Comparison of left ventricular assist and intra-aortic balloon counterpulsation during early reperfusion after ischemic arrest of the heart.

In most centers, intra-aortic balloon counterpulsation and inotrope infusion are used for patients who require support to be weaned from cardiopulmonary bypass at the end of a cardiac surgical procedure. Where available, early institution of a left ventricular assist device is an alternative with possible advantages. In a canine model of left ventricular failure caused by 45 minutes of normothermic ischemic arrest, these two methods of support were instituted after an initial 30-minute reperfusion period. Both methods provided adequate support of the circulation (cardiac output greater than 2 L/min and mean arterial pressure greater than 50 mm Hg). After only 3 hours, however, significant differences were seen between the two groups. When the hearts were examined histologically, dogs in the group with intra-aortic balloon counterpulsation and inotrope infusion had significantly more necrosis than those in the group with a left ventricular assist device, 7.7% +/- 5.0% (mean +/- standard deviation) versus 2.0% +/- 1.3%. Decreases in compliance and systolic function were significantly greater in the group with intra-aortic balloon counterpulsation and inotrope infusion when compared with those supported with a left ventricular assist device. These findings suggest that even when support with intra-aortic balloon counterpulsation and inotrope infusion resulted in satisfactory hemodynamics, early institution of a left ventricular assist device was significantly more effective in preserving myocardial structure and function.