Anticoagulation Use and Outcomes Among Patients with Atrial Fibrillation and Von Willebrand Disease

Intro: Von Willebrand disease (VWD) is a coagulopathy caused by deficiency or dysfunction of von Willebrand factor (VWF), resulting in prolonged and excessive bleeding. Patients are advised to avoid aspirin (ASA), P2Y12 inhibitors, or anticoagulation (AC) so as not to exacerbate this condition. However, typical treatment for atrial fibrillation (AF) includes anticoagulation, particularly if the risk of stroke by CHA 2DS 2-VASC score is 2+. Current recommendations suggest giving necessary antiplatelet (AP) or AC therapy over no treatment with assessment of bleeding risk throughout the course. However, this is a conditional recommendation based on low certainty in evidence, and there are no specific guidelines on treating AF in patients with VWD. This study aims to assess anticoagulation use, bleeding risk, and stroke risk in patients with VWF and AF. Methods: We conducted an IRB-approved analysis of coded data from institutional electronic medical records to select patients with diagnosis of VWD, low ristocetin cofactor level, or any abnormal VWF panel as well as patients with diagnosis of AF or atrial flutter. Three hundred and forty patients met criteria. Patients were manually screened for inclusion criteria and excluded for inaccurate diagnosis or insufficient data. Eighty-nine patients were included in the analysis. Primary endpoint was rate of major bleeding defined by ISTH criteria while on AC or AP. Categorical data were tested using the Fisher exact test at the nominal 0.05 two-sided significance level, and all person-time comparisons are made against the rate of bleeding on AC alone. Results: Most patients were female (64.0%; 57/89), and 28.1% (25/89) were deceased at the time of data collection. Date of diagnosis of AF ranged from 1980-2020. 42.7% (38/89) of patients were ever prescribed ASA, 43.8% (39/89) a P2Y12 inhibitor, 56.2% (50/89) AC, and 23.6% (21/89) had never been prescribed AP or AC. Of patients with a CHA 2DS 2-VASC of 2+, 57.5% (46/80) were ever prescribed AC. 32.0% (16/50) of patients ever prescribed AC and 25.6% (10/39) patients never prescribed AC had at least one major bleeding event (p=0.428). The rate of major bleeding on AC alone was 8.9 events per 100 person-years (32 events/359.2 years), 10.2 events per 100 person-years on AP alone (41 events/402.3 years) (p=0.572), and 1.06 events per 100 person-years (8 events/757.47 years) in patients never prescribed AC or AP (p=