Blood Coagulation in High Altitude Pulmonary Hypertension

Abstract

Blood coagulation studies were carried out in 38 Indian soldiers who were resident at altitudes between 3690 and 5540 m for 2 years. Compared with 16 sea-level controls, 6 of these 38 subjects who had developed pulmonary hypertension during their stay at high altitude showed a significant increase of plasma fibrinogen, fibrinolytic activity, platelet adhesiveness, platelet factor 3, factor V, and factor VIII. In the remaining 32 subjects who did not develop pulmonary hypertension there was a significant increase of plasma fibrinogen and fibrinolytic activity only.The above differences between subjects who develop pulmonary hypertension at high altitude and those who do not develop pulmonary hypertension suggest that high altitude pulmonary hypertension is of occlusive origin and is dependent on changes in blood coagulation at high altitude.