Patients with low compared with high body mass index gain more weight after implantation of a continuous-flow left ventricular assist device

Background: Patterns of weight change after implantation of a continuous-flow left ventricular assist device (CF-LVAD) can affect transplant candidacy and may influence outcomes. We evaluated changes in weight over a 24-month period from a national LVAD clinical trial database. Methods: A retrospective analysis was performed of 896 patients enrolled into the HeartMate II Clinical trials for bridge-to-transplant and destination therapy from March 2005 to January 2009. The patients were divided into 4 groups: underweight (body mass index [BMI] <18.5 [kg/m²]); normal (BMI 18.5 to 29.9); obese (BMI 30 to 34.9); and extremely obese (BMI≥35). Baseline BMI was compared with BMI at 6 months and 24 months after implant. BMI change >10% of baseline was considered clinically significant. Results: At 6 months, underweight and normal-weight patients had significant increases in BMI, with effects sustained up to 24 months (p < 0.01). Underweight patients gained weight most often, with 75% showing clinically meaningful weight gain at 24 months. Obese and extremely obese patients, in contrast, did not experience weight change over the same period. Pre-albumin levels improved from baseline to 6 months in all patients. Conclusions: Underweight and normal-weight patients had an increase in BMI after LVAD implantation, and these changes persisted through 24 months. The BMIs of obese and extremely obese patients remained unchanged. Nutritional status improved in all groups.