Von Willebrand Factor and ADAMTS13 as Predictors of Adverse Outcomes in Patients With Nonvalvular Atrial Fibrillation

Von Willebrand factor (VWF) elevation correlates with the left atrial blood stasis in nonvalvular atrial fibrillation (NVAF). However, the long-term impact of elevated VWF in patients with NVAF is not well established.

To assess the impact of VWF and a disintegrin and metalloproteinase with a thrombospondin type 1 motif, member 13 (ADAMTS13) in conjunction with echocardiographic measures of left atrium blood stasis on clinical outcomes, 414 NVAF prospectively recruited (October 4, 2007, to April 27, 2009) patients were followed for 3 years. VWF antigen, VWF activity, ADAMTS13 activity, and echocardiographic findings were assessed at baseline. Thromboembolism (TE) (stroke/transient ischemic attack (TIA)), myocardial infarction, or TE of other locations), major bleeding, clinically relevant nonmajor bleeding, and all-cause mortality were assessed by clinical follow-up, questionnaire, or telephone communication.

Among 374 patients (mean age, 63.4 ± 12.7 years; 25% females) who had complete follow-up data, there were 33 TE in 32 patients (8.6%), 18 deaths (5.1%), and 33 bleeding events (21 major bleeding and 12 clinically relevant nonmajor bleeding) in 25 patients (6.7%). VWF antigen was predictive of TE in the univariate examination (hazard ratio [HR]: 1.007, 95% confidence interval [CI]: 1.002, 1.013, P = 0.011) but not in multivariate analysis. VWF was an independent predictor of all-cause mortality (HR: 1.011, 95% CI: 1.003, 1.020, P = 0.011) and a composite of TE and all-cause mortality (HR: 1.006, 95% CI: 1.001, 1.012, P = 0.039) in multivariate analysis. ADAMTS13 was not predictive of clinical outcomes in multivariate analysis.

Among patients with NVAF, VWF is an independent predictor of poor outcomes including death and a composite of death and TE. As such, VWF measure may help identify high-risk patients and provide further stratification beyond CHA₂DS₂-VASc assessment.