Effects of Angiotensin-Converting Enzyme Inhibitors and Beta Blockers on Clinical Outcomes in Patients With and Without Coronary Artery Obstructions at Angiography (from a Register-Based Cohort Study on Acute Coronary Syndromes)

We sought to determine the effectiveness of angiotensin-converting enzyme (ACE) inhibition and β-blocker treatment as a function of the degree of coronary artery disease (CAD) obstruction at angiography. The Evaluation of Methods and Management of Acute Coronary Events registry enrolled patients who had been hospitalized for an acute coronary syndrome. There were 1,602 patients who had cardiac catheterization that were used for this analysis. The main outcome measures were evidence-based therapies prescribed at discharge and 6-month incidence of all-cause mortality. The cohort consisted of 1,252 patients with obstructive CAD (>50% luminal diameter obstructed) and 350 patients with nonobstructive CAD. Multivariate logistic regression analysis adjusted for further medications and other clinical factors was performed. Patients with nonobstructive CAD had significantly (p <0.001) higher rates of β-blocker (77.8% vs 63.3%) and lower rates of ACE-inhibitor (57.7% vs 66.4%) prescriptions. In patients with nonobstructive CAD, ACE-inhibitor therapy was clearly associated with a lower 6-month mortality (odds ratio [OR] 0.31, 95% confidence interval [CI] 0.03 to 0.78, p = 0.004). No significant association between β-blocker use and death was found. In patients with obstructive CAD, both β blockers (OR 0.47, 95% CI 0.32 to 0.67, p <0.001) and ACE inhibitors (OR 0.47, 95% CI 0.26 to 0.87, p = 0.01) were significantly associated with a reduced risk of 6-month mortality. In conclusion, ACE-inhibitor therapy seems to be an effective first-line treatment for preventing the occurrence of mortality in patients with nonobstructive CAD.