Post-COVID syndrome and capillary bed abnormalities detected by videocapillaroscopy

Abstract

Post-COVID syndrome (PCS) is a pressing problem in clinical practice. Dyspnea, along with neurologic and cardiovascular symptoms, is the most common symptom indicating low exercise capacity (EC) that reduces quality of life. The aim of this study was to investigate shortness of breath and the capillary bed abnormalities detected video capillaroscopy (VCS) in patients with PCS.Methods. The study included patients with PCS (n = 60) suffering from shortness of breath. Dyspnea was assessed using the 6-minute walk test (6-MWT). The capillary bed abnormality was diagnosed using VCS.Results. Patients with ACL walked an average of 79.5% of the predicted distance in the 6-MWT. They also had a decrease in pulse oximetry readings. The patients were divided into 2 groups: 1st – patients with desaturation, 2nd – patients without desaturation. Significant differences were observed between patients with and without desaturation, especially in the 6-MWT distance, pulse oximetry, and dyspnea before and after the 6-MWT. Patients with desaturation had a higher desaturation-to-distance ratio, a higher O2-GAP index, and higher cardiac effort levels, as well as a significant decrease in the proportion of perfused capillaries (PPC), mean capillary density, and a marked increase in the proportion of tortuous and branched capillaries. There was a direct correlation between PPC and diffusing lung capacity for carbon monoxide (DLCO), and carbon monoxide transfer coefficient (DLCO/Va), distance traveled during the 6-MWT and percentage (%) of predicted distance, inverse correlation between PPC and cardiac effort. There was a direct correlation between the percentage (%) of capillary recovery and 6-MWT distance and the percentage (%) of predicted distance, as well as an inverse correlation with the ratio of desaturation indicators and walking distance. Similarly, there was a direct correlation between mean capillary density and DLCO/Va, while the proportion (%) of tortuous capillaries was inversely correlated with DLCO, and the proportion (%) of branched capillaries was inversely correlated with DLCO/Va.Conclusion. The multifactorial nature of the mechanisms of dyspnea in patients with PCS was demonstrated, with the important role of vasculopathy. Continuous monitoring of pulse oximetry, heart rate and VCS are effective methods to screen and assess the condition of patients with PCS and dyspnea.