Left Ventricular Assist Device Outflow Graft Obstruction: A Complication Specific to Polytetrafluoroethylene Covering. A Word of Caution!

Pump thrombosis is an established complication of left ventricular assist devices (LVADs). Outflow graft obstruction has been previously described as one cause of LVAD thrombosis. We identified four cases of outflow graft obstruction that were attributed to a commonly applied polytetrafluoroethylene (PTFE) covering of the outflow graft. In this set of patients, the outflow graft was obstructed by a thrombus which formed between the outflow graft and its external PTFE covering, leading to impingement of the outflow graft. Patients typically presented after a median duration of 26 months (range 23-41 months) of support with gradual increase of heart failure symptoms and low pump flows. Computed tomography angiography was found to be the best diagnostic modality. Treatments included surgical LVAD replacement as well as percutaneous intraluminal stenting of the outflow graft. Our findings indicate that PTFE graft covering of the LVAD outflow graft can lead to graft occlusion and should be reconsidered as a potentially harmful modification to the approved device implant technique.