Angioplasty is more effective than optimal drug therapy in reducing long-term risk for major cardiac events among survivors of myocardial infarction who have silent ischemia, according to an article in the May 9 issue of the Journal of the American Medical Association.

Silent, or asymptomatic, ischemia has been shown to predict adverse prognosis in patients after myocardial infarction, coronary artery bypass graft surgery, and percutaneous coronary intervention with or without stenting, according to background information in the article. However, the effect of interventions on long-term prognosis of patients with silent ischemia after myocardial infarction is not known.

Paul Erne, MD, of the Division of Cardiology, Kantonsspital Luzern, Luzern, Switzerland, and colleagues conducted a randomized, unblinded, controlled trial from May 2, 1991, to February 25, 1997 to determine how angioplasty compared with drug therapy in improving long-term outcome of asymptomatic patients with silent ischemia.

A total of 201 survivors of a recent myocardial infarction who had silent myocardial ischemia verified by stress imaging, and one- or two-vessel coronary artery disease participated. Ninety-six patients underwent angioplasty, and 105 patients received intensive drug therapy. All patients received 100 mg per day aspirin and statin therapy. Follow-up ended on May 23, 2006.

Patients in the intervention group experienced 27 major adverse cardiac events during an average follow-up of 10.2 years. During the same period, 67 adverse cardiac events occurred in the drug group, corresponding with an absolute event reduction of 6.3 percent per year. The rate of ischemia among patients in the intervention group was 11.6 percent at the final follow-up compared with 28.9 percent for the drug therapy group, despite use of fewer drugs.

"We found a persistent benefit of PCI compared with optimized drug therapy," the authors reported. "This benefit became apparent only after two years of observation, with survival curves continuously diverging up to the final follow-up after ten years."

"This is the first, to our knowledge, long-term outcome study of an invasive therapy compared with an intensive anti-ischemic drug therapy in asymptomatic patients with silent ischemia after a recent MI," the authors wrote.

"Our findings argue for an ischemic-targeted approach to PCI among asymptomatic survivors of myocardial infarction," they concluded.