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CC BY 4.0 · TH Open 2023; 07(03): e244-e250
DOI: 10.1055/a-2159-9957
Original Article

Surgery As a Trigger for Incident Venous Thromboembolism: Results from a Population-Based Case-Crossover Study

Dana Meknas
1   Department of Clinical Medicine, Thrombosis Research Group, UiT—The Arctic University of Norway, Tromsø, Norway
2   Department of Orthopedic Surgery, University Hospital of North Norway, Tromsø, Norway
,
Sigrid K. Brækkan
1   Department of Clinical Medicine, Thrombosis Research Group, UiT—The Arctic University of Norway, Tromsø, Norway
3   Division of Internal Medicine, Thrombosis Research Center, University Hospital of North Norway, Tromsø, Norway
,
John-Bjarne Hansen
1   Department of Clinical Medicine, Thrombosis Research Group, UiT—The Arctic University of Norway, Tromsø, Norway
3   Division of Internal Medicine, Thrombosis Research Center, University Hospital of North Norway, Tromsø, Norway
,
Vânia M. Morelli
1   Department of Clinical Medicine, Thrombosis Research Group, UiT—The Arctic University of Norway, Tromsø, Norway
3   Division of Internal Medicine, Thrombosis Research Center, University Hospital of North Norway, Tromsø, Norway
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Abstract

Background Surgery is a major transient risk factor for venous thromboembolism (VTE). However, the impact of major surgery as a VTE trigger has been scarcely investigated using a case-crossover design.

Aim To investigate the role of major surgery as a trigger for incident VTE in a population-based case-crossover study while adjusting for other concomitant VTE triggers.

Methods We conducted a case-crossover study with 531 cancer-free VTE cases derived from the Tromsø Study cohort. Triggers were registered during the 90 days before a VTE event (hazard period) and in four preceding 90-day control periods. Conditional logistic regression was used to estimate odds ratios (ORs) with 95% confidence intervals (CIs) for VTE according to major surgery and after adjustment for other VTE triggers.

Results Surgery was registered in 85 of the 531 (16.0%) hazard periods and in 38 of the 2,124 (1.8%) control periods, yielding an OR for VTE of 11.40 (95% CI: 7.42–17.51). The OR decreased to 4.10 (95% CI: 2.40–6.94) after adjustment for immobilization and infection and was further attenuated to 3.31 (95% CI: 1.83–5.96) when additionally adjusted for trauma, blood transfusion, and central venous catheter. In a mediation analysis, 51.4% (95% CI: 35.5–79.7%) of the effect of surgery on VTE risk could be mediated through immobilization and infection.

Conclusions Major surgery was a trigger for VTE, but the association between surgery and VTE risk was in part explained by other VTE triggers often coexisting with surgery, particularly immobilization and infection.

Keywords

case-crossover study - venous thromboembolism - risk factor - surgery - immobilization - infection

Author's Contributions

D. Meknas analyzed data, interpreted the results, and drafted the manuscript. S. K. Brækkan and J.B. Hansen designed the study, organized data collection, interpreted the results, and revised the manuscript. V.M. Morelli designed the study, analyzed data, interpreted the results, contributed to the manuscript draft, and revised the manuscript. All authors reviewed and approved the final version of the manuscript.




Publication History

Received: 21 April 2023

Accepted: 14 July 2023

Accepted Manuscript online:
24 August 2023

Article published online:
20 September 2023

© 2023. The Author(s). This is an open access article published by Thieme under the terms of the Creative Commons Attribution License, permitting unrestricted use, distribution, and reproduction so long as the original work is properly cited. (https://creativecommons.org/licenses/by/4.0/)

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