VWF and thyrotoxicosis: The seminal meta-analysis by Stuijver et al. evaluated the effects of thyroid hormones on the coagulation and fibrinolytic system, and showed that thyrotoxicosis shifts the hemostatic balance towards a hypercoagulable and hypofibrinolytic state with a rise in factors VIII (FVIII) and IX (FIX), fibrinogen, von Willebrand factor (vWF), and plasminogen activator inhibitor-1 (PAI-1), as shown in Figure 3.