Researchers in the U.K. have developed a novel prognostic tool based on magnetic resonance imaging (MRI) that could remove the need for invasive catheterization techniques used nowadays. A study published today in JACC Advances shows that this new method yields comparable results to heart catheter tests and can accurately predict future outcomes in patients diagnosed with advanced heart failure.
“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,” said Pankaj Garg, MD, PhD, associate professor of cardiovascular medicine at the University of East Anglia and consultant cardiologist at the Norfolk and Norwich University Hospital. “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.”
Cardiac catheterization is a technique that involves the insertion of a catheter that is guided through a blood vessel until it reaches the heart. In advanced heart failure patients, this technique can be used to measure blood oxygen levels inside the heart, serving as a prognostic tool to guide decision-making and monitor therapy responses.
“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,” said Garg. “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.”
The method developed by Garg and colleagues relies on an established MRI technique known as T2 mapping, which is already used to give a broad estimation of oxygen levels in the brain and other body tissues. The key innovation lies in the development of a novel formula to quantify oxygenation more accurately.
“Blood with different oxygen levels behaves slightly differently in a magnetic field,” said Garg. “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 technique was first tested in a cohort of 30 patients who also underwent heart catheterization. Results showed a significant correlation between the results of both methods that stayed consistent even when adjusting for factors such as age, sex, and a number of established cardiac markers.
Then, a validation cohort of 628 patients recently diagnosed with heart failure were assessed using the MRI technique. Within a median follow-up period of three years, patients with higher oxygen readings were found to be significantly less likely to die or be hospitalized. Compared to other non-invasive techniques currently used to assess overall heart function, such as ultrasound and blood tests, the new method was shown to be a much better predictor of patient outcomes.
“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,” said Gareth Matthews, MD, PhD, clinical lecturer at Norwich Medical School. “It has real potential to widen access to safer heart failure assessment across the NHS.”
