ICD therapy demonstrated a U-shaped efficacy pattern in patients with low ejection fraction, reducing mortality by 49% (p<0.001) in intermediate-risk patients but showing no benefit in low- or very high-risk subsets.
Cohort (n=1,191)
Yes
Does primary ICD therapy reduce all-cause mortality across different risk strata in patients with ischemic left ventricular dysfunction?
ICD efficacy in ischemic left ventricular dysfunction follows a U-shaped pattern, with pronounced mortality benefit in intermediate-risk patients but attenuated efficacy in lower- and higher-risk subsets.
Effect estimate: 49% reduction
p-value: p=< 0.001
OBJECTIVES: The study was designed to develop a simple risk stratification score for primary therapy with an implantable cardioverter-defibrillator (ICD). BACKGROUND: Current guidelines recommend primary ICD therapy in patients with a low ejection fraction (EF). However, the benefit of the ICD in the low EF population may not be uniform. METHODS: Best-subset proportional-hazards regression analysis was used to develop a simple clinical risk score for the end point of all-cause mortality in patients allocated to the conventional therapy arm of MADIT (Multicenter Automatic Defibrillator Implantation Trial)-II after excluding a pre-specified subgroup of very high-risk (VHR) patients (defined by blood urea nitrogen BUN >or=50 mg/dl and/or serum creatinine >or=2.5 mg/dl). The benefit of the ICD was then assessed within risk score categories and separately in VHR patients. RESULTS: The selected risk score model comprised 5 clinical factors (New York Heart Association functional class >II, age >70 years, BUN >26 mg/dl, QRS duration >0.12 s, and atrial fibrillation). Crude mortality rates in the conventional group were 8% and 28% in patients with 0 and >or=1 risk factors, respectively, and 43% in VHR patients. Defibrillator therapy was associated with a 49% reduction in the risk of death (p or=1 risk factors (n = 786), whereas no ICD benefit was identified in patients with 0 risk factors (n = 345; hazard ratio 0.96; p = 0.91) and in VHR patients (n = 60; hazard ratio 1.00; p > 0.99). CONCLUSIONS: Our data suggest a U-shaped pattern for ICD efficacy in the low-EF population, with pronounced benefit in intermediate-risk patients and attenuated efficacy in lower- and higher-risk subsets.
Goldenberg et al. (Tue,) conducted a cohort in Ischemic Left Ventricular Dysfunction (n=1,191). Implantable cardioverter-defibrillator (ICD) vs. Conventional therapy was evaluated on All-cause mortality (49% reduction, p=< 0.001). ICD therapy demonstrated a U-shaped efficacy pattern in patients with low ejection fraction, reducing mortality by 49% (p<0.001) in intermediate-risk patients but showing no benefit in low- or very high-risk subsets.