Abstract

JACOBSON, B F; LOUW, S; SCHAPKAITZ, E  and  LAHER, F. THrombosis AETiology of Aviation-Related Travel: The THETA θ study. SAMJ, S. Afr. med. j. [online]. 2024, vol.114, n.9, pp.1-4. ISSN 2078-5135.  https://doi.org/10.7196/samj.2024.v114i9.2109.

BACKGROUND: Long-haul flights have been associated with a two- to four-fold increased risk of aviation-related thrombosis (ART). Several studies have investigated the extent to which hypoxic hypobaric exposure, dehydration and prolonged immobilisation during air travel induce changes in haemostasis OBJECTIVE: To investigate the role of high altitude as a risk factor for ART METHODS: Healthy volunteers aged >18 years (N=40), without risk factors for venous thromboembolism, were exposed to an exacerbated altitude of 18 000 feet (5 486 m) for 1 hour. During the flight, the oxygen (O₂) levels of the participants, who received supplemental O₂, were measured by pulse oximetry and maintained at >92%. Venous blood and urine samples were collected prior to departure and immediately after flying in an unpressurised twin-engine airplane. D-dimer levels, thromboelastography (TEG) parameters, von Willebrand factor (VWF) activity and urine osmolality were measured RESULTS: The participants were 19 men and 21 women, with a mean (standard deviation) age of 46 (14) years. A significant difference in D-dimer levels, VWF activity, urine osmolality and TEG parameters (reaction (R) time, kinetic (K) time and maximum amplitude (MA)) before and after the 1-hour flight was observed (p<0.001). Urine osmolality correlated positively with VWF activity levels (r=0.469; p<0.002 CONCLUSION: Air travel at high altitude induced a hypercoagulable state in healthy volunteers. Future research should focus on whether thromboprophylaxis can significantly obviate the activation of coagulation in response to high altitude

Keywords : Flying; aetiology; thrombosis; aviation.

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