Hospital team discovers why a routine treatment for severe Covid-19 can fail

Researchers in Swansea have made a breakthrough in understanding one of the most damaging consequences of Covid-19.

They have confirmed significant findings in how the virus alters the body’s blood clotting process, which means current treatments can fail.

Main image above: research assistant Jan Whitley and research nurse Jun Cezar Zaldua, who made numerous trips into Covid hotspots

The team at the Welsh Centre for Emergency Medicine Research, based at Morriston Hospital, found evidence that standard blood-thinning drugs are less effective in patients with severe Covid.

Their discovery could mean changes in the way Covid patients are treated in future.

Covid is known to trigger the formation of abnormal blood clots, which can lead to damage in organs including the brain and lung, causing life-threatening complications such as stroke.

What is not as clear is why this happens. And that is what the centre has been investigating after it was awarded Welsh Government funding.

The centre, based in Morriston’s Emergency Department, was founded and is led by Professor Adrian Evans.

He said: “Covid-19 is known to have an adverse effect on the clotting process of the body.

“It leads to activation of the clotting mechanism which in turn results in formation of clots within the organs. This often leads to multi-organ failure.

“One of the treatments to prevent this is to give clot-breaking drugs such as heparin. But it is not always effective, so some Covid patients end up with organ damage.”

In September 2020, following the first Covid wave, the team was awarded a Welsh Government Ser Cymru grant to look at why the clots formed and why they were resistant to breaking down.

The value of the research was around £130,000, including the Welsh Government grant and match-funding.

It involved the use of new biomarkers, a form of blood test, which the team previously developed to screen patients at risk of thromboembolic disease such as stroke, sepsis and deep vein thrombosis.

For this study, around 1,000 patients were screened for suitability when they arrived at Morriston Hospital. Blood samples were then taken from 155 of them, all with suspected Covid.

Further samples were taken after 24 hours, three to five days and one week.

The samples were collected by research assistant Jan Whitley and research nurse Jun Cezar Zaldua, who made numerous trips into Covid hotspots including the Emergency Department and intensive care.

The results were then analysed in the Welsh Centre’s laboratory, as was a large volume of clinical and scientific data collected at the bedside.

Professor Evans (pictured left) said: “We have shown that Covid-19 can lead to the formation of an abnormally strong clot despite full anticoagulation treatment in many cases.

“In those patients who did poorly there was clear evidence that the heparin wasn’t as effective as it should be in reducing clot formation and improving blood flow to the organs, such as the lungs, kidney and brain.”

The findings have been presented at the International Symposium for Intensive Care and Emergency Medicine in Brussels by Dr Oliver Watson and Dr Matthew Howard, clinical research fellows working at the centre.

Dr Watson said the research found that patients who died due to Covid-19 or required an admission to ICU had a compromised ability to break down clots compared to patients with a less severe infection.

“This effect can lead to microscopic blood clots forming in organs of the body leading to the multi-organ failure which is the cause of death in many Covid patients,” he said.

Using a technique known as fractal dimension analysis, which the centre developed in collaboration with Swansea University College of Engineering and Medicine, the team found that anticoagulant drugs used to prevent blood clots are less effective in Covid than in other infections.

“So the blood thinning medications were not having the intended therapeutic effect of breaking the clots down,” added Dr Watson.

“Hopefully this can be fed back to clinicians to tailor treatments in patients with the most severe cases of Covid-19.”

As well as being presented at the Brussels event, the findings have been published in a specialist journal, with more publications set to follow.

Further studies are planned in collaboration with Pennsylvania University, with which the Morriston centre has an ongoing research collaboration.

These studies will try to determine which specific mechanisms promote abnormal clotting in acute diseases such as Covid - using new pioneering techniques on clotting to further validate the findings.

Dr Suresh Pillai, Morriston Hospital consultant in emergency medicine and critical care and clinical lead for the study, said abnormal clotting problems were difficult to manage.

“Any new discoveries will lead the way to improve our understanding of the relationship between Covid and clotting and treatment failure,” he said.