Effects of aortic balloon pumping during cardiopulmonary bypass on myocardial perfusion, metabolism, and contractility.

This study was undertaken to determine if the production of pulsatile flow by the intra-aortic balloon pump during cardiopulmonary bypass has any beneficial effect on coronary flow, regional myocardial flow, myocardial metabolism, and left ventricular function. Thirty-six conditioned dogs were subjected to one hour of total normothermic cardiopulmonary bypass. They were divided into the following five groups: (1) controls, beating heart and femoral inflow; (2) balloon, beating heart, and femoral inflow; (3) balloon, beating heart, and aortic inflow; (4) control, fibrillating heart and femoral inflow; and (5) balloon, fibrillating heart, and femoral inflow. Total coronary flow, left ventricular flow, coronary sinus flow, and the endocardial-to-epicardial flow ratio increased in group 3. This increase in flow may have been in part due to increased resistance to flow in the descending aorta by the balloon. No differences in flow were noted in the other groups, all of which were perfused via the femoral artery. No significant differences in myocardial metabolism or left ventricular contractility could be demonstrated between balloon-treated and control groups in these normal hearts.