Evaluation of preoperative intra-aortic balloon pump support in high risk coronary patients.

OBJECTIVE: The intra-aortic balloon pump (IABP) is an established additional support to pharmacological treatment of the failing heart after myocardial infarction, unstable angina and cardiac surgery. The effect of preoperative IABP in high risk patients was evaluated.

METHODS: Between June 1994 and March 1996 all high risk patients for CABG (two or more of these criteria: Left ventricular ejection fraction (LVEF) < or = 40%, left main stem stenosis > or = 70%, REDO-CABG, unstable angina) were randomized into either of 3 groups: (1) IABP 1 day prior to surgery, (2) IABP 1-2 h prior to CPB and (3) no preoperative IABP, controls.

EXCLUSION CRITERIA: cardiogenic shock preoperatively. Fifty-two patients have entered the study-group 1 (13 patients), group 2 (19 patients) and group 3 (20 patients). Preoperative patient characteristics and operative data revealed no group differences. There were 56% REDO's, unstable angina 59%, LVEF < or = 40%, 87% (34.0 +/- 11.6%) and left main stem stenosis in 35%.

RESULTS: The CPB-time was shorter in groups 1 and 2 88.7 +/- 20.3 min than in group 3 105.5 +/- 26.8 min, P < 0.001, while ischemia time did not differ. Hospital mortality was higher in group 3, 25% vs. 6% (groups 1 and 2). Postoperative low cardiac output was seen in 12 patients (60%) in group 3 vs. 6 patients (19%) in groups 1 and 2, P < 0.05. Cardiac index increased significantly prior to CPB in groups 1 and 2. After CPB cardiac index was significantly higher in groups 1 and 2 compared to Group 3 and continued to increase. The IABP was removed after 3.1 +/- 1.0 days in group 3 vs. 1.3 +/- 0.6 days in groups 1 and 2, P < 0.001. In group 3, 11 patients required IABP postoperatively compared to only 4 patients in groups 1 and 2. ICU stay was shorter in groups 1 and 2--2.3 +/- 0.9 days vs. 3.5 +/- 1.1 days for group 3, P = 0.004. All patients received dopamin postoperatively, however in a lower dose in groups 1 and 2, 4.5 vs. 13.5 microg/kg/min. Dobutamine was added in 23% of the patients (group 1), 32% (group 2) and 95% (group 3). Adrenalin/amrinonum was required in 40% of the patients in group 3, 5% in group 2 and none in group 1. Group 1 patients had a better improvement of cardiac performance than group 2, while other parameters did not differ. Three months follow up of hospital survivors showed no group differences.

CONCLUSIONS: The use of preoperative IABP in high risk patients lowers hospital mortality and shortens the stay in ICU, due to improved cardiac performance, compared to a controls. The procedure was cost-beneficial. One day preoperative IABP treatment improves cardiac performance more than 1-2 h preoperative IABP treatment, but does not significantly affect the outcome in terms of hospital mortality or postoperative morbidity.