Effect of body mass index and device type on infection in left ventricular assist device support beyond 30 days

Infection as a complication of long-term left ventricular assist device (LVAD) support leads to significant morbidity and mortality. Obesity, a possible risk factor for other postoperative cardiovascular surgical site infections, is an increasingly prevalent condition among recipients of LVAD devices. We retrospectively analyzed 145 LVADs that remained in place beyond 30 days over a nine-year period at a single medical institution. Statistical analysis was carried out using univariate and multivariable logistic regression and chi(2)-testing where indicated. Body mass index (BMI) had no effect on the incidence of infectious outcomes regardless of age, gender, underlying pathogen or device type. This included the morbidly obese population as well (BMI >or=40). Independent of BMI, device type did have an effect, with the HeartMate XVE increasing the risk for infections [odds ratio (OR) 4.3 with 95% confidence interval (CI) 2.1-8.8, P=0.0001] and the HeartMate II reducing the risk (OR 0.21 with 95% CI 0.09-0.50, P=0.0001). The risk for infection after LVAD placement for long-term support is likely to be a multi-factorial phenomenon. BMI, including morbid obesity, does not appear to be a statistically significant relevant factor in determining that risk. Device type may have an effect, however, on risk of infection in long-term support.