F5 and obesity due to melanocortin 4 receptor deficiency: All 3 components of Virchow’s triad are disrupted with aging, due to progressive loss of venous structural integrity, endothelial dysfunction, changes in the microcirculation,32,33 and upregulation of procoagulant coagulation factors (FV, FVII, FVIII, and FIX), thrombin, the von Willebrand factor, and d-dimer.32,33 This disruption is further compounded by the development of acquired prothrombotic states, such as cancer, autoimmune disorders, obesity, diabetes, or sedentary lifestyles, and states of abnormal blood flow, such as valvular stenosis and atrial fibrillation.