Abstract 12777: The Lingering Snag in Era of Mechanical Pumps: A Case of Acute Pump Thrombosis Immediately After Heartmate 3 Implantation

Abstract

Background: Pump thrombosis (PT) remains a dreaded complication of left ventricle assist device (LVAD) implantation. PT immediately after HeartMate 3 (HM3) implantation is rare but should be kelp in mind if early low flow alarms are noted. Case: A 57-year-old male with ischemic cardiomyopathy, Stage D heart failure (LVEF ~20%), INTERMACS category 3 on 5mcg/kg/min Dobutamine drip underwent advanced heart failure therapy evaluation and was deemed suitable candidate for LVAD implant. His ECHO showed LVIDD 6.04 cm and LV Diastolic Volume Index 122 mL. He underwent HM3 implantation via left anterior thoracotomy and upper-hemi sternotomy on 5/24/2022. Surgery was successful and the patient was taken off bypass. Pre-implant some LV trabeculations and debris were removed. However, less than 1 hour from being off bypass, the low flow alarms began which did not resolve after volume and blood pressure optimization. No RV failure was noted on TEE. Decision was made to re-open the sternum. Upon exploration, no compression of the outflow graft was noted, and inlet cannula was not mispositioned. Inspection of LVAD inlet and outlet cannula showed significant amount of white thrombus (Figure 1) and device was ultimately exchanged. Thrombus was confirmed on histopathological analysis. Post-operatively no low flow alarms were noted after pump exchange. Factor V Leiden screen and protein C activity were normal and Antithrombin 3 was falsely low (due to recent thrombus) on post-op day 1. Discussion: This is the second case of HM 3 device thrombosis within 1 hour of implant in the literature. Most of the earlier reported cases were on post-Op Day 3. The etiology of PT is unknown and further investigation is required to elucidate the same. This case will create awareness among physicians to keep PT in differentials when low flow alarms are encountered immediately post-op despite volume and BP optimization.