{Reference Type}: Journal Article
{Title}: Early Online.
{Author}: Jacobson BF;Louw S;Schapkaitz E;Laher F;
{Journal}: S Afr Med J
{Volume}: 114
{Issue}: 7
{Year}: 2024 Jul 19
暂无{DOI}: 10.7196/SAMJ.2024.v114i9.2109
{Abstract}: <B>BACKGROUND: </B>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.<BR><B>OBJECTIVE: </B>To investigate the role of high altitude as a risk factor for ART.<BR><B>METHODS: </B>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.<BR><B>RESULTS: </B>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).<BR><B>CONCLUSIONS: </B>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.