A 57-YR-OLD man with a history of nonischemic cardiomyopathy treated with a HeartMate 2 left ventricular assist device (LVAD) (Thoratec, Pleasanton, CA) 1 yr ago presented for orthotropic heart transplantation. The modern LVAD receives blood from the left ventricular apex and provides continuous flow to the ascending aorta with minimal pulsatility.1,2
Native regular cardiac rhythm is still critical for the right heart to pump blood to supply inflow to the LVAD. Total cardiac output is the sum of the LVAD flow and left ventricular cardiac output. Mild aortic regurgitation was present in both systole (panel A
) and diastole (panel B
) by color flow Doppler (see video, Supplemental Digital Content 1, http://links.lww.com/ALN/A745
, which shows continuous aortic regurgitation). In the presence of the LVAD, the left ventricular systolic pressure might be lower than the constant back pressure generated from the device. A structurally incompetent aortic valve will demonstrate aortic regurgitation in diastole as well as in systole if the left ventricular systolic pressure remains low. Aortic regurgitation causes blood backflow to the left ventricle and a circuitry between the left ventricle and ascending aorta. LVAD flow will read artificially higher than the effective flow delivered to vital organs. Therapeutic interventions consist of afterload reduction, decreasing LVAD pump speed, volume loading, and inotropic support both for the right ventricle to pump more blood to the left and to increase left ventricular systolic pressure. Aortic regurgitation usually progresses over time while on LVAD support because of either structural changes or increased aortic back pressure. Our patient tolerated this mild continuous aortic regurgitation well before cardiopulmonary bypass and underwent successful heart transplantation.