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 analysed separately for each age group and divided into four 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 the 5–7 age group compared with the other patient groups. Arterial limb diameter was lower in the 5–7 age group, while venous limb diameter was significantly wider in the 15–17 age group compared with the other patient groups. Dilated capillaries (8.7%), capillary tortuosity (14.4%), crossed capillaries (43.1%), micro-haemorrhages (2.7%) and 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. [ABSTRACT FROM AUTHOR]