Prosthetic valve thrombosis on venoarterial extracorporeal membrane oxygenation support: Risk factors and outcomes

IntroductionIn patients with prior valve replacement requiring venoarterial extracorporeal membrane oxygenation (VA ECMO), there is a risk of prosthetic valve thrombosis (PVT) due to intracardiac stasis. We describe our experience with PVT in patients on VA ECMO.MethodsThis was a retrospective cohort study of patients with prior valve replacement undergoing VA ECMO. Patients who developed PVT on VA ECMO were compared to those who did not.ResultsForty-six patients who had prior valve replacement (total of 63 valves) were placed on VA ECMO. Six patients (13%) suffered PVT on VA ECMO. There was no difference in the rate of PVT in mitral versus aortic valve prostheses (22% [5/23] vs 3% [1/32]; p = .07) or between tissue and mechanical valves (16% [8/50] vs 0% [0/13]; p = .19). There were no differences in ECMO parameters, including site of cannulation (central vs peripheral), initial ECMO flow, time to initiation of anticoagulation, or use of a concomitant IABP between patients who did and did not develop PVT. Patients who developed PVT demonstrated significantly lower pulse pressures compared to those who did not (12.7 mmHg vs 32.7 mmHg; p = .03). Surgical thrombectomy was performed in three of the six patients with PVT and one survived to discharge.ConclusionPVT occurred in 13% of patients on VA ECMO after prior valve replacement. The only predictor of PVT on VA ECMO was a lower pulse pressure. Strategies to maintain intracardiac flow and pulsatility may reduce this risk. Treatment options are limited and pose significant risk, and therefore prevention is key.