Mechanical thromboprophylaxis is effective in reducing postoperative venous thromboembolism.

Abstract

Venous thromboembolism (VTE) is a result of factors described by Virchow’s triad: venous stasis, hypercoagulability, and endothelial injury. Clinically manifested as pulmonary embolism (PE), deep vein thrombosis (DVT) or both, VTE is a major cause of postoperative morbidity and mortality, frequently occurring early after discharge from hospital. Venous stasis in surgical patients is multifactorial. Leg immobility during surgery under general or regional anaesthesia is usually followed by reduced mobility of variable magnitude and duration during the postoperative phase. Specific types of surgery such as bariatric surgery, or operations requiring high-pressure pneumoperitoneum, reverse Trendelenburg or lithotomy positions are likely to exaggerate venous stasis. During operative recovery, reduction in leg mobility may be the result of the waning effects of regional anaesthesia, pain (particularly when the procedure was performed on a leg), sedation for intubated patients or cognitive impairment, unilateral or bilateral leg oedema, or physician orders. Development of complications may also adversely affect patient mobility. Under-recognized causes of venous stasis include vein compression or infiltration by a pelvic tumour, and venous ligation because of injury during procedures such as excision of a pelvic tumour. Furthermore, operative venodilatation may cause endothelial injury to the leg veins.