Post-Covid anticoagulant reduces risk of thrombosis by 67%, study points out

by

Covid is already known to be a thromboembolic disease — that is, it has a high risk of causing thrombosis during infection, especially in patients who are hospitalized for a long time.

Older individuals or individuals with a history of the problem are at increased risk in post-Covid for the occurrence of blood clots that can cause potentially fatal deep vein thrombosis, cerebral thrombosis or pulmonary embolism.

To try to get around this situation, a national multicenter study evaluated the action of anticoagulant use for up to 35 days after hospital discharge in patients at higher risk for thrombosis, and found a significant reduction in events with the drug.

The results were published in this Wednesday (15) issue of The Lancet. The study brought together researchers from several hospitals and educational institutions in Brazil and abroad, including the international research institute Science Valley, founded in Santo André (SP), the Hospital das Clínicas at USP, the Hospital and Maternity Christóvão da Gama, also in Santo André, Unesp in Botucatu, Hospital do Rocio, in Campo Largo (PR), and Instituto Couto Maia, in Salvador (BA).

Patients who had a severe condition of Covid and at high risk for thrombosis participated in the study, half of whom were admitted to the ICU between October 2020 and July 2021.

The research, coordinated by vascular surgeon and Science Valley co-founder Eduardo Ramacciotti, recruited more than 900 patients in 14 hospital centers across the country, of which 320 were randomized to receive the drug or placebo (160 in each group) for 35 days after discharge hospital.

An incidence of thromboembolic events in the analyzed period of 3.14% was observed in patients treated with 10mg of Xarelto (brand name for the drug rivaroxaban), a common anticoagulant, compared to 9.43% in the group that received the placebo, indicating a reduction risk of thrombosis of 67%.

The analysis of subgroups in the trial further indicated that the reduction in the risk of death from deep vein thrombosis was about 87% in the treated group compared to patients who received the placebo, with a single death observed among patients who received the anticoagulant and eight in the control group.

To determine the risk of thrombosis, patients were classified according to an assessment of risk factors — such as older age, thrombophilia, history of cancer or venous thrombosis — called Improve (an acronym for the international registry on medical prevention in venous thromboembolism).

“We investigated which population would benefit most from the treatment, and it is the one with high risk of thrombosis and low risk of bleeding. Our objective was to assess whether the drug prevented thromboembolic events in the 35 days after discharge in this population”, explains Ramacciotti.

The researchers looked for cases of clots during the treatment period in tests such as CT angiography (tomography of blood vessels) and leg Doppler, among others.

According to the doctor, the study methodology calculated the number of events accumulated up to day 35, and not the number of days until the formation of the clot.

“The period of 35 days was precisely so that the patients would not be lost to follow-up, that is, they gave up during the study. And in that sense, they [os pacientes] collaborated in an exceptional way, almost 90% returning for follow-up in the treated arm”, he says.

Rivaroxaban is an oral inhibitor of clotting factor 10, acting on one of the molecules that cause blood clotting, and is used both in the treatment of deep vein thrombosis and in the treatment of other vascular diseases such as atrial fibrillation and also in stroke victims ischemic. It is also used as a prophylaxis for orthopedic surgery.

The choice to use the drug in the study was its indication in the package insert for a wide range of thromboembolic events, in addition to the recommendation by the FDA (Food and Drugs Administration, the American agency that regulates drugs) for extra-hospital use.

“In Brazil, there is no indication in the package insert by Anvisa [Agência Nacional de Vigilância Sanitária] for treatment after hospital discharge, but we believe that with the very robust results of this study and the incorporation of treatment as a protocol in several countries, it will be incorporated at least initially with the ‘off label’ use and then this will also be extended in the country,” says the doctor.

The “off label” use consists of using a drug in a different way than recommended by the package insert and approved by Anvisa.

In the case of rivaroxaban, it is commonly used to treat deep vein thrombosis, but it can also be used prophylactically—that is, for prevention.

.

You May Also Like

Recommended for you