Prediction of Nonarrhythmic Mortality in Primary Prevention Implantable Cardioverter-Defibrillator Patients With Ischemic and Nonischemic Cardiomyopathy

ObjectivesThe objective of this study was to investigate the feasibility of identifying heart failure patients who are less likely to benefit from implantable cardioverter-defibrillator (ICD) therapy among those eligible for primary prevention ICDs.BackgroundThe cost-effectiveness of ICDs in primary prevention may be improved dramatically.MethodsUsing a cause-of-death analysis approach, we evaluated the discriminative and predictive values of a risk score with regard to overall mortality and specific causes of death by examining 2,485 patients enrolled in the French Primary Prevention ICD program (2002 to 2012). The risk score included points for New York Heart Association functional class III or greater, age >70 years, QRS duration >120 ms, atrial fibrillation, and glomerular filtration rate <60 ml/min. Sensitivity analyses were performed for ischemic and nonischemic cardiomyopathy, as well as for patients undergoing cardiac resynchronization therapy.ResultsAfter a mean follow-up of 3.0 ± 2.1 years, the overall mortality rate was 5.9 per 100 patient-years (95% confidence interval: 5.4 to 6.5), which increased with the number of risk factors (0 to 5, respectively), as follows: 2.5, 2.9, 4.8, 9.0, 12.3, and 14.8 per 100 patient-years (p < 0.001). The higher mortality rate among patients with the highest scores resulted from an increase in nonarrhythmic mortality (from 2.1 to 14.8 per 100 patient-years, p < 0.001), whereas the occurrence of appropriate ICD therapies did not change significantly across the categories. The C statistic testing of the score was observed to be highly similar for patients with ischemic cardiomyopathy (0.685) and nonischemic cardiomyopathy (0.658) and those receiving cardiac resynchronization therapy (0.678).ConclusionsOur findings suggest the feasibility of and interest in identifying patients eligible for primary prevention ICD implantation who are at significant risk of nonarrhythmic death in the real-world setting.