In patients with asymptomatic ischemia following myocardial infarction, is percutaneous coronary intervention superior to medical therapy for preventing adverse cardiac events?

In patients with silent ischemia following myocardial infarction (MI), percutaneous angioplasty is more effective than medical treatment for reducing long-term adverse cardiac events and cardiac death, and for improving exercise tolerance. (LOE = 1b)

Erne P, Schoenenberger AW, Burckhardt D, et al. Effects of percutaneous coronary interventions in silent ischemia after myocardial infarction: the SWISS II randomized controlled trial. JAMA 2007;297:1985-1991.  [PMID:17488963]

Randomized controlled trial (nonblinded)

Industry + foundation

Concealed

Inpatient (any location) with outpatient follow-up

Patients with a first ST-elevation or non-ST-elevation MI within 3 months were eligible for this study and had to meet the following criteria enrollment: maximal symptom-limited exercise testing with no chest pain, but with STsegment depression; silent ischemia confirmed with stress imaging; and 1-vessel or 2-vessel coronary artery disease. Patients were then randomized to balloon angioplasty or medical management. As the study was conducted between 1991 and 1997, stents were not used, and medical treatment did not include current standards such as clopidogrel and high-dose statins. Medical therapy was to include bisoprolol, amlodipine, and molsidomine (a long-acting nitrate). Both groups received aspirin and a statin. The primary end point was survival free of major adverse cardiac events (cardiac death, nonfatal MI, and symptom-driven revascularization) at 10 years. Outcome assessors were blinded to treatment groups, and results were analyzed by intention to treat. Of 1057 patients assessed for eligibility, 216 patients met enrollment criteria and 201 agreed to participate. Patients' mean age was 55 years, and most were men (86% - 89%). Groups were not equally matched for baseline characteristics: Patients in the medical management group were 4.3 kilograms heavier (P = .02), while dyslipidemia was more prevalent (75% vs 58%; P = .01) and mean ejection fraction (EF) was lower (53.9% vs 59.7%; P < .001) in the angioplasty group. Balloon angioplasty was performed on all patients assigned to that group, with complete revascularization achieved in 95%. Beta-blocker use in the medical management group was initially 95%, but declined to 84% by the end of the study, and the initially high rates of calcium channel blocker and nitrate use were not maintained. Still, at the end of the study, both beta-blocker use and calcium channel blocker use were 2 times greater in the medical group. At a mean follow-up of 10.2 years, the primary end point occurred in significantly more patients in the medical management group, a difference that remained significant after adjusting for factors including age, sex, weight, diabetes, dyslipidemia, number of diseased vessels, circumflex lesions, and EF (9.5% vs 3.2%; number needed to treat = 16; 95% CI, 11.2 - 25.6). Each adverse cardiac event comprising the primary end point was significantly reduced in the angioplasty group, including cardiac death. Patients in the angioplasty group were able to achieve higher workloads with less ischemia than medically managed patients on bicycle ergometry. In addition, at the end of the study, EF was preserved in the angioplasty group, but declined by close to 10% in the medical management group.