Global Reach 2018: Influence of Excessive Erythrocytosis on Coagulation and Fibrinolytic Factors in Andean Highlanders

Abstract

Increased coagulation and reduced fibrinolysis are central factors underlying thrombotic risk and events. High altitude-induced excessive erythrocytosis (EE) is prevalent in Andean highlanders, contributing to increased cardiovascular risk. Disruption in the coagulation-fibrinolytic axis resulting in uncontrolled fibrin deposition may underlie the increased thrombotic risk associated with high altitude EE. The experimental aim of this study was to determinewhether EE is associated with a prothrombotic blood coagulation and fibrinolytic profile in Andean highlanders. Plasma coagulation (von Willebrand factor [vWf], factor VII, VIII, and X) and fibrinolytic (tissue-type plasminogen activator [t-PA] and plasminogen activator inhibitor-1 [PAI-1]) factors as well as D-dimer levels were determined in 26 male residents of Cerro de Pasco, Peru (4,340 m): 12 without EE (age: 40±13 yr; Hb: 17.4±1.9 g/dL) and 14 with EE (43±15 yr; 24.4±1.6 g/dL). There were no significant differences in vWf (40.5+24.8 vs 45.5+22.4 %), factor VII (77.0+14.5 vs 72.5+8.9 %), factor VIII (55.6+19.8 vs 60.7+26.8 %) and factor X (73.9+8.3 vs 67.3+10.9 %) between the Andean highlanders without or with EE. t-PA antigen (8.5+3.6 vs 9.6+5.4 ng/mL), t-PA activity (5.5+2.4 vs 5.8+1.6 IU/mL), PAI antigen (45.0+33.8 vs 40.5+15.8 ng/mL), PAI-1 activity (0.24+0.09 vs 0.25+0.11 IU/mL) and the molar concentration ratio of active t-PA to active PAI-1 (1:0.051+0.034 vs 1:0.046+0.021 mmol/L) were also similar between the groups as were D-dimer levels (235.0+126.4 ng/mL vs 268.4+173.7 ng/mL). In conclusion, the results of the present study indicate that EE is not associated with prothrombotic disruptions in coagulation or the fibrinolytic system in Andean highlanders. Although dysregulation in both pathways is known to increase thrombotic risk, EE does not appear to directly influence either pathway to affect vascular risk in Andean men.