Prophylaxis of venous thromboembolism in bariatric surgery.

Patients with morbid obesity who undergo bariatric surgery are usually considered at high risk of developing venous thromboembolism. Considering that deep vein thrombosis is often asymptomatic, primary prevention is the key to reducing morbidity and mortality. Between 1995 and 2003, 151 patients underwent surgery for morbid obesity at the Obesity Surgery Centre-University of Sassari. At the beginning of our experience in this field, in the first 65 cases, prophylaxis of thromboembolism consisted in a single intravenous injection of heparin sodium at the time of induction of anaesthesia. The dose of heparin ranged from 2500 to 5000 IU according to weight and any diseases associated with obesity. In a later stage of our experience (86 cases) we modified the drug therapy and used low doses of calcic heparin: the dose was obtained by daily monitoring of Pt, TT and aPTT in order to obtain good anticoagulation. This treatment was usually begun 4-5 days before the operation and continued until the patient was discharged (8-9 days). In the first group of patients we had 2 cases (3%) of fatal acute pulmonary embolism. In the second group 1 (1.16%) case of non-fatal pulmonary embolism developed on postoperative day 20. No clear consensus emerges from the literature as to the best approach to reduce the risk of thromboembolism in bariatric surgery to a minimum. Our experience suggests that "personalized heparin prophylaxis" before, during and after bariatric surgery could be the key to reducing morbidity and mortality.