Rate of Thrombotic Events in the Setting of Holding Systemic Anticoagulation Therapy during Impella Support

Abstract

Anticoagulated purge solution and systemic anticoagulation are recommended during use of the Impella mechanical circulatory support device to maintain patency, pump function, and prevent thrombosis. Limited data support the use of anticoagulants other than heparin. We performed a retrospective evaluation of the incidence of thrombotic events and pump failure in patients treated with systemic heparin and bivalirudin between June 2015 to March 2019. We also assessed for an association between these events with interruption of systemic anticoagulation. Patients were included if they received ventricular support with an Impella device and were on systemic therapeutic anticoagulation for longer than 24 hours. Of 101 patients, 69 were eligible for analysis. All patients received heparin during therapy; 5 patients were transitioned to bivalirudin for suspected HIT. Overall, the median PTT for patients on systemic heparin was 66.5 seconds [IQR 56.85-80.95], and the median PTT was 73.6 seconds [60.7-82.9] for patients on systemic bivalirudin. There were 19 thrombotic events in 69 patients (27.5%); 15 events occurred in patients while on systemic heparin (10 limb thromboses, 3 systemic emboli, 1 device thromboses, and 1 intracardiac thrombus) compared to 2 events in the bivalirudin group (2 device thromboses). Forty patients (58%) had systemic anticoagulation held, of which 10 (25%) had a thrombotic event or device failure. No bivalirudin patients with events had their anticoagulation held. In those who did not have an event, anticoagulation was held for an average of 12 hours +/- 23h, compared to 14 +/- 19h in those on heparin who had an event. For those with an event, the median PTT in the heparin group was 65.1 [54.9-87.5] compared to a median PTT in the combined group of 75.2 [62.5-83.6] (p = 0.477). Therapeutic systemic anticoagulation in critically ill patients receiving Impella support is often held for extended duration of time because of bleeding or need for additional procedures. Holding systemic anticoagulation for an extended period may increase the risk of thrombotic events, particularly limb thrombosis.