ABO Blood Group and Bleeding Post-LVAD

Abstract

Purpose: Retrospective studies show that high dose aspirin (ASA) during Heart Mate (HM) II support is associated with more hemorrhagic events; however, limited prospective data exist on the impact of switching to reduced antiplatelet therapy. Methods: We implemented a clinical protocol to place all patients with HM II implantation (n= 26) from November 2014 to September 2015 on low dose aspirin (ASA) 81 mg daily. Concomitant anticoagulation with warfarin (target INR: 2-2.5) was maintained. Adverse events (AEs) were compared to a historical cohort of HM II patients (n= 69) on high dose ASA 325 mg daily and warfarin therapy (target INR: 2-3). Excluding perioperative events, initial hemorrhagic (gastrointestinal, intracranial, epistaxis), thrombotic (ischemic stroke, surgically confirmed pump thrombosis) and hemolysis (LDH > 2.5x upper limit of normal) events were retrieved up to 100 days after implantation. GI bleeding was defined by requiring a blood transfusion and a drop in hemoglobin of > 2g/dL. Survival free from AEs was calculated by Kaplan-Meier curves. Results: Patients in both groups had similar distributions of major demographics including age, gender and history of hypertension. The actual INR was similar across groups throughout HM II support. Hemorrhagic events occurred in only 3 patients on ASA 81 mg daily (12%, 0.17 events/100d) in comparison to 30 patients on ASA 325 (43%, 0.64 events/100d, p= 0.02, figure 1). Thrombotic events occurred in 2 patients on ASA 81 mg (8%, 0.1 events/100d) and in 4 patients on ASA 325 mg (6%; 0.07 events/100d, p= 0.70). Hemolysis occurred in 2 patients on ASA 81 daily (8%, 0.1 events/100d) and in 4 patients on ASA 325 mg daily (6%; 0.07 events/100d, p= 0.75). Conclusion: Low dose ASA in HM II patients treated concomitantly with warfarin is associated with a reduced risk of bleeding without increased thrombotic and hemolysis events.

ABO Blood Group and Bleeding and Survival in VA-ECMO Patients

“…3 More recently, the relationship between ABO blood group and influence on COVID-19 susceptibility and outcomes has piqued the interest of the scientific community, with observational studies concluding that the odds for COVID-19 infection were significantly increased for blood group A and decreased for blood group O, 17,18 reinforcing the idea that ABO phenotypes may affect a multitude of physiologic processes including innate immunity. In the cardiac surgical setting, the relationship between blood group and bleeding has been studied in several different populations, with conflicting results-several smallscale studies of LVAD patients have failed to demonstrate a difference in bleeding rates between O and non-O groups, [19][20][21] whereas Welsby et al found that in CABG patients, O blood group did not have increased blood loss and instead required fewer RBC transfusions intraoperatively compared to their non-O peers. 5 On the other hand, Mazzeffi et al reviewed 111 patients consisting of both VV-ECMO and VA-ECMO and found that group O had a higher rate of massive transfusions (defined as ≥40 RBC units) compared to non-O blood groups and more RBC transfusions after controlling for confounders, although the proportion of patients with bleeding events did not differ with regard to blood type.…”