Nailfold capillaroscopy: A sensitive method for evaluating microvascular involvement in children with SARS-CoV-2 infection.

Objectives: The hyperinflammatory state and the viral invasion may result in endothelial dysfunction in SARS-CoV-2 infection. Although a method foreseeing microvascular dysfunction has not been defined yet, studies conducted in patients diagnosed with COVID-19 have demonstrated the presence of endotheliitis. With this study, we aimed to investigate the microvascular circulation in patients diagnosed with COVID-19 and multisystem inflammatory syndrome in children (MIS-C) by nailfold videocapillaroscopy (NVC).

Methods: Thirty-one patients with SARS-CoV-2 infection, 25 of whom were diagnosed with COVID-19 and 6 with MIS-C and 58 healthy peers were included in the study. NVC was performed in eight fingers with 2 images per finger and 16 images were examined for the morphology of capillaries, presence of pericapillary edema, microhemorrhage, avascular area, and neoangiogenesis. Capillary length, capillary width, apical loop, arterial and venous width, and intercapillary distance were measured from three consecutive capillaries from the ring finger of the non-dominant hand.

Results: COVID-19 patients showed significantly more capillary ramification (p < 0.001), capillary meandering (p = 0.04), microhemorrhage (p < 0.001), neoangiogenesis (p < 0.001), capillary tortuosity (p = 0.003). Capillary density (p = 0.002) and capillary length (p = 0.002) were significantly lower in the patient group while intercapillary distance (p = 0.01) was significantly longer compared with healthy volunteers. Morphologically, patients with MIS-C had a higher frequency of capillary ramification and neoangiogenesis compared with COVID-19 patients (p = 0.04).

Conclusion: Abnormal capillary alterations seen in COVID-19 and MIS-C patients indicate both similar and different aspects of these two spectra of SARS-CoV-2 infection and NVC appears to be a simple and non-invasive method for evaluation of microvascular involvement.