Half of Covid-19 ICU patients form blood clots: study

A study of 184 coronavirus patients in intensive care found that half of them have thrombosis symptoms. Thrombosis is the formation of blood clots, which can cause life-threatening complications like strokes or heart attacks, NOS reports.

The study was done in three Dutch hospitals - the Leiden University Medical Center (LUMC), the Amphia Hospital in Beda, and the Erasmus Medical Center in Rotterdam. Doctors worldwide also reported more than average cases of thrombosis cases among Covid-19 patients.

"These results were received with surprise worldwide. Until now, the main focus has been on infections in the lungs and their consequences, but not on thrombosis complications," Internal Medicine professor Menno Huisman of LUMC, who led the study along with internist Rik Endeman of Erasmus MC, said to NOS. "Now we can also try do do something about it. By giving ICU patients an increased dose of blood thinners, you can reduce the risk of thrombosis complications and, if possible, improve their condition."

A combination of factors can cause blood clots in coronavirus patients, Huisman explained. "One of the factors is the high rate of inflammation of the coronavirus, which activates blood clotting." Another factor is that coronavirus patients who are intubated in intensive care are put in a medical coma, sometimes for a long period. "They lie motionless in bed for days. This makes it easy for blood clots to form in the legs." 

These clots could enter the lungs, or the heart or head, resulting in pulmonary embolism, heart infarction, or stroke. In this study, most of the patients who had blood clots had them in their lungs. To a lesser extent, clots were found int he head or heart - but that number is still seven to ten times higher than normal, Huisman said. A worrying finding is that the cerebral infarctions also affect people who had no risk factors prior to the coronavirus, such as high blood pressure, high cholesterol or a tobacco addiction. These patients were also quite young.

The guidelines for treating Covid-19 patients were amended when the initial results of this study were published in mid-April. It is now recommended that coronavirus patients in ICU are given double the amount of anticoagulant heparin, which they were already getting as a precaution. "Honestly, we don't yet know whether that is enough. Of course we hope so and there is reason to assume that. But we still have to find out," Huisman said to NOS. "We do that by looking at new ICU patients who have received a double dose of heparin from the start."