Effect of Synchronous and Asynchronous Pulsatile Flow During Left, Right, and Biventricular Bypass

摘要

Abstract:Ventricular assist devices augment flow from the left atrium to the aorta andlor from the right atrium to the pulmonary artery. Most devices are used in the asynchronous full‐to‐empty mode (asynchronous) but may also be used in a synchronous counterpulsation mode (synchronous). This study determines the optimal assist modes to reduce myocardial oxygen consumption (MVo2) and metabolism. Twelve pigs were instrumented with carotid artery and Bairn coronary sinus catheters for determination of MVo2and myocardial lactate production (LACT). Six were implanted with a Pierce‐Donachy left ventricular assist device (LVAD) and 6 with both right and left ventricular assist devices (BIVAD). Two periods each of control, synchronous, and asynchronous bypass were instituted, the midanterior descending coronary artery (LAD) was ligated, and the sequence was repeated. After each period, MVozand LACT were determined and myocardial biopsy specimens were obtained for tissue, lactate, and ATP assay. Following LAD ligation, biopsy specimens were obtained from both the infarct and nonin‐farct zones of the heart. MVo2decreased (p<0.05) in the asynchronous BIVAD mode compared with control. MVo2was unchanged in synchronous BIVAD or either LVAD mode. Tissue ATP and tissue lactate were unaffected by any mode of bypass. Only BIVAD in the asynchronous mode reduced MVo2. When ventricular assist devices are utilized to aid recovery of the natural heart, two devices should always be inserted to allow biventricular assist. Synchronous counterpulsation offers no ad