A new way to prevent repeat heart attacks?

A man having a blood test

According to news headlines, looking at how quickly your body can break down blood clots could predict your risk of a repeat heart attack. We look deeper at the research.  

9 February 2018

Testing blood samples to see how long it takes clots to break down could predict how likely it is that you'll suffer a repeat heart attack, and make new treatments possible, according to a new study.

The researchers, based at the University of Sheffield, analysed blood samples from more than 4,300 patients with acute coronary syndrome (ACS) as they were discharged from hospital. ACS is an umbrella term for situations where the blood supplied to the heart muscle is suddenly blocked, such as a heart attack or unstable angina.

The researchers measured the time it took for the clot to be naturally broken down by enzymes in the body. They found that the patients with the longest clot breakdown time had a 40 per cent higher risk of another heart attack or death due to heart and circulatory disease.

The researchers hope that, after further research, this study could lead to better tailored treatment after a heart attack

The study was partly funded by the BHF. Professor Storey, who led the study, said: “Our findings provide exciting clues as to why some patients are at higher risk after a heart attack and how we might address this with new treatments in the future.”

Previous research has shown that 20 per cent of people with ACS will have a repeat event within 12 months.

At the moment, heart attack patients are prescribed aspirin and another drug, such as clopidogrel. These medications are called antiplatelet drugs – they work by preventing platelets in the blood sticking together to form a clot.

The researchers hope that, after further research, this study could lead to better tailored treatment after a heart attack. They hope that further research will find out whether drugs that help clots break down faster, combined with existing antiplatelet medications, could reduce the risk of another heart attack or death from heart and circulatory disease. 

How good was the study?

One strength of this research was the large number of patients included, and that their data was collected in a real-world setting, at the hospital. 

A limitation of this study is that only one sample was taken from each patient to assess blood clot breakdown time – the researchers describe this as “only a snapshot assessment’.” Some of these processes may be affected by your body clock, but it’s not known what time samples were taken, though they know samples were collected during office hours.

How good was the news coverage?

The story was covered in the Daily Mail. A weakness of the Daily Mail’s coverage was that it suggested that the test alone offers a solution. For example, the headline said “Simple blood test could spare heart patients from deadly repeat attacks, scientists say”. The test is not particularly simple - testing clot breakdown times requires trained laboratory staff, so it would not be suitable as a bedside test. And the researchers suggest that new treatments would be needed to target clot breakdown in the high-risk patients identified by the test - not the existing antiplatelet treatments which aim to stop clots forming in the first place. 

The BHF view

Metin Avkiran, Associate Medical Director for Research at the British Heart Foundation, said:

“We know that heart attacks commonly occur because of a blood clot forming in a coronary artery, causing a blockage - so the correlation observed between the strength of blood clots and the likelihood of death from a new cardiovascular event is important.

“This interesting research could help us to assess the blood clotting properties of heart attack patients and might allow customised treatment of these patients to minimise their risk of death from further cardiovascular events. However we would need further research to draw firm conclusions and to determine the best treatments for people whose blood is prone to forming stronger clots.”

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