Kidney dysfunction and deterioration of ejection fraction pose independent risk factors for mortality in implantable cardioverter-defibrillator recipients for primary prevention

Abstract

Background: A growing number of patients with advanced heart failure fulfill a primary-prevention indication for an implantable cardioverter-defibrillator (ICD). This study seeks to identify new predictors of overall mortality in a Sudden Cardiac Death in Heart Failure Trial (SCD-HeFT)-like collective to enhance risk stratification.

Hypothesis: An impaired renal function and severely depressed left ventricular ejection fraction pose relevant risk factors for mortality in primary prevention ICD recipients.

Methods: Ninety-four consecutive ICD patients with New York Heart Association class II-III heart failure and depressed left ventricular function (left ventricular ejection fraction [LVEF] ≤ 35%) with no history of malignant ventricular arrhythmias were followed for 34 ± 20 months.

Results: During this period, 30 patients died (32%). Deceased patients revealed a significantly worse renal function before ICD implantation (1.55 ± 0.7 mg/dL vs 1.1 ± 0.4 mg/dL; P = 0.007), suffered more often from coronary artery disease (53 vs 29; P = 0.006), and were older (69.5 ± 8 y vs 67 ± 12 y; P = 0.0002) than surviving patients. Furthermore, increased serum creatinine at baseline (2 mg/dL vs 1 mg/dL; odds ratio [OR]: 3.96, 95% confidence interval [CI]: 1.2-13.04, P = 0.02), presence of coronary artery disease (OR: 8.6, 95% CI: 1.1-65, P = 0.036), and low LVEF (OR per 5% baseline LVEF deterioration: 1.4, 95% CI: 1-1.8, P = 0.034) represented strong and independent predictors for overall mortality.

Conclusions: Impaired renal function, the presence of coronary artery disease, and reduced LVEF before implantation represent independent predictors for mortality in a cohort of patients with advanced systolic heart failure. These conditions still bear a high mortality risk, even if ICD implantation effectively prevents sudden arrhythmic death. Indeed, in patients suffering from several of the identified "high-risk" comorbidities, primary-prevention ICD implantation might have a limited survival benefit. The possible adverse effects of these comorbidities should be openly discussed with the potential ICD recipient and his or her close relatives.