Mortality Reduction of Cardiac Resynchronization and Implantable Cardioverter-Defibrillator Therapy in Heart Failure: An Updated Meta-Analysis. Does Recent Evidence Change the Standard of Care?

Abstract

Background The recent publication of the MADIT-CRT and RAFT trials has more than doubled the number of patients in which a direct comparison of the combination of cardiac resynchronization therapy (CRT) and implantable cardioverter-defibrillator (ICD) versus ICD alone was carried out. The present meta-analysis aims to assess the impact of combined CRT and ICD therapy on survival of heart failure (HF) patients. Methods and Results Medline, Embase, and the Cochrane Library databases were searched, and all randomized controlled trials of CRT alone or combined with ICDs in HF resulting from left ventricular systolic dysfunction were included. Main outcome was all-cause mortality. Summary relative risk (RR) and 95% confidence interval (CI) were calculated employing random-effects models. Twelve studies were included, with a total of 8,284 randomized patients. For the comparison of CRT alone versus medical therapy, pooled analysis of 5 available trials demonstrated a significant reduction in all-cause mortality with CRT (RR 0.76, 95% CI: 0.64–0.9). Pooled analysis of 6 trials that compared the combination of CRT and ICD therapy to ICD alone also showed a statistically significant reduction in all-cause mortality (RR 0.83, 95% CI: 0.72–0.96). Stratified analysis showed significant mortality reductions in all New York Heart Association class subgroups, with greater effect in classes III–IV (RR 0.70; 95% CI: 0.57–0.88). Pooled estimates of implant-related risks were 0.6% for death and 8% for implant failure. Conclusion Combined CRT and ICD therapy reduces overall mortality in HF patients when compared with ICD alone.