Loss of von Willebrand factor large multimers is rather constant after 1 month of LVAD implantation

概要

Objectives
Left ventricular assist device (LVAD) has been widely used for patients with advanced heart failure. One of major complications in LVAD patients is bleeding, most frequently in the gastrointestinal (GI) tract. Excessive degradation of von Willebrand factor (vWF) large multimer, known as acquired von Willebrand Syndrome (AvWS), is considered as a major substrate condition for bleeding. Although GI bleeding develops constantly even after several years of LVAD implantation, it remains unclear whether severity of AvWS is elevated or decreased over time. Thus, this study sought to evaluate the long-term time dependent change of severity of AvWS after LVAD implantation.

Methods
A multi-center prospective observational study has been conducted in Japan, where patients who underwent LVADs implantation were enrolled preoperatively. In the study, we have analyzed patients enrolled between 31st, July 2017 and 7th, January 2020. Blood was analyzed preoperatively, and at 1 week, 1 month, 3 months, 6 months, 12monthns, 18 months and 24 months postoperatively.

Results
A total of 115 patients with LVAD implantation during the study period were analyzed in this study. Among them, HeartMate II, Jarvik 2000, EVAHEART 2, HVAD and HeartMate 3 were implanted in 64, 10, 10, 16 and 15 patients, respectively. EVAHEART 2 and HeartMate 3 implantation hardly induced loss of vWF large multimers throughout the follow-up period. HeartMate II and Jarvik 2000 implantation significantly reduced them at 1 week (81.7±41.1% vs 51.2±14.1%, 67.7±40.7% vs 32.1±19.5%, p value<0.01), HVAD implantation significantly reduced them at 1 month (74.3±38.8% vs 39.5±15.2% and became rather stable at lower levels after 1 month (24.2%, 42.4%,33.2% respectively). All indices among 5 group were stable 1 month after LVAD implantation.

Conclusions:
In this multi-center prospective observational study, vWF large multimer index were rather stable at 1 months after LVAD implantation till 2 years, revealing that the severity of AvWS was remained relatively unchanged for 2 years. The cut-off of vWF large multimer index on GI bleeding is 38.6% (sensitivity 81.8%, specificity 49.5%).