Cardiovascular MRI for patients with typical angina reduces revascularization procedures compared with immediate angiography

Reference

Nagel E, Greenwood JP, McCann GP, et al. Magnetic resonance perfusion or fractional flow reserve in coronary disease. N Engl J Med 2019;380(25):2418-2428.

Synopsis

These authors identified 918 adults with typical angina who either had 2 cardiovascular risk factors or an abnormal treadmill stress test result. Risk factors for inclusion were hypertension, diabetes mellitus, smoking, family history of heart disease, or hyperlipidemia. Patients with New York Heart Association Class III or IV heart failure, previous bypass surgery, a glomerular filtration rate of less than 30 mL/min/1.73m2, or a percutaneous coronary intervention (PCI) in the previous 6 months were excluded. The mean age was 62 years, 72% were men, and approximately 18% had a history of myocardial infarction or PCI. Groups were balanced at the start of the unmasked study, and the authors performed a modified intention-to-treat analysis, as well as an intention-to-treat analysis using imputation for those patients with missing data. Patients were randomized into 1 of 2 diagnostic strategies. The MRI group received myocardial perfusion cardiovascular MRI, and if 6% or more of the myocardium had evidence of inducible ischemia, it was followed by invasive angiography and possibly revascularization. The FFR group received invasive angiography and their FFR was calculated, with revascularization recommended if the FFR was less than 0.8 for a vessel. In both groups, revascularization could be PCI or bypass surgery and was based on national guidelines. The primary outcome was a composite of death, nonfatal myocardial infarction, and the need for target-vessel revascularization at 12 months. At the end of the year, 67 patients (evenly split between the groups) had withdrawn or were lost to follow-up. There were no differences between groups for the composite outcome or any of its constituents. There was also no statistically significant difference between groups with regard to the percentage that the test recommended revascularization (40.5% for MRI vs 45.9% for FFR). However, fewer patients in the MRI group underwent index revascularization (35.7% vs 45.0%; P = .005; number needed to treat to prevent 1 revascularization in 1 year = 11). Also, only half the patients in the MRI group required invasive angiography, compared with nearly all of the patients in the FFR group.