title: Incidence, clinical characteristics, and long-term prognosis of travel-associated pulmonary embolism.
abstract: OBJECTIVE
  Prolonged air travel is considered a risk factor for pulmonary embolism (PE). The clinical characteristics as well as the long-term prognosis of patients suffering from travel-associated PE ('economy-class syndrome', ECS) remain largely unknown. Owing to its proximity, our hospital is the primary referral centre for Frankfurt Airport, Europe's third-largest airport. The goal of our study was to follow-up all patients with ECS, who were admitted to our hospital between 1997 and 2006.
  
  
  RESULTS
  We systematically reviewed all medical charts from patients presenting with acute PE to our emergency room or intensive care unit (ICU) and performed a telephone follow-up on patients discharged alive. Together with the data provided from the statistics department of Fraport Inc., the operating company of the Frankfurt International Airport, we were also able to put the medical data in context with the corresponding number of passengers and flight distances. A total of 257 patients with acute PE were admitted to our emergency and ICU between 1997 and 2006. Out of these, 62 patients suffered from ECS (45 flight-associated PE and 17 from other travel-associated PE). ECS patients were prone to more haemodynamic relevant acute events, reflected by a higher rate of initial cardiopulmonary resuscitation (4.8% vs. 1.5%; P = 0.153) and higher percentage of massive PE (8% vs. 3%; P = 0.064). Nevertheless, intrahospital mortality was similar in both groups (ECS 4.8%, others 4.1%; P = 0.730). Interestingly, the long-term outcome of ECS patients was excellent (Kaplan-Meier analysis; P log-rank: 0.008 vs. other entities). In general, ECS was a rare event (one event/5 million passengers), where long-haul flights over 5000 km lead to a 17-fold risk increase compared with shorter flights.
  
  
  CONCLUSIONS
  Travel-associated PE was a common cause of PE in our hospital, with patients showing excellent long-term prognosis after discharge. The risk of ECS is rather low and strictly dependent on the flight distance.
authors.affiliation: Department of Cardiology, Johann Wolfgang Goethe-University Frankfurt, Theodor-Stern-Kai 7, D-60590 Frankfurt, Germany.
authors.forename: Ralf
authors.initials: R
authors.lastname: Lehmann
authors.forename: Christian
authors.initials: C
authors.lastname: Suess
authors.forename: Maria
authors.initials: M
authors.lastname: Leus
authors.forename: Beate
authors.initials: B
authors.lastname: Luxembourg
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Miesbach
authors.forename: Edelgard
authors.initials: E
authors.lastname: Lindhoff-Last
authors.forename: Andreas M
authors.initials: AM
authors.lastname: Zeiher
authors.forename: Ioakim
authors.initials: I
authors.lastname: Spyridopoulos
mesh_terms: D000328:Adult; D000337:Aerospace Medicine; D000368:Aged; D004812:Epidemiologic Methods; D005260:Female; D006801:Humans; D008297:Male; D008499:Medical Records / Q000706:statistics & numerical data; D008875:Middle Aged; D011379:Prognosis; D011655:Pulmonary Embolism / Q000145:classification / Q000453:epidemiology* / Q000209:etiology; D014195:Travel / Q000706:statistics & numerical data*