Extended use of bemiparin as thromboprophylaxis during bariatric surgery: results of anti-factor Xa activity measurements.

BACKGROUND: The incidence of venous thromboembolism (VTE) in morbidly obese patients after obesity surgery is between .2% and 3.5%. Because there are a lack of prospective studies on the type of drug, the correct dosage, and the optimal duration, there are no specific recommendations found in the guidelines on thrombophylaxis.

OBJECTIVES: To compare the incidence of VTE and hemorrhagic events in bariatric surgical patients receiving bemiparin thromboprophylaxis who have prophylactic and nonprophylactic Anti-factor Xa (AFXa) levels.

SETTING: University General Hospital of Ciudad Real, Spain, public practice.

METHODS: A cohort study of 122 morbidly obese patients who underwent bariatric surgery. The thromboprophylactic regimen consisted of bemiparin 5000 IU/24 hr for 30 days. AFXa levels were measured on the second and third day postoperation (prophylactic range: .3-.5 IU/mL). Body mass index, co-morbidities, prothrombotic risk factors, and thrombotic and hemorrhagic events were noted.

RESULTS: The mean body mass index was 48.4 kg/m2 . In 50 samples, the level of AFXa was within the prophylactic range; in 71, they were in the subprophylactic range. No VTEs were observed. Major hemorrhagic events were observed in 2.4%. We did not find a significant association between AFXa and thromboembolic and hemorrhagic events. There is a significant negative correlation between the level of AFXa and body mass index.

CONCLUSION: A regimen of 5000 IU/24 hr of bemiparin for 30 days after obesity surgery appears to prevent VTE without increasing the risk of a major hemorrhage. The level of AFXa is not associated with postoperative thrombotic or hemorrhagic events occurring after bariatric surgery.