Clinical Question: Is the administration of amlodipine beneficial for patients with coronary artery disease (CAD) and normal blood pressure?

Setting: Outpatient (specialty)

Study Design: Randomized controlled trial (double-blinded)

Allocation: Uncertain

Synopsis: In this study, investigators enrolled 1,997 patients, 32 to 82 years of age, who had established CAD (i.e., greater than 20 percent coronaryarterystenosis), and a diastolic blood pressure lower than 100 mm Hg, with or without treatment. They excluded patients with left main coronary artery obstruction greater than 50 percent, left ventricular ejection fraction less than 40 percent, or moderate to severe congestive heart failure. More than 75 percent of the participants were men, and nearly 90 percent were white. More than 60 percent had a history of hypertension, but less than one third currently were receiving a diuretic. Initial blood pressure measurement averaged 129/78 mm Hg for all patients.

After a two-week placebo run-in period to verify treatment compliance, participants were randomized in a double-blind fashion to receive amlodipine (10 mg per day), enalapril (20 mg per day), or placebo. Follow-up was complete for 24 months in more than 98 percent of the participants. Using intention-to-treat analysis, cardiovascular events occurred less often in patients receiving amlodipine (16.6 percent) and enalapril (20.2 percent) than in those taking placebo (23.1 percent). The difference was statistically significant only between the amlodipine and placebo groups (number needed to treat = 17; 95 percent confidence interval, 10.9 to 45.6).

Of the individual components of the composite end point of adverse cardiovascular events, only the need for revascularization and hospitalization for angina were statistically less in the amlodipine group. No differences existed among any of the groups in a reduction of nonfatal or fatal myocardial infarction (MI), cerebral vascular events, hospitalization for congestive heart failure, or all-cause mortality. All-cause hospitalization rates were not reported. There were no significant differences between the amlodipine and enalapril groups. No significant differences were noted in the progression of atherosclerosis in the amlodipine and enalapril groups compared with the placebo group.

Bottom Line: The administration of amlodipine to patients with established CAD without evidence of left ventricular dysfunction and normal blood pressure, with or without treatment, may reduce the risk of coronary revascularization or hospitalization for recurrent chest pain. The current study does not show a clear benefit of amlodipine over placebo in reducing the risk of other patient-oriented outcomes, including MI, stroke, all-cause hospitalization, or death. Therefore, the investigators simply may be measuring the effects of amlodipine as an antianginal medication. (Level of Evidence: 1b–)