Evaluation of a nonhemolytic left ventricular assist pump

Abstract

Cardiogenic shock following acute myocardial infarction is associated with a mortality rate as high as 95%. The treatment of cardiogenic shock with inotropic agents increases heart work and myocardial oxygen consumption. The increase in oxygen consumption is, in general, not met by a proportionate increase in coronary blood flow because of existing coronary artery disease and an inadequate coronary filling pressure. One technique to assist the heart, counterpulsation, employed a suction withdrawal pump connected to a cannula in the abdominal aorta [3, 6, 201. The pump was synchronized with the cardiac cycle to withdraw blood from the aorta during systole and reinfuse it during diastole, reducing aortic pressure and myocardial oxygen consumption while increasing coronary flow. Unfortunately, the excellent hemodynamic result was overshadowed by significant levels of hemolysis as a result of the pumping process [6]. The catheter technique of counterpulsation has been abandoned for the balloon assist technique [ 141. A sausage shaped balloon tipped catheter placed in the descending thoracic aorta is inflated in diastole and deflated in systole. This technique augments aortic diastolic pressure and cardiac output and reduces tension time