A Systematic Review and Meta-Analysis of Venous Thromboembolism Risk in Surgical Patients with Recent Air Travel

Abstract Aim Venous thromboembolism (VTE) is associated with recent surgery; additionally, long-haul air-travel increases VTE risk. As surgical tourism increases, more patients are flying long distances seeking surgical intervention. This meta-analysis aimed to estimate post-operative VTE risk in the context of recent air-travel. Method Embase, Ovid MEDLINE, Cochrane and Scopus databases were accessed from 1947 to May 2022. Inclusion criteria were any study design with adults undergoing surgical intervention with recent air-travel, reporting VTE incidence. PRISMA guidelines were followed with a registered protocol (PROSPERO:CRD42022323561). Data was extracted independently by two reviewers and pooled using fixed and random effects. Primary outcome was pooled VTE rate; secondary outcomes were pooled rates of deep vein thrombosis (DVT) and pulmonary embolism (PE). ROBINS-I tool was used to assess risk of bias. Results Seven retrospective studies were included, totalling 24,975 patients. Overall odds of VTE in the flying plus surgery group was 1.96 (95%CI 0.54-7.08). For surgery with post-operative flight odds ratio (OR) of VTE was 1.31 (95%CI 0.63-2.71), whilst for surgery with pre-operative flight OR was 7.86 (95%CI 0.23–265.26). Three studies reported DVT/PE incidence specifically. DVT: for surgery and air-travel DVT rate was 0.67% (95%CI 0.31%-1.51%) versus 0.45% (95%CI 0.10%-2.00%) in surgery alone. PE: for surgery and air travel, PE rate was 0.41 (95%CI 0.00%-1.29%) versus 0.55% (95%CI 0.31%-0.86%) for surgery alone. Conclusions Whilst meta-analysis demonstrates that air-travel confers no additional VTE risk for surgical patients, it does not account for confounding factors. Future research should risk score then propensity match participants to generate higher quality evidence.