Coagulation markers in patients with obstructive sleep apnea syndrome and effects of continuous positive airway pressure

The aim of our study is to determine association between obstructive sleep apnea (OSA) syndrome and levels of blood coagulation markers and evaluate possible effects of continuous positive airway pressure (CPAP) therapy. Materials and methods. We included 74 middle-aged (mean age 48 [40; 55] years) male patients with arterial hypertension (AH) of average duration 8 [5; 10] years without antiplatelet, anticoagulant therapy and diabetes mellitus. All patients underwent sleep breathing study. According to the severity of OSA, patients were divided into 2 groups: 40 patients with severe OSA - apnea/hypopnea index - AHI 50.2 (37.8; 75.2) and control group with 34 patients with mild or no OSA - AHI 4.8 (2.6; 7.8). In all patients were analyzed markers of hemostasis system and parameters of whole blood viscosity; 34 patients with severe OSA underwent 3-4 nights of effective CPAP therapy (with achievement AHI<5) with evaluation of the above analysis at baseline and in the end of therapy. Results. We found a significant increase of fibrinogen, plasminogen activator inhibitor-1 (PAI-1), plasmin-a2-antiplasmin complex (PAP), tissue plasminogen activator/plasminogen activator inhibitor-1 complex (tPA-PAI-1), whole blood viscosity at low shear rates and erythrocytes aggregation index in the group with severe OSA compared with controls. After short-term (3-4 nights) CPAP therapy significantly decreased all parameters of whole blood viscosity with achieved normal levels of hematocrit, but markers of hemostasis system showed no significant difference. Conclusion: the coagulation status of blood is elevated in severe OSA patients (with AH and obessity). Short-term CPAP therapy can improve parameters of whole blood viscosity with achieved normal values of hematocrit. These results suggest that even few nights of CPAP therapy may reduce cardiovascular risk in OSA, in part through improving of whole blood viscosity.