Fig. 5.

Pulmonary arterial walls are thickened in COVID-19 patients. (A) Representative hematoxylin and eosin staining images of the pulmonary arteries of patients who died of ARDS due to COVID-19 and H1N1 influenza. In COVID-19 patients, but not in H1N1 influenza patients, thickening of the pulmonary arterial walls was observed. Scale bars indicate 100 μm. (B) Box plots represent quantifications of pulmonary arterial wall thicknesses and lumen areas in COVID-19 and H1N1 influenza patients using H&E stained slides. The number of patients used for these analyses was 10 for COVID-19 and 10 for H1N1. *The Mann-Whitney U Test indicated that the two values are significantly different at p = 0.001.