Extract
At the end of last year, a novel coronavirus, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), resulted in an acute respiratory illness epidemic in Wuhan, China [1, 2]. The World Health Organisation (WHO) termed this illness Coronavirus Disease 2019 (COVID-19). The coronavirus family have been shown to enter cells through binding angiotensin-converting enzyme 2 (ACE2), found mainly on alveolar epithelium and endothelium. Activation of endothelial cells is thought to be the primary driver for the increasingly recognised complication of thrombosis. Viral inclusion bodies have been identified in endothelial cells in a variety of organs, from lung to gastro-intestinal tract [3]. The immune dysregulation characteristic of severe COVID-19 infection may be initiated by “pyroptosis”, a particularly pro-inflammatory form of apoptosis initially described in macrophages [4], with rapid viral replication leading to massive release of inflammatory mediators. One of the most consistent findings is that of a raised D-dimer. Although many inflammatory processes can influence D-dimer levels, it almost certainly reflects, to some extent, intra-vascular thrombosis in patients with COVID-19 [5, 6]. In the early studies emerging from China, an elevated D-dimer (>1000 ng·mL−1) at admission was associated with increased risk of in-hospital death [7]. An elevated D-dimer continues to be one of the most consistent markers of poor outcome [8].
Abstract
Pulmonary thrombosis appears to be common in Covid-19 pneumonia and takes two forms, proximal pulmonary emboli and/or distal thrombosis. We hypothesise mechanisms and discuss clinical implications.
Footnotes
Conflict of interest: Dr. Price reports personal fees from Actelion Johnson and Johnson, outside the submitted work;.
Conflict of interest: Dr. McCabe has nothing to disclose.
Conflict of interest: Dr. Garfield has nothing to disclose.
Conflict of interest: Dr. Wort reports grants and personal fees from Actelion Pharmaceuticals, grants and personal fees from Bayer, personal fees from MSD, personal fees from GSK, outside the submitted work;.
- Received May 5, 2020.
- Accepted May 29, 2020.
- Copyright ©ERS 2020
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