Randomized, controlled trial of low molecular weight heparin vs. no deep vein thrombosis prophylaxis for major colon and rectal surgery in Asian patients

PURPOSE: Routine deep venous thrombosis prophylaxis is controversial in Asian patients, because deep venous thrombosis incidence was considered negligible. Because of recent reports of significantly higher incidences, a randomized, controlled trial was conducted to assess the effectiveness and complications of enoxaparin prophylaxis (low molecular weight heparins) in major colorectal surgery. METHODS: Three hundred twenty consecutive patients were randomly assigned to control or low molecular weight heparins groups. Patients in the low molecular weight heparins group were given perioperative enoxaparin starting 12 hours before surgery. The surgeon (blinded) assessed for difficulties related to possible enoxaparin. administration. Independent blinded observers performed daily clinical assessments and Doppler studies (at the 3rd and 5th postoperative day). Deep venous thrombosis was confirmed by duplex ultrasound, and pulmonary embolism was confirmed by lung scans or postmortem examinations. RESULTS: Deep venous thrombosis developed in 5 of 169 (3 percent) controls and 0 of 134 low molecular weight heparins patients (P = 0.045). Three of the deep venous thrombosis patients had pulmonary embolism, which was fatal in one patient. The surgeons were unable to perceive any increased surgical difficulties in the low molecular weight heparins group. The bleeding-related complications were significantly higher in the low molecular weight heparins patients (controls, n = 3 (1.8 percent); low molecular weight heparins, n = 9 (6.7 percent)). However, apart from one subdural hematoma and two abdominal hemorrhages needing re-exploration, which also occurred in one of the controls. these complications were minor bruises at the wounds, drains. or injection sites. CONCLUSION: Deep venous thrombosis prophylaxis is needed in Asian patients undergoing major colorectal surgery.