Car Travel-Related Thrombosis: Fact or Fiction?

The condition sometimes referred to as "economy class syndrome," and also known as "traveler's thrombosis," is a distinctive pathological condition characterized by occurrence of venous thromboembolism (VTE) in a patient who has recently experienced a long journey (i.e., ≥ 4 h). Typically, the identified travel is by airplane, but travel with other vehicles, such as trains, trucks, buses, or cars, could potentially qualify as contributing to VTE events. Although the enhanced risk of VTE after long haul flights is now widely acknowledged, albeit potentially overhyped, the risk of venous thrombosis after prolonged travel by other modes of transport, in particular, by cars, is less well appreciated. Current evidence, collected from some epidemiological studies, suggests that if any risk of VTE can be attributed to prolonged and uninterrupted car travels, and we give moderate credibility to such an association, the risk may be similar to that already proven for long haul flights. The risk is especially high in individuals undergoing uninterrupted car journeys lasting 4 hours or longer, in vehicles with a narrow seat-pitch, and in particularly would affect those with pre-existing acquired or inherited prothrombotic conditions. The putative biological mechanisms basically entail venous stasis and edema, which are often compounded by a certain degree of hypercoagulability. When these factors are combined with preexistent prothrombotic conditions, the risk may be substantially magnified. In this perspective, then, 'car thrombosis' may be regarded as a trigger rather than a risk factor for venous thrombosis. Although the current evidence is certainly not solid enough to endorse the use of general chemical prophylaxis for lowering the risk of car-related VTE, a set of possible precautionary measures, with no or very little side effects, may be suggested before planning prolonged car travels, especially for at risk individuals.