Heparin-Induced Thrombocytopenia and Thrombosis with Axillary Impella 5.5 as Bridge-to-Transplant

Introduction A patient presenting with biventricular failure was managed with Impella 5.5 as BTT. His course was complicated by HITT causing device failure, and he successfully underwent heart transplant (HTx) after plasmapheresis. Case Report A 44-year-old man with DM, HTN, and HLD was transferred to our center in cardiogenic shock. Coronary angiography revealed slow flow without obstruction. TTE showed biventricular dysfunction with LVEF 10%. Impella CP was placed, and on transfer the device was exchanged for a surgically placed axillary Impella 5.5. Filling pressures and RV function improved with diuresis. Platelets decreased from 230 (1000/uL) to 96 by hospital day 10, and a PF4 antibody was sent (Fig 1A). The next day, Impella purge pressure doubled and purge flow decreased, concerning for device thrombosis. The PF4 antibody returned positive, suggesting HITT. Heparin was stopped and argatroban administered systemically and through the purge. Pump power and hemodynamics were maintained. While awaiting results of a serotonin release assay, a suitable donor was identified. The risks and benefits of HTx included risk of cardiopulmonary bypass with heparin-PF4 antibodies, risk of Impella exchange, and risk of imminent device failure and stroke. Preliminary SRA was positive. The patient underwent two sessions of plasmapheresis and was transplanted on day 13. In the OR, there was extensive thrombus encasing the device (B). The driveline was transected proximally, and the distal catheter was removed with the native heart to decrease risk of embolization. After HTx, the patient was placed on argatroban and transitioned to apixaban. Summary We describe using Impella 5.5 as BTT in severe biventricular failure, where RV function improved with LV unloading. The case is notable for TCS failure due to HITT despite only modest thrombocytopenia (nadir 86,000), and for proceeding with HTx after plasmapheresis rather than Impella exchange. The patient was anticoagulated for a month post-HTx and is doing well.