Aortic Counterpulsation for Myocardial Support: Towards a New Paradigm

Treatment for the failing heart comprises cardiopulmonary bypass (CPB), extracorporal membrane oxygenation internal/external counterpulsation, and various types of auxiliary pumps (artificial heart) such as ventricular-assist devices. Intra-aortic balloon pump (IABP) is the most commonly available and rapidly instituted form of mechanical support device for the ailing heart. As early as 1953, Arthur and Adrian Kantrowitz (brothers) published “experimental augmentation of coronary flow by retardation of arterial pulse pressure.”[1] There were numerous experimental studies during early 1950s by others with a concept of developing a mechanical device including CPB to support the failing heart. They demonstrated many benefits like increase in mean aortic diastolic pressure, diastolic pressure–time index, endocardial viability ratio, ejection fraction, cardiac output, coronary, cerebral and renal blood flow, myocardial oxygen supply, lactate utilization, and significant decreases in peak systolic aortic pressure, left ventricular end-diastolic pressure, tension time index, left ventricular work, myocardial oxygen consumption, and lactate production.[2] IABP is a form of internal aortic counterpulsation which augments the diastolic pressure during balloon inflation contributing to augmented coronary perfusion pressure, and presystolic rapid deflation helps reduce the left ventricular afterload, potentially reducing myocardial work. The hemodynamic and metabolic benefits of counterpulsation therapy in patients with acute cardiac dysfunction have led to the development of a noninvasive device that could perform diastolic augmentation sans common pitfalls associated with invasive counterpulsation devices (bleeding, thrombosis, limb ischemia etc.)