Correlações das alterações do parênquima e da densitovolumetria pulmonar por tomografia computadorizada do tórax com os testes de função pulmonar em pacientes com micobacterioses não tuberculosas

Abstract

Non-tuberculous mycobacteria (MNT) are increasingly recognized worldwide as an important cause of infection in immunocompetent patients, possibly due to an improvement in clinician awareness, an increase in the number of susceptible individuals and technological advances in molecular microbiology. NTM pulmonary disease (NTM-PD) is the most common clinical manifestation of NTM infections. The criteria established to confirm the diagnosis include: clinical data, identification of mycobacteria and changes in imaging tests. The purpose of this study was to evaluate changes in lung parenchyma through chest computed tomography (CT) densitometry and, secondarily, to analyze its correlation with pulmonary function testing (PFT) in patients with NTM-PD. Two cross-sectional studies were carried out with NTM-PD. The first study involved 19 patients diagnosed with MNT-PD, who underwent a subjective analysis of chest CT that demonstrated the main findings, in order of frequency: architectural distortion, interstitium changes, upper lobes predominant cavities and centrilobular nodules. The second study involved 31 patients with NTM-PD and a control group of 27 normal individuals matched for sex, age and body mass index. The main changes found in chest CT exams were: architectural distortion (80.6%), reticular opacities (77.4%), bronchiectasis (71%), cavities (64.5%), centrilobular nodules (61.3 %), atelectasis (51.6%), small consolidations (48.4%), large consolidations (32.3%) and emphysema (25.8%). Bronchiectasis and cavities predominated in the upper lobes (61.3%). In relation to the control group, patients with NTM-PD showed lower values of forced vital capacity (FVC, 82.7 ± 25.3 vs. 102 ± 8.12 % predicted, p=0.005) and forced expiratory volume in the first second (FEV1, 72.7 ± 25.4 vs. 101.2 ± 8.75 % predicted, p=0.003) and higher values of residual volume (RV, 119 ± 45.6 vs. 75.8 ± 23.2 % predicted, p=0.001), RV/total lung capacity (RV/TLC, 37.5 ± 12.4 vs. 25.7 ± 8.90 %, p=0.02), and airway resistance (Raw, 6.53 ± 3.77 vs. 2.31 ± 2.13 cmH2O/L/s, p<0.001). In CT pulmonary densitovolumetry, patients with NTM-PD had lower values of M3 and M15, compared to controls, with greater significant differences in measures of the apical and middle thirds. Patients with NTM-PD showed higher values of C85 and C97, although significant differences were observed only in measures of the basal third. We also evaluated correlations between the CT pulmonary densitovolumetry findings and the PFT parameters. FVC was negatively correlated with M3 in the apical third (r=-0.41; p=0.021) and M15 in the apical third (r=-0.35; p=0.047). TLC was negatively correlated with the measurements of M3 of the total lung (r=-0.67; p<0.0001); M3 in the middle third (r=-0.59; p=0.0003); M3 in apical third (r=-0.71; p<0.0001); M15 in whole lung (r=0.65; p=0.0002); and M15 in the apical third (r=-0.48; p=0.005). There were positive correlations of RV and Rwa with M3 in the measure of the apical third (r=0.47; p=0.007; r=0.40; p<0.026, respectively). As a conclusion, patients with NTM presented morphostructural changes in the airways, with a reduction in lung mass, especially in the more apical regions of the lungs, and important fibrotic changes that functionally impacted the reduction of lung volumes with reduced airflow in these patients