Background: COVID-19 is a multifaceted condition with a wide range of clinical manifestations, including microvascular/endothelial dysfunction, that starts in the early phase of the disease and may become dramatically harmful in the late stage, causing a massive pro-thrombotic state. Nailfold videocapillaroscopy (NVC) is the most used tool to identify microvascular status in a large spectrum of diseases [1]. Recently, non-specific NVC abnormalities have been described in a cohort of COVID-19 patients (no controls used) [2].

Objectives: To assess microvascular damage in recovered COVID-19 patients (range of 40-270 days from recovery) by considering the previous severity of the disease, and, as mandatory, the comparison with matched individuals suffering from primary Raynaud’s phenomenon (PRP) and healthy volunteers (HV).

Methods: NVC investigations were performed during standard clinical assessments in forty-four recovered COVID-19 patients (mean age 58±14 years, mean days from disease onset 129±54, mean days from disease recovery 106±52), twenty-two patients with PRP (mean age 60±15 years, mean years from disease onset 11±10) and twenty-two HV (mean age 60±14 years). COVID-19 patients were divided into two subgroups, according to the need of oxygen supplementation: twenty-two patients with severe lung involvement (need of Continuous Positive Airways Pressure and/or mechanical ventilation, mean age 57±12 years) vs twenty-two patients with mild-moderate lung involvement (need of Venturi mask or no need of oxygen supplementation, mean age 59±15 years). Clinical and demographic data of all the enrolled subjects were collected, during NVC examination. The following capillaroscopic parameters were evaluated: capillary number, dilated capillaries, giant capillaries, microhemorrhages, angiogenesis, disorganization of the microvascular array. A validated semiquantitative scoring (0-3) was adopted for NVC abnormalities [3-5]. Statistical analysis was carried out by non-parametric tests.

Results: After COVID-19 recovery, no statistically significant difference was observed between COVID-19 patients and control groups of subjects concerning the score for the following NVC parameters: dilated capillaries, giant capillaries, disorganization of the microvascular array, angiogenesis. However, the capillary number per linear millimeter was significantly lower in COVID-19 patients (8.3±0.9) than in PRP (8.8±0.7, p=0.05) and HV (9.3±0.6, p<0.0001). Surprisingly, recovered COVID-19 patients showed significantly less microhemorrhages (score 0.4±0.3) than subjects of the other groups (PRP 0.6±0.5, p=0.01; HV 0.6±0.6, p=0.05). In particular, recovered patients who had more severe COVID-19 showed less microhemorrhages than patients with mild/moderate disease (score 0.18±0.4 vs 0.36±0.5), but this didn’t reach the statistical significance (p=0.18). On the other hand, patients recovered from severe SARS-CoV-2 infection also showed higher rate of angiogenesis (0.18±0.4) than patients with mild/moderate disease (no case, p=0.04).

Conclusion: COVID-19 doesn’t seem to significantly induce, in short-term, specific alterations in peripheral microvascular array as evaluated by NVC, despite the severity of the disease, except for a significant reduction of the absolute number of nailfold capillaries. The topic needs longer time of evaluation and larger number of COVID-19 recovered cases to also assess the role of concomitant therapies.

References: [1]Ingegnoli F et al. Curr Rheumatol Rev. 2018;14:5-11.

[2]Natalello G et al. Microvasc Res. 2021;133:104071.

[3]Smith V et al. Autoimmun Rev 2020;19:102458.

[4]Cutolo M et al. Clin Rheumatol. 2019;38:2293-2297.

[5]Sulli A et al. Ann Rheum Dis. 2008;67:885-7.

Disclosure of Interests: None declared