High Mortality Rate Among Latin American Immigrants With Covid-19 Hospitalised in Milan, Italy: Data From the Luigi Sacco Hospital Registry (preprint)

Background: To assess differences in the probability of COVID-19-related death between native Italians and immigrants hospitalised with COVID-19. Methods This was a retrospective study of prospectively collected data conducted at the ASST Fatebenefratelli-Sacco Hospital in Milan, Italy, between 21 February and 31 November 2020. Uni- and multivariable Cox proportional hazard models were used to assess the impact of the patients' origin on the probability of COVID-19-related death. Results The study population consisted of 1,179 COVID-19 patients: 921 Italians (78.1%) and 258 immigrants (21.9%) from Latin America (99, 38.4%), Asia (72, 27.9%), Africa (50, 19.4%) and central/eastern Europe (37, 14.3%). The Italians were older (p 

Pulmonary Post-Mortem Findings in a Large Series of COVID-19 Cases from Northern Italy (preprint)

Importance: The analysis of lung tissues of patients with COVID-19 may help understand pathogenesis and clinical outcomes in this life-threatening respiratory illness.Objective: To determine the histological patterns in lung tissue of patients with severe COVID-19.Design and Participants: Lungs tissues of 38 cases who died for COVID-19 in two hospital of Northern Italy were systematically analysed. Hematoxylin-eosin staining, immunohistochemistry for the inflammatory infiltrate and cellular components, electron microscopy were performed.Results: The features of the exudative and proliferative phases of Diffuse Alveolar Disease (DAD) were found: capillary congestion, necrosis of pneumocytes, hyaline membrane, interstitial oedema, pneumocyte hyperplasia and reactive atypia, platelet-fibrin thrombi. The inflammatory infiltrate was composed by macrophages in alveolar lumens and lymphocytes mainly in the interstitium. Electron microscopy revealed viral particles within cytoplasmic vacuoles of pneumocytes.Conclusions and Relevance: The predominant pattern of lung lesions in COVID-19 patients is DAD, as described for the other two coronavirus that infect humans, SARS-CoV and MERS-CoV. Hyaline membrane formation and pneumocyte atypical hyperplasia are frequently found. The main relevant finding is the presence of platelet-fibrin thrombi in small arterial vessels; this important observation fits into the clinical context of coagulopathy which dominates in these patients and which is one of the main targets of therapy.Funding Statement: No FundingDeclaration of Interests: No Conflict of InterestEthics Approval Statement: Tissue samples were taken as part of routine autopsies

COVID-19: the key role of pulmonary capillary leakage. An observational cohort study (preprint)

Background: COVID-19 induces progressive hypoxemic respiratory failure and acute respiratory distress syndrome, mostly due to a dysregulated inflammatory response. Since the first observations of COVID-19 patients, significant hypoalbuminemia was detected. This study aimed to investigate the hypothesis that hypoalbuminemia in COVID-19 patients is due to pulmonary capillary leakage and to test its correlation with indicators of respiratory function. Methods: 174 COVID-19 patients, 92 admitted to the Intermediate Medicine ward (IMW), and 82 to the Intensive Care Unit (ICU) at Luigi Sacco Hospital in Milan were included in this study. Findings: Serum albumin concentration was decreased in the whole cohort, with ICU patients displaying lower values than IMW patients [20 (18-23) vs 28 (24-33) g/L, p<0.0001]. Lower albumin values were found in patients belonging to a more compromised group (lower PaO2 to FiO2 ratio and worst chest X-ray findings). In a subset of 26 patients, analysis of bronchoalveolar lavage fluid (BALF) highlighted high protein concentrations, which were correlated to Interleukin-8 and Interleukin-10 BALF concentration. The length of hospitalisation [20 (15-29) vs 8 (5-14) days, p<0.0001] and death rate (52.4% vs 21.7%, p<0.0001) were higher in ICU than in IMW patients, while a strict relation between hypoalbuminemia and 30 day-survival was detected in the whole cohort. Electron microscopy examinations of eight out of ten autopsy lung tissues showed diffuse loosening of interendothelial junctional complex. Interpretation: The degree of hypoalbuminemia can be considered as a useful severity marker in hospitalised COVID-19 patients. Pulmonary capillary leak syndrome secondary to the hyperinflammatory state plays a key role in the pathogenesis of COVID-19 respiratory dysfunction and should be regarded as a therapeutic target.

Analysis of the role of Chest X-Ray in a large cohort of 1117 patients with SARS-CoV-2 infection: an Italian multicenter study (preprint)

Objective. To describe the radiographic key patterns on CXR in patients with SARS-CoV-2 infection, assessing the prevalence of radiographic signs of interstitial pneumonia. To evaluate pattern variation between a baseline and a follow-up CXR.Materials and methods. 1117 patients tested positive for SARS-CoV-2 infection were retrospectively enrolled from four centers in Lombardy region. All patients underwent a CXR at presentation. Follow-up CXR was performed when clinically indicated.Two radiologists in each center reviewed CXR images and classified them as suggestive or not for interstitial pneumonia, recording the presence of ground-glass opacity (GGO), reticular pattern or consolidation and their distribution.Pearson’s chi-square test for categorical variables and McNemar test (chi-square for paired data) were performed.Results. Patients mean age 63.3 years, 767 were males (65.5%). The main result is the large proportion of positive CXR in COVID-19 patients.Baseline CXR was positive in 940 patients (80.3%), with significant differences in age and sex distribution between patients with positive and negative CXR. 382 patients underwent a follow-up CXR. The most frequent pattern on baseline CXR was the GGO (66.1%), on follow-up was consolidation (53.4%). The most common distributions were peripheral and middle-lower lung zone.Conclusions. We described key-patterns and their distribution on CXR in a large cohort of COVID-19 patients: GGO was the most frequent finding on baseline CXR, while we found an increase in the proportion of lung consolidation on follow-up CXR. CXR proved to be a reliable tool in our cohort obtaining positive results in 80.3% of the baseline cases.

Pulmonary post-mortem findings in a large series of COVID-19 cases from Northern Italy (preprint)

Importance. The analysis of lung tissues of patients with COVID-19 may help understand pathogenesis and clinical outcomes in this life-threatening respiratory illness. Objective. To determine the histological patterns in lung tissue of patients with severe COVID-19. Design and participants. Lungs tissues of 38 cases who died for COVID-19 in two hospital of Northern Italy were systematically analysed. Hematoxylin-eosin staining, immunohistochemistry for the inflammatory infiltrate and cellular components, electron microscopy were performed. Results. The features of the exudative and proliferative phases of Diffuse Alveolar Disease (DAD) were found: capillary congestion, necrosis of pneumocytes, hyaline membrane, interstitial oedema, pneumocyte hyperplasia and reactive atypia, platelet-fibrin thrombi. The inflammatory infiltrate was composed by macrophages in alveolar lumens and lymphocytes mainly in the interstitium. Electron microscopy revealed viral particles within cytoplasmic vacuoles of pneumocytes. Conclusions and relevance. The predominant pattern of lung lesions in COVID-19 patients is DAD, as described for the other two coronavirus that infect humans, SARS-CoV and MERS-CoV. Hyaline membrane formation and pneumocyte atypical hyperplasia are frequently found. The main relevant finding is the presence of platelet-fibrin thrombi in small arterial vessels; this important observation fits into the clinical context of coagulopathy which dominates in these patients and which is one of the main targets of therapy.