Covid-19 patients develop dangerous blood clots in leg arteries

New York: In a new study, the US researchers have revealed that Covid-19 is associated with life-threatening blood clots in the arteries of the legs.

Published in the journal Radiology, the research has shown that Covid-19 patients with symptoms of inadequate blood supply to the lower extremities tend to have larger clots and a significantly higher rate of amputation and death than uninfected people with the same condition.

"We found that arterial thrombosis associated with Covid-19 infection was characterised by dire outcomes, namely strikingly increased rates of amputation and death, which in our series were 25 per cent and 38 per cent, respectively," said study lead author Inessa A Goldman from the Albert Einstein College of Medicine in the US.

Covid-19's association with blood clots in the pulmonary arteries is well-established.

Less is known about the virus' connection to lower extremity arterial thrombosis, a condition characterised 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, radiologists 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 discolouration 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, they 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 in previous years and who were well matched with Covid-19 cohort for demographic and clinical characteristics.

The findings showed that all patients with Covid-19 infection undergoing lower extremity CT angiography had at least one clot in the leg, compared with only 69 per cent of controls.

The clots in the Covid-19 patients were significantly 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.

"For comparison, the rate of both amputation and death was only three per cent among controls," Goldman said.

The research 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.