Transient mechanical support of the failing heart

Mechanical aids for the failing heart are necessary in patients with postoperative low—output syndrome (LOS) following cardiac surgery and in cardiologic patients with impending cardiogenic shock due to unstable angina pectoris and acute myocardial infarction (MJ). The IABP is routinely used either in the ICU, the catheter laboratory or in the operation room. Its hemodynamic effects improve the myocardial energy imbalance by a reduction in systolic and an increase in diastolic arterial pressure. The device generally produces a 10% to 20% increase in cardiac output (CO) and at the same time enhances the coronary blood flow (CBF). Nowadays the balloon—catheter is usually inserted transcutanously via femoral artery into the thoracic aorta. From 1975 to 1984, 138 patients (pts) of 6022 pts undergoing open heart surgery at the University of Goettingen required IABP. Another group of 28 pts with cardiogenic shock following acute myocardial infarction without cardiac surgery needed IABP-treatment. Only 28,5% (n = 8) could be weaned from IABP, and 5 pts were discharged from the hospital. Our experience show the coronary artery disease group of IABP patients to be increasing, whereas the intra— and postoperative groups are decreasing, probably as a result of better intraoperative myocardial protection by cardioplegia. Partial venoarterial bypass (VABP) in combination with IABP is hemo— dynamically more effective than IABP and can be used in more severe LOS and in presence of right heart failure. Our own experimental results indicate, that VABP of only 35% of cardiac output (CO) combined with IABP can be an effective method to support the failing heart. A bypass of 48% of CO decreased significantly dp/dtmax (30%) and calculated myocardial oxygen requirement (E.g. according to Bretschneider, 16%). A simple system is the combination of VAPB cannulating the axillary artery and IABP.