Long-term prognostic value of stress perfusion cardiovascular magnetic resonance in patients without known coronary artery disease

BACKGROUND: To assess the incremental long-term prognostic value of vasodilator stress perfusion cardiovascular magnetic resonance (CMR) in patients without known coronary artery disease (CAD). METHODS: Between 2010 and 2011, consecutive patients with cardiovascular risk factors without known CAD referred for stress CMR were followed for the occurrence of major adverse cardiac events (MACE), defined by cardiovascular mortality or recurrent non-fatal myocardial infarction (MI). Uni- and multivariable Cox regressions were performed to determine the prognostic value of ischemia and unrecognized MI defined by sub-endocardial or transmural late gadolinium enhancement (LGE). RESULTS: Among 2,295 patients without known CAD, 2058 (89.7%) (71.2 ± 12.5 years; 37.5% males) completed the follow-up (median [IQR]: 8.3 [7.3-8.7] years), and 203 had MACE (9.9%). Using Kaplan-Meier analysis, ischemia and unrecognized MI were associated with MACE (hazard ratio, HR: 4.64 95% CI: 3.69-6.17 and HR: 2.88; 95% CI: 2.08-3.99, respectively; both p < 0.001). In multivariable stepwise Cox regression, ischemia and unrecognized MI were independent predictors of MACE (HR = 3.71; 95% CI 2.73-5.05, p < 0.001 and HR = 1.73; 95% CI 1.22-2.45, p = 0.002; respectively) and cardiovascular mortality (HR: 3.13; 95% CI: 2.17-4.51, p < 0.001 and HR = 1.73; 95% CI 1.15-2.62, p = 0.009; respectively). The addition of ischemia and unrecognized MI led to an improved model discrimination for MACE (change in C statistic from 0.61 to 0.72; NRI = 0.431; IDI = 0.053). CONCLUSIONS: Inducible ischemia and unrecognized MI identified by stress CMR have incremental long term prognostic value for the incidence of MACE in patients without known CAD over traditional risk factors and left ventricular ejection fraction.