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1130 Efficacy and Safety of Weight-Adjusted Extended Duration Tinzaparin for Prevention of Post-Operative Venous Thromboembolism after Bariatric Surgery

Antithrombotic Therapy
Program: Oral and Poster Abstracts
Session: 332. Antithrombotic Therapy: Poster I
Saturday, December 5, 2015, 5:30 PM-7:30 PM
Hall A, Level 2 (Orange County Convention Center)

Deborah M. Siegal, MD, MSc1, Pankaj Handa, MD2*, Emma Kolesar3*, Mehran Anvari, MD3*, Maria Tiboni, MD3*, James D. Douketis, MD4,5* and Mark A. Crowther, MD, MSc, FRCPC6

1McMaster University, Hamilton, ON, Canada
2Tan Tock Seng Hospital, Tan Tock Seng, Singapore
3St. Joseph's Healthcare Hamilton, McMaster University, Hamilton, ON, Canada
4St. Joseph's Healthcare Hamilton, Hamilton, ON, Canada
5Department of Medicine, McMaster University, Hamilton, ON, Canada
6St. Joseph's Hospital, McMaster University, Hamilton, ON, Canada

Background:Patients having bariatric surgery are at moderate-to-high risk for post-operative venous thromboembolism (VTE), with pulmonary embolism representing the most common cause of post-operative death. The optimal dosing and duration of anticoagulant prophylaxis is uncertain.

Aim:To evaluate the efficacy and safety of extended-duration, weight-adjusted tinzaparin for post-operative thromboprophylaxis after bariatric surgery.

Methods: Retrospective cohort of 793 bariatric surgery patients who received routine post-operative weight-adjusted tinzaparin, 4,500-14,000 IU daily (75 IU/kg, rounded to the nearest pre-filled syringe) for 7 days after hospital discharge. The primary efficacy and safety outcomes were the frequency of VTE and major bleeding, respectively, within 30 days of surgery in patients receiving at least 1 dose of tinzaparin.

Results: 793 patients who underwent bariatric surgery from 2009 to 2012 were reviewed. There were 44 (5.5%) patients excluded from analyses: need for therapeutic-dose anticoagulation (n=16); no post-operative tinzaparin (n=27); surgery aborted (n=1). There were 646 and 645 patients included in the 30-day efficacy and safety analyses, respectively (mean age, 44.6 years [SD 9.7], median body mass index, 47.1 kg/m2[range: 19.4-81.0]). An additional 106 patients had outcome data only during hospital admission. VTE occurred in 1/645 patients (0.3%; pulmonary embolism) after hospital discharge and in 1/752 patients (0.1%; superior mesenteric vein thrombosis) in hospital. Major bleeding occurred in 12/645 patients (1.9%). Trough anti-Xa levels measured 7-10 days post-operatively were undetectable in 143/190 (75.3%) patients. In the other 47 patients the median trough anti-Xa level was 0.12 IU (range: 0.10-0.41).

Conclusions: Weight-adjusted, extended-duration tinzaparin appears effective and safe for post-operative thromboprophylaxis after bariatric surgery. There was no drug accumulation with large doses of tinzaparin.

Disclosures: Siegal: Interactive Forums Inc.: Other: created educational slides ; Daiichi Sankyo: Other: participated in an advisory board ; Boerhinger Ingelheim: Other: participated in an advisory board ; Portola Pharmaceuticals: Other: participated in an advisory board . Douketis: Bayer: Consultancy ; Actelion: Consultancy ; Biotie: Other: Advisory board ; Sanofi-Aventis: Honoraria ; The Medicines Company: Other: Advisory board ; Janssen: Consultancy ; Daiichi-Sankyo: Consultancy ; Bristol-Myers Squibb: Consultancy , Honoraria ; Pfizer: Honoraria ; Boehringer Ingelheim: Consultancy , Honoraria .

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