Patients with systolic heart failure who received implantable cardioverter-defibrillators (ICD) did not benefit from a lower rate of death compared with usual care, according to results of the DANISH (Danish Study to Assess the Efficacy of ICDs in Patients With Non-ischemic Systolic Heart Failure on Mortality) trial, presented at the 2016 European Society of Cardiology Congress in Rome.

Findings were simultaneously published in the New England Journal of Medicine.

Lars Køber, MD, DMSc, of Rigshospitalet in Copenhagen, and colleagues assessed the effects of ICDs in patients with symptomatic systolic heart failure (with left ventricular ejection fraction ≤35%) not caused by coronary artery disease. This trial had a control group that received usual care; in both ICD and control groups, 58% of patients received cardiac resynchronization therapy (CRT).


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Death from any cause was the primary outcome, and sudden cardiac death and cardiovascular death served as the secondary outcomes.

Of the 556 patients assigned to receive an ICD, 120 died (death from any cause) compared with 131 in the control group who received usual care (hazard ratio [HR]: 0.87; 95% confidence interval [CI]: 0.68-1.12; P =.28). In terms of the secondary outcomes, 24 patients in the ICD group experienced sudden cardiac death vs 46 patients who received usual care (HR: 0.50; 95% CI: 0.31-0.82; P =.005). The median follow-up was 67.6 months.

Dr Køber and colleagues also reported device infection in 27 patients who received ICDs and in 20 patients in the control group (P =.29). Device infection risk was higher in the ICD group vs the control group among patients who did not receive CRT (HR: 6.35; 95% CI: 1.38-58.87; P =.006). Notably, whether or not a patient received CRT did not appear to effect ICD implantation (P =.73 for interaction).

Both the control and ICD groups experienced similar rates of resuscitated cardiac arrest or sustained ventricular tachycardia (control group: 2.5%; ICD group: 2.9%). In the ICD group, anti-tachycardia pacing was used to treat ventricular tachycardia in 97 patients, and appropriate shock for ventricular fibrillation or rapid ventricular tachycardia was administered to 64 patients.

The researchers also analyzed outcomes among patient subgroups (factors included sex, age, diabetes and hypertension statuses, NYHA functional class, among others). While results were similar across the board, age demonstrated a significant “treatment-by-subgroup interaction” (P =.009 for interaction). Patients younger than 68 years had a significantly lower rate of death from any cause compared to older patients (HR: 0.64; 95% CI: 0.45-0.90; P =.01).

Given the older age of the patients, the number of deaths related to noncardiovascular causes was not unusual for this trial. However, as the researchers noted, risk of death as well as device infection should prompt clinicians to carefully consider which patients receive ICDs.

ICD implantation did not improve mortality rates in patients with heart failure not caused by ischemic heart disease, but the risk of sudden cardiac death was reduced. Therefore, the DANISH investigators concluded that ICD implantation may benefit those patients unlikely to die from other causes.  

Disclosures: This trial was supported by unrestricted grants from Medtronic, St. Jude Medical, TrygFonden, and the Danish Heart Foundation.

References

  1. Køber L, Thune JJ, Nielsen JC, et al; for the DANISH Investigators. Defibrillator implantation in patients with nonischemic systolic heart failure. N Engl J Med. 2016. doi:10.1056/NEJMoa1608029.
  2. Køber L, Thune JJ, Nielsen JC, et al; for the DANISH Investigators. FP 1220. DANISH—a Danish randomized, controlled, multicenter study to assess the efficacy of implantable cardioverter defibrillator in patients with non-ischemic systolic heart failure on mortality. Presented at European Society of Cardiology Congress. August 27-31, 2016; Rome, Italy.