Does the Implantable Cardioverter-Defibrillator Benefit Vary With the Estimated Proportional Risk of Sudden Death in Heart Failure Patients?

BACKGROUND

Prediction of which heart failure patients are most likely to die of sudden death vs. non-sudden death is an important factor in determining who will benefit the most from an ICD.

OBJECTIVE

We developed the Seattle Proportional Risk Model (SPRM) to estimate the proportion of total mortality due to sudden death. We prospectively validated the model in HF-ACTION and tested whether the ICD benefit varied with the SPRM.

METHODS

Among 2331 patients enrolled, 1947 patients were retained for analysis over a median follow-up of 2.5 years. The SPRM was calculated using age, gender, diabetes, BMI, SBP, EF, NYHA, sodium, creatinine, and digoxin use.

RESULTS

ICD use (ICD or CRT-D) was present prior to death in 1204 patients (62%). SPRM was predictive of sudden death vs. non-sudden death in those without an ICD (P=0.002). The hazard ratio representing ICD versus no ICD was 0.63 for all-cause mortality (P=0.0002). The ICD benefit varied with the SPRM for all-cause mortality (P=0.001), with a greater benefit in those with a higher conditional probability of sudden death.

CONCLUSIONS

In an ambulatory NYHA II-IV HF population and EF ≤35%, the SPRM was predictive of the proportional risk of sudden vs. non-sudden death. ICDs were associated with a decreased risk of all-cause mortality by 37% and the ICD benefit varied with the SPRM. The SPRM may have utility in risk stratifying patients for a primary prevention ICD.