A randomized comparison of intra-aortic balloon pumping after primary coronary angioplasty in high risk patients with acute myocardial infarction

Abstract

Aims. Intra-aortic balloon pumping reduces afterload and may be effective in improving reperfusion in high risk infarct patients treated with primary angioplasty. Methods. High risk infarct patients referred from other centres for primary PTCA were randomized to treatment with or without an intra-aortic balloon pump. The primary end-point consisted of the combination of death, non-fatal reinfarction, stroke or an ejection fraction < 30% at the 6 month follow-up. A weighted unsatisfactory outcome score (as previously described by Braunwald), enzymatic infarct size and left ventricular ejection fraction were secondary end-points. Results. During a 3.5 year period, 238 patients were randomized, 118 to intra-aortic balloon pump therapy and 120 to no intra-aortic balloon pump therapy. Cross-over (25% in the intra-aortic balloon pump group and 31% in the no-intra-aortic balloon pump group) occurred in both treatment arms. The primary end-point was reached in 31 (26%) patients assigned to an intra-aortic balloon pump and in 31 (26%) assigned to no intra-aortic balloon pump (P = 0.94). Enzymatic infarct size (LDHQ72) was calculated in 163 (68%) patients and was not significantly different between either group (intra-aortic balloon pump: 1616 ± 1148, no intra-aortic balloon pump: 1608 ± 1163). The left ventricular ejection fraction was measured at the 6 month follow-up in 168 patients (80% of patients alive). No difference in ejection fraction was found in either group (intra-aortic balloon pump: 42 ± 13%, no intra-aortic balloon pump: 40 ± 14%, P = 0.51). Major complications occurred in 8% of patients treated with an intra-aortic balloon pump. Conclusion. Systematic use of intra-aortic balloon pumping after primary angioplasty does not lead to myocardial salvage or to a better clinical outcome in high-risk infarct patients. Use of intra-aortic balloon pumping after primary PTCA for acute myocardial infarction should be reserved for patients with severe haemodynamic compromise.