In a new study, researchers found COVID-19 is linked to life-threatening blood clots in the arteries of the legs.
They found COVID-19 patients with symptoms of inadequate blood supply to the lower extremities tend to have larger clots and a much higher rate of amputation and death than uninfected people with the same condition.
The research was conducted by a team at Montefiore Medical Center in NY.
COVID-19’s link to blood clots in the pulmonary arteries is well-established.
Less is known about the virus’s connection to lower extremity arterial thrombosis, a condition characterized by blood clots in the arteries that impede the flow of oxygenated blood to the lower extremities.
During the peak of the COVID-19 pandemic in New York City, the team observed an increase in patients testing positive for lower extremity arterial thrombosis on CT angiography exams.
The patients had arrived at hospitals with coldness, pain, or discoloration of their legs.
Frequently these symptoms of leg ischemia, a condition in which blood flow to the lower extremities is restricted, were accompanied by respiratory distress, cough, fever, and altered mental status.
The alarming trend prompted the researchers to look more closely at a possible connection between COVID-19 and lower extremity arterial thrombosis and whether people with the virus had a worse prognosis.
In March and April 2020, the team identified 16 COVID-19-positive patients, average age 70, who underwent CT angiography of the lower extremities for symptoms of leg ischemia.
These patients were compared with 32 COVID-19-negative patients, average age 71, who underwent CT angiography with similar symptoms.
All patients with COVID-19 infection undergoing lower extremity CT angiography had at least one clot in the leg, compared with only 69% of controls.
The clots in the COVID-19 patients were much larger and affected arteries higher up in the leg with greater frequency than those in controls. Death or limb amputation was more common in COVID-19 patients.
The team says the blood clots linked to COVID-19 infection strikingly increased rates of amputation and death, which in their series were 25% and 38%, respectively.
For comparison, the rate of both amputation and death was only 3% among controls.
It is unclear whether the patients’ concurrent COVID-19-related pneumonia, the virulence of the COVID-19-related clotting disorder or delayed initial arrival to the hospital contributed to these outcomes.
COVID-19 patients presenting with symptoms of leg ischemia only were more likely to avoid amputation or death than patients who had symptoms of ischemia and systemic symptoms including cough, respiratory distress or failure, hypoxia, fever, or altered mental status.
The team noted that with infection rates rising in many parts of the country, it is important that physicians be mindful of the connection between COVID-19 and lower extremity arterial thrombosis.
COVID-19’s association with lower extremity arterial thrombosis is likely related to a combination of factors, including an increased tendency of the blood to clot, damage to the lining of the arteries, and immune reactions tied to the SARS-CoV-2 virus and COVID-19 infection.
One author of the study is Inessa A. Goldman, M.D., a radiologist at Montefiore and an assistant professor at Albert Einstein College of Medicine in New York City.
The study is published in Radiology.
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