Cardiac resynchronization therapy outcomes by patient sex and baseline QRS duration: insights from AdaptResponse
C Blomstrom-Lundqvist, W Mullens, C Leclercq, M R Gold, A S Hersi, D Birnie, K Kusano, G Kaliska, A Rao, K Soejima, B Gerritse, R Crossland, G FilippatosAbstract
Background
AdaptResponse was a global randomized trial that compared adaptive cardiac resynchronization therapy (CRT) - an algorithm providing synchronized left ventricular pacing, to conventional biventricular CRT. Patients had symptomatic heart failure (HF) with reduced ejection fraction (EF), left bundle branch block (LBBB), and normal atrioventricular conduction. The overall death/HF event rates were low with both CRT arms combined (16.5% mortality at 5-years). Compared to historical CRT trials, AdaptResponse is unique with females accounting for 43% of the study cohort. This post-hoc analysis aimed to observe CRT outcomes by patient sex and baseline QRS duration, given the high number of females reinforcing such an analysis.
Methods
The AdaptResponse trial enrolled 3,617 patients with NYHA class II-IV HF, EF ≤35%, LBBB according to the Strauss criteria and baseline PR interval ≤200 ms. All patients received either adaptive or biventricular CRT therapy. In this post-hoc analysis, patients were stratified into four distinct groups based on sex (male or female) and baseline QRS duration (mid-QRS <150 ms or wide QRS ≥150 ms). The mid-QRS cohort included female patients with a QRS 130-149ms and male patients with a QRS 140-149ms. The sex difference in the lower QRS limit is aligned with the Strauss criteria for LBBB. The endpoints analyzed were all-cause mortality and the composite of death and adjudicated intervention for HF decompensation (death/HF events). Results are presented as Kaplan-Meier estimates.
Results
This analysis included 777 CRT patients with QRS <150ms (58% females) and 2838 CRT patients with QRS ≥150ms (39% females) followed for a median 59 months. Mortality was 24% lower in females than in males (HR=0.76; p<0.001; Figure 1). At 60 months, mortality was 16.9% for females and 22.3% for males within the QRS <150ms cohort, and 13.5% for females and 17.2% for males in the QRS≥150ms cohort (Figure 2). Similar results were observed for composite death/HF events.
Conclusion
In the AdaptResponse cohort, mortality was lower in female compared to male CRT patients in univariate analysis. Observed mortality in CRT patients with mid-QRS was higher than those with wide QRS within the same sex. Mortality and composite death/HF rates observed across sex and QRS width groups warrant further in-depth analysis of current CRT indications.For image description, please refer to the figure legend and surrounding text.For image description, please refer to the figure legend and surrounding text.