The value of high-resolution computed tomography (HRCT) to determine exercise ventilatory inefficiency and dynamic hyperinflation in adult patients with cystic fibrosis

Abstract

Introduction In Cystic Fibrosis (CF), exercise ventilatory inefficiency and dynamic hyperinflation (DH) cause exercise limitation and induce poor exercise tolerance. High-resolution computed tomography (HRCT) of the lung can detect pulmonary abnormalities in CF patients. We aimed to identify the determinants of exercise ventilatory inefficiency and DH using HRCT-derived metrics. Methods Fifty-two adult CF patients were prospectively enrolled; all participants underwent cardio-pulmonary exercise test (CPET) and HRCT. Radiological impairment was evaluated by the Brody II scoring system. Slope and intercept of the minute ventilation/CO 2 production (V’ E /V’ CO2 ) regression line and the ratio of inspiratory capacity/total lung capacity (IC/TLC) at rest and at peak of exercise were measured. Results Four groups of patients were identified based on the combination of ventilatory efficiency ( Vef ) or inefficiency ( Vin ) and the presence/absence of DH. Compared to other groups, CF adults with Vin and DH had worse functional status and higher total (T), bronchiectasis (B) and air trapping (AT) scores at HRCT. Significant correlations were found between V’ E /V’ CO2 intercept and V’ E /V’ CO2 slope (ρ − 0.455, p = 0.001) and between V’ E /V’ CO2 intercept and Δ inspiratory capacity (IC) (ρ − 0.334, p = 0.015 ). Regression analysis identified AT score (cut-off 7.9, odds ratio-OR 3.50) as the only independent predictor of V in and T (cut-off 53.6, OR 4.98), B (cut-off 16.1, OR 4.88), airways wall thickening (AWT) (cut-off 13, OR 3.41), and mucous plugging (MP) scores (cut-off 11.7, OR 4.18) as significant predictors of DH. Conclusion In adult CF cohort, values of HRCT metrics are determinants of Vin (AT) and DH (T, B, AWT, MP).

Identification of Subclinical Lung Involvement in ACPA-Positive Subjects through Functional Assessment and Serum Biomarkers

“…In our study, an abnormal V’E/V’CO 2 relationship was associated with HRCT abnormalities involving both airways and lung parenchyma. This is in line with what has already been described across a wide spectrum of lung diseases, including emphysema and cystic fibrosis [ 40 , 41 , 42 ]. CPET may thus have a diagnostic value in RA patients, non-invasively suggesting the presence of HRCT abnormalities.…”

Detection of Small Airway Dysfunction in Asymptomatic Smokers with Preserved Spirometry: The Value of the Impulse Oscillometry System

“…Whitney test; the Bonferroni post-hoc analysis, the ANOVA, and the nonparametric Kruskal-Wallis test were carried out for multiple comparisons; the statistical analysis of categorical variables was carried out via the χ 2 test, χ 2 for trend test or Fisher exact test, as previously described. 13 Concerning the correlation analysis, the Pearson (r) correlation coefficient was used for linear or normally distributed variables; the Spearman (ρ) correlation coefficient was used for not linear or not normally distributed variables.…”

Ventilatory efficiency and its clinical and prognostic value in adults with cystic fibrosis

“…Some studies have recently assessed the performance of pulmonary MRI using hyperpolarised gas among patients with CF and found a strong correlation between anomalies detected at MRI and abnormal LCI values [28,[32][33][34][35][36]. The extent of ventilatory efficiency alteration has been recently found to correlate with the degree of air trapping at HRCT scan but not with scores indicating airway disease such as bronchiectasis, mucous plugging and bronchial wall thickening [37], nor with the measures of transfer or diffusion capacity of the lung for carbon monoxide (T LCO or D LCO ) [20]. This comes as a surprise given that T LCO /D LCO is a recognised predictor of ventilatory inefficiency in COPD [38].…”