Abstract and Introduction
Abstract
Coronary Revascularization and Long-Term Mortality in MADIT-II. Introduction: Coronary revascularization (CR) may reduce arrhythmia risk and improve long-term outcome in patients with left ventricular dysfunction. This study was designed to evaluate the effect of elapsed time from CR on long-term mortality and arrhythmic risk among patients who receive an implantable cardioverter defibrillator (ICD).
Methods and Results: We evaluated the risk of 8-year mortality by elapsed time from CR to ICD implantation (categorized as: no CR; recent CR [<2 years]; or nonrecent CR [≥2 years], and assessed as a continuous measure) among 720 ICD recipients enrolled in the Multicenter Automatic Defibrillator Trial-II. At 8years of follow-up, patients who did not undergo CR and those who underwent nonrecent CR had significantly higher mortality rates than patients who underwent recent CR (54%, 54%, and 36%, respectively; P < 0.001). Multivariate analysis demonstrated that no- and nonrecent CR were associated with respective 48% (P = 0.022) and 67% (P < 0.001) increases in mortality risk compared with recent CR. Assessment of time from CR as a continuous measure showed that every year elapsed from CR was associated with an adjusted 6% increase in 8-year mortality (P < 0.001), and in respective 6% (P < 0.001) and 6% (P = 0.003) increased risk for in-trial appropriate ICD therapy of ventricular tachyarrhythmias and appropriate ICD shocks.
Conclusions: We observed a direct relationship between elapsed time from CR and long-term mortality following ICD implantation. The favorable long-term effect on outcome of recent CR may be related to a time-dependent effect of CR on ventricular arrhythmic burden and the need for appropriate ICD shocks.
Introduction
Coronary revascularization (CR) can reduce ischemia, infarct size, and adverse left ventricular remodeling among patients with a history of myocardial infarction. In most cases there is a time-dependent gradual progression of coronary artery disease after CR predisposing to recurrent ischemia or hibernation, which may trigger ventricular tachyarrhythmias. We have recently shown that the risk of life threatening ventricular arrhythmias and ICD shocks increase as a function of time elapsed since the last CR procedure. These findings may have important long-term implications since patients who received appropriate ICD therapy in both the Multicenter Automatic Defibrillator Implantation Trial II (MADIT-II) and the Sudden Cardiac Death in Heart Failure Trial (SCD-HeFT) trials were shown to have increased risk for subsequent mortality. However, currently there are no data regarding the effect of CR on long-term mortality following ICD implantation. We hypothesized that the favorable effects of CR on arrhythmic risk would translate into a long-term mortality reduction. Thus, we analyzed (1) the effect of elapsed time from CR on long-term mortality among ICD recipients during an extended (8-year) follow-up of MADIT-II and (2) the effect of elapsed time from CR on appropriate ICD therapy for ventricular arrhythmic events and appropriate ICD shocks during the in-trial phase of the study.