Effect of ramipril on morbidity and mode of death among survivors of acute myocardial infarction with clinical evidence of heart failure. A report from the AIRE Study Investigators.

BACKGROUND

The importance of the effects of ACE inhibitors on sudden death, progressive heart failure and recurrent infarction to the reduction in overall mortality in heart failure and after myocardial infarction is disputed.

METHODS

The AIRE study randomized 2006 patients with clinical or radiological evidence of heart failure within 2-9 days of a myocardial infarction to receive ramipiril 5 mg b.d. or matching placebo. Outcomes were assessed independently by members of an end-points committee blinded to treatment allocation.

RESULTS

Fewer patients developed severe resistant heart failure as their first validated end-point on rampril, despite the greater number of at-risk survivors, compared to placebo (n = 143 vs 178; risk reduction 23%; CI 5 to 39%; P = 0.017). Ramipril did not alter the rate of reinfarction or stroke. Irrespective of treatment allocation 182 (46%) patients developed resistant heart failure prior to death. A validated acute or remote myocardial reinfarction occurred in 76 (19%) patients prior to death and chest pain occurred in 90 (23%) patients around the time of death suggesting an ischaemic element to these deaths Eighty deaths occurred on the index admission, 167 during re-admission and 145 out-of-hospital. Sudden death accounted for 54% of all deaths and 93% of out-of-hospital deaths. Ramipril reduced the risk of sudden death by 30% (95% CI: 8-47%; P = 0.011). However, overall, 45% of those patients who died suddenly had severe or worsening heart failure prior to their death. Only 39% of sudden deaths were considered to be due to arrhythmias. Ramipril reduced the risk of death from circulatory failure by 18%, but this did not reach statistical significance (95% CI; 41 to -14%; P = 0.237). The magnitude of the effects on sudden death and death due to circulatory failure were not significantly different. However, 38% of the reduction in overall mortality was from the subgroup with sudden death who had developed prior severe resistant heart failure (placebo n = 35, ramipril n = 15), again emphasizing the marked benefit in preventing failure. Ramipril did not selectively alter the proportion of in- to out-of-hospital deaths.

CONCLUSION

Ramipril reduces mortality and progression to resistant heart failure among patients with evidence of heart failure early after myocardial infarction. Retarding the progression of heart failure appears to be a major factor contributing to the reduction in mortality both by reducing circulatory failure and by reducing sudden death.