Abstract 13047: Clinical Risk Stratification for Primary Prevention Implantable Cardioverter Defibrillators (ICDs)
Introduction: Clinical risk stratification may refine decision-making regarding primary prevention ICDs and provide a comparator for advanced diagnostic tests for prediction of sudden cardiac death.
Objective: To identify predictors of appropriate ICD shock competing with mortality using clinical variables.
Methods: We studied a prospective, multicenter, population-based cohort with LVEF ≤35% referred for primary prevention ICD in Ontario, Canada. Patients were followed for appropriate ICD shocks at 18 device follow-up centers and for survival via vital status registry. We used a Fine-Gray subdistribution hazard model to develop a risk score for simultaneous prediction of appropriate ICD shock and death.
Results: Among 7020 referred, 3445 pts underwent primary prevention ICD implant (80% men, 66 yrs [IQR: 58-73]). During 5918 person-years (PY) follow-up, there were 204 pts with appropriate shock (3.6 per 100 PY) and 292 deaths (4.9 per 100 PY). Competing risk predictors of appropriate shock included nonsustained ventricular tachycardia, atrial fibrillation, higher serum creatinine, digoxin and amiodarone use. QRS duration shorter or longer than 130 msec peak conferred lower risk of appropriate shock. Mortality risk was increased with worse NYHA heart failure class and lower systolic blood pressure. In a multivariate competing risk index, one-year cumulative incidence of appropriate shock was 0.9% in the lowest-risk decile, and 1.7%, 2.5%, 4.9%, and 9.3% in low, intermediate, high, and highest-risk groups, respectively. One-year cumulative incidence of death was 0.6%, 1.9%, 3.3%, 6.2%, and 17.7% in the lowest, low, intermediate, high, and highest-risk groups, respectively. In the highest 3 deciles, hazard ratios ranged from 4.04 to 7.79 for shock and from 11.48 to 36.22 for mortality (all p ≤.001 vs lowest-risk).
Conclusions: A stratification scheme using only clinical variables can identify patients less likely to benefit from prophylactic ICD.
- Implantable cardioconvertor defibrillator
- Sudden cardiac death
- Health services research
Author Disclosures: D.S. Lee: None. J. Hardy: None. R. Yee: None. J.S. Healey: None. D. Birnie: None. C.S. Simpson: None. E. Crystal: None. I. Mangat: None. K. Nanthakumar: None. X. Wang: None. A.D. Krahn: None. P. Dorian: None. P.C. Austin: None. J.V. Tu: None.
- © 2014 by American Heart Association, Inc.