Abstract: Mechanical support offered by rotary pumps is increasingly used to assist the failing heart, although several questions concerning physiology remain. In this study, we sought to evaluate the effect of left-ventricular assist device (VAD) therapy on coronary hemodynamics, myocardial oxygen consumption, and pulmonary blood flow in sheep. We performed an acute experiment in 10 sheep to obtain invasively measured coronary perfusion data, as well as pressure and flow conditions under cardiovascular assistance. A DeBakey VAD (MicroMed Cardiovascular, Inc., Houston, TX, USA) was implanted, and systemic and coronary hemodynamic measurements were performed at defined baseline conditions and at five levels of assistance. Data were measured when the pump was clamped, as well as under minimum, maximum, and moderate levels of assistance, and in a pump-off condition where backflow occurs. Coronary flow at the different levels of support showed no significant impact of pump activity. The change from baseline ranged from -10.8% to +4.6% (not significant [n.s.]). In the pulmonary artery, we observed a consistent increase in flow up to +4.5% (n.s.) and a decrease in the pulmonary artery pressure down to -14.4% (P = 0.004). Myocardial oxygen consumption fell with increasing pump support down to -34.6% (P = 0.008). Left-ventricular pressure fell about 52.2% (P = 0.016) as support was increased. These results show that blood flow in the coronary arteries is not affected by flow changes imposed by rotary blood pumps. An undiminished coronary perfusion at falling oxygen consumption might contribute to cardiac recovery.
Abstract: Axial blood pumps have very successfully entered the arena of prolonged clinical support. However, they offer only limited inherent load-responsive mechanisms for adjusting pumping performance to venous return and changes in the physiologic requirements of the patient. Therefore, excessive ventricular unloading can be observed in various situations of temporarily reduced venous return. In this study we report severe ventricular arrhythmias closely related to suction events in rotary blood pumps, a phenomenon that has not been described previously.
Abstract: Among medical subspecialties, paediatrics is relatively well represented on the Internet, as evidenced by the number of topical pages retrieved with different search engine queries. We sought to identify the kind of information that is readily available and to evaluate those resources for the quality of patient education from the consumer's perspective.
Abstract: Recurrent respiratory tract infections and dysphagia after the first years of life are rarely caused by vascular rings, and only a high index of clinical suspicion helps to avoid diagnostic delay and inappropriate treatment. Diagnostic workup in a 2-year-old girl with acute foreign body impaction into the esophagus and frequent respiratory tract infections revealed right descending aortic arch with ligamentum arteriosum as the cause of extrinsic esophageal-tracheal compression. Dividing the ligament gave release to the encircled esophagus and trachea. Relief of symptoms was achieved immediately after surgery.
Abstract: A new surgical technique for the management of shunting liver hemangiomas that otherwise would rapidly lead to intractable cardiac failure is presented. Rapid, significant reduction of shunt volume was achieved surgically by transhepatic compression sutures using PTFE pledgets and selective ligation of a large feeding vessel from the right hepatic artery.
Abstract: Pre- and postnatal pyelectasis detected by sonographic screening is of questionable pathologic importance. Therefore, we defined the natural course and diagnostic value of renal pelvis diameter (RPD) during fetal life and the neonatal period as such dilatation was revealed on routine sonography.
