Full Length Article| Volume 198, P1-6, February 2021

Weight-adjusted tinzaparin for venous thromboembolism prophylaxis in bariatric surgery patients weighing 160 kg or more

Published:November 21, 2020DOI:


      • Bariatric surgery patients are at an increased risk to venous thromboembolism (VTE).
      • Weight-adjusted heparin regimes for VTE prophylaxis remain heterogenous.
      • We analyzed a weight-adjusted tinzaparin regime in patients weighing 160 kg or more.
      • VTE rates were 0.57% while bleeding rates were 1.43%.
      • Weight-adjusted tinzaparin was associated with a low risk of bleeding and VTE events.



      Bariatric surgery patients experience an increased risk of venous thromboembolism (VTE), however, the optimal dose of low-molecular-weight heparin for VTE prophylaxis remains uncertain. Currently, St. Joseph's Healthcare Hamilton utilizes a weight-adjusted tinzaparin dosage (50 to 75 units/kg rounded to nearest pre-filled syringe) for postoperative VTE prophylaxis.


      This study analyzed the safety of weight-adjusted tinzaparin for VTE prophylaxis in bariatric surgery patients weighing ≥160 kg.


      This was a retrospective study involving patients weighing ≥160 kg that underwent bariatric surgery from September 2015 to September 2019. Patients received a single dose of weight-adjusted subcutaneous unfractionated heparin (UFH) [5000 or 7500 IU] immediately prior to surgery, subcutaneous UFH [5000 IU, 7500 IU, or unspecified] immediately postoperatively, and either 10,000 or 14,000 IU of tinzaparin, beginning on the day after surgery, for 10 days. Intra-operative sequential compression devices could be used at the attending surgeon's discretion. Occurrence of VTE and major bleeding within 30 days of surgery were assessed.


      A total of 389 patients were included for analysis, all patients received in-hospital follow-up while 349 patients had also 30-day follow-up. For the primary safety and efficacy analysis of in-hospital events, VTE and major bleeding rates were 0.26% [95% CI 0.01%–1.44%] (1/389) and 0.77% [95% CI 0.21%–2.24%] (3/389) respectively. For patients with 30-day follow-up VTE and major bleeding rates were 0.57% [95% CI 0.1%–2.07%] (2/349) and 1.43% [95% CI 0.61%–3.3%] (5/349) respectively.


      Weight-adjusted tinzaparin was associated with a low risk of bleeding and VTE events, supporting its use for VTE prophylaxis for patients weighing ≥160 kg.
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        • Colquitt J.
        • Clegg A.
        • Sidhu M.
        • Royle P.
        Surgery for morbid obesity.
        Cochrane Database Syst. Rev. 2003; 2 (In eng)CD003641
        • Estimate of Bariatric Surgery Numbers
        The American Society for Metabolic and Bariatric Surgery. 2011-2018; : 2018
        • Kearon C.
        • Akl E.A.
        • Comerota A.J.
        • et al.
        Antithrombotic therapy for VTE disease: antithrombotic therapy and prevention of thrombosis, 9th ed: American College of Chest Physicians Evidence-based Clinical Practice Guidelines.
        Chest. 2012; 141 (In eng): e419S-e496S
        • Stein P.D.
        • Beemath A.
        • Olson R.E.
        Obesity as a risk factor in venous thromboembolism.
        Am. J. Med. 2005; 118 (In eng): 978-980
        • Froehling D.A.
        • Daniels P.R.
        • Mauck K.F.
        • et al.
        Incidence of venous thromboembolism after bariatric surgery: a population-based cohort study.
        Obes. Surg. 2013; 23 (In eng): 1874-1879
        • Melinek J.
        • Livingston E.
        • Cortina G.
        • Fishbein M.C.
        Autopsy findings following gastric bypass surgery for morbid obesity.
        Arch. Pathol. Lab. Med. 2002; 126 (In eng): 1091-1095
        • Bartlett M.A.
        • Mauck K.F.
        • Daniels P.R.
        Prevention of venous thromboembolism in patients undergoing bariatric surgery.
        Vasc. Health Risk Manag. 2015; 11 (In eng): 461-477
        • Kothari S.N.
        • Lambert P.J.
        • Mathiason M.A.
        Best poster award. A comparison of thromboembolic and bleeding events following laparoscopic gastric bypass in patients treated with prophylactic regimens of unfractionated heparin or enoxaparin.
        Am. J. Surg. 2007; 194 (In eng): 709-711
        • Kalfarentzos F.
        • Stavropoulou F.
        • Yarmenitis S.
        • et al.
        Prophylaxis of venous thromboembolism using two different doses of low-molecular-weight heparin (nadroparin) in bariatric surgery: a prospective randomized trial.
        Obes. Surg. 2001; 11 (In eng): 670-676
        • Imberti D.
        • Baldini E.
        • Pierfranceschi M.G.
        • et al.
        Prophylaxis of venous thromboembolism with low molecular weight heparin in bariatric surgery: a prospective, randomised pilot study evaluating two doses of parnaparin (BAFLUX Study).
        Obes. Surg. 2014; 24 (In eng): 284-291
        • Scholten D.J.
        • Hoedema R.M.
        • Scholten S.E.
        A comparison of two different prophylactic dose regimens of low molecular weight heparin in bariatric surgery.
        Obes. Surg. 2002; 12 (In eng): 19-24
        • Raftopoulos I.
        • Martindale C.
        • Cronin A.
        • Steinberg J.
        The effect of extended post-discharge chemical thromboprophylaxis on venous thromboembolism rates after bariatric surgery: a prospective comparison trial.
        Surg. Endosc. 2008; 22 (In eng): 2384-2391
        • Becattini C.
        • Agnelli G.
        • Manina G.
        • Noya G.
        • Rondelli F.
        Venous thromboembolism after laparoscopic bariatric surgery for morbid obesity: clinical burden and prevention.
        Surg. Obes. Relat. Dis. 2012; 8 (In eng): 108-115
        • Ikesaka R.
        • Delluc A.
        • Le Gal G.
        • Carrier M.
        Efficacy and safety of weight-adjusted heparin prophylaxis for the prevention of acute venous thromboembolism among obese patients undergoing bariatric surgery: a systematic review and meta-analysis.
        Thromb. Res. 2014; 133 (In eng): 682-687
        • Singh K.
        • Podolsky E.R.
        • Um S.
        • et al.
        Evaluating the safety and efficacy of BMI-based preoperative administration of low-molecular-weight heparin in morbidly obese patients undergoing Roux-en-Y gastric bypass surgery.
        Obes. Surg. 2012; 22 (In eng): 47-51
        • Finks J.F.
        • English W.J.
        • Carlin A.M.
        • et al.
        Predicting risk for venous thromboembolism with bariatric surgery: results from the Michigan Bariatric Surgery Collaborative.
        Ann. Surg. 2012; 255 (In eng): 1100-1104
      1. (NCD-RisC) NRFC. Trends in adult body-mass index in 200 countries from 1975 to 2014: a pooled analysis of 1698 population-based measurement studies with 19·2 million participants. Lancet 2016;387(10026):1377–1396. (In eng). DOI:

        • Schulman S.
        • Kearon C.
        • Haemostasis SoCoAotSaSCotISoTa
        Definition of major bleeding in clinical investigations of antihemostatic medicinal products in non-surgical patients.
        J. Thromb. Haemost. 2005; 3 (In eng): 692-694
        • Wang T.F.
        • Carrier M.
        How I treat obese patients with oral anticoagulants.
        Blood. 2020; 135 (In eng): 904-911
        • Carrier M.
        • Le Gal G.
        • Wells P.S.
        • Rodger M.A.
        Systematic review: case-fatality rates of recurrent venous thromboembolism and major bleeding events among patients treated for venous thromboembolism.
        Ann. Intern. Med. 2010; 152 (In eng): 578-589
        • Douketis J.D.
        • Spyropoulos A.C.
        • Kaatz S.
        • et al.
        Perioperative bridging anticoagulation in patients with atrial fibrillation.
        N. Engl. J. Med. 2015; 373 (In eng): 823-833
      2. Douketis JD, Spyropoulos AC, Duncan J, et al. Perioperative management of patients with atrial fibrillation receiving a direct oral anticoagulant. JAMA Intern Med 2019 (In eng). DOI:

        • Chan N.C.
        • Stehouwer A.C.
        • Hirsh J.
        • et al.
        Lack of consistency in the relationship between asymptomatic DVT detected by venography and symptomatic VTE in thromboprophylaxis trials.
        Thromb. Haemost. 2015; 114 (In eng): 1049-1057
        • Tseng E.K.
        • Kolesar E.
        • Handa P.
        • et al.
        Weight-adjusted tinzaparin for the prevention of venous thromboembolism after bariatric surgery.
        J. Thromb. Haemost. 2018; 16 (In eng): 2008-2015