Reduced prevalence of arterial thrombosis in von Willebrand disease

Background: High von Willebrand factor (VWF) levels are an established risk factor for arterial thrombosis, including coronary heart disease and ischemic stroke. It has been hypothesized that von Willebrand disease (VWD) patients are protected against arterial thrombosis; however, this has never been confirmed in clinical studies. Objectives: To investigate the prevalence of arterial thrombosis in VWD patients relative to the general population. Patients/Methods: We included 635 adult patients with VWF levels ≤ 30 U dL-1, aged 16-85 years, from the nationwide cross-sectional 'Willebrand in the Netherlands' (WiN) study and compared the prevalence of arterial thrombosis with two reference populations from the general Dutch population adjusted for age and sex as standardized morbidity ratios (SMRs). Results: Twenty-nine arterial thrombotic events occurred in 21 patients (3.3%). Five patients suffered an acute myocardial infarction and three an ischemic stroke. Unstable angina pectoris was recorded 12 times, transient ischemic attack nine. The prevalence of all arterial thrombotic events combined (acute myocardial infarction, ischemic stroke and coronary heart disease) was 39% and 63% lower than in the two reference populations. The prevalence of cardiovascular disease in VWD was lower than in the general population, SMR 0.60 (95% CI, 0.32-0.98) for coronary heart disease and SMR 0.40 (95% CI, 0.13-0.83) for acute myocardial infarction. For ischemic stroke the prevalence was 35-67% lower compared with two reference populations, SMR 0.65 (95% CI, 0.12-1.59) and 0.33 (95% CI, 0.06-0.80), respectively. Conclusions: This is the first study showing that VWD patients have a reduced prevalence of arterial thrombosis and provides important insights into the role of VWF in the pathogenesis of arterial thrombosis. © 2013 International Society on Thrombosis and Haemostasis.