Baseline capillaroscopy provides no evidence of microvascular changes to predict long-COVID syndrome.

Background: Long-COVID refers to a variety of symptoms that continue for at least 4 weeks following the onset of acute COVID-19 infection. "Microclots/microvasculopathy" is a potential cutting-edge theory. Nailfold capillaroscopy is a non-invasive method used to assess microvascularity. In this study, we aimed to compare baseline characteristics and capillaroscopic findings of patients with and without long-COVID syndrome.

Methods: Baseline clinical characteristics of 53 patients who tested positive for SARS-CoV-2 were recorded. At the time of COVID-19 diagnosis, patients underwent nailfold capillaroscopy. One year later, patients were rescreened for long-COVID symptoms. Comparisons were made between patients with and without long-COVID syndrome in terms of their baseline characteristics and capillaroscopic findings.

Results: There were 35 individuals (66%) with long-COVID syndrome. The most common symptoms related to long-COVID were fatigue (43.4%), myalgia (34%), arthralgia (20.8%), dyspnea (20.8%). In total, 22 patients (41.5%) had abnormal capillaroscopy findings. Like other baseline characteristics, the proportion of patients with abnormal capillaroscopic findings (40% vs 44%, p=0.76) was similar between patients with and without long-COVID syndrome.

Conclusion: Microvasculopathy and microthrombotic vascular damage are among the strongest hypotheses discussed in this regard. Our results may suggest that factors, rather than baseline microvasculopathy, may drive pathophysiological mechanism underlying the poorly understood long-COVID syndrome (Tab. 2, Ref. 35).