75 Does the “Obesity Paradox” in Chronic Heart Failure Fade after Mechanical Circulatory Support with Continuous Flow Devices: Analysis from the Interagency Registry for Mechanically Assisted Circulatory Support

Abstract

Purpose In the paradox, overweight patients with chronic heart failure demonstrate increased survival as compared to their lean counterparts. Since the natural history of systolic heart failure is modified by mechanical circulatory support (MCS), we hypothesized that obese patients on continuous flow left ventricular assist devices (CF LVADs) would have equivalent survival. Methods and Materials 1435 patients implanted with a CF LVAD were identified from the Interagency Registry for Mechanically Assisted Circulatory Support (INTERMACS) and grouped according to BMI categories. Kaplan-Meier (KM) and adjusted Cox Proportional Hazards analyses were performed. Results The median BMI in this cohort was 27.9kg/m 2 with 37% obese. The obese patient was younger, more likely to have diabetes, and less likely to be in NYHA class IV on inotropes. Over a mean follow-up period of 9.4 months, mortality was 15.9%. In KM analyses, no difference in survival was observed among the BMI categories. After adjusting for relavant covariates including diabetes, we identified equivalent survival in the patient with a BMI ≥ 30 (RR 0.89, p=0.47). Diabetes remained a significant risk factor with the lean diabetic patient carrying the highest mortality risk (RR 2.01, p=0.0008, compared to the obese non-diabetic). Conclusions Survival with a CF LVAD is equivalent in patients with obesity and advanced heart failure. Future studies targetting other endpoints, including adverse events and recurrent hospitalizations, are necessary to determine if diet-induced obesity is a significant risk factor in selecting patients for long term MCS with CF LVADs.