P1645: impact of von willebrand factor and adamts13 on cardiovascular complications and bleeding in patients with non-valvular atrial fibrillation and normal sinus rhythm controls: 10 years follow up.

Topic: 34. Thrombosis and vascular biology - Biology & Translational Research Background: Increasing Von Willebrand factor (VWF) correlates with the development of left atrial blood stasis in non-valvular atrial fibrillation (NVAF). However, the long-term impact of elevated VWF relative to ADAMTS13 activity level, its key regulator, is not well established in patients NVAF. Aims: To assess the long-term impact of VWF and ADAMTS13 activity levels on clinical outcomes of patients with NVAF and normal sinus rhythm controls. Methods: Baseline VWF antigen, VWF activity, ADAMTS13 activity, and echocardiographic measures were obtained for all subjects. Adverse cardiovascular events, major bleeding, clinically relevant non-major bleeding (CRNMB), and all-cause mortality were assessed by clinical follow-up, questionnaire, or telephone communication. Results: During 10 years of follow-up, there were 7 strokes, 2 TIA, 10 other thromboembolic events and 96 deaths in NVAF group compared to 2 TIA events, 4 systemic emboli and 30 deaths in NSR control group. In general, there were more adverse cardiovascular events in NVAF compared to NSR groups (p=0.022, see Figure). Major bleeding and CRNMB happened in 21 and 45 in NVAF and 1 and 12 in NSR patients. VWF antigen concentration and activity were an independent predictor of all-cause mortality (HR: 1.011, 95%CI: 1.008, 1.014, p<0.0001, and HR 1.010 (95%Cl:1.007,1.013, p<0.001) while lower activity of ADAMTS13 was associated with better survival ((HR 0.992, 95%CI 0.987, 0.996, P=0.0004). Presence of left atrial appendage thrombus, spontaneous echo contrast, low left atrial appendage emptying velocity, and increased left atrium volume index were not associated with adverse cardiovascular events or bleeding in NVAF patients. Summary/Conclusion: Higher level of VWF at baseline predicted a higher risk of death while lower activity of its key regulator ADAMTS13, was associated with better survival in NVAF and NSR patients.Keywords: ADAMTS13, Thromboembolism, von Willebrand factor (vWF), Bleeding