Extrinsic outflow graft flow obstruction in patients with HeartMate3 LVAD.

Blood flow obstruction at the level of the outflow graft is a rare but severe complication of LVAD support. We present a series of five patients supported with HeartMate3 LVAD (Abbott Labs, Chicago, IL) that developed an outflow graft obstruction after 607-1250 days of support, during prolonged antithrombotic therapy. Three patients presented with severe symptoms of heart failure, were treated with endovascular stenting and experienced full recovery. Preoperative computed tomography angiography and intraoperative angiography together with intravascular ultrasound provided diagnosis and guided treatment. In two patients, outflow obstruction was an occasional finding at imaging without heart failure symptoms and a "watchful waiting" approach was adopted: delayed treatment in one of them was futile. This late adverse event is peculiar for its pathophysiology and not yet discussed among the mechanical circulatory support community.