Severely Ill Patients with SARS-CoV-2 Virus Respond to Blood-Clot-Busting Drug

Physicians at the Icahn School of Medicine at Mount Sinai (New York, NY, USA) who led a small, preliminary case series have found that five severely ill patients with the SARS-CoV-2 virus responded to the blood-clot-busting drug tPA when it was introduced as a life-saving measure.

This response, and the large number of critically ill COVID-19 patients who have blood clots in their lungs, have raised new questions concerning the course of the disease and may present new possibilities for treating it.


According to Mount Sinai’s paper, the critically ill COVID-19 patients had relatively well-preserved lung mechanics, and did not develop stiffness of the lungs, despite severe gas exchange abnormalities. This feature is more consistent with pulmonary vascular disease and not with classic Acute Respiratory Distress Syndrome (ARDS). The COVID-19 patients also demonstrated markedly abnormal coagulation with elevated D-dimers—small protein fragments present in the blood after a blood clot—and higher rates of venous thromboembolism, a condition where blood clots that form in the deep veins of the legs or groin travel and become lodged in the lungs. The paper has cited autopsy studies from the SARS outbreak in the early 2000s, which revealed that patients had “pulmonary thrombi, pulmonary infarcts, and microthrombi —tiny clots composed of platelets—in other organs.” SARS-CoV-1, the virus that caused SARS, and SARS-CoV-2, which causes COVID-19, belong to the same family of coronaviruses.

With mounting evidence that a consistent pattern of COVID-19 patients are presenting with blood clots, Mount Sinai has provided treatment guidelines for its eight hospitals that address the significant role of microthrombi may play in patients with severe cases of COVID-19. The new guidelines help to inform clinical decision-making on administering anti-coagulation therapy for critically ill patients throughout the Health System. They call for patients who require hospitalization to be assessed for blood clots in their lungs by measuring their oxygen levels, testing for markers of clotting in their blood, and assessing their difficulty breathing or shortness of breath.

“This case series pushes us to consider avenues of clinical investigation that are different from what they are now,” said the paper’s first author, Hooman D. Poor, MD, Assistant Professor of Medicine (Pulmonology, Critical Care and Sleep Medicine, and Cardiology). “Perhaps we should be looking at the disease from the standpoint of clots that form in the blood vessels and travel to the lungs.”

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Icahn School of Medicine at Mount Sinai