Risk factors for thromboembolic events in pediatric patients with ventricular assist devices

Pediatric patients on ventricular assist devices (VAD) are at risk of thromboembolic (TE) complications. Our objective was to identify factors associated with TE events, including the role of initial anticoagulation strategy and device type in the pediatric VAD population.

This was a retrospective, single-center review (2005-2022) of children who were implanted with paracorporeal pulsatile (PP), paracorporeal continuous (PC), or a combination of devices. Patient- and device-related factors were collected. Kaplan-Meier survival analysis was performed to determine freedom from TE. Cox proportional hazard analysis was conducted to look for factors associated with TE events.

Ninety-five patients included with a median age of 0.9 years (interquartile range, 0.3, 5.4); median weight of 8.4 kg (interquartile range, 4.5, 17.8), and 63.2% with noncongenital heart disease. Device breakdown included 47.4% PC, 24.2% PP, and 23.2% combination of devices. Initial anticoagulation was either heparin (61.5%) or bivalirudin (38.5%). In Kaplan-Meier analysis, unadjusted freedom from a TE event was significantly greater in those who received bivalirudin as their initial anticoagulation strategy (P = .02) and PP VADs (P = .02). In multivariate analysis, initial anticoagulation strategy with bivalirudin (hazard ratio, 0.30; 95% confidence interval, 0.12-0.75, P = .01) was associated with a reduced hazard of TE events, whereas PC device strategy was found to be associated with an increased hazard (hazard ratio, 2.78; 95% confidence interval, 1.12-6.88, P = .03).

This study suggests that PC device strategy and heparin as an initial anticoagulation strategy are associated with increased hazard of TE events. Further research is required to understand the interaction between device type and initial anticoagulation strategy.