A systematic review and meta-analysis of venous thromboembolism risk in surgical patients with recent air travel.

ObjectiveRisk of venous thromboembolism (VTE) is classically associated with recent surgery; additionally, long-haul air travel is a known VTE risk factor. This meta-analysis aimed to estimate the post-operative VTE risk associated with recent air travel.MethodsEmbase, Medline, Cochrane and Scopus databases were accessed from inception to May 2024. Inclusion criteria were any study design of participants undergoing surgical intervention with recent air travel, reporting VTE incidence. Papers were screened and data extracted independently by two reviewers, then pooled using fixed and random effects. The primary outcome was pooled VTE rate, with secondary outcomes of pooled rate of deep vein thrombosis (DVT) and pulmonary embolism (PE). Subgroup analyses of pre- and post-operative flight, flight >4 h and high VTE risk surgery were conducted. The ROBINS-I tool was used to assess risk of bias.ResultsSeven retrospective studies were included in the analysis, totalling 24,975 patients. The pooled VTE odds ratio (OR) in the flying plus surgery group was 1.96 (95% CI: 0.54-7.08). For surgery with post-operative flight, the VTE OR was 1.31 (95% CI: 0.63-2.71), whilst for surgery with pre-operative flight the OR was 7.86 (95% CI: 0.23-265.26). In a subgroup analysis of air travel >4 h, the VTE OR was 2.35 (95% CI: 0.29-19.36). In the subgroup analysis of high VTE risk surgery, the VTE OR was 1.20 (95% CI: 0.45-3.20). Three studies reported DVT/PE incidence specifically. For surgery and recent air travel, the pooled DVT rate was 0.67% (95% CI: 0.31%-1.51%) versus 0.45% (95% CI: 0.10%-2.00%) in surgery alone. For surgery and recent air travel, the pooled PE rate was 0.41 (95% CI: 0.00%-1.29%) versus 0.55% (95% CI: 0.31%-0.86%) for surgery alone.ConclusionThis meta-analysis suggests that air travel confers no additional VTE risk for patients undergoing surgical intervention. However, this does not account for confounding factors. Future research should risk score then propensity match participants to generate higher quality evidence.