Resynchronization–Defibrillation Sustains Long-Term Survival Benefit in Heart Failure

John L. Sapp, MD

Credit: JACC Journals

A new long-term follow-up trial provided insight into the benefit of a cardiac-resynchronization therapy defibrillator (CRT-D), compared with a standard implantable cardioverter-defibrillator (ICD), on survival outcomes among patients with heart failure.¹

Results from the analysis of the Resynchronization–Defibrillation for Ambulatory Heart Failure Trial (RAFT) showed the survival benefit among the CRT-D-treated population with reduced ejection fraction, a widened QRS complex, and New York Heart Association (NYHA) class II or III heart failure was sustained across nearly 14 years of follow-up.

“This long-term follow-up trial showed a benefit with respect to mortality among patients who received a CRT-D as compared with those who received a standard ICD, and this benefit appears to have been sustained over time,” wrote the RAFT Long-Term study team, led by John L. Sapp, MD, QEII Health Sciences Centre, Dalhousie University.

CRT has shown a reduction in both mortality and heart failure outcomes among patients with symptomatic heart failure, a reduced ejection fraction, and a wide QRS complex despite optimal medical therapy, establishing it as standard care in appropriate patients.² Implantation of a CRT device is a lifelong intervention, suggesting clinical decision-making is dependent on findings from long-term outcome studies of CRT.

Across the double-blind, randomized controlled RAFT trial, with a mean follow-up of 40 months for nearly 1800 patients, CRT was shown to significantly reduce the risk of death or hospitalization for heart failure than an implantable cardioverter-defibrillators (ICD) (hazard ratio [HR], 0.75; 95% CI, 0.64 to 0.87; P <.001).³ Secondary outcome events, including death from any cause, death from any cardiovascular cause, and hospitalization for heart failure, were significantly lower with CRT.

To gather evidence on the long-term effect of CRT on mortality, Sapp and colleagues assessed survival outcomes for patients enrolling at the 8 highest-enrolling participating study sites.¹ Eligible participants with NYHA class II or III heart failure, a left ventricular ejection fraction of ≤30%, and an intrinsic QRS duration of ≥120 msec, were randomly assigned to receive either an ICD alone or a CRT defibrillator (CRT-D).

These patients were observed at follow-up visits 1 month after device implantation and every 6 months until all patients had ≥18 months of follow-up. Each follow-up visit consisted of a clinical assessment and device interrogation. The primary study outcome was death from any cause, with key secondary outcomes including a composite of death from any cause, heart transplantation, or implantation of a ventricular assist device.

The RAFT trial enrolled 1798 patients at 34 centers – for the long-term survival trial, 1050 patients from eight centers were included for analysis. The first patient was enrolled in January 2003 and follow-up continued until death or December 31, 2021. Among the entire study population, the median duration of follow-up consisted of 7.8 years and those who survived experienced a median follow-up of 13.9 years.

Upon analysis, investigators found death occurred in 405 of 530 patients (76.4%) assigned to the ICD group and in 370 of 520 patients (71.2%) assigned to the CRT-D group. Based on these data, the team indicated the time until death appeared longer in the CRT-D group than in the ICD group (acceleration factor, 0.80; 95% CI, 0.69 to 0.92; P = .002).

Meanwhile, a secondary outcome event happened in 392 patients (75.4%) in the CRT-D group and 412 patients (77.7%) in the ICD group. Again, the time until the composite endpoint was noted as longer in the CRT-D than in the ICD group (acceleration factor, 0.85; 95% CI, 0.74 to 0.98).

Sapp and colleagues indicated the findings from RAFT are complementary to observations from other randomized controlled trials, including the MADIT-CRT trial and the CARE-HF trial. Each trial reported a reduction in mortality and long-term persistence of the original benefit of CRT implantation.

“The present trial extends these observations over a longer follow-up time and supports the durability of the improvement in survival among patients with heart failure, reduced left ventricular ejection fraction, and prolonged QRS duration who received a CRT-D device,” investigators wrote.

References

1. _NEJM
2. _{Tang ASL, Wells GA, Talajic M, et al. Cardiac-resynchronization therapy for mild- to-moderate heart failure. N Engl J Med 2010;363:2385-95}
3. _{Heidenreich PA, Bozkurt B, Aguilar D, et al. 2022 AHA/ACC/HFSA guideline for the management of heart failure: a report of the American College of Cardiology/ American Heart Association Joint Committee on Clinical Practice Guidelines. Circulation 2022;145(18):e895-e1032}