Introduction and objective:
Obstructive sleep apnea (OSA) is distinguished by recurrent partial or complete obstruction of the upper airways during sleep. The prevalence of OSA worldwide is estimated at 3–24% of the general population. Patients with OSA are predisposed to having endothelial dysfunction due to different mechanisms. The aim of a study was to assess the impact of 3 -month CPAP treatment on microcirculation among patients with OSA, and to determine changes in blood pressure after implemented therapy.

Material and methods:
The study included 30 patients with newly-diagnosed OSA. Microcirculation assessment was performed by Laser Doppler Flowmetry before and 3 months after implementation of CPAP therapy. Patients were also asked to perform measurements of blood pressure twice, 7 days prior to the appointment.

Results:
Improvement was observed in selected PORH parameters, such as AH, which was significantly increased after 3 months of treatment of CPAP (p<0.05). There was also a significant decrease in the RL/BZ parameter. Other PORH parameters did not differ significantly. Blood pressure, both diastolic and systolic, significantly decreased after therapy.

Conclusions:
Current study does not exactly explain the accurate mechanism underlying the changes of PORH after CPAP treatment among patients with OSA. However, it was demonstrated that 3 months adequate treatment improved endothelial function among the studied group. Assessment of microcirculation by LDF PORH protocol is a promising method, due to simplicity for the examinator, and non-invasive procedure. Due to the small study group, further investigation of microcirculation among patients with OSA should be performed, including the influence of co-morbidities and medications intake.