Summary

D-dimer, a degradation product of fibrin, is being increasinglyused as a marker and prognostic factor in various thromboticdiseases. Previous reports have shown that obstructive sleepapnea is associated with platelet activation and hypercoagulability.The aim of the study was to assess the potential role of theplasma D-dimer test in patients with obstructive sleep apnea.We designed a prospective group comparison study in a tertiary-care, university-affiliated medical center. One hundred andthree patients of mean age 57 years (range 50–76 years) withsymptoms suggestive of obstructive sleep apnea were included.Polysomnography was performed in all cases,and blood was collectedfor plasma D-dimer measurement by MiniQuant turbid-metric assay.The demographic and polysomnograph data werecompared between patients with normal and high (>250 ng/ml)D-dimer levels.The group with higher D-dimer values had lowermean minimal oxygen saturation (72.1± 16.4 vs. 81.7± 11.6%,p=0.008) and a longer mean period of oxygen saturation below90% (84.1± 86.2 vs. 38.5± 70.8 minutes, p=0.032).There was nocorrelation of respiratory disturbance index and sleep architecturewith D-dimer values.We concluded that sleep apnea syndromeis associated with fibrinolytic activity. Oxygen desaturationseems to be one of the mediatory factors in the putativeconnection between obstructive sleep apnea and hypercoagulabilitystate.