VENOUS THROMBOEMBOLISM ASSOCIATED WITH AIR-TRAVEL - A REPORT OF 33 PATIENTS

Background: The medical literature suggests long distance travel, part icularly air travel, may be a risk factor fur venous thromboembolism, but the risk is poorly quantified. Methods: We reviewed 134 records of patients hospitalized with venous thromboembolism for comments regard ing recent travel. Patients who had traveled within 31 d prior to veno us thromboembolism were defined as recent travelers, Results: Of 134 p atient records, 66 (49%) had documented inquiries regarding travel and 33 (50%) were recent air travelers. Data regarding demographics, mode of travel, dal: oi onset of symptoms in relation to travel, and other risk factors for venous thromboembolism were abstracted from the reco rds of the recent travelers. There were 12 (36%) travelers who had no other predisposition For venous thromboembolism. All had traveled non- stop by aircraft for 4 or more hours; none was identified as a crewmem ber. The median day of onset of venous thromboembolism was on travel d ay 4 (range: day 1-31). There were 8 (24%) patients who had onset duri ng air travel or on the day of arrival, and 27 (82%) had onset by trav el day lj. Air travel for 4 or more hours within the preceding 31 d wa s the most common risk factor for venous thromboembolism in our study patients and was present in 50%. This incidence is much higher than pr eviously described, perhaps due to limiting the study population to th ose in which the presence or absence of travel was documented. Conclus ion: Prospective studies ate needed to better define the risk factors for venous thromboembolism among long distance air passengers and crew -members, and to determine effective preventive measures.