Changing standard of care for mild heart attacks

A new Flinders University study, recently funded by the federal government, is set to determine whether a cardiac CT scan is a more suitable investigative tool for mild heart attacks than the current standard, which is invasive coronary angiography.

If proven successful by a randomised control trial, changing the standard of care has the potential to reduce the risk of complications and the transfer of regional patients to metropolitan settings.

“Due to the uptake of high-sensitivity troponin tests – tests that can identify damage to the heart muscle, even at low levels – more patients are being identified as having heart damage and sent for an invasive coronary angiogram,” says Chief Investigator Associate Professor Sam Lehman, a practising cardiologist and academic with Flinders University’s College of Medicine and Public Health.

Associate Professor Sam Lehman. Image credit: Ashford Cardiac Clinic

“This is despite the fact that most patients with lower levels of troponin are not found to need surgery to reduce or remove a blockage.

“Our current standard of care is based on evidence that was established in an earlier era, when our tests were less sensitive. The benefit of the current standard has not been established with the more modern troponin tests and has significant implications for rural and regional areas, where patients are often transferred to metropolitan centres, potentially unnecessarily.”

The project, which has received almost $1 million from the Medical Research Future Fund, will undertake a randomised control trial featuring 3000 patients, evaluating the safety of first-line investigation with CT coronary angiography (CTCA), compared to invasive coronary angiography (ICA).

Over 12 months, the researchers will monitor for cardiovascular death and new or recurrent myocardial injury (damage to the heart) among patients with suspected acute coronary syndrome and low-level troponin elevation.

The trial will also evaluate if the CT angiography is a better method with regards to bleeding, the potential to injure the heart muscle during the procedure, and patient satisfaction. It will also create a machine learning algorithm to better support clinicians decide which diagnostic technique should be used for each patient.

“Overall, the aim of the trial is to advance the evidence-base we have for these procedures and support their translation into practice and policies,” says Associate Professor Lehman.

“Alongside a reduction in health care costs, there is potential for early CT coronary angiography to be a non-invasive alternative to ICA, leading to a reduction in ad hoc revascularisations (surgery to unblock the heart), reducing the potential for patient harm and providing for more accessible treatment throughout Australia.

“Rural and remote areas often have less access to cardiac expertise that can inform care, with only 11.5% of cardiologists located in these geographic regions, despite 28% of Australia’s population living in these areas, potentially driving inappropriate treatment.

“Changing the standard of care could drive more appropriate access to acute cardiac investigations and equitable health outcomes in regional and remote areas.”

The project ‘Impact of non-invasive coronary angiography on suspected acute coronary syndromes with low concentration troponin elevation’ has been awarded $999,542.50 by the Medical Research Future Fund 2021 Cardiovascular Health Grant Opportunity.

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