Unidirectional balloon pumping in the inferior vena cava and aorta: Effects on canine hemodynamics in cardiogenic shock

Abstract

Clinical applications of counterpulsation and, in particular, of intra-aortic balloon pumping (IABP) have been successful in the management of refractory left ventricular power failure. Synchronous external counterpulsation has emerged as an appealing noninvasive form of temporary cardiac assistance. To evaluate this modality, we performed 30 experiments in 6 dogs by inducing hypo- and hypervolemic cardiogenic shock with propranolol (1.5 mg. per kilogram) and ligation of the left anterior descending coronary artery (LAD). Unidirectional dual-chambered balloons were positioned in the inferior vena cava (IVCBP) and in the descending thoracic aorta (IABP) of the same animal to simulate external counterpulsation, and two assist consoles were synchronized to the electrocardiogram. The results indicate that IVCBP is detrimental in hypovolemic cardiogenic shock and that these results can be reversed with the addition of IABP. In contrast, IVCBP alone in hypervolemic cardiogenic shock resulted in significant hemodynamic improvement. It is concluded that the primary hemodynamic effects of these experiments, in which the venous hemodynamics of external counterpulsation have been simulated, may be related in great part to venous diastolic augmentation and to the state of hydration.