Doctors may be able to assess the level of illness in people with heart failure using an MRI scan, according to research from the University of East Anglia.
People with heart failure often undergo right heart catheterisation, a test in which a tube is placed into the heart to measure blood oxygen levels. Clinicians use this measurement to assess the stage of the condition.
The procedure involves insertion of a tube into the heart and carries risk, particularly for patients with health limitations or multiple conditions.
Researchers at the University of East Anglia developed a method to estimate blood oxygen levels using cardiac MRI data. The research team stated that this approach could reduce the need for catheter-based testing in the future.
Lead researcher Prof Pankaj Garg, from UEA’s Norwich Medical School, said; “Heart failure affects hundreds of thousands of people in the UK and significantly weakens the heart’s ability to pump blood. Doctors often need detailed information about a patient’s circulation to decide on the best treatment.
“We wanted to develop a safe, non-invasive alternative which could allow far more patients to be properly assessed – and allow repeat monitoring without the risks of a catheter test.
“Our breakthrough could be a game changer for assessing advanced heart failure. It could allow us to measure risk more safely and more often, especially for patients who are too frail or high-risk for an invasive catheter procedure.”
The research team used a form of MRI measurement known as T2 mapping to estimate oxygen levels in blood returning to the heart. This measurement is used as an indicator of how the heart is functioning.
Prof Garg said; “Blood with different oxygen levels behaves slightly differently in a magnetic field. By measuring how that blood reacts, we were able to develop a formula that predicts the oxygen reading without ever inserting a tube or taking a blood sample.”
The method was first tested in 30 patients, where MRI-based estimates aligned with results from catheter-based measurements. The researchers then examined data from 628 people with heart failure at diagnosis and followed them for about three years. Participants with higher oxygen measurements on MRI experienced fewer deaths or hospital admissions related to heart failure.
The researchers reported that the MRI-based measurement remained consistent after accounting for age, co-existing conditions and heart performance.
Prof Garg said, “One of the most important markers in advanced heart failure is how much oxygen is left in blood returning to the right side of the heart. Until now, getting that number has usually meant a tube test. Our study shows it can be estimated non-invasively from a standard heart MRI.”
Co-author Dr Gareth Matthews, from the University of East Anglia, said; “Because this can be done as part of a standard cardiac MRI, it needs no extra hardware and no contrast dye, and adds only seconds to the scan.
“It has real potential to widen access to safer heart failure assessment across the NHS,” he added.
The research team stated that further studies are required to confirm the findings across hospital settings and patient groups, and to determine how the measurement can be used in clinical decision-making.
The study, titled ‘Development and validation of a non-invasive model of mixed venous oxygen saturation in heart failure’, is published in JACC Advances.