Long-Term Outcomes of Resynchronization-Defibrillation for Heart Failure
John L Sapp1, Soori Sivakumaran1, Calum J Redpath1
1From QEII Health Sciences Centre, Dalhousie University, Halifax, NS (J.L.S., R.P.), the Mazankowski Alberta Heart Institute, University of Alberta, Edmonton (S.S., S.K.), the University of Ottawa Heart Institute, Ottawa (C.J.R., N.H.N.L., G.W.), Schulich School of Medicine and Dentistry, Western University, London, ON (H.K., J.M., C.E.M., A.S.L.T.), Libin Cardiovascular Institute, Calgary, AB (D.V.E., G.S.), McMaster University, Hamilton, ON (J.S.H.), Montreal Heart Institute, Montreal (B.T., B.M., M.T., J.R.), Royal Jubilee Hospital, Victoria, BC (L.D.S.), and the University of Toronto, Toronto (S.M.) - all in Canada; and King Abdulaziz University, Jeddah, Saudi Arabia (A.M.).
Insights
Cardiac-resynchronization therapy defibrillators (CRT-D) significantly improved long-term survival in heart failure patients compared to implantable cardioverter-defibrillators (ICDs). This survival benefit was sustained over a median follow-up of nearly 14 years.
Area of Science:
- Cardiology
- Medical Devices
Background:
- The Resynchronization-Defibrillation for Ambulatory Heart Failure Trial (RAFT) previously indicated a 5-year mortality benefit for CRT compared to ICDs.
- The long-term survival impact of CRT in heart failure patients remained unknown.
Purpose of the Study:
- To evaluate the long-term survival outcomes of CRT defibrillators (CRT-D) versus implantable cardioverter-defibrillators (ICDs) in heart failure patients.
- To determine if the initial survival benefit of CRT-D is sustained over an extended follow-up period.
Main Methods:
- Randomized assignment of patients with NYHA class II/III heart failure, LVEF ≤30%, and QRS duration ≥120 ms (or paced ≥200 ms) to either ICD or CRT-D.
- Long-term outcomes were assessed in 1050 patients from the eight highest-enrolling sites.
- Primary outcome: all-cause mortality; Secondary outcome: composite of death, heart transplantation, or ventricular assist device implantation.
Main Results:
- Over a median follow-up of 7.7 years (survivors: 13.9 years), CRT-D was associated with a longer time until death compared to ICD (acceleration factor 0.80, P=0.002).
- Mortality occurred in 71.2% of the CRT-D group versus 76.4% of the ICD group.
- Secondary outcome events occurred in 75.4% of the CRT-D group versus 77.7% of the ICD group.
Conclusions:
- The survival benefit of CRT-D over ICD in patients with reduced ejection fraction, widened QRS, and moderate heart failure is sustained long-term.
- The findings suggest CRT-D provides a lasting survival advantage in this patient population, extending beyond initial trial observations.
Background:
The Resynchronization-Defibrillation for Ambulatory Heart Failure Trial (RAFT) showed a greater benefit with respect to mortality at 5 years among patients who received cardiac-resynchronization therapy (CRT) than among those who received implantable cardioverter-defibrillators (ICDs). However, the effect of CRT on long-term survival is not known.
Methods:
We randomly assigned patients with New York Heart Association (NYHA) class II or III heart failure, a left ventricular ejection fraction of 30% or less, and an intrinsic QRS duration of 120 msec or more (or a paced QRS duration of 200 msec or more) to receive either an ICD alone or a CRT defibrillator (CRT-D). We assessed long-term outcomes among patients at the eight highest-enrolling participating sites. The primary outcome was death from any cause; the secondary outcome was a composite of death from any cause, heart transplantation, or implantation of a ventricular assist device.
Results:
The trial enrolled 1798 patients, of whom 1050 were included in the long-term survival trial; the median duration of follow-up for the 1050 patients was 7.7 years (interquartile range, 3.9 to 12.8), and the median duration of follow-up for those who survived was 13.9 years (interquartile range, 12.8 to 15.7). 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. The time until death appeared to be longer for those assigned to receive a CRT-D than for those assigned to receive an ICD (acceleration factor, 0.80; 95% confidence interval, 0.69 to 0.92; P = 0.002). A secondary-outcome event occurred in 412 patients (77.7%) in the ICD group and in 392 (75.4%) in the CRT-D group.
Conclusions:
Among patients with a reduced ejection fraction, a widened QRS complex, and NYHA class II or III heart failure, the survival benefit associated with receipt of a CRT-D as compared with ICD appeared to be sustained during a median of nearly 14 years of follow-up. (RAFT ClinicalTrials.gov number, NCT00251251.).
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