title: D-dimer is not elevated in asymptomatic high altitude climbers after descent to 5340 m: the Mount Everest Deep Venous Thrombosis Study (Ev-DVT).
abstract: We performed this study to determine the prevalence of elevated D-dimer, a marker for deep venous thrombosis (DVT), in asymptomatic high altitude climbers. On-site personnel enrolled a convenience sample of climbers at Mt. Everest Base Camp (Nepal), elevation 5340 m (17,500 ft), during a single spring climbing season. Subjects were enrolled after descent to base camp from higher elevation. The subjects completed a questionnaire to evaluate their risk factors for DVT. We then performed a D-dimer test in asymptomatic individuals. If the D-dimer test was negative, DVT was considered ruled out. Ultrasound was available to perform lower-extremity compression ultrasounds to evaluate for DVT in case the D-dimer was positive. We enrolled 76 high altitude climbers. None had a positive D-dimer test. The absence of positive D-dimer tests suggests a low prevalence of DVT in asymptomatic high altitude climbers.
authors.affiliation: Division of Emergency Medicine, Stanford University Medical Center, Stanford, California, USA. zafren@alaska.com
authors.forename: Ken
authors.initials: K
authors.lastname: Zafren
authors.forename: Joanne
authors.initials: J
authors.lastname: Feldman
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Becker
authors.forename: Sarah R
authors.initials: SR
authors.lastname: Williams
authors.forename: Eric A
authors.initials: EA
authors.lastname: Weiss
authors.forename: Tom
authors.initials: T
authors.lastname: Deloughery
mesh_terms: D000328:Adult; D000531:Altitude; D000532:Altitude Sickness / Q000150:complications*; D016001:Confidence Intervals; D005260:Female; D005338:Fibrin Fibrinogen Degradation Products / Q000378:metabolism*; D006801:Humans; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D020246:Venous Thrombosis / Q000097:blood* / Q000453:epidemiology* / Q000209:etiology; D055815:Young Adult
chemical_list: D005338:Fibrin Fibrinogen Degradation Products; C036309:fibrin fragment D