Multicentre retrospective detection of nailfold videocapillaroscopy abnormalities in long covid patients

Background: SARS-CoV-2 induces acute non-specific endothelial/microvascular alterations that have been identified by nailfold videocapillaroscopy (NVC). Details on NVC abnormalities in long covid (LC) patients (pts) are unknown. Methods: LC pts without and with systemic sclerosis (non-SSc-LC and SSc-LC), recovered COVID-19 (RC) pts that did not develop LC and healthy matched control subjects (CNT) that underwent NVC examinations were evaluated in a multicentre national study from the Capillaroscopy and Microcirculation in Rheumatic Diseases Study Group of the Italian Society of Rheumatology. Retrospective collection was performed for demographic data, course of SARS-CoV-2 infection, comorbidities, concomitant drugs. NVC alterations were quantified by validated scores. Pre-COVID-19 and post-COVID-19 microvascular status was analysed by NVC. Results: 62 non-SSc-LC pts (49 female/13 male, 51±16 years old), 24 SSc-LC pts (21 female/3 male, 59±17 years old), 23 RC pts (18 female/5 male, 51±18 years old) and 84 CNT (68 female/16 male, 52±12 years old) were analysed. Non-SSc-LC pts showed significantly more dilated capillaries (p<0.01, p multivariate<0.01), microhaemorrhages (p=0.01, p multivariate<0.05), abnormal shapes (p<0.05, p multivariate<0.05) than CNT and of note, lower mean capillary number per linear millimetre (p<0.01, p multivariate<0.01) than both RC pts and CTN (p<0.01, p multivariate<0.05).Of highest interest, 16 non-SSc-LC pts showed statistically significantly more dilated capillaries (p<0.05) and microhaemorrhages (p<0.05) in NVC examinations after COVID-19, compared with pre-COVID-19 status.Similarly, SSc-LC pts (24) showed significantly lower capillary density (p=0.01) and more dilated capillaries (p<0.01) in NVC examinations after COVID-19, compared with pre-COVID-19 status. Conclusions: LC pts show more microvascular alterations at NVC as compared with RC patients and CNT, which may contribute to the pathogenesis of persistent organ/systems dysfunction.