Prevention of venous thromboembolism: focus on mechanical prophylaxis.

Venous thromboembolism (VTE), including deep vein thrombosis and pulmonary embolism, is a leading health-care problem whose pathogenesis is usually related to the so-called Virchow's triad and involves a variety of factors classified as inherited or acquired, predisposing, or triggers. The main goal of thromboprophylaxis is to reduce mortality and morbidity associated with VTE risk factors. Although striking evidence now indicates that the various pharmacological anticoagulant therapies can substantially lower the risk, this benefit might be offset by a small but definite risk of hemorrhage in some circumstances. Mechanical prophylaxis methods have been suggested because they counteract most of the components of the Virchow's triad and are not associated with any bleeding risk. Although early and frequent ambulation has been historically advised for preventing VTE, this measure is inadequate per se and frequently not feasible as the sole means of mechanical thromboprophylaxis. Accordingly, additional measures are being used in clinical practice, including graded compression stockings, intermittent pneumatic compression devices, and venous foot pumps. Although the efficiency of these measures has been extensively assessed in several clinical studies, there remain unanswered questions, including their suboptimal use and the lack of unequivocal clinical evidence supporting real benefits for preventing VTE. Overall, mechanical compression methods can reduce the risk of VTE by nearly two thirds when used as the only form of thromboprophylaxis and by about half when combined with a pharmacological approach. The main mechanism of action appears to be related to a milking (wavelike) effect to evacuate leg veins and reduce venous stasis because an effect on the enhancement of fibrinolysis remains unproven. Although the biological and clinical evidence suggests that graduate compression stockings are an effective, relatively cheap, and more comfortable thromboprophylactic measure, they appear less effective overall than intermittent pneumatic compression. In conclusion, although the preventive benefits of mechanical prophylaxis on VTE might be circumscribed to select medical and surgical settings, there appears to exist no clinical reason to discourage adoption of these measures when indicated. © Thieme Medical Publishers.