The preoperative intraaortic balloon pump in coronary bypass surgery: a lack of evidence of effectiveness

Abstract

Background: There is limited evidence demonstrating the effectiveness of preoperative intraaortic balloon pump (IABP) use in isolated coronary artery bypass graft (CABG) surgery. A single-center randomized trial demonstrated its benefit. We undertook a multicenter observational study to verify this finding.

Methods: In 29,950 consecutive patients undergoing isolated CABG between 1995 and 2000 at 10 centers, we compared patients with and without a preoperative IABP. We also compared the effect of preoperative IABP use within 7 high-risk clinical subgroups. To validate the previous randomized trial, patients with any 2 of the following were also analyzed: left main > 70%, ejection fraction < 40%, redo CABG, or preoperative intravenous nitroglycerin.

Results: Preoperative IABPs were used in 1896 patients (6.3%). These patients had more comorbid conditions and a higher crude mortality than those who did not have preoperative IABPs (9.5% vs 2.3%, P < .0001). Preoperative IABP patients were caliper matched to non-preoperative IABP patients using a propensity score. Excess mortality associated with preoperative IABP persisted (9.2% vs 5.8%, P = .0004). In 7 high-risk subgroups, mortality was significantly higher with preoperative IABP. We used propensity caliper matching to compare preoperative IABP with non-preoperative IABP patients who met trial criteria (n = 4332). Preoperative IABP was associated with higher mortality (11.0% vs 6.5%, P = .0009). Removing emergency patients did not alter results.

Conclusions: Use of preoperative IABPs was consistently associated with higher mortality. Despite detailed statistical analysis, we were unable to show benefit from preoperative IABP use or confirm the results of a single-center trial that demonstrated its benefit. Assessment of preoperative IABP efficacy will require a randomized trial.