Vitamin K reduces bleeding in left ventricular assist device recipients

Background: Despite advances in left ventricular assist device (LVAD) design that permit support without anticoagulation, LVAD recipients often suffer profound bleeding complications. This bleeding diathesis maybe attributable to pre-operative right-ventricular failure with concomitant hepatic dysfunction. The purpose of this study was to characterize coagulation abnormalities in LVAD recipients and determine the impact of pre-operative vitamin K administration on the incidence of postoperative bleeding. Methods: Hemostatic and liver function profiles were obtained in 66 recipients of the Heart-mate LVAD; 39 of these patients received perioperative vitamin K. Results: During LVAD support, hepatic synthetic function improved as evidenced by increases in clotting factors II, V, VII, XI. There was ongoing fibrinolysis with elevation of fibrinopeptide A and D-dimers and diminution of fibrinogen; however, plasminogen levels did not decline suggesting that systemic disseminated intravascular coagulation (DIC) did not occur. Bleeding requiring re-exploration more than 48 hours postimplantation occurred in 9 of 66 patients (13.6%). Prior to implantation, patients that bled had decreased levels of factor II (52.2 +/- 27.1% vs 69.7 +/- 26.6%; p = 0.048) and prolonged prothrombin times (16.5 +/- 2.4 seconds vs 13.8 +/- 3.1 seconds; p = 0.005) compared to patients that did not bleed. Seven of 27 patients (25.9%) not treated with vitamin K bled, while only 2 of 39 (5.1%) patients treated with vitamin K required re-exploration for bleeding (p = 0.026). Conclusions: We conclude that: (1) Liver synthetic function improves during LVAD support resulting in Increased levels of circulating coagulation factors; (2) ongoing fibrinolysis occurs but likely only represents remodeling of fibrin on the LVAD surface; (3) perioperative vitamin K reduces nonsurgical bleeding in LVAD recipients.