Impact of stress perfusion abnormalities by cardiac magnetic resonance on long-term prognosis in patients without significant epicardial coronary artery stenosis: a comparative study by chest pain

Background Myocardial perfusion abnormalities detected by stress perfusion cardiac magnetic resonance (CMR) are established markers of adverse prognosis in patients with chest pain and non-obstructive epicardial coronary artery disease. However, the prognostic significance of CMR-detected perfusion abnormalities in patients without chest pain, particularly when significant epicardial coronary stenosis is carefully excluded, remains unclear. Purpose To investigate the long-term prognostic impact of stress perfusion CMR-detected perfusion abnormalities in patients without significant epicardial coronary artery disease, focusing on differences according to chest pain status. Methods This single-center retrospective study screened 3,301 consecutive patients who underwent stress perfusion CMR between May 2008 and July 2023. The main exclusion criteria were ischemic heart disease, defined as a history of myocardial infarction or prior treatment for coronary artery disease, and significant epicardial coronary disease (>50% stenosis or fractional flow reserve <0.80). We also excluded patients with unavailable coronary evaluation, late gadolinium enhancement on CMR, major cardiac comorbidities, and follow-up shorter than 90 days. After these exclusions, 597 patients were included and followed through September 2024. Patients were stratified by the presence or absence of chest pain. Within each stratum, outcomes were compared according to the presence or absence of myocardial perfusion abnormality. The primary endpoint was all-cause mortality, and the secondary endpoints were major adverse cardiac and cerebrovascular events (MACCE) and hard cardiac events. MACCE comprised cardiac death, non-fatal myocardial infarction, unplanned revascularization, heart failure hospitalization, new-onset arrhythmia, or stroke, while hard cardiac events comprised cardiac death or non-fatal myocardial infarction. Results During a median follow-up of 8.6 years, perfusion abnormality was not associated with higher mortality in patients without chest pain (p=0.57) (Figure 1A) In contrast, perfusion abnormality was associated with higher all-cause mortality among those with chest pain (p<0.01) (Figure 1B). In multivariable Cox analysis, perfusion abnormality independently predicted all-cause mortality in patients with chest pain (Hazard ratio:2.44, 95%CI:1.03-5.74), whereas in patients without chest pain it was not associated with mortality. Perfusion abnormality was not associated with MACCE or hard cardiac events regardless of chest pain. Conclusion In patients without significant epicardial coronary disease, stress perfusion CMR-detected perfusion abnormalities were associated with higher long-term all-cause mortality only in those with chest pain. These findings suggest that chest pain status should be considered when interpreting stress perfusion CMR perfusion abnormalities in patients without significant epicardial coronary disease.