P59: Treatment of Impella 5.5 Purge Dysfunction with Tissue Plasminogen Activator Prevents Subsequent Pump Exchanges

Background: The Impella 5.5 is a temporary, percutaneous left ventricular assist device (VAD) that contains a purge system to prevent blood from entering the motor housing. Acute pump failure can occur if purge flow is significantly disrupted and can be predicted by changes in purge pressure or flow rate. The use of alteplase (tPA) in a temporary purge solution is one intervention used to salvage pumps at risk of failure. We share our center’s experience using tPA to treat purge dysfunction in the Impella 5.5 population. Methods: We retrospectively reviewed all Impella 5.5 patients implanted at a single academic center from November 2020 to January 2023 (n=90). Cases were identified by tPA use in the purge system and purge dysfunction was verified by EMR documentation of a notable change in purge pressure or flow rate. Results: tPA was used to treat purge system dysfunction in 10 patients (11.1%) supported for an average of 25 days (Table 1). Nine patients (90%) had dextrose and sodium bicarbonate purge solution with systemic bivalirudin anticoagulation, and one patient had dextrose and heparin purge solution with systemic heparin anticoagulation. On average, purge dysfunction requiring tPA use occurred on post-operative day 13 and required 10 ± 9 mg of tPA in solution. Nine patients (90%) had successful restoration of baseline purge pressure and flow following tPA administration, while the other patient was transitioned to comfort measures shortly after and success could not be determined. No patients required a pump exchange for continued purge dysfunction. Of those treated with tPA, 6 patients (55%) survived to discharge. Other than an incidental finding in one patient questionable for subarachnoid hemorrhage that not impacting clinical care, there were no other major bleeding events or strokes within 48 hours of tPA administration. Conclusion: In cases of identified purge dysfunction prior to pump failure, tPA is an effective intervention for resolution and return to baseline purge function in the Impella 5.5 device preventing the need for surgical pump exchange.