June 3rd, 2014
Prophylactic ICDs Appear Effective in Less Severe HF Patients
Implantable cardioverter-defibrillators are routinely implanted in heart failure patients with ejection fractions of 35% and lower to prevent sudden cardiac death. However, the benefits in patients at the higher end of the spectrum — EFs between 30% and 35% — have not been well demonstrated in clinical trials, since few patients in this range have been enrolled in such trials.
Sana Al-Khatib and colleagues analyzed data from the National Cardiovascular Data Registry ICD registry and the Get With The Guidelines–Heart Failure database. They compared the mortality benefit associated with ICDs in patients with EFs between 30% and 35% with the benefit in those with EFs below 30%. At follow-up, the ICD-associated reduction in mortality was similar in both groups. At 3 years, among patients with EFs 30%-35%, adjusted mortality rates were 47.1% in those with ICDs versus 58.o% in those without ICDs. Among patients with EFs <30%, mortality rates were 46.1% and 57.o%, respectively. The hazard ratio for mortality among ICD patients with EFs 30%-35% was 0.83 (CI 0.69 – 0.99, p = .04). The HR among ICD patients with EF <30% was 0.72 (CI 0.65 – 0.81, p < 0.001).
The authors write that their findings “support guidelines’ recommendations to implant a prophylactic ICD in eligible patients with an LVEF of 35% or less.” Although “the difference in absolute risk by 3 years was not large (3.6% at 3 years),” the add, “it was significant and close in magnitude to what was observed in the clinical trials of prophylactic ICDs.”