Pulmonary function tests.

BackgroundPersistent respiratory symptoms in COVID-19 patients have raised concerns about structural remodelling in the lung. We assessed structural changes and their correlation with reduced DLCO, eight months after discharge, in previously hospitalised COVID-19 patients.Materials and MethodsAn exploratory observational study was conducted on 26 male patients (mean age: 60 years, range: 50–69) previously hospitalised for COVID-19. CT scans, performed eight months post-discharge, were analysed using functional respiratory imaging (FRI) to assess lung structure and function. Analyses were made based on diffusion capacity for carbon monoxide (DLCO).ResultsPatients with low DLCO (≤75%; n = 9) exhibited a significantly lower proportion of small blood vessels with a cross-sectional area 75%; n = 17) (median (IQR) 56 (51–59) % vs. 60 (56–64) %, p = 0.008), as well as a reduced absolute volume of small vessels with a cross-sectional area ConclusionsWe demonstrate long-term vascular and airway remodelling detected with FRI in previously hospitalised COVID-19 patients and highlight potential mechanisms underlying persistent pulmonary dysfunction and emphasise the need to investigate the underlying pathophysiology to identify potential individualised treatment strategies for this patient group.