Abstract 12577: Degree of Obesity is Associated with Short Term Response and Long Term Survival after Cardiac Resynchronization Therapy

Abstract

Background: An “obesity paradoxℍ with heart failure has been described whereby higher body mass index (BMI) is associated with greater survival. However, little is known about the impact of obesity on survival after cardiac resynchronization therapy (CRT).

Objective: To test the hypothesis that response to CRT may be different in patients with different levels of obesity.

Methods: We prospectively studied 316 consecutive CRT patients with NYHA class III/IV heart failure, QRS width ≥120ms, and left ventricular (LV) ejection fraction (EF) ≤35%. Patients were divided into 3 BMI groups: <25 kg/m², 25 to 30 kg/m², and ≥30 kg/m². LV end-diastolic volume index (EDVI) and EF were calculated by biplane Simpson’s rule before and 6 months after CRT. More than moderate mitral regurgitation (MR) was considered as significant. Long-term outcome events were pre-specified as death, transplant or LV assist device over 3 years.

Results: Of 316 patients aged 65±11 years with EF 24±6%, 76 (24%) had BMI <25 kg/m², 111 (35%) had BMI 25-30 kg/m², and 129 (41%) had BMI ≥30 kg/m². Baseline characteristics differed as follows: BMI <25 kg/m² had larger mean EDVI (107 vs. 99 and 95 ml/m² in others, p=0.048) and lower mean EF (23% vs. 25% in others, p=0.02), BMI 25-30 kg/m² had a higher % of ischemic disease, p=0.01 and BMI ≥30 kg/m² were younger (62 vs. 66 and 68 yrs, p=0.001). After CRT the BMI <25 kg/m² group had a lesser degree of improvement in EDVI and more of these patients had significant MR, p=0.003. There were 93 outcome events: 70 deaths, 13 transplants, and 10 LV assist devices over 3 years. Significant differences between BMI groups (p=0.006) remained after Cox regression adjustment for all differences in baseline characteristics.

Conclusions: There appears to be an “obesity paradox” among patients after CRT such that higher BMI is associated with greater survival. After CRT, the lowest BMI group had less LV reverse remodeling, more significant MR and less favorable long-term survival.