Comparação de achados de radiografia simples e tomografia computadorizada do tórax com testes de função pulmonar em pacientes pós-infecção por SARS-CoV-2

Abstract

In December 2019, in Wuhan, China, an acute respiratory syndrome was identified due to a new coronavirus and that triggered a pandemic from 2020 onwards. The syndrome has been called coronavirus disease-19 (COVID-19) and the agent has been called severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2). Evidence shows that a wide variety of symptoms remain after the initial phase of the disease, characterizing post-COVID syndrome or long-term COVID. The most prevalent symptoms and signs of this syndrome are odynophagia, fatigue, chronic cough, chest pain, dyspnea, palpitations, diarrhea, nausea, sleep and emotional disturbances. Similar to outbreaks of other coronaviruses (SARS-CoV-1 and MERS-CoV), it is presumed that residual lung changes may persist after the initial infection. This observational study in patients with long-standing COVID aimed to evaluate parenchymal changes in plain radiographs (RX) and and chest computed tomography (CT) scans and their correlation with pulmonary function tests (PFT-spirometry and impulse oscillometry-IOS), performed in adult individuals, who had COVID and had symptoms after 3 weeks or more of the acute phase. Comparative analyses were performed between the main imaging aspects, patterns of pulmonary involvement, clinical presentations, and respiratory function tests. The descriptive analysis was presented in the form of tables of the observed data, by frequency and percentage, and illustrative graphics for categorical data. The inferential analysis consisted of the chi-square test or Fisher's exact test to evaluate the interrelations between the clinical variables, COVID-related, spirometry, FOT, CT and X-ray. Most patients were under 60 years of age, 59.6% were female, and 42.6% were obese. The most prevalent symptoms in the post-acute phase were dyspnea, fatigue and cough (72.3%, 63.8% and 34.0%, respectively) and predominated in patients with moderate severity in the acute phase (53.2%). The patients were hospitalized for an average of 14 days, 68.1% of them required oxygen therapy and most did not require mechanical ventilation (87.2%). In the spirometry findings, 54.5% of the patients presented normal results and most of the abnormal findings were of a restrictive pattern (34.1%). In the group with alterations in pulmonary function tests, hospitalized patients had greater alterations in IOS (78.9%; p = 0.05). The most common CT findings were ground-glass opacities (72.3%), septal thickening (61.7%), parenchymal bands (57.4%), air trapping (36.2%), and subpleural lines (27.7%). The most common CT patterns were resorption (63.8%), airway disease (air trapping - 42.6%), and fibrosis-like lesions (46.8%). On RXs, the most frequent findings were blurring of the vascular network (67.4%) and architectural distortion (14.0%). The radiographic and tomographic findings of post-acute COVID-19 were in agreement with those described in the literature, with emphasis on ground-glass opacities, parenchymal bands, air trapping, and subpleural linear opacities, and corresponded to the patterns of resorption, airway disease, and fibrosis-like lesions on CT. We were also able to corroborate the restrictive/obstructive patterns in spirometry, correlating them with the greater presence of changes in IOS (small airway disease).