Enoxaparin for the prevention of post surgical pulmonary embolism

Objective To evaluate the efficacy and safety of the administration of enoxaparin,a low molecular weight heparin (LMWH),in the prevention of post surgical deep vein thrombosis (DVT) and pulmonary embolism (PE).Methods 1 928 patients hospitalized for general surgery were randomly divided into:(① test group (n=960) to receive enoxaparin (40 mg,s.c.,12 hours before and after surgery,then once daily for 7 consecutive days); ② control group (n=968) without intervention.The incidence of DVT,PE and bleeding were recorded for statistical analysis during hospitalization and a 2 months follow-up after discharge.Results ① No significant difference was found between the two groups in age,sex,average body mass index,type of surgery,and DVT/PE risk factors (obesity,varicose veins,and history of:venous thrombosis,chronic obstructive pulmonary disease,chronic heart failure,and hormone therapy).The percentage of non-malignant/malignant tumor surgery were 36.5％/63.5％ (average operation time 2.3 hours) in control group and 35.6％/64.4％ (2.2 hours) in test group (both P＞0.05).② During the hospitalization period,59 eases (incidence =6.1 ％) of DVT and 14 cases (incidence =1.4 ％ ) of PE (among them 6 were fetal,42.8％ of all PE cases) were found in the control group,while 28 cases of DVT (2.9％) and 3 cases (0.3％) of PE (1 fetal,33.3％ of all PE cases) were found in test group.The incidence of DVT,PE (total),and PE (fetal) were significant lower in test group (P＜ 0.05 or P＜ 0.01).During the follow-up,14 more cases of DVT (1.4％) and 1 more case (0.1％ ) of PE (a fetal) were found in the control group,and 2 more DVT cases (0.2％) in test group,with the DVT incidence in test group significantly lower (P＜0.01).(③ During the enoxaparin administration,30 cases (3.1 ％) minor bleeding and 8 cases (0.8％) major bleeding were found in the control group,while 33 cases (3.4％) minor bleeding events and 9 cases (0.9％) major bleeding events were found in the test group.The results in the two groups were not significantly different in either type of bleeding events (both P＞0.05).Also no significant difference was found in the bleeding events after the ending of enoxaparin administration and during the follow-up.Conclusion Enoxaparin may reduce the incidence of DVT and PE in patients undergoing general surgery without increased risk of bleeding. Key words: Low molecular weight heparin; Pulmonary embolism; Deep vein thrombosis; General surgery; Prophylaxis