Abstract 21156: Abo Status and Stroke Free Survival in Lvad Patients

Abstract

Introduction: Left Ventricular Assist Devices (LVAD) improve survival in selected patients. Complications include thromboembolism and bleeding. Alterations in von Willebrand factor (vWF) multimers may play a role, especially with continuous flow LVADs. AbO antigens are expressed on vWF where these antigens influence its processing into subunits. There are reports of higher bleeding rates in O patients and higher thrombosis rates in non-O patients. Hypothesis: ABO status is routinely determined prior to LVAD implantation and we correlated ABO status with outcomes. It may allow adjustment of anticoagulation to minimize adverse events. Methods: We studied adults with first implant of continuous axial LVAD entered into the Interagency Registry for Mechanically Assisted Circulatory Support (INTERMACS). The implant operations occurred between the second quarters of 2012-2016. A total pf 6,462 patients were studied. A Cox proportional hazards model was analyzed using gender, age category, BMI, white race and blood type to predict the hazard rate of stroke or death after implant. Follow up was from time of implant until death, transplant, exchange, recovery, stroke or end of data set. Results: Increases in the hazard rate was seen in females (HR 1,26, 95% CI: 1.13-1.41; p<0.0001); age >50 (HR 1.62; 95% CI 1.42- 1.84; p<0.0001), and white race (HR 1.18; 95% CI: 1.06-1.31; p=0.002). Blood group O decreased the hazard rate compared to patients with non-O blood group (HR 0.92; 95% CI: 0.83-1.00; p=0.06). Conclusions: O blood group was associated with improved stroke free survival in multivariate analysis including gender, age category, BMI and race. This effect could be due to the lower levels of vWF in O blood group patients. Further work is being done to assess the effect of ABO blood group status on other thromboembolic events as well as bleeding outcomes. The impact of antiplatelet agents and anticoagulants on these outcomes will also need to be evaluated.