiatzis, Gerasimos Terzis, Serafeim Nanas, Grigoris Stratakos, Davina C M Simoes, Olga Georgiadou, Spyros Zakynthinos, Charis Roussos (2005)  Skeletal muscle adaptations to interval training in patients with advanced COPD.   Chest 128: 6. 3838-3845 Dec  
Abstract: STUDY OBJECTIVES: To investigate the response to interval exercise (IE) training by looking at changes in morphologic and biochemical characteristics of the vastus lateralis muscle, and to compare these changes to those incurred after constant-load exercise (CLE) training. DESIGN: Randomized, controlled, parallel, two-group study (IE vs CLE training). SETTING: Multidisciplinary, outpatient, hospital-based, pulmonary rehabilitation program. PATIENTS: Nineteen patients with stable advanced COPD (mean +/- SEM FEV1, 40 +/- 4% predicted). INTERVENTIONS: Patients (n = 10) assigned to IE training exercised at a mean intensity of 124 +/- 15% of baseline peak exercise capacity (peak work rate [Wpeak]) with 30-s work periods interspersed with 30-s rest periods for 45 min/d. Patients (n = 9) allocated to CLE training exercised at a mean intensity of 75 +/- 5% Wpeak for 30 min/d. Patients exercised 3 d/wk for 10 weeks. MEASUREMENTS AND RESULTS: Needle biopsies of the right vastus lateralis muscle were performed before and after rehabilitation. After IE training, the cross-sectional areas of type I and IIa fibers were significantly increased (type I before, 3,972 +/- 455 microm2; after, 4,934 +/- 467 microm2 [p = 0.004]; type IIa before, 3,695 +/- 372 microm2; after, 4,486 +/- 346 microm2 [p = 0.008]), whereas the capillary-to-fiber ratio was significantly enlarged (from 1.13 +/- 0.08 to 1.24 +/- 0.07 [p = 0.013]). Citrate synthase activity increased (from 14.3 +/- 1.4 to 20.5 +/- 4.2 micromol/min/g), albeit not significantly (p = 0.097). There was also a significant improvement in Wpeak (by 19 +/- 5%; p = 0.04) and in lactate threshold (by 17 +/- 5%; p = 0.02). The magnitude of changes in all the above variables was not significantly different compared to that incurred after CLE training. During training sessions, however, ratings of dyspnea and leg discomfort, expressed as fraction of values achieved at baseline Wpeak, were significantly lower (p < 0.05) for IE training (73 +/- 9% and 60 +/- 8%, respectively) compared to CLE training (83 +/- 10% and 87 +/- 13%, respectively). CONCLUSIONS: High-intensity IE training is equally effective to moderately intense CLE training in inducing peripheral muscle adaptations; however, IE is associated with fewer training symptoms.
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2004
 
PMID 
John N Nanas, Eleftheria P Tsagalou, John Kanakakis, Serafim N Nanas, John V Terrovitis, Thomas Moon, Maria I Anastasiou-Nana (2004)  Long-term intermittent dobutamine infusion, combined with oral amiodarone for end-stage heart failure: a randomized double-blind study.   Chest 125: 4. 1198-1204 Apr  
Abstract: STUDY OBJECTIVES: To examine the effects of long-term intermittent dobutamine infusion, combined with oral amiodarone in patients with congestive heart failure (CHF) refractory to standard medical treatment. DESIGN: Prospective, randomized, double-blind, placebo-controlled clinical trial. SETTING: Inpatient and outpatient heart failure clinic in a university teaching hospital. PATIENTS AND INTERVENTIONS: Thirty patients with end-stage CHF refractory to standard medical treatment who could be weaned from dobutamine therapy after a first 72-h infusion were randomized in a double-blind manner to receive IV infusions of placebo (group 1; 14 patients) vs dobutamine in a dose of 10 micro g/kg/min (group 2; 16 patients) for 8 h every 14 days. All patients received standard medical therapy and also were treated with oral amiodarone, 400 mg/d, which was started at least 2 weeks before randomization. MEASUREMENTS AND RESULTS: Kaplan-Meier survival analysis showed a 60% reduction in the risk of death from any cause in the group treated with the combination of dobutamine and amiodarone, compared with the group treated with placebo and amiodarone (hazard ratio, 0.403; 95% confidence interval, 0.164 to 0.992; p = 0.048). The 1-year and 2-year survival rates were 69% and 44%, respectively, in the dobutamine-treated group, vs 28% and 21%, respectively, in the placebo-treated group (p < 0.05 for both comparisons). Median survival times were 574 and 144 days, respectively, for groups 2 and 1. At 6 months, the New York Heart Association functional class was significantly improved in the patients who survived from both groups. CONCLUSIONS: Long-term intermittent dobutamine infusion combined with amiodarone added to the conventional drugs improved the survival of patients with advanced CHF that was refractory to conventional treatment.
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DOI   
PMID 
I Vogiatzis, S Nanas, E Kastanakis, O Georgiadou, O Papazahou, Ch Roussos (2004)  Dynamic hyperinflation and tolerance to interval exercise in patients with advanced COPD.   Eur Respir J 24: 3. 385-390 Sep  
Abstract: Dynamic hyperinflation (DH) contributes importantly to the limitation of constant-load exercise (CLE) in patients with chronic obstructive pulmonary disease (COPD). However, its role in the limitation of interval exercise (IE) remains to be explored. The change (Delta) in inspiratory capacity (IC) was measured to reflect changes in DH in 27 COPD patients (forced expiratory volume in one second mean+/-SEM % predicted: 40+/-3) at the end of a symptom-limited CLE test at 80% of peak work capacity (WRmax) and an IE test at 100% WRmax (30 s of work, alternated with 30 s of unloaded pedalling). At the limit of tolerance in both IE and CLE, patients exhibited similar DH (DeltaIC: 0.39+/-0.05 L and 0.45+/-0.05 L, respectively). However, exercise endurance time (t end) for IE (32.7+/-3.0 min) was significantly greater than for CLE (10.3+/-1.6 min). The IE t end correlated with resting IC, expressed as % pred normal. At 30 and 90% of total IE t end, DeltaIC (0.43+/-0.06 and 0.39+/-0.05 L, respectively) and minute ventilation (31.1+/-1.6 and 32.7+/-2.2 L.min(-1), respectively) were not significantly different. Resting hyperinflation helps to explain the limitation of interval exercise. Implementation of interval exercise for rehabilitation should provide important clinical benefits because it prolongs exercise endurance time and allows sustaining higher stable ventilation.
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DOI   
PMID 
Serafim N Nanas, John V Terrovitis, Christos Charitos, Ourania Papazachou, Zafiria Margari, Eleftheria P Tsagalou, Christos Kassiotis, Elias Tsolakis, Savas Toumanidis, John N Nanas (2004)  Ventilatory response to exercise and kinetics of oxygen recovery are similar in cardiac transplant recipients and patients with mild chronic heart failure.   J Heart Lung Transplant 23: 10. 1154-1159 Oct  
Abstract: BACKGROUND: Exercise capacity, assessed by cardiopulmonary exercise treadmill testing (CPET), does not return to normal following heart transplantation. This study evaluated the ventilatory response to exercise and the kinetics of oxygen (O(2)) recovery in heart transplant recipients (HTR) compared to healthy volunteers (HV) and heart failure patients. METHODS: Eighteen patients with end-stage heart failure (ESHF), 12 with mild heart failure (MHF) matched for peak oxygen consumption (Vo(2)) with the HTR, 12 HTR and 12 HV underwent CPET for measurements of peak Vo(2), Vo(2) at anaerobic threshold (AT), first-degree slope of Vo(2) decline during early recovery (Vo(2)/t-slope), time required for a 50% fall from peak Vo(2) (T(1/2) of Vo(2)) and the slopes of VE/Vco(2) and VE/Vo(2). RESULTS: The MHF and HTR groups had similar ventilatory responses to exercise and O(2) recovery kinetics. Peak Vo(2) (18.5 +/- 5.7 vs 9.4 +/- 0.9 ml/kg/min, p < 0.001), AT (13.8 +/- 4.8 vs 6.7 +/- 1.8 ml/kg/min, p < 0.001) and Vo(2)/t-slope (0.6 +/- 0.2 vs 0.3 +/- 0.2 liter/min/min, p = 0.055) were higher in the HTR than in the ESHF group. In contrast, HTR had lower VE/Vco(2)-slope (31.4 +/- 3.8 vs 39.2 +/- 9.9, p = 0.015) and T(1/2) Vo(2) (1.5 +/- 0.3 vs 2.4 +/- 1.1 minute, p = 0.014) than the ESHF group. Compared to HV, HTR had lower Vo(2) peak (18.5 +/- 5.7 vs 28.4 +/- 6.9 ml/kg/min, p < 0.001), AT (13.8 +/- 4.8 vs 19.8 +/- 4.5 ml/kg/min, p = 0.04), Vo(2)/t-slope (0.6 +/- 0.2 vs 1.0 +/- 0.4 liter/min/min, p = 0.005) and steeper VE/Vco(2) slope (31.4 +/- 3.8 vs 23.6 +/- 2.7, p = 0.062). Heart rate deceleration during recovery was significantly slower in HTR than in all other groups. CONCLUSIONS: Exercise intolerance and delayed O(2) recovery kinetics were only partially reversed after heart transplantation. This finding suggests that some of the pathophysiologic mechanisms of heart failure persist after heart transplantation.
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2003
 
PMID 
Serafim Nanas, John Nanas, Ourania Papazachou, Christos Kassiotis, Antonios Papamichalopoulos, Joseph Milic-Emili, Charis Roussos (2003)  Resting lung function and hemodynamic parameters as predictors of exercise capacity in patients with chronic heart failure.   Chest 123: 5. 1386-1393 May  
Abstract: STUDY OBJECTIVES: The aim of this study was to examine the role of resting pulmonary function and hemodynamic parameters as predictors of exercise capacity in patients with chronic heart failure. MEASUREMENTS AND RESULTS: Fifty-one patients with chronic heart failure underwent resting pulmonary function testing, including inspiratory capacity (IC) and symptom-limited, treadmill cardiopulmonary exercise testing (CPET). Right-heart catheterization and radionuclide ventriculography were performed within 2 days of CPET. Mean (+/- SD) left ventricular ejection fraction was 31 +/- 12% and cardiac index was 2.34 +/- 0.77 L/min/m(2). Percentage of predicted FEV(1) was 92 +/- 14%, percentage of predicted FVC was 94 +/- 15%, FEV(1)/FVC was 81 +/- 4%, and percentage of predicted IC was 84 +/- 18%. Mean peak oxygen uptake (peak O(2)) was 17.9 +/- 5.4 mL/kg/min. Analysis of variance among the three functional Weber classes showed statistically significant differences for pulmonary capillary wedge pressure (PCWP) and IC. Specifically, the more severe the exercise intolerance, the lower was IC and the higher was PCWP. In a multivariate stepwise regression analysis, using peak O(2) (liters per minute) as the dependent variable and the pulmonary function test measurements as independent variables, the only significant predictor selected was IC (r = 0.71, p < 0.0001). In a final stepwise regression analysis including all the independent variables of the resting pulmonary function tests and hemodynamic measurements, the two predictors selected were IC and PCWP (r(2) = 0.58). CONCLUSIONS: In patients with chronic heart failure, IC is inversely related to PCWP and is a strong independent predictor of functional capacity.
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2002
 
PMID 
I Vogiatzis, S Nanas, C Roussos (2002)  Interval training as an alternative modality to continuous exercise in patients with COPD.   Eur Respir J 20: 1. 12-19 Jul  
Abstract: Understanding of what constitutes a training load adequate to induce training effects in patients with chronic obstructive pulmonary disease (COPD) is still evolving. The present study investigated whether interval training (IT) is effective in terms of inducing measurable improvements in physiological response and compared its effects on exercise tolerance (ET) and quality of life to those of continuous training (CT). Thirty-six COPD patients, with a forced expiratory volume in one second of 45+/-4% of the predicted value (mean+/-SEM), were randomly assigned to CT (exercise at 50% of baseline peak work-rate) or IT (work for 30 s at 100% of peak work-rate alternating with 30-s rest intervals) groups that cycled 40 min x day(-1) and 2 days x week(-1) for 12 weeks. After training, both groups showed significantly improved ET (IT, 57+/-6 to 71+/-8 W; CT, 57+/-5 to 70+/-6 W) and total quality-of-life score of the Chronic Respiratory Disease Questionnaire (IT, 77+/-3 to 88+/-2; CT, 78+/-3 to 93+/-2). At identical levels of exercise, minute ventilation was significantly reduced (IT, 35.8+/-2.5 to 31.7+/-2.5 L x min(-1); CT, 36.4+/-2.7 to 32.5+/-2.7 L x min(-1)). The magnitude of improvement in these variables was not significantly different among groups. The present data expand on the principles of exercise prescription for chronic obstructive pulmonary disease patients by demonstrating that interval training elicits substantial training effects, which are similar in magnitude to those produced by continuous training at half the exercise intensity but double the exercise time.
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PMID 
Nikos A Zakopoulos, Vasilios T Kotsis, Vassiliki Ch Pitiriga, Savvas T Toumanidis, John P Lekakis, Serafim N Nanas, Kostas N Vemmos, Stamatios F Stamatelopoulos, Spyridon D Moulopoulos (2002)  White-coat effect in normotension and hypertension.   Blood Press Monit 7: 5. 271-276 Oct  
Abstract: OBJECTIVES: The difference between clinic and daytime ambulatory blood pressure is referred to as the white-coat effect. In this study, we investigated (i) the magnitude of the white-coat effect in subjects with different daytime ambulatory blood pressure levels, and (ii) the association of the white-coat effect with left ventricular mass. METHODS: A total of 1581 subjects underwent clinic blood pressure readings, 24-h ambulatory blood pressure monitoring and left ventricular echocardiographic assessment. Their mean daytime systolic blood pressure varied from 88.0 to 208.9 mmHg and their mean daytime diastolic blood pressure from 40.3 to 133.0 mmHg. RESULTS: A negative correlation was found between the systolic or diastolic white-coat effect and the systolic or diastolic daytime ambulatory blood pressure (r = -0.22, P < 0.000 and r = -0.50, P < 0.000, respectively). Left ventricular mass significantly correlated with ambulatory blood pressure (P < 0.001), but there was no association between left ventricular mass and clinic blood pressure or white-coat effect. Furthermore, the white-coat effect was reversed at the highest level of systolic or diastolic daytime ambulatory blood pressure (systolic over 170 mmHg or diastolic over 100 mmHg) when systolic or diastolic daytime ambulatory blood pressure was higher than systolic or diastolic clinic blood pressure (ambulatory blood pressure hypertension). CONCLUSIONS: The white-coat effect shows an inverse association with daytime ambulatory blood pressure level (systolic or diastolic), being significantly more prominent for levels below 140/80 mmHg for systolic/diastolic daytime ambulatory blood pressure and reversed with daytime ambulatory blood pressure levels above 170/100 mmHg.
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2001
 
PMID 
N A Zakopoulos, S N Nanas, J P Lekakis, K N Vemmos, V T Kotsis, V C Pitiriga, S F Stamatelopoulos, S D Moulopoulos (2001)  Reproducibility of ambulatory blood pressure measurements in essential hypertension.   Blood Press Monit 6: 1. 41-45 Feb  
Abstract: BACKGROUND: Data on the reproducibility of serial measurements of ambulatory blood pressure in hypertensive patients are lacking. The purpose of this study was to examine (1) the reproducibility of four consecutive ambulatory blood pressure measurements, and (2) the reproducibility of nocturnal falls in blood pressure in hypertensive patients. METHODS: Twenty patients with mild to moderate essential hypertension underwent four separate ambulatory blood pressure monitorings, on the same day of the week, at 30-day intervals. Antihypertensive therapy was discontinued for 2 weeks before each recording. Comparing the mean values of blood pressure over 24h, as well as diurnal, nocturnal and hourly periods, among the four recordings determined the reproducibility of blood pressure measurements. A day/night difference in mean systolic and in mean diastolic blood pressure defined the nocturnal fall in blood pressure. RESULTS: No significant differences were observed in either hourly, 24-h, diurnal or nocturnal systolic blood pressure, diastolic blood pressure and heart rate, or in the nocturnal fall in systolic and diastolic blood pressure among the four recordings. CONCLUSIONS: Hourly systolic blood pressure, diastolic blood pressure, heart rate, and nocturnal fall in blood pressure were reproducible in four ambulatory blood pressure monitorings recorded over 4 months. These findings suggest that ambulatory blood pressure monitoring is a reliable tool to monitor blood pressure changes.
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PMID 
S Nanas, J Nanas, C Kassiotis, C Nikolaou, E Tsagalou, D Sakellariou, I Terovitis, O Papazachou, S Drakos, A Papamichalopoulos, C Roussos (2001)  Early recovery of oxygen kinetics after submaximal exercise test predicts functional capacity in patients with chronic heart failure.   Eur J Heart Fail 3: 6. 685-692 Dec  
Abstract: BACKGROUND: Oxygen (O2) uptake at peak exercise (VO2 peak) is an objective measurement of functional capacity in patients with chronic heart failure (CHF). The significance of recovery O2 kinetics parameters in predicting exercise capacity, and the parameters of submaximal exercise testing have not been thoroughly examined. METHODS AND RESULTS: Thirty-six patients (mean age = 48+/-14 years) with CHF and New York Heart Association functional class I, II, or III, and eight healthy volunteers (mean age = 39+/-13 years) were studied with maximal and submaximal cardiopulmonary exercise testing (CPET). The first degree slope of O2 uptake decay during early recovery from maximal (VO2/t-slope), and submaximal exercise (VO2/t-slope)(sub), were calculated, along with VO2 half-time (T(1/2)VO2). Patients with CHF had a longer recovery of O2 uptake after exercise than healthy volunteers, expressed by a lower VO2/t-slope (0.616+/-0.317 vs. 0.956+/-0.347 l min(-1) min(-1), P=0.029) and greater T(1/2)VO2 (1.28+/-0.30 vs. 1.05+/-0.15 min, P = 0.005). VO2/t-slope correlated with the VO2 peak (r = 0.84, P<0.001), anaerobic threshold (r = 0.79, P<0.001), and T(1/2)VO2, a previously established estimate of recovery O2 kinetics (r = -0.59, P<0.001). (VO2/t-slope)(sub) was highly correlated with VO2/t-slope after maximal exercise (r=0.87, P<0.001), with the VO2 peak (r=0.87, P<0.001) and with T(1/2)VO2 after maximal exercise (r=-0.62, P<0.001). VO2/t-slope after maximal and submaximal exercise was reduced in patients with severe exercise intolerance (F=9.3, P<0.001 and F=12.8, P<0.001, respectively). CONCLUSIONS: Early recovery O2 kinetics parameters after maximal and submaximal exercise correlate closely with established indices of exercise capacity in patients with CHF and in healthy volunteers. These findings support the use of early recovery O2 kinetics after submaximal exercise testing as an index of functional capacity in patients with CHF.
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PMID 
E Pouliou, S Nanas, A Papamichalopoulos, T Kyprianou, G Perpati, I Mavrou, C Roussos (2001)  Prolonged oxygen kinetics during early recovery from maximal exercise in adult patients with cystic fibrosis.   Chest 119: 4. 1073-1078 Apr  
Abstract: Study objectives: To explore the significance of oxygen kinetics during early recovery after maximal cardiopulmonary exercise testing (CPET) in the assessment of functional capacity and severity of the disease in cystic fibrosis (CF) patients. PARTICIPANTS: Eighteen patients with CF (9 male/9 female; mean +/- SD age, 23 +/- 13 years) and 11 healthy subjects (3 male/8 female; mean age, 29 +/- 4 years) underwent maximum CPET on a treadmill. Breath-by-breath analysis was used for measuring oxygen consumption (VO(2)), carbon dioxide production, and ventilation. Maximum VO(2) (VO(2)peak) and the first-degree slope of VO(2) decline during early recovery (VO(2)/t-slope) were calculated. To assess the severity of the disease, we used standard indexes like FEV(1) (% predicted), VO(2)peak, and a widely accepted system of clinical evaluation, the Schwachman score (SS). RESULTS: VO(2)/t-slope was significantly lower in CF patients compared to healthy subjects (0.61 +/- 0.31 L/min/min vs 1.1 +/- 0.13 L/min/min; p < 0.01) and was closely correlated to FEV(1)(r = 0.90, p < 0.001), VO(2)peak (r = 0.81, p < 0.001), and the SS (r = 0.81, p < 0.001). The multivariate analysis showed that the only independent predictor of the SS is the VO(2)/t-slope. CONCLUSION: We conclude that in CF patients, the prolonged oxygen kinetics during early recovery from maximal exercise is related to the disease severity.
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PMID 
J N Nanas, S N Nanas, D A Kontoyannis, K S Moussoutzani, A C Rapti, C E Charitos, J V Terrovitis, S F Stamatelopoulos, S D Moulopoulos (2001)  Limitation of infarct size by fixed coronary arterial stenosis maintained during reperfusion.   J Cardiovasc Surg (Torino) 42: 1. 27-35 Feb  
Abstract: BACKGROUND: The effect on infarct size of a pre-infarction high-grade, fixed coronary arterial stenosis maintained during reperfusion, was evaluated. METHODS: This experimental study was carried out in the research laboratory of a University Hospital. A canine occlusion-reperfusion model was used. Twenty-eight dogs underwent proximal left anterior descending (LAD) coronary artery occlusion (O). In Group 1 (n=6) the O lasted for 6 hours. In Group 2 (n=6) the O lasted for 2 hours followed by 4 hours of reperfusion (R). In Group 3 (n=3), LAD was stenosed for 30 minutes followed by O for 6 hours. In Group 4 (n=7) LAD was stenosed for 30 minutes followed by O for 2 hours and then 4 hours of R during which the artery was kept stenosed at the same degree (fixed) as the initial one. In Group 5 (n=6) the protocol was identical to Group 4 with the additional use of the intra-aortic balloon pump during R. RESULTS: The infarcted myocardium was almost the same in Groups 1 and 3 (80.0+/-10.6% vs 77.3+/-3.8%, respectively, p=NS), but less in Group 2 (59.0+/-19.9%, p=0.046 vs Group 1). There were no hemodynamic differences between Groups 4 and 5 and the infarcted myocardium was almost identical in both groups (37.7+/-18.8% and 38.7+/-19.1%, respectively, p=NS). The combined results of Groups 4 and 5, regarding the infarcted myocardium, was 38.1+/-18% (p=0.037 vs Group 2). CONCLUSIONS: In this acute coronary occlusion model, a pre-existing high-grade stenosis that maintained during reperfusion increased the amount of salvaged ischemic myocardium.
Notes:
1999
 
PMID 
S Nanas, J Nanas, C Kassiotis, G Alexopoulos, A Samakovli, J Kanakakis, E Tsolakis, C Roussos (1999)  Respiratory muscles performance is related to oxygen kinetics during maximal exercise and early recovery in patients with congestive heart failure.   Circulation 100: 5. 503-508 Aug  
Abstract: BACKGROUND: Dyspnea and fatigue are the main causes of exercise limitation in chronic heart failure (CHF) patients, whose peak inspiratory (Pi(max)) and expiratory pressures (Pe(max)) are often reduced. The aim of this study was to examine the relationship between respiratory muscle performance and oxygen kinetics. METHODS AND RESULTS: A total of 55 patients (NYHA class I to III) and 11 healthy subjects underwent cardiopulmonary exercise tests (CPET) on a treadmill. In 45 of the 55 patients (group I) and in healthy subjects (group II), pulmonary function tests, Pi(max), and Pe(max) were measured before and 10 minutes after exercise, and oxygen kinetics were monitored throughout and during early recovery from CPET. The first degree slope of oxygen consumption (VO(2)) decline during early recovery (VO(2)/t-slope) and VO(2) half-time (T(1/2)) were calculated. In 10 of the 55 CHF patients (group III), the measurements of Pi(max) were repeated 2, 5, and 10 minutes after CPET. A >10% reduction in Pi(max) after CPET (subgroup IA) was measured in 11 of 45 patients. In contrast, 34 of 45 CHF patients (subgroup IB) and all control subjects (group II) had Pi(max)>90% of baseline value after CPET. Subgroup IA patients had significantly lower peak VO(2) (13.5+/-2.1 versus 17.8+/-5.6 mL. kg(-1). min(-1); P<0.001), lower anaerobic thresholds (10.1+/-2.4 versus 13.6+/-4.6 mL. kg(-1). min(-1); P=0.003) and lower VO(2)/t-slopes (0.365+/-0.126 versus 0.519+/-0.227 L. min(-1). min(-1); P=0.008) than subgroup IB patients. CONCLUSIONS: The reduction of Pi(max) after exercise is associated with prolonged early recovery of oxygen kinetics, which may explain, in part, the role played by respiratory muscles in exercise intolerance in CHF patients.
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PMID 
N A Zakopoulos, S T Toumanidis, G J Barlas, S N Nanas, J P Lekakis, S F Stamatelopoulos, S D Moulopoulos (1999)  A pressure-time index' for assessing the severity of essential hypertension.   J Hypertens 17: 10. 1387-1393 Oct  
Abstract: OBJECTIVE: A new derivative of 24 h ambulatory blood pressure monitoring (ABPM) is introduced and its association with left ventricular mass index (LVMI) in essential hypertension is examined. PATIENT: population One hundred and fifty-three previously untreated essential hypertension patients. METHODS: Patients underwent casual blood pressure (BP) readings, 24 h ABPM and left ventricular echocardiographic assessment The following 24 h awake and sleep ABP variables were calculated: mean systolic and diastolic BP, systolic and diastolic BP loads (percentage of systolic readings > 140/120 mmHg (day/ night) and diastolic readings > 90/80 mmHg (day/night)), standard deviation of systolic and diastolic ABP and nocturnal fall of systolic BP, as well as the integrated areas under the ABP curve. The area under the BP curve divided in horizontal slices was accurately modelled by a sigmoid curve. The parameters controlling the shape of the curve and in particular that regarding its 'slope' is hereafter called the 'pressure-time index'. RESULTS: 'Systolic pressure-time index 24 h' (SPTI24) is related to left ventricular mass index (multivariate analysis, P= 0.008). Using either partial correlation coefficients or a multivariate analysis, SPTI24 is related to left ventricular mass index, independently of age, casual blood pressure, mean systolic and diastolic ABP, systolic and diastolic BP loads, BP variability (standard deviation (SD), nocturnal fall of systolic BP) and integrated area under the curve (multivariate analysis, P= 0.004). CONCLUSIONS: In essential hypertension, the SPTI24 is related to LVMI independently of age, casual blood pressure, integrated area under the curve or any other derivative of 24 h ABPM, and might be used to assess the extent of hypertensive load.
Notes:
1998
 
PMID 
I V Terrovitis, S N Nanas, A K Rombos, G Tolis, J N Nanas (1998)  Reversible symmetric polyneuropathy with paraplegia after heart transplantation.   Transplantation 65: 10. 1394-1395 May  
Abstract: BACKGROUND: Neurotoxicity is a well-recognized side effect of cyclosporine therapy in transplant recipients. Cyclosporine can cause a wide range of adverse effects on both the central and peripheral nervous systems. METHODS: We present a case history of symmetric polyneuropathy with flaccid paraplegia, a rare neurological complication of cyclosporine administration. RESULTS: Blood levels of the drug above the therapeutic range accompanied the neurological manifestations. The syndrome subsided fully with dose reduction. Patients' symptoms were attributed to axonal degeneration of the peripheral nerves, according to electromyography findings. CONCLUSIONS: Cyclosporine neurotoxicity should always be considered in patients with neurological complications following transplantation. The case presented in this article illustrates an additional potential mechanism of this adverse effect, namely, axonal degeneration of the peripheral nerves, causing symmetric polyneuropathy.
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PMID 
A Prekates, S Nanas, A Argyropoulou, G Margariti, T Kyprianou, E Papagalos, O Paniara, C Roussos (1998)  The diagnostic value of gram stain of bronchoalveolar lavage samples in patients with suspected ventilator-associated pneumonia.   Scand J Infect Dis 30: 1. 43-47  
Abstract: Ventilator-associated pneumonia (VAP) is one of the most common causes of morbidity and mortality in intensive care unit patients. However, the diagnosis is quite difficult. Gram stain (GS) of bronchoalveolar lavage (BAL) sample is a time-saving diagnostic method for VAP. However, its clinical significance has not been adequately investigated. The aim of this study was to determine its sensitivity and specificity for VAP diagnosis. We prospectively performed GS and quantitative bacterial cultures (QBC) of BAL samples, obtained through fiberoptic bronchoscope, in 75 consecutive postoperative and/or multiple trauma patients with suspected VAP. We considered BAL-GS as positive for VAP diagnosis when (i) polymorphonuclear neutrophils were > 25 per optic field at a magnification x 100 (p.o.f x 100); (ii) squamous epithelial cells were < 1% p.o.f x 100; and (iii) one or more microorganisms were seen p.o.f. at a magnification x 1,000 (p.o.f. x 1,000). VAP was diagnosed with criteria similar to those used in previous studies. Pneumonia was the final diagnosis in 22/75 (29%) patients. The BAL-GS was positive in 17/22 patients with VAP and in 7/53 patients without VAP. Accordingly, the sensitivity of BAL-GS for VAP diagnosis was 77%, the specificity 87%, the positive predictive value 71% and the negative predictive value 90%. Our data suggest that BAL-GS has good sensitivity and high specificity for VAP diagnosis. It could therefore constitute a useful complementary tool in the task of early diagnosis and treatment of VAP.
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PMID 
C E Charitos, J N Nanas, S N Nanas, I Chatzigeorgiou, N Alevizakos, K Cosmas, S D Moulopoulos (1998)  Right and left ventricular interaction in ventricular fibrillation with mechanical maintenance of the circulation.   J Cardiovasc Surg (Torino) 39: 3. 363-366 Jun  
Abstract: OBJECTIVE: To investigate the possible mechanisms of right and left ventricular interaction during ventricular fibrillation (VF) with mechanical maintenance of the circulation. EXPERIMENTAL DESIGN: In this experimental study, two para-aortic counterpulsation devices (PACDs) were implanted in 14 mongrel dogs. SETTING: The PACD is a spheroid, valveless, with one opening, 100 ml stroke volume assisting device. After midsternotomy and pericardiotomy, two PACDs were implanted on the ascending aorta and the pulmonary artery, respectively. Catheters were placed into the aortic arch, and the left and right ventricles. An electromagnetic probe was placed on the descending aorta. INTERVENTIONS: After the completion of the experimental preparation, VF was induced and the two devices were synchronized and pumped simultaneously for 10 minutes (A). Subsequently, the left sided PACD pumped alone for the same period of time (B). This sequence was repeated 1-10 times in each experiment. MEASURES: The aortic pressures, the left and right ventricular pressures and the cardiac index were obtained at the end of each intervention. RESULTS: The simultaneous pumping of the two devices (A) compared with the pumping of that implanted on the ascending aorta (B) resulted in: higher peak aortic pressure 119.1+/-32.1 mmHg (A) vs 105.7+/-36.4 mmHg (B), p<0.001, mean aortic pressure 42.1+/-13.2 mmHg vs 27.8+/-10.5 mmHg, p<0.001, mean left ventricular pressure 18.4+4.0 mmHg vs 11.7+/-3.6 mmHg, p<0.001, and cardiac index 105.7+/-40.1 ml/kg/min vs 82.0+/-39.9 ml/kg/mm, p<0.001, and lower right ventricular pressure 10.1+/-3.2 mmHg vs 13.3+/-2.6 mmHg, p<0.001. CONCLUSIONS: Maintenance of the circulation during VF with the PACD implanted on the ascending aorta results in equalization of the right and left ventricular pressures. In contrast, when both devices are pumping simultaneously, the left ventricular pressure is significantly higher than the right one and the assistance is more effective.
Notes:
 
PMID 
C E Charitos, J N Nanas, D A Kontoyiannis, S N Nanas, G Z Stamatopoulos, A C Rapti, S F Stamatelopoulos, S D Moulopoulos (1998)  The efficacy of the high volume counterpulsation technique at very low levels of aortic pressure.   J Cardiovasc Surg (Torino) 39: 5. 625-632 Oct  
Abstract: BACKGROUND: The objective of the present study was to identify the hemodynamic variables, that preclude the effectiveness of the counterpulsation technique. METHODS: In order to achieve high counterpulsation volume two devices were used simultaneously. The para-aortic counterpulsation device pumping 60-70 ml was implanted on the ascending aorta, and the intra-aortic balloon (20 ml) was placed in the descending aorta of 14 dogs with severe cardiogenic shock. Both devices were synchronized to provide aortic diastolic augmentation. The mechanical assistance provided by these devices was considered adequate when the mean aortic pressure during the supportive period was at least 50 mmHg, a pressure compatible with life. RESULTS: The mechanical assistance provided by the two devices was adequate in none (0%) of the cases with a systolic aortic pressure below 30 mmHg (Group I), in 71% of the cases with a systolic aortic pressure between 30-56 mmHg (Group II), and in 100% of the cases with a systolic aortic pressure above 56 mmHg (Group III). In group II the left ventricular end-diastolic pressure was higher in the cases responding adequately to mechanical assistance (Subgroup IIa) than in the ones where no adequate response was obtained (Subgroup IIb). CONCLUSIONS: The very low levels of the systolic aortic pressure was the most important factor precluding the adequate effectiveness of the counterpulsation technique.
Notes:
1997
 
PMID 
N Sphiris, S Nanas, H Paraskevopoulou, A Lymberis, T Kyprianou, E Liakopoulou, C Roussos (1997)  A decision support software package for medical treatment of I.C.U. patients.   Stud Health Technol Inform 43 Pt B: 911-914  
Abstract: Critically ill patients admitted in I.C.U. often have multiple complicated problems which necessitate the use of a large number of drugs. The multiple potential interactions between substances and underlying pathologies as well as between substances themselves, obviate the need for a decision support system. We therefore developed a software package for medical treatment support in I.C.U. environment which is based on Microsoft Visual Basic 3.0 and it is organised around the commercially available RDBMS Access 2.0. The database consist of: a) all available substances, b) all generic names of medications available in Greece for each substance, c) incompatibilities (2,300 cases), d) interactions (50,000 cases) and e) cost information for each drug. This system assures the safety of the administered treatment, helps to adjust the dose according to the situation of each patient (anthropometric data, laboratory result, prognostic/severity score e.t.c.) and screens for possible interactions and incompatibilities between the administered drugs. It could also be used for education, treatment algorithms application and it will serve cost-reduction policy. It is a useful and powerful tool for ICU staff which does not impose additional work to the daily practice routine and it is currently under evaluation in clinical settings.
Notes:
 
PMID 
A Prekates, S Nanas, G Nakos, J Floros, A Argyropoulou, O Paniara, C Roussos (1997)  Conditional evaluation of broncho-alveolar lavage in mechanically ventilated patients with suspected unilateral lobar pneumonia.   S Afr Med J 87: 5 Suppl. 643-648 May  
Abstract: OBJECTIVE: In an attempt to improve our ability to diagnose the cause of ventilator-associated pneumonia (VAP), we explore the usefulness of the conditional evaluation of bronchoalveolar lavage (BAL) samples from the involved and non-involved areas in patients with suspected unilateral lobar VAP (UL-VAP). DESIGN: Prospective study. SETTING: University teaching hospital intensive care unit. PATIENTS: We studied 19 consecutive patients with suspected UL-VAP. MEASUREMENTS AND MAIN RESULTS: Nine of the 12 patients (47%) developed UL-VAP. There was a significant difference between the involved and non-involved areas in UL-VAP patients (P < 0.001) in respect of the quantitative bacterial cultures (QBCs) of BAL samples for each micro-organism, whereas there was no difference in patients without UL-VAP. When we applied the criterion of usual BAL (one micro-organism in concentrations > 10(5) colony-forming units per millilitre) for UL-VAP diagnosis, the sensitivity was 100%, the specificity 70%, the positive predictive value 75%, and the negative predictive value 100%. When we used the conditional evaluation of the BAL results for UL-VAP diagnosis, in the involved and non-involved areas, the sensitivity was 78%, the specificity 90%, the positive predictive value 87.5% and the negative predictive value 82%. A statistically significant difference was found when we compared the difference in QBCs between the BAL samples for each micro-organism, between the involved and non-involved areas in patients with and without VAP (P < 0.001). CONCLUSION: These data suggest that utilisation of the conditional evaluation of the QBCs of BAL samples improves significantly our ability to diagnose the cause of UL-VAP.
Notes:
 
PMID 
E Agapitos, J Nanas, N Kavantzas, S Nanas, D Yova, A Trikoupis, P Davaris (1997)  The application of image analysis in the measurement of the myocardial infarct area in an experimental model.   Gen Diagn Pathol 143: 4. 215-218 Dec  
Abstract: BACKGROUND: Thrombolytic therapy improves left ventricular ejection fraction and survival. Using the image analysis method, the study was undertaken to evaluate the effects of intraaortic balloon pump used in conjunction with reperfusion in reducing infarct size by measuring the infarct area. Also, the usefulness of image analysis as an objective method for the measurement of myocardial infarct area is evaluated. METHODS: 22 dogs were subjected to proximal left anterior descending coronary artery occlusion. The dogs were classified into 3 groups. In group I (n = 7), occlusion lasted for 6 hours. In group II (n = 6), 2 hours of occlusion were followed by reperfusion. In group III, (n = 9) after 2 hours of occlusion, the dogs were assisted with the intraaortic balloon pump throughout the 4 hours of reperfusion. The measurement of the infarcted area components (fragmentation, edema, hemorrhage and polymorphonuclear infiltrations) was followed by a semiautomatic method including in connection a microscope photographic camera, a scanner and a computer with the appropriate software. The results were analyzed statistically using the t-test. RESULT: In group I, the mean value of fragmentation was 28.2%, in group II, 10.1% (p < 0.01 versus group I) and in group III, 3.9% (p < 0.01 versus I and p < 0.05 versus group II). CONCLUSION: Reperfusion and intraaortic balloon pump increased the salvage of the ischemic myocardium over that achieved by reperfusion alone in a canine occlusion - reperfusion model. Image analysis could be considered as an accurate and objective method for the measurement of the myocardial infarct area in the experimental model of our study and it could be used in any other experimental study in which the accurate measurement of myocardial infarct area is needed.
Notes:
 
PMID 
S N Nanas, J N Nanas, C E Charitos, A Gougoulakis, K Makaritsis, J Chatzigeorgiou, K Moussoutzani, M I Anastasiou-Nana, S D Moulopoulos (1997)  High stroke volume para-aortic counterpulsation device versus centrifugal pump in cardiogenic shock: experimental study.   World J Surg 21: 3. 318-2l; discussion 322 Mar/Apr  
Abstract: During the last decades a number of left ventricular assist devices has been used especially for patients resistant to pharmacologic treatment and to intraaortic balloon pump (IABP) support for left ventricular failure. A high stroke volume para-aortic counterpulsation device (PACD) has been developed utilizing the principle of the diastolic counterpulsation technique. In this study the hemodynamic effects of the valveless PACD were compared to those of the centrifugal blood pump (CBP) in nine dogs in acute experimental cardiogenic shock. Hemodynamic measurements were obtained at baseline with both devices off, PACD on and CBP off, or PACD off and CBP on. There was no difference in mean aortic pressure between PACD on (60.0 +/- 11.5 mmHg) and CBP on (69.0 +/- 26.8 mmHg). Similarly, there was no difference in left ventricular end-diastolic pressure with the PACD on (11.9 +/- 5.4 mmHg) versus the CBP on (9.9 +/- 5.2 mmHg) or the cardiac index with the PACD on (84 +/- 36 ml/kg/min) versus the CBP on (77 +/- 36 ml/kg/min). However, the left ventricular systolic pressure (55.0 +/- 19.0 with PACD versus 73.0 +/- 26.0 with CBP,p < 0.001), the tension time index (712 +/- 381 versus 1333 +/- 694,p < 0.01), and the double product (5629 +/- 2574 versus 7440 +/- 3294,p < 0.01) were significantly lower during assistance with the PACD than with the CBP. It was concluded that PACD is at least as effective as CBP for restoring hemodynamic status during acute experimental cardiogenic shock. Moreover, the PACD unloads the left ventricle more effectively than CBP, making it suitable for left ventricular mechanical support in cases with reversible myocardial damage.
Notes:
1996
 
PMID 
J N Nanas, C T Lolas, C E Charitos, S N Nanas, Z J Margari, E V Agapitos, S D Moulopoulos (1996)  A valveless high stroke volume counterpulsation device restores hemodynamics in patients with congestive heart failure and intractable cardiogenic shock awaiting heart transplantation.   J Thorac Cardiovasc Surg 111: 1. 55-61 Jan  
Abstract: The paraaortic counterpulsation device is a round pumping chamber with one valveless opening 20 mm in diameter and a 100 ml stroke volume. The paraaortic counterpulsation device was implanted on the ascending aorta of three male patients with intractable cardiogenic shock. Patients were assisted for 4 hours and 8 and 54 days, respectively; the first patient died as a result of nonresponding peripheral vasodilation and the other two died of septic shock. The two patients who were assisted for 8 and 54 days were conscious and able to function in a limited manner during the mechanical assistance. Discontinuation of the mechanical support for a few seconds was followed by low systolic arterial pressure (30 to 60 mm Hg) and syncopal episodes. Biochemical tests and autopsy results in these patients showed no evidence of blood cell destruction, thrombus formation, brain infarction, or other distal emboli. In conclusion, satisfactory hemodynamic effects, excellent biocompatibility, and simplicity of the implantation procedure in these patients encourage the use of the paraaortic counterpulsation device as a bridge to heart transplantation.
Notes:
 
DOI   
PMID 
J N Nanas, S N Nanas, D A Kontoyannis, K S Moussoutzani, J P Hatzigeorgiou, P B Heras, K P Makaritsis, E B Agapitos, S D Moulopoulos (1996)  Myocardial salvage by the use of reperfusion and intraaortic balloon pump: experimental study.   Ann Thorac Surg 61: 2. 629-634 Feb  
Abstract: BACKGROUND. Thrombolytic therapy improves left ventricular ejection fraction and survival. The study was undertaken to evaluate the effects of intraaortic balloon pump used in conjunction with reperfusion in reducing infarct size. METHODS. Twenty-two dogs were subjected to proximal left anterior descending coronary artery occlusion. In group 1 (n = 7) occlusion lasted for 6 hours. In group 2 (n = 6) 2 hours of occlusion was followed by reperfusion. In group 3 (n = 9) after 2 hours of occlusion the dogs were assisted with the intraaortic balloon pump throughout the 4 hours of reperfusion. At the end of 6 hours the infarcted myocardium of the left ventricle was determined and expressed as percentage of the myocardium at risk. RESULTS. In group 1, the infarcted myocardium was 79.3 +/- 9.9% of the myocardium at risk, in group 2, 59.0 +/- 19.9% (p < 0.05 versus group 1), and in group 3, 37.1 +/- 16.7% (p < 0.001 versus group 1 and p < 0.05 versus group 2). Endocardial viability ratio was increased by the intraaortic balloon pump; in group 1 it was 1.02 +/- 0.14, in group 2, 1.25 +/- 0.24, and in group 3, 1.47 +/- 0.31 (p < 0.001 versus group 1 and p < 0.02 versus group 2). CONCLUSIONS. Reperfusion and intraaortic balloon pump increased salvage of the ischemic myocardium over that achieved by reperfusion alone in a canine occlusion-reperfusion model.
Notes:
1994
 
PMID 
S T Toumanidis, A Danopoulos, N Vassilopoulos, S N Nanas, P Kostamis, D A Sideris, S D Moulopoulos (1994)  Acute effects of external and internal pacing on ejection fraction in patients with severe cardiac failure.   Acta Cardiol 49: 1. 25-41  
Abstract: The present study aims at evaluating the acute hemodynamic effects of external and internal (3 and 15 mA) pacing on 30 patients with severe cardiac failure. The global and regional ejection fraction were calculated by repeated radionuclide ventriculography at rest (control) and during increasing pacing rates. Blood pressure was measured at the end of each scintigraphy data acquisition period. The pacing rate was increased by 10 beats/min in every step and varied between +10 to +60 beats/min above the resting heart rate. The ejection fraction during pacing was lower than the resting ejection fraction in every pacing mode (resting ejection fraction = 23.30 +/- 7.67%, external pacing = 19.36 +/- 9.30%, p < 0.05, internal pacing 3 mA = 22.15 +/- 7.00%, p = N.S., internal pacing 15 mA = 19.92 +/- 6.95%, p < 0.05). The resting ejection fraction was higher than the ejection fraction in every pacing rate. In 4 out of 30 patients the ejection fraction was higher in every pacing mode and rate than the resting ejection fraction. The regional ejection fraction of the interventricular septum during internal pacing was lower (p < 0.001) than resting and/or external pacing. In conclusion, pacing in patients with severe cardiac failure reduces the control ejection fraction. This reduction increases as the pacing rate increases. The reduction is greater with internal pacing of 15 mA while the hemodynamic effect in external pacing did not differ significantly from internal pacing. Overall, the resting ejection fraction was higher than the paced ejection fraction, although in some patients pacing improved their resting ejection fraction.
Notes:
 
PMID 
M I Anastasiou-Nana, J N Nanas, S N Nanas, A Rapti, A Poyadjis, S Stathaki, S D Moulopoulos (1994)  Effects of amiodarone on refractory ventricular fibrillation in acute myocardial infarction: experimental study.   J Am Coll Cardiol 23: 1. 253-258 Jan  
Abstract: OBJECTIVES. The aim of this study was to evaluate the efficacy of a single dose of intravenous amiodarone in facilitating defibrillation of ventricular fibrillation refractory to lidocaine and epinephrine plus direct current countershocks in experimental acute myocardial infarction. BACKGROUND. Amiodarone has been hailed as the most effective single antiarrhythmic drug for the treatment of ventricular arrhythmias. However, intravenous amiodarone has only sporadically been used in the defibrillation of ventricular fibrillation in acute myocardial infarction. METHODS. Acute myocardial infarction was induced in 60 dogs by ligation of the proximal left anterior descending coronary artery for 2 h. Animals that developed spontaneous ventricular fibrillation were treated with lidocaine and epinephrine plus five direct-current countershocks. Dogs with ventricular fibrillation refractory to this regimen were randomized to further treatment with additional intravenous administration of epinephrine and bolus lidocaine plus < or = 15 direct-current countershocks (group I) or administration of amiodarone, 10 mg/kg body weight intravenously, followed by defibrillation with direct-current counter-shock (group II). RESULTS. Sixteen (27%) of the 60 dogs in which the protocol was attempted developed spontaneous ventricular fibrillation 21 min after ligation and were included in the study. Lidocaine and epinephrine plus five direct-current countershocks succeeded in converting ventricular fibrillation in one dog (6%). The other 15 dogs were randomized to group I (8 dogs) or group II (7 dogs). Defibrillation was achieved in one of the eight dogs in group I and in six of the seven dogs in group II (p < 0.005). CONCLUSIONS. In an experimental model of acute ischemia, intravenous amiodarone (10 mg/kg) influences positively the response to defibrillation of ventricular fibrillation refractory to lidocaine and epinephrine plus direct current countershocks.
Notes:
1993
 
PMID 
S D Moulopoulos, S F Stamateolopoulos, J N Nanas, D A Kontoyannis, S N Nanas (1993)  Effect of protracted dobutamine infusion on survival of patients in cardiogenic shock treated with intraaortic balloon pumping.   Chest 103: 1. 248-252 Jan  
Abstract: The survival of subjects with postmyocardial infarction cardiogenic shock treated with intra-aortic balloon pumping (IABP) differs significantly among various reports. Differences in the criteria for IABP application and in the timing of its initiation have been considered as the main reasons for variations in survival. This study examines whether the way patients in cardiogenic shock are treated prior to IABP may affect their survival. Fifty-five patients in severe postmyocardial infarction cardiogenic shock were classified into three groups according to the rate of dobutamine infusion prior to IABP: the "nondobutamine" (group A, n = 31), the "high-dose dobutamine" (8 to 20 micrograms.kg-1.min-1, group B, n = 17), and the "low-dose dobutamine" (up to 7 micrograms.kg-1.min-1, group C, n = 7). All subjects seen from 1978 to 1983 were recruited for group A, from 1986 to 1990 for group B, and in years 1984, 1985, and 1991 for group C, without using any other classification criteria. It was shown a posteriori that the three groups did not differ in the features of the subjects, in the severity of shock, and in the time length between onset of shock and pumping initiation. None of the 17 subjects of group B could survive under pumping, while 10 of the 31 subjects in group A and 4 of the 7 subjects in group C were weaned off pumping. Conclusions: A protracted, high-dose pre-IABP administration of dobutamine may adversely affect the survival of patients with postmyocardial infarction cardiogenic shock.
Notes:
 
PMID 
P Athanassiadou, P Athanassiades, K Kyrkou, E Giahnaki, E Giannioti, S Nanas (1993)  Expression of vimentin and epidermal growth factor receptor in effusions from patients with breast cancer; correlation with oestrogen and progesterone receptor status.   Cytopathology 4: 2. 91-98  
Abstract: The epidermal growth factor receptor (EGFr) status and the vimentin (V) status of malignant cells in pleural fluids from patients with breast cancer were determined using an immunoperoxidase labelling technique. The results were correlated with the oestrogen receptor (ER) and the progesterone receptor (PR) status of the primary tumour and with disease-free survival time of the patient. A negative correlation between EGFr and V status and hormone receptor status was found. The longest mean survival time occurred in patients with negative EGFr and V status and positive hormone receptor (ER and PR) status. The shortest mean survival time occurred in patients with positive EGFr and V and negative ER and PR status.
Notes:
1992
 
PMID 
S Nanas, S Magder (1992)  Adaptations of the peripheral circulation to PEEP.   Am Rev Respir Dis 146: 3. 688-693 Sep  
Abstract: The purpose of this study was to determine the role of changes in the parameters of venous return on the homeostatic adaption to the application of PEEP. We studied 13 dogs anesthetized with alpha-chloralose, intubated, and ventilated. We measured central venous pressure (CVP), arterial pressure (Pao) and cardiac output by thermal dilution. The cardiac output was transiently stopped by inflating a balloon in the right atrium, and the subsequent plateau in the CVP was used to obtain mean circulatory filling pressure (MCFP). Total blood volume was measured with Evans blue. To measure vascular capacitance and compliance, we rapidly infused 4 ml/kg or 8 ml/kg of blood and repeated the MCFP measurement. The same volume was withdrawn after the measurement. The volume and MCFP were used to construct pressure-volume (P-V) lines, and the unstressed volume was calculated by extrapolating the P-V to zero pressure. The P-V appeared linear in the range studied. PEEP produced a left shift of the curves and, thus, a decrease in unstressed volume. The shift with 20 cm H2O of PEEP was greater than with 10 cm H2O of PEEP. The rise in MCFP matched the rise in CVP so that the pressure gradient for venous return did not change. However, there was also an increase in the resistance to venous return, which resulted in a lower cardiac output than expected for the rise in MCFP. In conclusion, homeostatic adjustments to PEEP included a decrease in vascular capacitance, which is partially offset by a rise in the resistance to venous return.
Notes:
1991
 
PMID 
P G Antonatos, S G Foussas, S N Nanas, D G Karamoussalis, A G Theocharis, L P Anthopoulos, S D Moulopoulos (1991)  Effect of acute changes in aortic pressure on the coronary reserve.   Cardiovasc Res 25: 12. 995-1001 Dec  
Abstract: STUDY OBJECTIVE--The aim was to evaluate the effect of acute changes in aortic pressure on the coronary reserve and hyperaemic response. DESIGN--Aortic pressure changes were induced either by intra-aortic balloon pumping or by the production of acute aortic regurgitation. A transient 20 s occlusion of the left anterior descending coronary artery was used as the hyperaemic stimulus. EXPERIMENTAL SUBJECTS--The experiments were performed on 19 open chest anaesthetised dogs, weight 13-32 kg. MEASUREMENTS AND MAIN RESULTS--During intra-aortic balloon pumping the mean diastolic aortic pressure increased by 24.7(SEM 2.9) mm Hg (p less than 0.001), while in aortic regurgitation it decreased by 47.7(11.1) mm Hg (p less than 0.01). At the peak hyperaemic response the driving coronary pressure was 121.4(2.8) mm Hg during intra-aortic balloon pumping and 59.8(11.5) mm Hg during aortic regurgitation. The peak hyperaemic flow increased by 12.0(3.8) ml.min-1 (p less than 0.01) during intra-aortic balloon pumping, compared to the values before pumping and decreased by 14.9(4.2) ml.min-1 (p less than 0.01) during aortic regurgitation, compared to the values before aortic regurgitation. The coronary reserve, expressed as the ratio of the hyperaemic to the resting flow, increased by 0.7(0.1) (p less than 0.001) during intra-aortic balloon pumping and decreased by 0.4(0.2) (p less than 0.05) during aortic regurgitation. A positive significant correlation coefficient was found at the peak hyperaemic response between the mean aortic pressure and the total forward effective coronary flow, and between the mean diastolic aortic pressure and the diastolic component of the coronary flow, during both intra-aortic balloon pumping and aortic regurgitation. CONCLUSIONS--The results suggest that coronary reserve increases during intra-aortic balloon pumping and decreases during aortic regurgitation; these changes could be attributed to the effect of the pressure changes on the hyperaemic flow.
Notes:
1990
 
PMID 
S D Moulopoulos, S F Stamatelopoulos, N A Zakopoulos, S T Toumanidis, S N Nanas, J A Papadakis, J E Kanakakis, D S Moulopoulos, H Psihogios (1990)  Effect of 24-hour blood pressure and heart rate variations on left ventricular hypertrophy and dilatation in essential hypertension.   Am Heart J 119: 5. 1147-1152 May  
Abstract: This study correlates variables derived from blood pressure (BP) and heart rate (HR) monitoring with the degree of left ventricular structural changes in essential hypertension. Forty patients with mild-to-moderate hypertension according to World Health Organization criteria underwent 24-hour ambulatory monitoring. Echocardiographic (posterior wall and interventricular septum thickness, left ventricular mass) or ECG (SV1 + RV5) indices of hypertrophy were significantly (p less than 0.01) correlated (positive correlations) with derivatives of BP monitoring (mean systolic and diastolic BP values) but not with HR derivatives. Echocardiographic indices of dilatation (left ventricular end-diastolic volume and diameter) were significantly (p less than 0.01 to less than 0.001) correlated (negative correlations) with derivatives of HR monitoring (mean HR values, mainly during the night) but not with BP derivatives. It is concluded that in essential hypertension, left ventricular hypertrophy depends on mean 24-hour systolic and diastolic BP values, whereas left ventricular dilatation appears to be more prominent in patients with bradycardia mainly during the night.
Notes:
 
PMID 
J N Nanas, A Poyiadjis, C Charitos, S N Nanas, D Kontoyiannis, M Anastasiou-Nana, N Alevizakos, V Voudris, S D Moulopoulos (1990)  Additional salutary hemodynamic effects of the combined use of the paraaortic counterpulsation device and intraaortic balloon pump versus a paraaortic counterpulsation device alone.   ASAIO Trans 36: 3. M505-M509 Jul/Sep  
Abstract: The hemodynamic effects of the combined use of the paraaortic counterpulsation device (PACD) (stroke volume 65 ml) implanted on the ascending aorta, and a 20 ml intraaortic balloon pump (IABP) placed in the descending aorta, were compared with the PACD working alone in 12 dogs after the induction of heart failure. Heart failure was characterized by left ventricular end-diastolic pressure (LVEDP) greater than 18 mmHg and systolic aortic pressure (SAP) in stage A: 116 mmHg greater than or equal to SAP greater than 70 mmHg; in stage B: 70 mmHg greater than or equal to SAP greater than 30 mmHg; and in stage C: SAP less than or equal to 30 mmHg. Both modalities of mechanical assistance produced significant salutary hemodynamic effects in stages A and B. No difference was observed in stage C. In conclusion, the combined use of PACD and IABP is more effective than the use of either of these devices alone. This modality of mechanical assistance may easily be applied in patients that cannot be weaned from extracorporeal circulation, and in whom IABP was unsuccessfully applied.
Notes:
1989
 
PMID 
P N Adamapoulos, S Nanas, V I Pyrgakis, F Fotopoulos, D Moulopoulos (1989)  Technology, coronary heart disease and its risk factors.   Int Angiol 8: 3. 125-128 Jul/Sep  
Abstract: Cardiovascular diseases, predominantly coronary heart disease (CHD), are the leading public health problem in industrialized countries. They are associated with a number of variables, such as blood pressure (BP), smoking serum level of lipids, obesity etc for which technological progress is also incriminated. This relation has not been evaluated in Greece. This country is a developing one with different status of technology in different areas. In Athens it is almost similar to Western societies, but in rural areas it varies. This paper reports on morbidity of CHD and its risk factors (RF) in Greek populations with different technology.
Notes:
1988
 
PMID 
J N Nanas, S N Nanas, C E Charitos, D Kontoyiannis, A D Poyiadjis, G Stamatopoulos, A Melkaoui, G Kokollis, S D Moulopoulos (1988)  Hemodynamic effects of a counterpulsation device implanted on the ascending aorta in severe cardiogenic shock.   ASAIO Trans 34: 3. 229-234 Jul/Sep  
Abstract: A valveless, single orifice counterpulsation device (CD) with maximum stroke volume of 100 ml was implanted on the ascending aorta of nine dogs. Its pneumatic driver was gaited by the ECG to provide aortic diastolic augmentation, with a stroke volume of 60-70 ml. In the same animals a 20 ml intraaortic balloon (IAB) was placed into the descending aorta. An attempt was made to evaluate the effectiveness of the CD on severe cardiogenic shock and to compare its hemodynamic effects with those of the IABP. Severe cardiogenic shock was induced by coronary artery ligation, propranolol administration, and fluid infusion and was characterized by a LVEDP of 22.2 +/- 6.4 mmHg, ASP less than 70 mmHg and greater than or equal to 30 mmHg, and a reduction of CI by 71.7%. The CD had a significant beneficial effect in all measured parameters. The LVEDP decreased by a mean of 44.3% (P less than 0.001) below control value, and the AEDP by 60.2% (P less than 0.001). The PADA increased by 108.5% (P less than 0.001), and the CI by 155.8% (P less than 0.004). The IABP did not significantly change any of the hemodynamic variables. In conclusion, the CD has significant salutary hemodynamic effects in severe cardiogenic shock where IABP is ineffective.
Notes:
1987
 
PMID 
S Nanas, W H Pan, J Stamler, K Liu, A Dyer, R Stamler, J A Schoenberger, R B Shekelle (1987)  The role of relative weight in the positive association between age and serum cholesterol in men and women.   J Chronic Dis 40: 9. 887-892  
Abstract: With advancing age from youth on, there is an increase in mean serum cholesterol level of populations in "western" industrialized countries. Since serum cholesterol is one of the established major risk factors for premature coronary heart disease, it is important to explore the degree to which this age trend is physiologic or due to modern life styles. This study used cross-sectional data for 19,730 white men and 13,872 white women from the Chicago Heart Association Detection Project in Industry to investigate one aspect of this question: does weight explain the association between age and serum cholesterol, in particular whether older age is associated with higher serum cholesterol in the absence of overweight. The relationships among age, relative weight, and serum cholesterol were examined through assessment of mean serum cholesterol levels in 25 subgroups stratified by age (18-24, 25-34, 35-44, 45-54, 55-64) and by relative weight (less than 100, 100-109, 110-119, 120-134, greater than or equal to 135). Age and serum cholesterol were positively associated with each other. In women, it was a simple, linear relationship. In men, the degree of this positive association was less in people over age 35-44 than people in younger ages. These age-cholesterol patterns were present in men and women at desirable weight. However, in men aged 18-54, the positive association between age and prevalence of marked hypercholesterolemia (serum cholesterol greater than or equal to 250) was lower in people at desirable relative weight in comparison to those at higher relative weight.(ABSTRACT TRUNCATED AT 250 WORDS)
Notes:
 
PMID 
E J Diamantopoulos, L Anthopoulos, S Nanas, G Maliaras, D Chrisos, S D Moulopoulos (1987)  Detection of arrhythmias in a representative sample of the Athens population.   Eur Heart J 8 Suppl D: 17-19 Aug  
Abstract: The prevalence and type of arrhythmias has been studied in a representative sample of 2000 Athenians, aged 18-81 years, who underwent exercise testing on a treadmill according to the Bruce protocol. It was found that 121 persons (mean age 55.7 +/- 14.9 years, 31% greater than 65 years), exhibited arrhythmias on the ECG during either the exercise or the 10 min period following it (prevalence 6.05%). The age-adjusted prevalence was 6.7%, that is 7.1% for men and 6.2% for women. Out of these 2000 Athenians 43 (2.15%) exhibited unifocal VPCs (23 with greater than or equal to 3 VPCs min-1 and 20 with less than 2 VPCs min-1), 10 (0.5%) multifocal VPCs (6 with single and 4 with paired VPCs), 12 (0.6%) bigeminy, 25 (1.25%) supraventricular PCs, 16 (0.8%), supraventricular PCs and VPCs, 5 (0.25%) respiratory arrhythmia, 3 (0.15%) coronary sinus rhythm, 3 (0.15%) atrial fibrillation, one (0.05%) ventricular tachycardia, 2 (0.1%) first-degree and one (0.05%) second-degree AV block. In 32 out of those 121 persons arrhythmias were present also at rest (26.5%). Ventricular premature contractions and/or supraventricular PCs were the most common type of arrhythmias (87.6%). The majority of VPCs (69%) and supraventricular PCs (80%) appeared during the 10-min observation period following exercise. Coronary heart disease and valvular heart defects were found more frequently among the participants with than those without arrhythmias at exercise testing (19.83% vs. 8.83% and 2.48% vs. 0.27%, respectively).
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PMID 
S D Moulopoulos, P N Adamopoulos, E I Diamantopoulos, S N Nanas, L N Anthopoulos, M Iliadi-Alexandrou (1987)  Coronary heart disease risk factors in a random sample of Athenian adults. The Athens Study.   Am J Epidemiol 126: 5. 882-892 Nov  
Abstract: Risk factors for cardiovascular diseases not previously investigated in Greece were studied in a random sample of 4,097 Athenian adults. Mean systolic and diastolic blood pressures increased with age in both sexes. Similar findings were observed for mean serum total cholesterol up to age 50 years, but no significant changes were observed in older persons. Smoking was more common for men than for women and less common in those aged more than 50 years. Mean values of body mass index were higher for men than for women in those less than 45 years, but the opposite was observed for the older age groups. The age-adjusted prevalence rate of borderline hypertension was 10.1% for men and 9.1% for women and of stable hypertension (greater than 160/95 mmHg), 8.1% and 8.6%, respectively; the age-adjusted prevalence rate of obesity was 23.5% for men and 23.2% for women and of hypercholesterolemia (total cholesterol greater than or equal to 260 mg/100 ml), 20.1% for men and 17.3% for women. The associations of age and systolic blood pressure and of age and diastolic blood pressure persisted even after controlling for body mass index, total cholesterol, and smoking. In the examined representative sample, the prevalence rates of risk factors for cardiovascular diseases are the same or greater than those in industrialized countries.
Notes:
1986
 
PMID 
S D Moulopoulos, S Stamatelopoulos, S Nanas, K Economides (1986)  Medical education and experience affecting intra-observer variability.   Med Educ 20: 2. 133-135 Mar  
Abstract: Intra-observer variability for history and simple test evaluation was assessed in a group of 10 final-year medical students and in five senior hospital staff members. Substantial agreement between the results of two evaluations made 7-10 days apart was found in 20 out of 30 instances for staff and in 17 out of 60 instances for students. However, there were instances when variability seemed to be unrelated to the academic standard of students or to the training and experience of staff. It is concluded that the nature of diagnostic procedure and present training in medical school or long-term experience may not be the only factors that affect intra-observer variability in everyday simple diagnostic applications.
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PMID 
W H Pan, S Nanas, A Dyer, K Liu, A McDonald, J A Schoenberger, R B Shekelle, R Stamler, J Stamler (1986)  The role of weight in the positive association between age and blood pressure.   Am J Epidemiol 124: 4. 612-623 Oct  
Abstract: This study used cross-sectional data for 19,704 white men and 13,895 white women from the Chicago Heart Association Detection Project in Industry (November 1967 to January 1973) to investigate whether weight explains the association between age and blood pressure, and in particular, whether age is associated with blood pressure and hypertension in the absence of overweight. The relations among age, relative weight, and blood pressure were examined through assessment of mean blood pressure levels and prevalence of hypertension in 25 subgroups stratified by age (18-24, 25-34, 35-44, 45-54, and 55-64 years) and by relative weight (less than 100%, 100-109%, 110-119%, 120-134%, and greater than or equal to 135%). For all five relative weight groups, for both men and women, mean diastolic blood pressure was higher at successive ages. This phenomenon was also seen for systolic blood pressure after ages 35-44 years for men, and after ages 25-34 years for women. On the other hand, the higher the relative weight was, the higher the blood pressure was. Regression analysis demonstrated that the observed relation between age and blood pressure was consistent for all five relative weight groups, including those at desirable weight. These data indicate that for US subjects, age and blood pressure are generally associated in the absence of overweight.
Notes:
1985
 
PMID 
P G Antonatos, L P Anthopoulos, D D Kandyla, S G Foussas, S N Nanas, C J Karvounis, S D Moulopoulos (1985)  Intraventricular pumping at the mitral ring in mitral regurgitation.   Life Support Syst 3 Suppl 1: 167-171  
Abstract: This study aims at evaluating the effect of a small spherical balloon functioning during acute mitral regurgitation. Acute mitral regurgitation was produced in 11 mongrel dogs with a specially designed curved blade introduced through the left ventricular apex. Left atrial pressure, electrocardiogram, left ventricular pressure (in 8 dogs) and aortic flow (in 7 dogs) were monitored. The mean left atrial pressure increased by 9.45 +/- 2.44 mmHg (p less than 0.01) and the v wave by 14.09 +/- 2.94 mmHg (p less than 0.001). The systolic left ventricular pressure and the aortic flow decreased. The heart remained in sinus rhythm & the rate did not change significantly. After the production of mitral regurgitation, a small spherical balloon (9 to 16 cc capacity) mounted on a catheter was introduced to the left ventricle through the apex and positioned in the mitral ring. The balloon was inflated by means of a pump during systole and deflated during diastole. During its function the mean left atrial pressure decreased by 4.37 +/- 0.84 mmHg (p less than 0.001) and the v wave by 8.64 +/- 1.23 mm Hg (p less than 0.001). The systolic left ventricular pressure and the aortic flow increased. The peak systolic gradient across the mitral valve increased by 20.5 +/- 3.86 mmHg (p less than 0.01). The heart rate did not change. It is suggested that in acute mitral regurgitation the function of a small balloon could improve the hemodynamic condition by acting as a valve at the mitral ring for reduction of regurgitation and possibly by improving systolic function in severe heart failure.
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1984
 
PMID 
R Cooper, M Trevisan, L Van Horn, E Larbi, K Liu, S Nanas, H Ueshima, C Sempos, D Ostrow, J Stamler (1984)  Effect of dietary sodium reduction on red blood cell sodium concentration and sodium-lithium countertransport.   Hypertension 6: 5. 731-735 Sep/Oct  
Abstract: A randomized, crossover trial was carried out on the effect of moderate sodium reduction on red-blood-cell sodium metabolism. The participants were healthy high school students (mean age = 16 years, n = 33). Changes in sodium-lithium countertransport and intracellular sodium concentration were evaluated 24 days after a decrease in dietary sodium from approximately 110 to 40 mEq per day. Dietary sodium restriction had no significant effect on either sodium-lithium countertransport or intracellular sodium concentration.
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PMID 
R Cooper, L Van Horn, K Liu, M Trevisan, S Nanas, H Ueshima, E Larbi, C S Yu, C Sempos, D LeGrady (1984)  A randomized trial on the effect of decreased dietary sodium intake on blood pressure in adolescents.   J Hypertens 2: 4. 361-366 Aug  
Abstract: A randomized crossover trial on the effect of salt restriction on blood pressure was carried out involving 124 adolescents (mean age 16 years). Dietary sodium was reduced from approximately 110 to 45 mEq/24 h for a period of 24 days. Blood pressure was non-significantly lower at the end of the experimental diet for all participants. A slight (0.7 kg), yet statistically significant fall in weight was observed (P less than 0.05). Subgroup analysis demonstrated that participants whose body mass index was below the median had a statistically significant fall in systolic blood pressure (P less than 0.05); fall in weight and increase in heart rate were also more pronounced in the less obese individuals. It would appear that moderate sodium reduction does not have an overall short-term effect on blood pressure in normotensive adolescents. However, body size as reflected in body mass index may influence blood pressure response to sodium reduction.
Notes:
1983
 
PMID 
M Trevisan, R Cooper, D Ostrow, C Sempos, S Sparks, S Nanas, W Miller, J Stamler (1983)  Red cell cation transport: differences between black and white school children.   J Hypertens 1: 3. 245-249 Oct  
Abstract: Differences in red cell sodium content and sodium-lithium countertransport were studied in black and white children with a mean age of 12 years. For both boys and girls red cell sodium content was higher in blacks and countertransport lower (P less than 0.05). For both ethnic groups red cell sodium was lower in girls than boys and a consistent positive relationship was noted between body mass index and countertransport. Despite the lower red cell Na-Li countertransport values in black compared to white children, a significant positive correlation with systolic blood pressure was found independent of adiposity. In contrast, no correlation was evident between Na-Li countertransport and blood pressure in the white children. If red cell cation transport is confirmed as a marker for hypertension, study of racial differences may help explain the twofold higher prevalence of this disease among blacks.
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PMID 
R Cooper, D LeGrady, S Nanas, M Trevisan, M Mansour, P Histand, D Ostrow, J Stamler (1983)  Increased sodium-lithium countertransport in college students with elevated blood pressure.   JAMA 249: 8. 1030-1034 Feb  
Abstract: Blood pressure screening was carried out on a university campus to identify early hypertension or high-normal BP in young adults. Compared with normotensive control subjects of a similar age, drawn from the same population, persons identified as being at the upper end of the BP distribution had significantly increased levels of sodium-lithium countertransport. This difference persisted when other potential confounding variables, eg, overweight, sex, ethnicity, sodium excretion, and age, were taken into account. A positive family history was associated with slightly higher levels of sodium-lithium countertransport, although the effect could be explained by higher present levels of BP. These data suggest that abnormalities of cation transport are present early in the course of the development of hypertension. Measurement of transport levels may provide an estimate of risk of hypertension and allow identification of susceptible persons.
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1982
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