Angiotensin-converting enzyme inhibitors and stroke risk: benefit beyond blood pressure reduction?

Abstract

Hypertension, a leading cause of morbidity and mortality, accounts for 25-49% of all strokes. Randomized placebo-controlled trials primarily with diuretics and beta-blockers administered in patients with hypertension have demonstrated a 38% reduction in primary stroke. Placebo-controlled trials with angiotensin-converting enzyme (ACE) inhibitors have not been conducted in patients with hypertension. However, in a meta-analysis of four placebo-controlled trials of ACE inhibitors in patients with coronary heart disease and/or diabetes mellitus, the overall risk of primary stroke was significantly reduced. Results of the Heart Outcomes Prevention Evaluation trial, which produced a substantial reduction in stroke with an apparently small reduction in blood pressure, suggest that the benefit of ACE inhibitors may be related to their effects on the renin-angiotensin-aldosterone system more than on blood pressure reduction. In active-control comparisons in patients with hypertension, ACE inhibitors have demonstrated reductions in primary stroke risk similar to reductions with diuretics, beta-blockers, and calcium channel blockers. The data suggest that for primary prevention of stroke antihypertensive therapy should be individualized in patients. Relatively few data are available concerning the benefit of antihypertensive therapy in the secondary prevention of stroke. In patients who had experienced a stroke or transient ischemic attack, therapy with a diuretic or a combination of a diuretic plus an ACE inhibitor could be recommended based on available outcome studies conducted in this patient population. It is premature to conclude that the benefit of ACE inhibitor therapy in primary or secondary prevention of stroke is an effect independent of blood pressure reduction. Hypertension detection, treatment, and control in patients still must be the principal focus of clinicians for both primary and secondary prevention of stroke.