Body mass index and outcome after ventricular assist device placement

The implantation of ventricular assist devices (VAD) is an established treatment for end-stage congestive heart failure. Extremes of body mass index (BMI) are associated with decreased survival after cardiac surgery. Many patients with congestive heart failure develop cardiac cachexia. In this study the association between BMI and outcomes after VAD implantation was investigated.

Consecutive patients (n = 590) who underwent VAD placement between 1996 and 2006 were divided into five groups based on BMI (kg/m2) quintiles (<20; 20-24; 25-29; 30-35; and >35). In a multivariate analysis adjusted for age, sex, diagnosis, emergency level, and type of device (left ventricular or biventricular assist device), procedural success (recovery, transplantation, or 30-day survival) and complications were analyzed. The best group was set as reference category for calculation of odds ratios.

The groups with both extremes of BMI had the worst outcomes. The best procedural success was in the group with BMI 25 to 29 kg/m2. Underweight patients had similar survival rates to patients with normal weight. Overweight and obese patients did not have decreased survival. Extreme obesity at the time of VAD implantation showed elevated risk for postoperative death. There was no significant difference for BMI groups in the type of complications and cause of death. Cumulative survival curves for BMI category and overall VAD patient survival showed no significant differences.

Cardiac cachexia need not be an exclusion criterion for VAD placement. Underweight patients appear to have benefit from mechanical support. Severely obese patients should be carefully selected before VAD placement.