The biological basis of thrombosis and bleeding in patients with ventricular assist devices.

The clinical success of left ventricular assist devices (LVADs) has been tempered by significant hemorrhagic and thromboembolic complications. In the case of LVADs, where the biomaterial is in direct contact with the blood circulation, significant changes in systemic immunologic and thrombostatic functions have been well documented. Although further investigation is warranted, significant advances have been made in both cellular biology and LVAD technology to better understand the delicate balance between the procoagulant milieu predisposing to thrombosis and the risks of both surgical and non-surgical bleeding.