It has been recently hypothesized that infection by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) may lead to fibrotic sequelae in patients recovering from coronavirus disease 2019 (COVID-19). In this observational study, hospitalized patients with COVID-19 had a HRCT of the chest performed to detect the extension of fibrotic abnormalities via Hounsfield Units (HU). At follow-up, the lung density significantly improved in both lungs and in each lobe of all patients, being in the normal range (− 950 to − 700 HU). This study provides preliminary evidence that hospitalized patients with mild-to-moderate forms of COVID-19 are not at risk of developing pulmonary fibrosis.

Background: Progression of the disease in idiopathic pulmonary fibrosis (IPF) is difficult to predict, due to its variable and heterogenous course. The relationship between radiographic progression and functional decline in IPF is unclear. We sought to confirm that a simple HRCT fibrosis visual score is a reliable predictor of mortality in IPF, when longitudinally followed; and to ascertain which pulmonary functional variables best reflect clinically significant radiographic progression. Methods: One-hundred-twenty-three consecutive patients with IPF from 2 centers were followed for an average of 3 years. Longitudinal changes of HRCT fibrosis scores, forced vital capacity (FVC), total lung capacity and diffusing lung capacity for carbon monoxide were considered. HRCTs were scored by 2 chest radiologists. The primary outcome was lung transplant (LTx)-free survival after the follow-up HRCT. Results: During the follow-up period, 43 deaths and 11 LTx occurred. On average, the HRCT fibrosis score increased significantly, and a longitudinal increase > 7% predicted LTx-free survival significantly, with good specificity, but limited sensitivity. The correlation between radiographic and functional progression was moderately significant. HRCT progression and FVC decline predicted LTx-free survival independently and significantly, with better sensitivity, but worse specificity for a ≥ 5% decline of FVC. However, the area under the curve towards LTx-survival were only 0.61 and 0.62, respectively. Conclusions: The HRCT fibrosis visual score is a reliable and responsive tool to detect clinically meaningful disease progression. Although no individual pulmonary function test closely reflects radiographic progression, a longitudinal FVC decline improves sensitivity in the detection of clinically significant disease progression. However, the accuracy of these methods remains limited, and better prognostication models need to be found.

Background: Associated pulmonary hypertension (APH) is frequently observed in fibrosing interstitial pneumonias (FIP), such as idiopathic pulmonary fibrosis (IPF). APH is associated with worse prognosis, but it remains unclear whether it is associated with greater functional impairment. Six-minute walk distance (6MWD) is widely used to assess functional capacity in pulmonary hypertension and FIP. Objectives: To investigate if APH independently contributes to exercise intolerance in FIP, irrespective of the extent of underlying fibrosis. Methods: Patients diagnosed with FIP (September 2009 to June 2017) were included in the study if they underwent right heart catheterization, high-resolution chest computed tomography (HRCT), and 6MWD within 3 months. Recruitment was not limited only to patients undergoing lung transplant assessment. APH was defined as mean pulmonary artery pressure (mPAP) ≥25 mm Hg. The extent of fibrosis was quantified on HRCT using a visual fibrosis score by 2 separate observers. Results: Seventy-two patients (60 with IPF) were identified. Fifty-five patients had APH. mPAP was not significantly different in subgroups stratified according to the extent of fibrosis on HRCT. Pulmonary vascular resistance (PVR) was the strongest predictor of 6MWD on both univariate and stepwise regression analyses, and remained so considering only patients with normal wedge pressure (< 15 mm Hg) (n = 61). HRCT fibrosis score and pulmonary function tests did not significantly correlate with 6MWD. Conclusions: In patients with FIP, PVR is a significant contributor of 6MWD, independently from the extent of fibrosis on HRCT. These results strengthen both the rationale to use 6MWD as endpoint in FIP and to target APH with specific therapies.