Cardiac resynchronization therapy displays long-term benefits vs. ICD in HFrEF
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Key takeaways:
- Long-term CRT-D use was tied to improved survival and time to adverse events vs. ICD therapy in patients with HFrEF.
- The median follow-up of patients who survived to the trial conclusion was nearly 14 years.
Researchers reported extended survival and greater time until adverse events among patients with HF with reduced ejection fraction assigned to cardiac resynchronization therapy vs. implantable cardioverter defibrillator therapy.
The 14-year results of the RAFT trial were published in The New England Journal of Medicine.
“With CRT-D, we observed an approximately 20% reduction in the rate of death, which persisted through [14 years] of observation,” John L. Sapp, MD, professor in the division of cardiology at the Queen Elizabeth II (QEII) Health Sciences Centre at Dalhousie University in Halifax, Nova Scotia, Canada, told Healio. “CRT appears to offer quite a robust benefit in this population. The improvement was observed despite the inclusion of some patients who, in retrospect, would be expected to receive less benefit from CRT — patients with non-[left bundle branch block], patients with atrial fibrillation and patients with QRS durations between 120 to 150 [milliseconds].”
In the original RAFT study, which had a mean follow-up of 3.3 years, CRT defibrillator (CRT-D) therapy was associated with reduced HF hospitalization and mortality compared with ICD therapy in patients with NYHA class II or III HF, left ventricular ejection fraction of 30% and QRS of at least 120 milliseconds intrinsic or 200 milliseconds paced on optimal medical therapy.
For the longer-term After RAFT study, 111 RAFT trial participants were followed over 7.9 years and those previously assigned to ICD therapy were offered the option to crossover to CRT-D. The primary outcome was time to HF hospitalization, death, cardiac transplantation or implantation of a ventricular assist device.
As Healio previously reported, in patients with HFrEF, long-term CRT use was associated with better outcomes compared with ICD alone. Thirty-two participants crossed over, with a median time to crossover of 5.3 years.
The present study included 1,050 RAFT participants at eight sites enrolled starting in January 2003 and followed until death or Dec. 31, 2021 (mean age, 67 years; 84% men; median follow-up among those who survived, 13.9 years). The primary outcome was all-cause death. The secondary outcome was a composite of all-cause death, heart transplantation or implant of a ventricular assist device.
All-cause death occurred in 71.2% of patients assigned to CRT-D and 76.4% of patients assigned to ICD, and the time until death appeared longer in the CRT-D group compared with the ICD group (acceleration factor, 0.8; 95% CI, 0.69-0.92; P = .002).
The composite secondary composite outcome occurred in 75.4% of patients assigned to CRT-D group and 77.7% of those assigned to ICD therapy, and the time until the composite outcome event was longer in the CRT-D compared with the ICD group (acceleration factor, 0.85; 95% CI, 0.74-0.98), according to the study.
“Although the patients were treated appropriately for HF at the time of study enrollment, new drugs are now part of standard care for HF. It is uncertain how newer drugs for HF impacted survival in this trial, or how they would have impacted the findings if they were available at the time the trial started,” Sapp told Healio. “Nonetheless, the mechanism by which CRT improves heart function is mechanical — by improving effectiveness of cardiac contraction — which might be independent of pharmacologic effects.
“The survival benefit remained despite the fact that the long-term nature of this trial limited the analysis of subtle variations in clinical occurrences during the trial period, such as worsening of HF, changes to pharmacologic management, crossover between the treatment groups, or a change in the function of implanted leads — all examples of nonfatal, yet important changes that may reduce the effectiveness of CRT,” he said.
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