Diffuse alveolar damage and thrombi are the most common lung histopathological lesions reported in patients with severe COVID-19. Although some studies have suggested increased pulmonary angiogenesis, the presence of vascular proliferation in COVID-19 lungs has not been well characterised. Glomeruloid-like microscopic foci and/or coalescent vascular proliferations measuring up to 2 cm were present in the lung of 14 out of 16 autopsied patients. These lesions expressed CD31, CD34 and vascular endothelial cadherin. Platelet-derived growth factor receptor-β immunohistochemistry and dual immunostaining for CD34/smooth muscle actin demonstrated the presence of pericytes. These vascular alterations may contribute to the severe and refractory hypoxaemia that is common in patients with severe COVID-19.

中文翻译：

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重症 COVID-19 患者的肺血管增生：尸检研究

弥漫性肺泡损伤和血栓是重症 COVID-19 患者最常见的肺组织病理学病变。尽管一些研究表明肺血管生成增加，但 COVID-19 肺中血管增殖的存在尚未得到很好的表征。在 16 名尸检患者中，有 14 名的肺中存在肾小球样微观病灶和/或高达 2 cm 的融合血管增生。这些病变表达 CD31、CD34 和血管内皮钙粘蛋白。血小板衍生生长因子受体-β 免疫组织化学和 CD34/平滑肌肌动蛋白双重免疫染色证明存在周细胞。这些血管改变可能导致严重和难治性低氧血症，这在严重的 COVID-19 患者中很常见。