Nailfold capillaroscopic changes of sleep apnea patients

Obstructive Sleep Apnea Syndrome (OSAS) have frequent association with comorbidities and this makes it an independent risk factor for cardiovascular disease. Not only endothelial dysfunction, but also arterial stiffening, increased inflammatory mediators, oxidative stress after hypoxemia that develops due to OSAS, cause vascular pathologies in all diameters of vessels. Nail bed capillaroscopy is a simple, noninvasive, useful method to examine microcirculation and evaluate nail bed capillary abnormalities in diseases that cause vascular damage. The aim of this study is to examine microvascular changes in the nail bed of OSAS patients by capillaroscopy.

59 OSAS patients and 60 healthy cases (totally 119) were included. One single attended polysomnography was applied with Embla N7000 series (RemLogic Eastmed, Natus); and apnea-hypopnea index (AHI), oxygen de-saturation index >4% (ODI4%), minimum oxygen saturation (SaO2 Min.), total duration of oxygen desaturation, comorbidities, body mass index (BMI), smoking habit, sleep questionnaire applications were analyzed. Nailfold capillaroscopy was performed using a digital dermoscope (Molemax II, X30) and all images were evaluated for capillary density, capillary loop enlargement, capillary tortuosity, branching vessels, micro hemorrhages, avascular areas and splinter hemorrhages.

The prevalence rates of all capillaroscopy findings were significantly higher in the patient group (p < 0.05). There was an inverse and moderate relationship between AHI and mean saturation (p < 0.05). A statistically significant correlation was detected between the presence of hypertension (HT) and the severity of capillary tortuosity (CT) (p = 0.002), avascular area (AA) (p = 0.004), and periungual cyanosis (PUC) (p = 0.042); also between smoking habit and intensity of capillary dilatation, enlargement dilatation-enlarged giant capillaries (CELON) (p = 0.004), CT (p = 0.018) findings. Capillary distribution (CD), CELON, CT and AA findings were significantly higher in the group with low mean saturation (p < 0.05). DM was found to be significantly higher in individuals with high Epworth Sleep Scale (ESS) (p = 0.035).

In this study; 1) the nail bed capillaroscopy was used to examine vascular damage in OSAS, and 2) irregularities detected in the distal nail bed specific to a disease have been mentioned for the first time. It has been shown that endothelial damage is particularly related to the severity of hypoxia. HT and smoking history causes endothelial damage independent of the severity of the disease and hypoxia. Also, ESS may be more determinant in the screening of sleep disorders in diabetic patients.