Long-Term Benefits Among Mild Heart Failure Patients Receiving CRT
What are the extrapolated long-term benefits (beyond the follow-up of randomized controlled clinical trial) from cardiac resynchronization therapy (CRT) in patients with mild heart failure (HF)?
The authors used the 5-year follow-up data of the REVERSE study (REsynchronization reVErses Remodeling in Systolic left vEntricular dysfunction) to extrapolate survival and HF hospitalizations in patients with CRT devices. They performed two comparisons: CRT-ON versus CRT-OFF and CRT defibrillators (CRT-D) versus CRT pacemakers (CRT-P). Treatment-specific all-cause mortality, disease progression, and HF-related hospitalization rates were estimated with multivariate regression models. Rank-preserving structural failure time (RPSFT) models were used to adjust for crossover in the survival analysis.
CRT-ON was predicted to increase survival by 22.8%, leading to an expected survival of 9.76 years (CRT-ON) versus 7.5 years (CRT-OFF). CRT-D showed a significant improvement in survival compared with CRT-P offering 2.77 additional life-years. New York Heart Association (NYHA) functional class II patients had a 30.6% higher HF hospitalization risk than class I (I vs. II incident rate ratio, 0.69; 95% confidence interval, 0.57-0.85; p < 0.001) and three times lower rate compared with class III.
According to this analysis, there are important long-term benefits of CRT in mild HF. CRT was predicted to reduce mortality, with CRT-D prolonging life more than CRT-P.
The design of the REVERSE trial included an obligatory crossover of CRT-OFF patients to CRT-ON therapy after 1-2 years. Despite the availability of 5-year follow-up data, this crossover necessitated the use of an advanced statistical method called rank-preserving structural failure time (RPSFT), a rarely used method. According to the analysis, CRT prolonged survival by more than 2 years compared with optimal medical therapy, and CRT-D devices prolonged survival by almost 3 years compared with CRT-P devices. These findings are particularly striking in the light of data suggesting underutilization of CRT in the real world.
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