Long-Term Effect of ICDs in Nonischemic Heart Failure With Reduced Ejection Fraction: Extended Follow-Up Analysis of
Jawad H Butt1, Seiko N Doi2, Jens J Thune3
1Department of Cardiology, Copenhagen University Hospital-Rigshospitalet, Copenhagen, Denmark; Department of Cardiology, Zealand University Hospital, Roskilde, Denmark.
Insights
Implantable cardioverter-defibrillators (ICDs) did not reduce overall mortality in nonischemic heart failure with reduced ejection fraction (HFrEF) patients long-term. However, ICDs significantly lowered sudden cardiac death rates, particularly in younger individuals.
Area of Science:
- Cardiology
- Electrophysiology
- Heart Failure Management
Background:
- Causes of death in heart failure with reduced ejection fraction (HFrEF) can evolve, impacting the risk-benefit of interventions like implantable cardioverter-defibrillators (ICDs).
- Long-term data is crucial for assessing sustained efficacy of ICDs in preventing sudden cardiac death (SCD) in HFrEF patients.
- The DANISH trial investigated ICDs in nonischemic HFrEF, necessitating extended follow-up to understand long-term outcomes.
Purpose of the Study:
- To evaluate the long-term impact of primary prevention ICD implantation versus usual care in patients with nonischemic HFrEF.
- To analyze the sustained effect of ICDs on all-cause mortality and sudden cardiovascular death over an extended follow-up period.
- To investigate age-related differences in the long-term efficacy of ICDs for primary prevention in nonischemic HFrEF.
Main Methods:
- The Danish Study To Assess the Efficacy of ICDs in Patients With Nonischemic Systolic Heart Failure on Mortality (DANISH) trial included 1,116 patients with nonischemic HFrEF.
- Participants had left ventricular ejection fraction ≤35%, NYHA class II-III (or IV with CRT), and elevated natriuretic peptides.
- Extended follow-up was conducted until January 31, 2024, with primary endpoint as all-cause death and secondary endpoints including cardiovascular death and SCD.
Main Results:
- Over a median follow-up of 13.2 years, ICD implantation did not significantly reduce long-term all-cause mortality (HR: 0.96; 95% CI: 0.82-1.13).
- ICD implantation significantly reduced the long-term rate of sudden cardiovascular death (HR: 0.54; 95% CI: 0.36-0.80).
- Age modified the effect on SCD; ICDs benefited patients ≤70 years (HR: 0.38) but not those >70 years (HR: 1.27; Pinteraction = 0.01).
Conclusions:
- Long-term primary prevention ICD implantation in nonischemic HFrEF patients did not reduce all-cause death.
- ICDs significantly reduced sudden cardiovascular death in this population over 13.2 years of follow-up.
- Younger patients (≤70 years) demonstrated a greater benefit from ICDs regarding sudden cardiovascular death prevention.
Background:
The most common causes of death may change over time in heart failure with reduced ejection fraction (HFrEF). These shifts can influence the risk-benefit balance of interventions such as implantable cardioverter-defibrillators (ICDs), which are designed to prevent sudden cardiac death. Long-term follow-up is therefore essential to determine whether early benefits are sustained, attenuated, or lost over time.
Objectives:
This study sought to examine the long-term effect of primary prevention ICD implantation, compared with usual clinical care, in patients with nonischemic HFrEF enrolled in the DANISH (Danish Study To Assess the Efficacy of ICDs in Patients With Nonischemic Systolic Heart Failure on Mortality) trial.
Methods:
The DANISH trial enrolled 1,116 patients with nonischemic HFrEF, left ventricular ejection fraction ≤35%, NYHA functional class II-III (class IV if cardiac resynchronization therapy was planned), and elevated natriuretic peptide levels. The primary outcome was all-cause death, and secondary outcomes were cardiovascular death and sudden cardiovascular death. In this study with extended follow-up, patients were followed until death or January 31, 2024, whichever came first.
Results:
During a median follow-up of 13.2 years (Q1-Q3: 11.6-14.6 years), 294 patients (52.9%) in the ICD group and 299 (53.4%) in the control group died. Compared with usual clinical care, ICD implantation did not significantly reduce the long-term rate of all-cause death (HR: 0.96; 95% CI: 0.82-1.13), but it did reduce the long-term rate of sudden cardiovascular death (HR: 0.54; 95% CI: 0.36-0.80). The effect of ICD implantation on all-cause death was consistent regardless of age (Pinteraction = 0.89). However, age significantly modified the effect of ICD implantation on sudden cardiovascular death, such that ICD implantation reduced the rate of this outcome in patients ≤70 years (HR: 0.38; 95% CI: 0.23-0.62), but not in those >70 years (HR: 1.27; 95% CI: 0.56-2.89; Pinteraction = 0.01). Similar trends were observed when age was analyzed as a continuous variable. The effect of ICD implantation was generally consistent across other key subgroups, including cardiac resynchronization therapy use at baseline.
Conclusions:
In patients with nonischemic HFrEF, during a median follow-up of 13.2 years, primary prevention ICD implantation did not reduce all-cause death, but it did reduce sudden cardiovascular death, and younger individuals appeared to derive a greater benefit. (Danish ICD Study in Patients With Dilated Cardiomyopathy [DANISH]; NCT00542945).
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