Internal Versus External Compression of a Left Ventricular Assist Device Outflow Graft

Abstract

Obstruction within the circuit of a left ventricular assist device (LVAD) is a challenging situation for clinicians to definitively diagnose and manage. Available diagnostic tools are limited in their ability to visualize large portions within the device and cannulas, often leading to uncertainty as to whether redo surgery is required or if there are feasible medical or percutaneous alternatives. Here, we report a case of LVAD outflow graft obstruction, which by computed tomographic angiography (CTA) appeared to be intramural thrombus, but by intravascular ultrasound (IVUS) was shown to be compression external to the graft. A 62-year-old female with a continuous flow LVAD (HeartMate II Abbott, IL) 5 years prior presented to the emergency department with frequent low-flow alarms and syncope. The patient’s post-LVAD course had been complicated by outflow graft infection 1 year after initial implantation, necessitating an outflow graft replacement. She had also experienced multiple bleeding events for which her warfarin therapeutic goal was lowered. In the preceding year, her LVAD flows had steadily declined from 4.5 to 5.0 L/min to 2.7 to 2.8 L/min with an increasing frequency of low-flow alarms not responsive to the intravenous fluid administration or changes in LVAD …