Can We Do Better? Identifying Orthopedic Surgery Patients at High Risk for Venous Thromboembolism Despite Thromboprophylaxis.
Bibliographic record
Abstract
Abstract Background Routine administration of thromboprophylaxis is the standard of care for patients undergoing major orthopedic surgery due to the very high rate of postoperative venous thromboembolism (VTE). However, because prophylaxis is not 100% effective, a significant proportion of patients who receive thromboprophylaxis develop post-operative VTE (“breakthrough VTE”). Clinical and surgical characteristics that are associated with the development of VTE in orthopedic surgery patients who receive standard thromboprophylaxis have not been well characterized. Objectives To evaluate the incidence of and risk factors for breakthrough VTE in patients who underwent major orthopedic surgery at a tertiary care hospital in Montreal, Canada. Methods Charts from consecutive patients who underwent total hip arthroplasty (THA), total knee arthroplasty (TKA) or hip fracture surgery (HFS) (hip pinning or hemiarthroplasty) from August 1, 1999 to April 30, 2000 were abstracted using standardized case report forms. Data were collected on patient characteristics (including VTE risk factors and postoperative complications), surgical characteristics (including type of surgery, operative factors, type of anesthetic) and thromboprophylaxis regimen. The results of any tests performed for clinically suspected VTE were documented, and associations between potential risk factors and objectively confirmed VTE were examined. Results Over the 9 month study period, 310 patients underwent major orthopedic surgery (34% THA, 30% TKA, and 36% HFS) and received standard thromboprophylaxis with either dalteparin or enoxaparin (mean duration of prophylaxis: 7 days). Of 83 suspected VTE, 44 (7 proximal DVTs and 37 distal DVTs; 14% of study population; median onset 6 days post-op) were confirmed with objective testing (compression ultrasonography). Multivariate analyses showed that knee surgery (odds ratio [OR] 4.8, 95% confidence interval 2.3, 10.1) and type of low molecular weight heparin (enoxaparin: protective) (OR 0.39, 95% confidence interval 0.20, 0.80) independently predicted VTE. Patient characteristics such as previous VTE, malignancy, hormonal therapy or varicose veins were not associated with VTE. Conclusion Despite receiving standard thromboprophylaxis, 14% of patients undergoing major orthopedic surgery developed symptomatic breakthrough VTE. Factors that independently predicted VTE in our population were TKR surgery and type of low molecular weight heparin. Our results suggest that TKR patients may warrant more aggressive post-operative physiotherapy and ambulation and adjunctive prophylactic measures such as pneumatic compression. In addition, due to the heterogeneity of different low molecular weight heparin compounds, direct comparison of the effectiveness of enoxaparin with dalteparin for orthopedic prophylaxis in prospective, randomized trials seems warranted.
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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 | 0.000 | 0.004 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 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".