Vasculopathy and Increased Vascular Congestion in Fatal COVID-19 and Acute Respiratory Distress Syndrome.

Rationale: The leading cause of death in coronavirus disease 2019 (COVID-19) is severe pneumonia, with many patients developing acute respiratory distress syndrome (ARDS) and diffuse alveolar damage (DAD). Whether DAD in fatal COVID-19 is distinct from other causes of DAD remains unknown. Objective: To compare lung parenchymal and vascular alterations between patients with fatal COVID-19 pneumonia and other DAD-causing etiologies using a multidimensional approach. Methods: This autopsy cohort consisted of consecutive patients with COVID-19 pneumonia (n = 20) and with respiratory failure and histologic DAD (n = 21; non-COVID-19 viral and nonviral etiologies). Premortem chest computed tomography (CT) scans were evaluated for vascular changes. Postmortem lung tissues were compared using histopathological and computational analyses. Machine-learning-derived morphometric analysis of the microvasculature was performed, with a random forest classifier quantifying vascular congestion (CVasc) in different microscopic compartments. Respiratory mechanics and gas-exchange parameters were evaluated longitudinally in patients with ARDS. Measurements and Main Results: In premortem CT, patients with COVID-19 showed more dilated vasculature when all lung segments were evaluated (P = 0.001) compared with controls with DAD. Histopathology revealed vasculopathic changes, including hemangiomatosis-like changes (P = 0.043), thromboemboli (P = 0.0038), pulmonary infarcts (P = 0.047), and perivascular inflammation (P < 0.001). Generalized estimating equations revealed significant regional differences in the lung microarchitecture among all DAD-causing entities. COVID-19 showed a larger overall CVasc range (P = 0.002). Alveolar-septal congestion was associated with a significantly shorter time to death from symptom onset (P = 0.03), length of hospital stay (P = 0.02), and increased ventilatory ratio [an estimate for pulmonary dead space fraction (Vd); p = 0.043] in all cases of ARDS. Conclusions: Severe COVID-19 pneumonia is characterized by significant vasculopathy and aberrant alveolar-septal congestion. Our findings also highlight the role that vascular alterations may play in Vd and clinical outcomes in ARDS in general.

Towards a "Net" generation of Pathologists: the pathCast online remote learning platform.

In recent years, digital and communication technology has been changing the way to spread knowledge in Medicine. In the field of Pathology, several remote learning resources have been made available through multiple social media platforms (Facebook, Twitter and others), YouTube channels and dedicated Websites, with a growing number of freely available lectures or tutorials, broadcasted live and/or archived for on-demand viewing. All these internet-based resources enable the pursuit of a flexible, independent, self-motivated and self-directed way of learning that fits perfectly with the increasing limitations of time, space and speed of modern day learners.These resources have played a significant role in filling the void of conventional education during the ongoing Covid-19 pandemic. Moreover, with their widespread diffusion throughout communities of Pathologists from all over the world they help to reduce the educational gap between resource-rich and resource-poor countries, having the potential to become standardized knowledge-sharing platforms and to be incorporated into curricula at any level.pathCast is one of the most robust and reliable open-access online remote learning platforms for pathologists, which live-streams lectures across the world. In the present paper we describe its structure, its acceptance by the global community of pathologists, what innovation elements has introduced regarding methodologies for education and its powerful and positive impact for residency training and continuing life-long education of practicing pathologists. A comprehensive list of the pathCast lectures with the respective links is also provided along with a brief discussion on other freely accessible online educational resources for pathologists.