Thrombosis in patients with hemorrhagic disorders

Venous thromboembolism is common in the general population with increasing age as one of the most important risk factors. The care of hemophilia and von Willebrand disease has improved in recent decades, resulting in the expectation of a growing population of aging people with these disorders. Thrombosis seems rare in hemorrhagic disorders but studies documenting the true epidemiology are virtually lacking. Events have been reported, however, primarily catheter-related thrombophlebitis in hemophilia, but also deep vein thrombosis and pulmonary embolism have been described in von Willebrand disease, usually in conjunction with major surgery and prolonged replacement therapy with high factor levels. Thromboprophylaxis is likely not warranted in most cases. Instead, well-designed therapy and careful monitoring are important measures to prevent risk. In von Willebrand disease particularly, the variation of the phenotype and products used for replacement are challenges, as infusion of von Willebrand factor will increase the endogenous level of factor VIII. Long-term replacement therapy into old age is becoming more common in hemophilia but will not increase occurrence of thromboembolic disease, as factor levels still will be low and have a preventive effect.