Prognostic value of stress cardiovascular magnetic resonance in asymptomatic patients without known coronary artery disease

Objectives: A few studies suggest a significant prognostic value of silent myocardial ischaemia detected in asymptomatic patients. However, the current guidelines do not recommend stress testing in asymptomatic individuals. To assess the long-term prognostic value of vasodilator stress perfusion cardiovascular magnetic resonance (CMR) in asymptomatic individuals without known coronary artery disease (CAD).

Methods: Between 2009 and 2011, a retrospective cohort study with a median follow-up of 9.2 years (interquartile range: 7.8-9.6) included 1,027 consecutive asymptomatic individuals with ≥ 2 cardiovascular risk factors but without known known CAD referred for stress CMR. Major adverse cardiovascular events (MACE) included cardiovascular mortality and nonfatal myocardial infarction (MI).

Results: Among 1,027 asymptomatic subjects, 903 (87.9%) (mean age 70.6 ± 12.4 years and 46.2% males) completed the follow-up, and 91 had MACE (10.1%). Using Kaplan-Meier analysis, silent ischaemia and unrecognised MI were associated with MACE (hazard ratio [HR]: 8.70; 95% CI: 5.79-13.10 and HR: 3.40; 95% CI: 2.15-5.38, respectively; both p < 0.001). In multivariable stepwise Cox regression, silent ischaemia and unrecognised MI were independent predictors of MACE (HR: 6.66; 95% CI 4.41-9.23; and HR: 2.42; 95% CI 1.23-3.21, respectively; both p < 0.001). The addition of silent ischaemia and unrecognised MI led to improved model discrimination for MACE (change in C statistic from 0.66 to 0.82; NRI = 0.497; IDI = 0.070).

Conclusions: Silent ischaemia and unrecognised MI are good long-term predictors for the incidence of MACE in selected asymptomatic individuals with multiple risk factors and without known CAD. These stress CMR parameters have incremental long-term prognostic value to predict MACE over traditional risk factors.

Key points: • Silent ischaemia and unrecognised myocardial infarction defined by stress CMR are good long-term predictors of cardiovascular events in asymptomatic individuals without known coronary artery disease. • The addition of stress cardiac MR imaging led to improved model discrimination for cardiovascular events over traditional risk factors in this specific population.