Women with left ventricle systolic dysfunction (LVSD) who received an implantable cardioverter-defibrillator (ICD) had a lower risk of death and hospitalization than men but a higher risk for procedure-related complications, according to a study published June 2 in the Journal of the American Heart Association.

Overall, older patients were at higher risk for death and heart failure (HF)-related hospitalizations but not for all-cause hospitalizations. Age and sex differences did not vary by the severity of HF symptoms or etiology of systolic dysfunction.

Data for the study came from two sources: information on ICD eligibility, clinical characteristics, and provider details were collected from the ACC’s ICD Registry, while information on outcomes, including procedure-related complications, hospitalization, and death, came from the Cardiovascular Research Network Virtual Data Warehouse. Records were gathered from treatment that occurred between January 1, 2006, and December 31, 2010.

Researchers studied 2,954 patients with a left ventricular ejection fraction less than or equal to 35 percent undergoing first-time ICD treatment for primary prevention. Among the patients, 769 were women (26 percent) and 2,827 (62 percent) were older than 65.

In a median follow-up of 2.4 years, outcome rates per 1,000 patient-years were 109 for death, 438 for hospitalization, and 111 for HF hospitalizations.  Procedure-related complications occurred in 8.36 percent of the patient population.

The study also found that women had a significantly lower risk of death compared to men (hazard ratio of 0.67) but a higher risk of complications (hazard ratio of 1.38). Furthermore, patients older than 65 had a higher risk of death (hazard ratio of 1.55) and HF hospitalization (hazard ratio of 1.25) than younger patients.

According to Frederick Masoudi, MD, MSPH, FACC, lead author of the study, senior medical officer of the NCDR, and a professor of medicine at the University of Colorado Anschutz Medical Campus, there was a need for this study because “the randomized trials did not enroll many women or elderly patients. The outcomes of such patients in ‘real-world’ contemporary practice are important given the widespread use of ICD therapy.”

Masoudi adds that the study found that “the burden of adverse outcomes after primary prevention ICD implantation is substantial, and varies according to patient age and sex, not by baseline HF characteristics.”

“This study is important to the large population of patients with LVSD who are considering ICD therapy for primary prevention, to the clinicians caring for them, and to investigators interested in understanding the risks of clinically meaningful outcomes in the growing population of patients receiving this potentially life-saving therapy,” he concludes. 

Keywords: Aged, Cost of Illness, Defibrillators, Implantable, Heart Failure, Heart Ventricles, Primary Prevention, Registries, Sex Characteristics, Stroke Volume, Ventricular Dysfunction, Left

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