Dynamic LVAD Inflow Cannula Obstruction Due to Mobile Thrombi

Abstract

<h3>Introduction</h3> While LVAD outflow cannula obstructions are commonly described, we present a rare case of fulminant heart failure secondary to dynamic inflow cannula obstruction due to mobile thrombi within the left ventricular cavity. <h3>Case Report</h3> A 65 year old man with a history of ischemic cardiomyopathy and chronic kidney disease (CKD) underwent implantation of a continuous flow left ventricular assist device (LVAD; HeartWare™ HVAD™, Medtronic plc) as a bridge to transplantation. Three years following implantation, he presented with progressive fulminant right heart failure (RHF) followed by a sudden decrease in LVAD flow from 3.5 to 1.5 liters/min (Figure 1A). INR was 2.6, lactate dehydrogenase (LDH) level was normal and transthoracic echocardiogram showed a midline septum and the aortic valve opening with every beat. On admission, flows did not improve despite inotropic support. Outflow graft obstruction was suspected, however imaging was not pursued due to the risk of further renal injury with intravenous contrast, and that ultimately definitive treatment strategy remained heart transplantation. His UNOS listing status was upgraded from 4 to 2E. Anticoagulation was not escalated beyond aspirin and warfarin due to recurrent gastrointestinal bleeding. He continued to experience recurrent abrupt changes in LVAD flows (Figure 1B) without additional evidence to support pump thrombosis. Five weeks later, at the time of heart-kidney transplant, a partially obstructive thrombus within the inflow cannula as well as a mobile thrombus attached to the endocardium, prolapsing intermittently into the inflow cannula were visualized (Figure 1C-1D). <h3>Summary</h3> Dynamic inflow cannula obstruction should be suspected in the setting of heart failure and sudden changes in LVAD pump power consumption even when a lack corroborating imaging and laboratory evidence exists.