A new study aims to improve heart attack test accuracy, by analysing routine blood tests from 20,000 patients at University Hospital Southampton.
The CHARIOT study, led by Southampton cardiologist and researcher Professor Nick Curzen, aims to improve the standard test for a heart attack to ensure patients get the right treatment.
To do this, his team will analyse blood test results from 20,000 patients admitted to University Hospital Southampton, taken as a routine part of their care.
Detecting heart damage
Heart damage during a heart attack releases the protein troponin into the bloodstream, and it is this that the standard heart attack test detects. However, raised troponin isn’t always the result of a heart attack, and can indicate other problems with the heart.
“Troponin can be raised in conditions that are not a heart attack,” explains Dr Mark Mariathas, who is involved in the study. “This is to do with the balance between supply and demand of oxygen to the heart - if this balance is compromised, with the oxygen demand of the heart outweighing the supply, you will get a rise in the troponin.”
Because of this, many patients who are not affected by a heart attack, but show raised troponin, undergo a series of unnecessary and sometimes risky procedures for treating heart attacks.
Putting patients first
A key challenge is that the level of troponin indicating a heart attack was originally determined by measuring troponin in the blood of healthy people between the ages of 18 and 40 years old. Those in the highest 1% are considered to have abnormally high levels.
However, patients treated for a heart attack in the hospital are generally older and suffer with significant medical conditions. Both old age and health problems such as heart failure, hypertension or sepsis can cause an increase in their troponin level, even if they haven’t suffered a heart attack.
“The problem comes when someone comes in to the hospital who hasn’t had symptoms of a heart attack, and we decide to check the troponin,” says Dr Mariathas. “We don’t really know what a raised troponin level in these patients means when the underlying cause is not a heart attack.”
To address this, the researchers aim to build as complete a picture as possible of troponin levels across patient ages and conditions. They will do this by including troponin testing in all routine blood tests at University Hospital Southampton, and use that data to set new test limits better aligned to age and accounting for other factors that contribute to high troponin.
For example, they expect patients with limited oxygen supply to the heart to have chronically high troponin levels, such as patients in the intensive care unit, having major surgery or those with the lung condition chronic obstructive pulmonary disease (COPD).
“We’re expecting the results from the study to change the way clinicians look at the troponin blood test,” says Dr Mariathas, “and show that patients in hospital tend to have higher troponin levels than a healthy population.”
Through this study, they hope to improve the detection of heart attacks and ensure the often life-saving treatment is targeted to those who truly need it.
Should you wish to withdraw your data from the study or for more information about the study, please call the Coronary Research Group on 023 8120 8538, or email Zoe at zoe.nicholas@uhs.nhs.uk or Mark at mark.mariathas@uhs.nhs.uk.
Alternatively, you can write to: Coronary Research Group, Cardiovascular & Thoracic Unit, Southampton General Hospital, Tremona Road, Southampton, SO16 6YD.