New 'clot-tracking' technology to guide better heart attack care

New imaging technology can identify smaller blood clots that current heart scans cannot pick-up, and could help guide more efficient treatment for people who’ve had a heart attack, according to research we've funded and presented at the European Society of Cardiology Congress.

When patients go to hospital with chest pain or a suspected heart attack they will have a special type of X-ray called an invasive coronary angiography. This creates images to reveal any narrowings, or blockages in the coronary arteries that supply blood to the heart. This is a critical step in a patient’s care as it helps doctors to decide the best course of treatment.

However, coronary angiograms can only detect larger blood clots which are formed when high-risk plaques rupture, causing a type 1 heart attack. Unfortunately, a large proportion of heart attacks are due to the rupturing of smaller plaques that lead to clots which are not visible by invasive angiography, leaving doctors puzzled as to which artery caused the heart attack.

Also, a large proportion of elderly patients, up to 50 per cent in some studies, have signs and symptoms of a heart attack that’s caused by an imbalance of oxygen supply to the heart - a type 2 heart attack – and therefore might undergo unnecessary invasive angiographies.

Improving diagnosis and care

Now, researchers from the BHF Centre of Research Excellence at the University of Edinburgh have developed the first tool that can spot these tiny blood clots in the coronary arteries and those that develop elsewhere. The researchers say that this technology could help doctors to better distinguish between a type 1 and 2 heart attack, improve the care that patients receive, and enable follow-up scans to check that treatment is successful.

They used an imaging ‘tag’ called 18F-GP1 that specifically binds to a protein on the outside of activated platelets – the cells responsible for blood to clot. The team performed a non-invasive heart scan with the addition of the new tag on 94 patients – 44 who had a heart attack five to 30 days previously, and 50 who did not have a heart attack.

The new tag identified blood clots in the coronary arteries of 80 per cent of the heart attack patients, and did not show-up on the scans of the control participants. They then looked at the 42 blood vessels that were known to cause the patients’ heart attack, and found that the tag was able to identify their location with high accuracy.

Detecting blood clots elsewhere

The tag also detected blood clots outside of the coronary arteries. It successfully revealed clots in the left ventricle - the part of the heart responsible for pumping blood to the rest of the body, the tiny blood vessels that run throughout the heart muscle, and in the arteries that supply blood to the lungs. This means 18F-GP1 could detect alternative causes of a heart attack, which would provide additional information to that generated from a traditional angiogram.

Alternatively, if the tag doesn’t detect clots on the scan, then doctors could confidently know that the chest pain is not a result of a high-risk plaque rupturing, avoiding the need for invasive surgical procedures.

Dr Evangelos Tzolos, BHF Clinical Research Fellow at the University of Edinburgh, said:

“Our clot-tracking technology can detect clots that aren’t visible with the naked eye or current heart scans, and has the power to determine how active or ‘risky’ they are and help us differentiate between different type of heart attacks.

“We now need to test this technology on more people before it can be used in the NHS and establish how it could better detect blood clots responsible for heart attacks and strokes.”

Professor James Leiper, our Associate Medical Director, said:

“Most heart scans can detect the blockages caused by large blood clots. However, many people who’ve had a heart attack have tiny but life-threatening blockages in their heart that go undetected. We therefore need more sensitive and selective imaging techniques to detect these problem clots. This new tag appears to be a promising way of detecting smaller clots and with further research it could help to guide even better heart attack care.” 

Find out more about our heart attack research