The Lancet Haematology: Attention should be paid to venous thromboembolism prophylaxis in the management of COVID-19

Since December, 2019, the coronavirus disease 2019 (COVID-19) has spread globally, infecting more than 1 million people and causing more than 70 000 deaths.

Among patients with COVID-19, especially those who are severely and critically ill, a variety of potential risk factors for venous thromboembolism exist, including infection, immobilisation, respiratory failure, mechanical ventilation, and central venous catheter use.

However, to the best of our knowledge, risk of venous thromboembolism in these patients has not yet been reported. Here we use a nationwide dataset from China to provide a delineation of venous thromboembolism risk in patients with COVID-19.

On behalf of the National Clinical Research Centre for Respiratory Disease, together with the National Health Commission of the People’s Republic of China, we collected data from 1099 patients with laboratory-confirmed COVID-19 in 31 provincial administrative regions throughout the country.

The study was supported by the National Health Commission, was designed by the investigators, and was approved by the institutional review board of the National Health Commission. Written informed consent from the patients was waived in light of the urgent need to collect data, and the fact that this was a retrospective analysis of deidentified data. Data were analysed and interpreted by the authors. Continuous variables were expressed as medians with IQR. Wilcoxon rank-sum tests were applied to continuous variables, and χ2 tests were used for categorical variables. To estimate the odds ratio (OR) associated with venous thromboembolism risk, variables including outcomes and laboratory findings that were adjusted by age (by use of logistic regression) were further analysed by logistic regression.

American Journal of Respiratory and Critical Care Medicine: Severe Acute Respiratory Syndrome and Venous Thromboembolism in Multiple Organs

Severe acute respiratory syndrome (SARS) is now known to be caused by a novel coronavirus, the SARS-associated coronavirus (SARS-CoV) (1). It is characterized by severe systemic symptoms in multiple organs, such as lung, immune system, and small vessels, and finally becomes respiratory failure. Initial autopsies reported the predominant pathological findings to be diffuse lung injury, injured immune organs, inflammatory response in systemic small vessels, and general toxic reaction (2).

Changes in coagulation and the development of thrombi have been reported in patients with SARS, but the extent of the effects of the SARS-associated coronavirus on the systemic circulation has yet to be established. Limited data are available on the extent of the damage to the systemic vasculature and circulation in patients with SARS. In the present study, an autopsy was performed on a 57-year-old man diagnosed with SARS and specimens from multiple organs were analyzed to assess pathological changes in the vasculature. Specimens from multiple organs, including the lungs, heart, liver, kidneys, adrenal glands, spleen, esophagus, stomach, intestine, vermiform appendix, pancreas, brain, cerebellum, brainstem, hilus of lung, mesenteric lymph node, and muscle tissues, were analyzed by light microscopy. Examination of all of the specimens revealed systemic circulatory disturbance and polyangiitis. Proliferation, swelling, and apoptosis of endothelial cells, and edema, inflammatory cell infiltration, and fibrinoid necrosis were observed in the walls of small blood vessels in specimens from the lungs, heart, liver, kidneys, adrenal glands, brain, gastrointestinal tract, and muscle tissues. In addition, thrombi were evident in the veins and microcirculation of the soft tissues surrounding the lungs, spleen, pancreas, kidneys, adrenal glands, and mesenteric lymph nodes (Figure 1A–1F).

This autopsy case report has demonstrated that in addition to the well-established diffuse alveolar damage and damage to the immune system, SARS is associated with systemic circulatory disturbance and polyangiitis, in particular thrombosis in the veins and microcirculation in multiple organs and tissues. To our knowledge, this is the first study to show the extent of the damage to the vasculature and circulation that can occur in patients with SARS.

Deep vein thrombosis and/or pulmonary embolism have been reported in patients with SARS previously (34). However, the pathogenesis of deep vein thrombosis in patients with SARS remains unknown. Emerging evidence suggests that viral infection may have a role in the onset of venous thromboembolism (56). The present study adds to this evidence by demonstrating widespread thrombosis associated with SARS.