Impact of body mass index on adverse events after implantation of left ventricular assist devices: An IMACS registry analysis

Background: Limited data exist describing impact of body mass index (BMI) on post‒left ventricular assist device (post-LVAD) outcomes. We sought to define the relationship between body mass index (BMI) and adverse events (AEs) after LVAD implantation by examining the ISHLT Mechanically Assisted Circulatory Support (IMACS) registry.

Methods: Patients implanted with a contemporary continuous flow (CF)-LVAD were stratified into 4 groups using pre-operative BMI: underweight (UW; BMI ≤18.5 kg/m²); non-obese (NO; BMI >18.5 to <30 kg/m²); obese (OB; BMI ≥30 to <40 kg/m²); and morbidly obese (MO; BMI ≥40 kg/m²). Freedom from AEs was evaluated using the Kaplan-Meier method and risk factors for development of first AE were identified using multiphase parametric hazard modeling. AEs included infection, thromboembolic events, bleeding, device malfunction, and neurologic dysfunction.

Results: Between 2013 and 2015, a total of 9,408 patients underwent implantation of a CF-LVAD, which consisted of 368 (4%) UW, 5,719 (61%) NO, 2,770 (29%) OB, and 444 (5%) MO patients. Survival among the 4 BMI cohorts was similar at 2years (70.8% to 75.8%, p = 0.24). MO patients were less likely to be free from a non‒VAD-related infection (p < 0.0001) or device-related infection (p = 0.0014) at 2years (50.3%, 70.7%) when compared with OB (58.3%, 78.7%), NO (65.2%, 81.4%), and UW (68.9%, 77.4%) patients. UW (81.5%) and NO (81.3%) patients were more likely to be free from device malfunction at 2years when compared with OB (78.3%) and MO (72.6%) (p = 0.0006). Thromboembolic events were rare and more common in the UW cohort (p = 0.026).

Conclusions: Although BMI was not correlated with 2-year mortality, an increased rate of infectious and device-related AEs was noted in OB and MO LVAD patients. In a group with few options for transplant, the event morbidity in obese patients can be expected to impact morbidity with longer support durations.