Women benefit more from cardiac resynchronization therapy compared to men- Insights from a Large Multicenter Cohort of CRT-D Recipients

Background

Cardiac resynchronization therapy (CRT) has become a cornerstone in heart failure (HF) therapy reducing morbidity and mortality. While the rate of CRT-Defibrillator (CRT-D) implantations is reported to be higher in men than women evidence from randomized controlled trials on the effects of gender on CRT response is scarce.

Purpose

The purpose of this study was to investigate the gender-specific response rate to cardiac resynchronization therapy.

Methods

Perioperative and outcome data were prospectively collected from 802 consecutive patients (168 female, 634 male) after CRT-D implantation in three tertiary European centers. The primary endpoint was all-cause mortality. Secondary endpoint was response to CRT as measured in improvement of left ventricular ejection fraction (LVEF), NYHA functional class, and QRS shortening 6 months after implantation.

Results

Female patients had significantly higher baseline LVEF values (27.0±7.1% vs. 25.2±7.2%, p<0.001), as well as significantly lower rates of ischemic cardiomyopathy (ICM; 39.3% vs 64.0%, p<0.001) and atrial fibrillation (AF; 28.5% vs. 39.0%, p=0.014). During the median follow-up period of 27.6 months (IQR: 13.2-53.1 the primary endpoint of all-cause death occurred in 267 patients (33.3%) and more often in males (n= 225, 35.5%) than in females (n=42, 25.0% p=0.010, figure 1). In the univariate analysis, AF, ICM, diabetes, chronic renal insufficiency, gender and age were significantly associated with the primary outcome. After adjustment for those covariates,  gender remained significantly associated with all-cause mortality (HR 1.34 [95% CI, 0.95- 1.87], p=0.012).  With respect to the secondary endpoint, echocardiographic response to CRT was significantly greater in female than in male patients (ΔLVEF +9.4±10.6% vs. +5.8±9.1%; p=0.002). Regarding other parameters indicating response to CRT (change in NYHA functional class, QRS shortening), we found no significant difference between male and female patients.

Conclusion

This multicentric cohort results with 10-year follow-up time suggest that women with symptomatic heart failure have a lower long-term all-cause mortality following CRT implantation compared to men. CRT response as measured as improvement in LVEF is more frequent and more pronounced in women than men during follow-up. Based on these data women seem to be optimal CRT candidates. Further investigations with larger patient cohort and a 50% female inclusion rate are urgently warranted to confirm these findings.

Table 1. Baseline data

LVEDD, left ventricular end-diastolic diameter; LVEF, left ventricular ejection fraction; NYHA, New York heart association; ICM, ischemic cardiomyopathy; AF, atrial fibrillation.