Intra-aortic balloon counterpulsation: outcome in cardiac surgical patients

To identify the major determinants of survival and nonsurvival for patients in need of intra-aortic balloon pump (IABP) support after cardiac surgery and to define the role of ventilator-associated pneumonia.

Retrospective study.

University and general hospital.

A total of 105 consecutive patients undergoing cardiac surgery requiring IABP support and prolonged mechanical ventilation for >24 hours.

All patients were assigned into 1 of 2 groups: survival (n = 69) and nonsurvival (n = 36).

Differences between the survival and nonsurvival groups were tested with the Student's t-test, chi-square test, and frequency analysis. The overall survival rate was 65.7%. Nonsurvivors (34.3%) had higher rates of acute myocardial infarction (27.7% v 4.3%; p < 0.002), Canadian Cardiovascular Society functional class III and IV (44.4% and 13.8%; p < 0.001), and depressed left ventricular ejection fraction (31.3 +/- 6.4% v 42.4 +/- 7.2%; p < 0.001). The nonsurvival group had longer duration of cardiopulmonary bypass (165 +/- 74.3 minutes v 135 +/- 36 minutes; p < 0.006) and aortic occlusion (81.8 +/- 9 minutes v 68.6 +/- 25.7 minutes; p < 0.004). In the nonsurvival group, 21 patients were not weaned from the IABP, and 15 patients were weaned from the IABP but died from renal failure (26.6%), multiorgan failure (13.3%), infection, and respiratory failure (66.6%). In the nonsurvival group, mechanical ventilation time was longer in patients weaned from the IABP.

These data suggest that for patients not weaned from the IABP, the major determinants of death are low cardiac output (33.3%) and multiorgan failure (47.6%). Patients with a left ventricular ejection fraction of <30% have a poorer outcome. In patients weaned from the IABP, ventilator-associated pneumonia (66.6%) was the major cause of death.