Given its clinical advantages, lack of ionizing radiation, and cost-effectiveness, stress cardiovascular magnetic resonance imaging (CMR) is expected to be increasingly used for evaluating ischemic heart disease, a new review concludes.
Published online Monday and in the Oct. 19 issue of the Journal of the American College of Cardiology, as its JACC Review Topic of the Week, the paper reviews the basics principles of stress CMR, the data supporting its clinical use, the added value of myocardial blood flow quantification, and the assessment of myocardial function and viability routinely obtained during a stress CMR study.
Led by Amit R. Patel, MD, from the University of Chicago, the authors noted that stress CMR has been extensively validated for the evaluation of patients with known and suspected coronary artery disease (CAD).
“There is a large body of literature, including randomized controlled trials, validating its diagnostic performance, risk stratification capabilities, and ability to guide appropriate use of coronary intervention,” they said.
“Specifically, stress CMR has shown higher diagnostic sensitivity than single-photon emission computed tomography imaging in detecting angiographically significant coronary artery disease.”
Furthermore, Patel and colleagues noted that stress CMR is “particularly valuable” for the evaluation of patients with moderate to high pretest probability of having stable ischemic heart disease (SIHD), and for patients known to have challenging imaging characteristics, including women, individuals with prior revascularization and those with left ventricular dysfunction.
Stress CMR benefit
According to the review, multiple recent studies have reported the clinical utility of stress CMR for the evaluation of patients with known or suspected CAD.
“Stress cardiovascular magnetic resonance imaging (CMR) is a cost-effective, noninvasive test that accurately assesses myocardial ischemia, myocardial viability, and cardiac function without the need for ionizing radiation,” the authors said.
“A revascularization strategy guided by stress CMR has effectiveness comparable to that guided by invasive measurement of fractional flow reserve and can be particularly helpful in clinically stable patients with a moderate to high pretest probability of ischemic heart disease,” said the team, adding that quantification of myocardial blood flow from stress CMR images “is an emerging application for assessment of ischemic burden and coronary microvascular function.”
However, Patel and colleagues added that although stress CMR is an “excellent tool” for the assessment of SIHD, it does have limitations.
“Notably, stress CMR cannot readily be combined with exercise at present,” they noted – adding that prototype treadmills that can be used in the MRI environment are in development.
“There are also several potential patient-related factors that might limit its widespread use,” the reviewers noted, adding that claustrophobic and obese patients may not be able to tolerate the tests, but also noting that modern wide-bore scanners combined with the use of low-dose oral sedation have reduced this challenge to exist in only 3% to 4% of all patients.
A cost-effective approach
The authors noted that the utilization of stress CMR has also been hampered by relatively common misperceptions that consider stress CMR to be an expensive procedure.
“Indeed, the payment for a stress CMR examination ($680.74) by the Hospital Outpatient Prospective Payment System in the year 2020 was considerably less than that for SPECT ($1,272.05) and positron emission tomography ($1,443.00 or $2,250.50 if combined with computed tomography transmission scan), paving the way for it to be a highly cost-effective strategy for assessing SIHD,” they argue
They added that stress CMR has also shown superiority to single-photon emission computed tomography (SPECT) and equivalence to a fractional flow reserve-guided invasive angiographic approach to patient evaluation.
“Given its clinical advantages, lack of ionizing radiation, and cost-effectiveness, it should be expected that stress CMR will be increasingly used for the evaluation of ischemic heart disease,” they said.
Patel AR, Salerno M, Kwong RY, et al. Stress Cardiac Magnetic Resonance Myocardial Perfusion Imaging: JACC Review Topic of the Week. J Am Coll Cardiol 2021;78:1655-1668.
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