Evaluation Of Stress Cardiac Magnetic Resonance Imaging In Risk Reclassification Of Patients With Suspected Coronary Artery Disease

Key PointsQuestionIs stress cardiac magnetic resonance imaging able to reclassify risk in patients with suspected coronary artery disease, across American College of Cardiology/American Heart Association guideline-based risk categories? FindingsIn a multicenter cohort study of 1698 consecutive patients (median follow-up, 5.4 years) without a history of coronary artery disease, stress cardiac magnetic resonance imaging was performed for evaluation of suspected coronary artery disease. Stress cardiac magnetic resonance imaging significantly reclassified patient risk for cardiovascular death and myocardial infarction across American College of Cardiology/American Heart Association guideline-based risk categories. MeaningThe findings of this study suggest that, in patients with suspected coronary artery disease, stress cardiac magnetic resonance imaging may provide incremental prognostic value for cardiovascular death and myocardial infarction and aid in clinical decision-making by reclassifying a substantial proportion of patients at intermediate risk.ImportanceThe role of stress cardiac magnetic resonance (CMR) imaging in clinical decision-making by reclassification of risk across American College of Cardiology/American Heart Association guideline-recommended categories has not been established. ObjectiveTo examine the utility of stress CMR imaging for risk reclassification in patients without a history of coronary artery disease (CAD) who presented with suspected myocardial ischemia. Design, Setting, and ParticipantsA retrospective, multicenter cohort study with median follow-up of 5.4 years (interquartile range, 4.6-6.9) was conducted at 13 centers across 11 US states. Participants included 1698 consecutive patients aged 35 to 85 years with 2 or more coronary risk factors but no history of CAD who presented with suspected myocardial ischemia to undergo stress CMR imaging. The study was conducted from February 18, 2019, to March 1, 2020. Main Outcomes and MeasuresCardiovascular (CV) death and nonfatal myocardial infarction (MI). Major adverse CV events (MACE) including CV death, nonfatal MI, hospitalization for heart failure or unstable angina, and late, unplanned coronary artery bypass graft surgery. ResultsOf the 1698 patients, 873 were men (51.4%); mean (SD) age was 62 (11) years, accounting for 67 CV death/nonfatal MIs and 190 MACE. Clinical models of pretest risk were constructed and patients were categorized using guideline-based categories of low (<1% per year), intermediate (1%-3% per year), and high (>3% year) risk. Stress CMR imaging provided risk reclassification across all baseline models. For CV death/nonfatal MI, adding stress CMR-assessed left ventricular ejection fraction, presence of ischemia, and late gadolinium enhancement to a model incorporating the validated CAD Consortium score, hypertension, smoking, and diabetes provided significant net reclassification improvement of 0.266 (95% CI, 0.091-0.441) and C statistic improvement of 0.086 (95% CI, 0.022-0.149). Stress CMR imaging reclassified 60.3% of patients in the intermediate pretest risk category (52.4% reclassified as low risk and 7.9% as high risk) with corresponding changes in the observed event rates of 0.6% per year for low posttest risk and 4.9% per year for high posttest risk. For MACE, stress CMR imaging further provided significant net reclassification improvement (0.361; 95% CI, 0.255-0.468) and C statistic improvement (0.092; 95% CI, 0.054-0.131), and reclassified 59.9% of patients in the intermediate pretest risk group (48.7% reclassified as low risk and 11.2% as high risk). Conclusions and RelevanceIn this multicenter cohort of patients with no history of CAD presenting with suspected myocardial ischemia, stress CMR imaging reclassified patient risk across guideline-based risk categories, beyond clinical risk factors. The findings of this study support the value of stress CMR imaging for clinical decision-making, especially in patients at intermediate risk for CV death and nonfatal MI.This cohort study examines the use of stress cardiac magnetic resonance imaging in reclassification of risk for cardiovascular death and nonfatal myocardial infarction in patients with suspected myocardial ischemia.