Description of the Characteristics of the Nailfold Capillary Structure in Healthy Children: A Multi-Centric Study.

BACKGROUND:Nailfold videocapillaroscopy (NVC) is the primary diagnostic tool for the assessment of microcirculation in the pediatric population. OBJECTIVE:To define and standardize age-specific normal NVC patterns in healthy children and adolescents. METHODS:A cross-sectional observational multicentric study was conducted in 564 participants aged 5-17 years. Dino-Lite CapillaryScope 200 Pro Model MEDL4N Pro was performed at 200× magnification. Quantitative and qualitative NVC parameters were analyzed separately for each age group and divided into 4 groups based on age categories. RESULTS:Of the 564 healthy participants, 54.9% were female. A total of 1184 images and 3384 capillaries were analysed. Positive correlations were observed between age and capillary density (p < 0.001, R = 0.450, CI95% 0.398-0.503). There was also a positive correlation between age and arterial/venous, loop diameter and capillary length, whereas there was a weak negative correlation between intercapillary distance. However, no correlation was found between age and capillary width. In addition, capillary density was significantly lower in 5-7 age group compared to the other patient groups. Arterial limb diameter was lower in 5-7 age group, while venous limb diameter was significantly wider in 15-17 age group compared to the other patient groups. Dilated capillaries (8.7%), capillary tortuosity (14.4%), crossed capillaries (43.1%), micro-haemorrhages (2.7%), avascular area (4.8%) were present in all age groups. Excellent intra- and interobserver ICC values were obtained for all parameters. CONCLUSION:These findings hold potential significance for future studies, aiding in the analysis and differentiation of children suspected of rheumatological diseases with potential microangiopathy.