Long-Term Outcomes of Implantable Cardioverter-Defibrillator Therapy in the SCD-HeFT
Jeanne E Poole1, Brian Olshansky2, Daniel B Mark3
1Department of Medicine, Division of Cardiology, University of Washington, Seattle, Washington.
Insights
The implantable cardioverter-defibrillator (ICD) significantly reduced mortality in heart failure patients over 11 years. This benefit was most pronounced in patients with ischemic heart failure and NYHA class II symptoms.
Area of Science:
- Cardiology
- Clinical Trials
- Heart Failure Management
Background:
- The Sudden Cardiac Death in Heart Failure Trial (SCD-HeFT) initially randomized 2,521 moderate heart failure patients to amiodarone, placebo, or implantable cardioverter-defibrillator (ICD) therapy.
- The original trial demonstrated that ICD therapy significantly reduced all-cause mortality by 23% compared to placebo over a median follow-up of 45.5 months.
- Amiodarone did not affect survival rates compared to placebo in the initial study period.
Purpose of the Study:
- To describe the extended, long-term survival outcomes for the SCD-HeFT cohort.
- To analyze the durability and patterns of treatment benefit from ICD therapy over an 11-year follow-up period.
- To identify subgroups of heart failure patients who derive the most significant long-term benefit from ICD implantation.
Main Methods:
- Extended mortality data were collected for 1,855 patients alive at the end of the SCD-HeFT trial between 2010 and 2011.
- These data were combined with the 666 deaths from the original study for comprehensive long-term outcome analysis.
- Intention-to-treat analysis was employed to compare long-term survival between treatment groups and within pre-specified subgroups based on heart failure etiology and New York Heart Association (NYHA) functional class.
Main Results:
- Over a median follow-up of 11.0 years, the implantable cardioverter-defibrillator (ICD) group showed a significant overall survival benefit compared to the placebo group (HR: 0.87; 95% CI: 0.76 to 0.98; p=0.028).
- The survival benefit of ICD therapy showed attenuation after 6 years of follow-up (p=0.0015 for interaction).
- Long-term ICD benefit varied by heart failure etiology and NYHA class: it was significant for ischemic heart failure (HR: 0.81; p=0.009) and NYHA functional class II (HR: 0.76; p=0.001), but not for non-ischemic heart failure or NYHA class III.
Conclusions:
- Extended follow-up of the SCD-HeFT cohort to 11 years confirms a significant long-term survival benefit of ICD therapy.
- The treatment benefit of ICDs is heterogeneous, with the most substantial long-term survival advantage observed in patients with ischemic heart failure and those classified as NYHA functional class II at enrollment.
- These findings highlight the sustained, yet variable, impact of ICDs on long-term mortality in specific heart failure patient populations.
Background:
The SCD-HeFT (Sudden Cardiac Death in Heart Failure Trial) randomized 2,521 patients with moderate heart failure (HF) to amiodarone, placebo drug, or implantable cardioverter-defibrillator (ICD) therapy. Original trial follow-up ended October 31, 2003. Over a median 45.5-month follow-up, amiodarone, compared with placebo, did not affect survival, whereas randomization to an ICD significantly decreased all-cause mortality by 23%.
Objectives:
This study sought to describe the extended treatment group survival of the SCD-HeFT cohort.
Methods:
Mortality outcomes for the 1,855 patients alive at the end of the SCD-HeFT trial were collected between 2010 and 2011. These data were combined with the 666 deaths from the original study to compare long-term outcomes overall and for key pre-specified subgroups.
Results:
Median (25th to 75th percentiles) follow-up was 11.0 (10.0 to 12.2) years. On the basis of intention-to-treat analysis, the ICD group had overall survival benefit versus placebo drug (hazard ratio [HR]: 0.87; 95% confidence interval [CI]: 0.76 to 0.98; p = 0.028). When treatment benefit was examined as a function of time from randomization, attenuation of the ICD benefit was observed after 6 years (p value for the interaction = 0.0015). Subgroup analysis revealed long-term ICD benefit varied according to HF etiology and New York Heart Association (NYHA) functional class: ischemic HF HR: 0.81; 95% CI: 0.69 to 0.95; p = 0.009; nonischemic HF HR: 0.97; 95% CI: 0.79 to 1.20; p = 0.802; NYHA functional class II HR: 0.76; 95% CI: 0.65 to 0.90; p = 0.001; NYHA functional class III HR: 1.06; 95% CI: 0.86 to 1.31; p = 0.575.
Conclusions:
Follow-up of SCD-HeFT patients to 11 years demonstrated heterogenous treatment-related patterns of long-term survival with ICD benefit most evident at 11 years for ischemic HF patients and for those with NYHA functional class II symptoms at trial enrollment. (SCD-HeFT 10 Year Follow-up [SCD-HeFT10 Yr]; NCT01058837).
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