Left ventricular assist device outcomes based on flow configuration and pre-operative left ventricular dimension: An Interagency Registry for Mechanically Assisted Circulatory Support Analysis.

BACKGROUND: Axial configuration (AC) and centrifugal configuration (CC) left ventricular assist devices (LVAD) have different flow characteristics, and whether the interaction between device flow configuration and the pre-operative left ventricular internal diastolic diameter (LVIDD) mediates adverse events after LVAD implantation is unknown.

METHODS: We queried 9,424 continuous-flow LVAD recipients who received LVADs from April 2008 to June of 2015 in the Interagency Registry for Mechanically Assisted Circulatory Support (INTERMACS). The pre-operative LVIDD * flow configuration interaction term was tested in multivariable models to determine its relationship to adverse events.

RESULTS: The pre-operative LVIDD * flow configuration interaction was a significant predictor of device thrombosis. As the LVIDD increased, the risk of AC device thrombosis increased compared with CC devices (p = 0.0099). At 7.0 cm, the hazard ratio (HR) for AC device thrombosis compared with the CC device was 1.61 (95% confidence interval [CI], 1.17-2.22; p = 0.004) and continued to rise as the LVIDD increased. The LVIDD * flow configuration interaction did not predict stroke, gastrointestinal bleeding, or patient survival. In multivariable models, the hazard of stroke was higher with the CC device regardless of the LVIDD (HR, 1.96; 95% CI, 1.64-2.36; p < 0.0001). Adjusted analyses showed LVAD implantation into a larger left ventricle was associated with a lower risk of death (HR, 0.90; 95% CI, 0.85-0.95; p = 0.0004) per centimeter of LVIDD.

CONCLUSIONS: Our study suggests that the pre-operative LVIDD, flow configuration, and interaction terms should be considered individually when choosing the appropriate LVAD to mitigate the rates of device thrombosis, stroke, and death.