Are Symptomatic Endpoints Acceptable in Venous Thromboprophylactic Studies?

Chemoprophylaxis with subcutaneous low-molecular-weight heparin has been shown to reduce deep vein thrombosis detected by surrogate endpoints such as fibrinogen scanning and venography. However, there have been few trials which have assessed clinical endpoints attributed to fatal and non-fatal pulmonary embolism following surgery. As these clinical endpoints are rare, large-scale trials using vascular mortality, vascular morbidity and the incidence of haemorrhage as clinical endpoints need to be performed to assess the efficacy of chemical thromboprophylaxis. The benefit of using clinical endpoints against the risk of haemorrhage should also be evaluated.