Covid-19 and thrombosis: what do we know about the risks and treatment?
Jacqui Wise
Abstract
Covid-19 and thrombosis: what do we know about the risks and treatment?Doctors are seeing high rates of blood clots in patients who are seriously ill with covid-19, but questions remain over best practice, reports Jacqui Wise Jacqui Wise London How common is thrombosis in critically ill patients with covid-19?A recent Dutch study of 184 patients with covid-19 pneumonia admitted to an intensive care unit (ICU) found a 49% cumulative incidence of thrombotic complications-mainly changes seen on computed tomography (CT) pulmonary angiograms. 1 The authors said that this level was "remarkably high," given that all patients received at least standard doses of thromboprophylaxis.Other studies from France and the Netherlands have also suggested that thrombosis occurs in 20-30% of critically ill covid-19 patients, even with prophylaxis. 2 3"The extent of thrombosis we are seeing with covid is extraordinary," Roopen Arya, clinical director for haematology at King's College Hospital, told The BMJ. "I would say that one third of those severely affected with covid in critical care is a conservative estimate." Why are covid-19 patients at particular risk of thrombosis?Covid-19 causes massive inflammation boosting cytokines, which increase the liver's production of clotting factors, explains Beverley Hunt, medical director of Thrombosis UK and a practising clinician.For example, fibrinogen levels in a severely ill covid-19 patient are 10-14 g/L, compared with 2-4 g/L normally and 5-6 g/L in a pregnant woman."A covid patient's blood is enormously sticky," she told The BMJ.