Relation of pre-event use of inhibitors of the renin-angiotensin system with myocardial infarct size in patients presenting with a first ST-segment elevation myocardial infarction.

Agents that block the renin-angiotensin system (RAS), including angiotensin-converting enzyme inhibitors and angiotensin receptor blockers, are of proven benefit in patients after ST-segment elevation myocardial infarction (STEMI). However, no studies have evaluated the benefit of pre-event use of RAS inhibitors before STEMI. A retrospective review was performed of patients admitted to a single hospital with the diagnosis of STEMI and without a history of coronary disease or the equivalent, including diabetes mellitus, peripheral vascular disease, or stroke. Patients were stratified according to the use of RAS inhibitors before STEMI. Compared to patients not taking RAS inhibitors, patients who were taking RAS inhibitors had a lower peak troponin I level (79 vs 120 ng/dl, p = 0.016). Of the patients who had medically treated hypertension, those receiving RAS inhibitors had a significantly lower peak troponin I compared to those receiving non-RAS agents (79 vs 130 ng/dl, p = 0.015), despite equivalent blood pressure across the 2 groups. The beneficial effect of RAS inhibitor pretreatment remained when concomitant aspirin and statin use were controlled for. In conclusion, in patients presenting with a first STEMI, pretreatment with RAS inhibitors conferred a cardioprotective effect. The mechanism of this benefit appears to be independent of an effect on blood pressure control and was not wholly due to the effect of concomitant use of other medicines known to be protective in patients with STEMI.