Authors: Ackermann M, Verleden SE, Kuehnel M, Haverich A, Welte T

PMID: 32437596 PMCID: PMC7412750 DOI: 10.1056/NEJMoa2015432

Abstract

Background: Progressive respiratory failure is the primary cause of death in the coronavirus disease 2019 (Covid-19) pandemic. Despite widespread interest in the pathophysiology of the disease, relatively little is known about the associated morphologic and molecular changes in the peripheral lung of patients who die from Covid-19.

Methods: We examined 7 lungs obtained during autopsy from patients who died from Covid-19 and compared them with 7 lungs obtained during autopsy from patients who died from acute respiratory distress syndrome (ARDS) secondary to influenza A(H1N1) infection and 10 age-matched, uninfected control lungs. The lungs were studied with the use of seven-color immunohistochemical analysis, micro-computed tomographic imaging, scanning electron microscopy, corrosion casting, and direct multiplexed measurement of gene expression.

Results: In patients who died from Covid-19-associated or influenza-associated respiratory failure, the histologic pattern in the peripheral lung was diffuse alveolar damage with perivascular T-cell infiltration. The lungs from patients with Covid-19 also showed distinctive vascular features, consisting of severe endothelial injury associated with the presence of intracellular virus and disrupted cell membranes. Histologic analysis of pulmonary vessels in patients with Covid-19 showed widespread thrombosis with microangiopathy. Alveolar capillary microthrombi were 9 times as prevalent in patients with Covid-19 as in patients with influenza (P<0.001). In lungs from patients with Covid-19, the amount of new vessel growth - predominantly through a mechanism of intussusceptive angiogenesis - was 2.7 times as high as that in the lungs from patients with influenza (P<0.001). Conclusions: In our small series, vascular angiogenesis distinguished the pulmonary pathobiology of Covid-19 from that of equally severe influenza virus infection. The universality and clinical implications of our observations require further research to define. (Funded by the National Institutes of Health and others.).[/fusion_text][fusion_text columns="" column_min_width="" column_spacing="" rule_style="" rule_size="" rule_color="" hue="" saturation="" lightness="" alpha="" content_alignment_medium="" content_alignment_small="" content_alignment="" hide_on_mobile="small-visibility,medium-visibility,large-visibility" sticky_display="normal,sticky" class="" id="" margin_top="" margin_right="" margin_bottom="" margin_left="" fusion_font_family_text_font="" fusion_font_variant_text_font="" font_size="" line_height="" letter_spacing="" text_transform="" text_color="" animation_type="" animation_direction="left" animation_color="" animation_speed="0.3" animation_delay="0" animation_offset="" logics=""]Keywords: endothelialitis, thrombosis, angiogenesis, vascular, COVID-19, SARS-CoV-2