From the Guidelines
Long-haul flights increase the risk of venous thromboembolism (VTE), with the risk rising approximately 18% for each 2-hour increase in travel duration, as confirmed by recent evidence 1. The highest risk period is within the first 2-4 weeks after travel. For most healthy travelers, simple preventive measures are sufficient:
- Staying hydrated
- Avoiding alcohol and sedatives
- Performing regular calf muscle exercises
- Walking periodically during the flight
- Wearing loose-fitting clothing For higher-risk individuals (those with previous VTE, recent surgery, active cancer, pregnancy, hormone therapy, or known thrombophilia),
- Graduated compression stockings providing 15-30 mmHg of pressure at the ankle are recommended 1. For the highest-risk travelers,
- Prophylactic low molecular weight heparin (such as enoxaparin 40mg subcutaneously before departure) or direct oral anticoagulants (such as rivaroxaban 10mg daily starting 2-4 hours before flight) may be considered, though this should be discussed with a healthcare provider 1. The mechanism behind flight-related VTE involves prolonged immobility leading to venous stasis, dehydration from low cabin humidity, and hypoxia from reduced cabin pressure, all contributing to hypercoagulability. Aspirin is not recommended for VTE prevention during air travel as it has not shown significant benefit for this specific purpose. It is essential to note that the risk of VTE in individuals with pro-thrombotic risk factors, such as chronic heart failure, is substantially higher than in the general population 1. Therefore, it is crucial to assess individual risk factors and take appropriate preventive measures to minimize the risk of VTE during long-haul flights.
From the Research
Long Haul Flight and Venous Thromboembolism Risk
- There is no direct evidence in the provided studies that specifically addresses the risk of venous thromboembolism (VTE) associated with long haul flights 2, 3, 4, 5, 6.
- However, the studies discuss the risk factors and prophylaxis strategies for VTE in various populations, including hospitalized patients and those with specific medical conditions.
- A study from 2022 discusses the use of low molecular weight heparin combined with aspirin to prevent perioperative VTE in patients with splenic rupture and lower extremity fracture, but does not address long haul flight specifically 5.
- Another study from 2024 explores the definition of high risk for VTE and approaches to determining an appropriate threshold for pharmacological prophylaxis, but also does not address long haul flight 6.
- The absence of direct evidence on long haul flight and VTE risk suggests that further research is needed to understand this specific relationship.