Single-photon emission tomography of the lungs in the diagnosis of coagulopathyin patients in the postcovid period

Abstract

Introduction. Exposure to SARS-CoV-2 leads to damage and dysfunction of the microvasculature of the lungs. The development of vasculitis, an increase in the permeability of the vessel wall, changes in the vascular-platelet and coagulation hemostasis, lead to the development of thrombosis / thromboembolism and hemorrhages. Single-photon emission tomography of the lungs is optimal for assessing changes in microcirculation in the lungs of patients with COVID-19 infection, since CT angiography can detect these formidable complications only in the large vessels of the lungs.Оbjective оf the work. To assess changes in the microvasculature of the lungs in patients with the development of postcovid syndrome and to assess the possibilities of single photon emission computed tomography in the diagnosis of thromboembolism, thrombosis and hemorrhages.Material and methods. The data of radiological studies performed in 138 patients in the postcovid period were analyzed, directed for examination to assess changes in blood circulation in the lungs and identify complications of the disease (thromboembolism, thrombosis, hemorrhages).Results. In patients who underwent an infection caused by the SARS-CoV-2 virus in a mild form, we identified changes in microcirculation most characteristic of manifestations of vasculitis and small local blood flow defects close to a triangular shape (microthrombosis), which correlated with an increase in fibrinogen (4.32 ± 0.21 g/L) (rs = 0.97; p = 0.001). Signs of microthrombosis, pulmonary embolism were detected in 35.9% of moderately severe patients who did not receive anticoagulant therapy or was prescribed it on day 10–12 of illness, and in 67.2% of severe and extremely severe patients who received anticoagulant therapy during the illness. Signs of postthromboembolic changes were detected in 16 patients (59.2%) in the late postcovid period, which correlated to a high degree (rs = 0.81; p = 0.03) with an increase in the level of fibrinogen (4.5 ± 1.9 mg/l).Conclusions. The severity of microcirculation disorders in the lungs depends on the severity of the disease and the timing of the postcovid period. Signs of small branch thromboembolism / thrombosis are detected in the early postcovid period. In patients who have undergone COVID-19 with the development of thrombosis, signs of postponed pulmonary embolism are revealed and zones of local pneumosclerosis are formed.