Efficacy and Safety of Weight-Adjusted Extended Duration Tinzaparin for Prevention of Post-Operative Venous Thromboembolism after Bariatric Surgery
Bibliographic record
Abstract
Abstract 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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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.002 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.001 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".