Effects of Percutaneous Coronary Interventions in Silent Ischemia After Myocardial Infarction
The SWISSI II Randomized Controlled Trial
- Paul Erne, MD;
- Andreas W. Schoenenberger, MD;
- Dieter Burckhardt, MD;
- Michel Zuber, MD;
- Wolfgang Kiowski, MD;
- Peter T. Buser, MD;
- Paul Dubach, MD;
- Therese J. Resink, PhD;
- Matthias Pfisterer, MD
- Author Affiliations: Division of Cardiology, Kantonsspital Luzern, Luzern, Switzerland (Drs Erne and Zuber); Division of Geriatrics, Department of General Internal Medicine, University Hospital, Berne, Switzerland (Dr Schoenenberger); Division of Cardiology (Drs Burckhardt, Buser, and Pfisterer), Department of Research (Dr Resink), University Hospital, Basel, Switzerland; Department of Social and Preventive Medicine, University of Berne, Berne, Switzerland (Dr Schoenenberger); Heart and Vascular Center Zürich, Klinik im Park, Zürich, Switzerland (Dr Kiowski); and Division of Cardiology, Rhätisches Kantonsspital, Switzerland (Dr Dubach).
- Corresponding Author: Paul Erne, MD, Division of Cardiology, Kantonsspital Luzern, CH-6000 Luzern 16, Switzerland (Paul.Erne{at}ksl.ch).
Abstract
Context The effect of a percutaneous coronary intervention (PCI) on the long-term prognosis of patients with silent ischemia after a myocardial infarction (MI) is not known.
Objective To determine whether PCI compared with drug therapy improves long-term outcome of asymptomatic patients with silent ischemia after an MI.
Design, Setting, and Participants Randomized, unblinded, controlled trial (Swiss Interventional Study on Silent Ischemia Type II [SWISSI II]) conducted from May 2, 1991, to February 25, 1997, at 3 public hospitals in Switzerland of 201 patients with a recent MI, silent myocardial ischemia verified by stress imaging, and 1- or 2-vessel coronary artery disease. Follow-up ended on May 23, 2006.
Interventions Percutaneous coronary intervention aimed at full revascularization (n = 96) or intensive anti-ischemic drug therapy (n = 105). All patients received 100 mg/d of aspirin and a statin.
Main Outcome Measures Survival free of major adverse cardiac events defined as cardiac death, nonfatal MI, and/or symptom-driven revascularization. Secondary measures included exercise-induced ischemia and resting left ventricular ejection fraction during follow-up.
Results During a mean (SD) follow-up of 10.2 (2.6) years, 27 major adverse cardiac events occurred in the PCI group and 67 events occurred in the anti-ischemic drug therapy group (adjusted hazard ratio, 0.33; 95% confidence interval, 0.20-0.55; P<.001), which corresponds to an absolute event reduction of 6.3% per year (95% confidence interval, 3.7%-8.9%; P<.001). Patients in the PCI group had lower rates of ischemia (11.6% vs 28.9% in patients in the drug therapy group at final follow-up; P = .03) despite fewer drugs. Left ventricular ejection fraction remained preserved in PCI patients (mean [SD] of 53.9% [9.9%] at baseline to 55.6% [8.1%] at final follow-up) and decreased significantly (P<.001) in drug therapy patients (mean [SD] of 59.7% [11.8%] at baseline to 48.8% [7.9%] at final follow-up).
Conclusion Among patients with recent MI, silent myocardial ischemia verified by stress imaging, and 1- or 2-vessel coronary artery disease, PCI compared with anti-ischemic drug therapy reduced the long-term risk of major cardiac events.
Trial Registration clinicaltrials.gov Identifier: NCT00387231
