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

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.

Conclusions: 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.