Incidence, Clinical Characteristics, and Long-Term Prognosis of Travel-Associated Pulmonary Embolism

Abstract

Conclusions: Travel-associated pulmonary embolism (PE) has an excellent long-term prognosis. The risk is low and is strictly dependent on flight distance. Summary: Retrospective analyses of travelers arriving at Charles de Gaulle Airport in Paris and the Madrid-Barajas Airport have determined that distance traveled is a significant contributing risk for PE associated with air travel (N Engl J Med 2001;345:779-83 and Arch Intern Med 2003;163:2766-71). The incidence of PE among passengers traveling >5000 km is 1.5 cases/million compared with 0.01 cases/million in those traveling <5000 km. In this article the authors sought to determine the proportion of travel-associated PE compared with other associated causes of PE and the long-term prognosis after affected patients. Travel-associated PE was defined as that occurring ≤2 months of travel. The study monitored patients with travel-related PE who were admitted to the University of Frankfurt Hospital between 1997 and 2006. This hospital serves as the primary referral center for Frankfurt International Airport, the largest airport in Germany and third largest in Europe. Approximately one-third of the passengers arriving at this airport have traveled >5000 km. Flight distances of passengers with travel-related PE were obtained from data from FRAPORT AG, the operating company of Frankfurt International Airport. Between 1997 and 2006, 257 passengers with acute PE were admitted to the Frankfurt University Hospital intensive care unit. Of these, 62 had travel-related PE (45 flight-associated PEs; 17 other travel-associated PEs). Patients with travel-related PE had a nonsignificantly higher rate of initial cardiopulmonary resuscitation (4.8% vs 1.5%; P = .153) and a higher percentage of massive PE (8% vs 3%; P = .064). Mortality was similar in both travel-related and non-travel-related PE (4.8% vs 4.1% respectively, P = .730). Long-term outcome of travel-related PE patients was excellent (Kaplan-Meier analysis; log-rank P = .008) vs other entities associated with PE. Only 13% of patients with travel-related PE had no other identifiable risk factors, including thrombophilia, 40%; neoplasm, 7%; and family history of venous thromboembolism or recurrent thromboembolic event, 26%. Travel-related PE was rare, with one event per 5,000,000 passengers. Flights >5000 km led to a 17-fold increase compared with shorter flights. Comment: The main points of this study are that travel-related PE is exceedingly rare and is vanishingly rare in shorter flights. Virtually all patients with travel-related PE have additional risk factors for venous thromboembolism. Overall, the patients do well, with no difference in hospital mortality compared with other patients with PE, and the patients with travel-related PE have a better long-term prognosis.