The World's ageing population with a life expectancy that is steadily increasing raises the question of the benefit of screening for coronary artery disease (CAD) in very old patients with high risk of CAD. Current guidelines discourage the performance of stress testing in asymptomatic elderly.
To assess the prognostic value of vasodilator stress perfusion cardiac magnetic resonance (CMR) in elderly patients aged > 75 years without previous known CAD.
Consecutive elderly patients > 75 years without known CAD referred for vasodilator stress perfusion CMR were followed for major adverse cardiovascular events (MACE) defined as cardiac death, non-fatal myocardial infarction or stroke. Univariable and multivariable Cox regressions for MACE were performed to determine the prognostic association of inducible ischemia or late gadolinium enhancement (LGE) by CMR beyond traditional clinical risk indexes.
Of 754 elderly high risk patients (82.0 ± 3.9 years, 48.4% men), 747 (99%) completed the CMR protocol, and among those 659 (88.2%) completed the follow-up (median follow-up 5.7 ± 2.5 years). Reasons for failure to complete CMR included claustrophobia (n = 3), declining participation (n = 2) and intolerance to stress agent (n = 2). Stress CMR was well tolerated without occurrence of death or severe disabling adverse event. Patients without inducible ischemia or LGE experienced a substantially lower annual rate of MACE (5.5% vs. 9.9% for those with ischemia and vs. 6.9% for those with ischemia and/or LGE). In a multivariable stepwise Cox regression including clinical characteristics and CMR indexes, the absence of inducible ischemia was an independent predictor of a lower incidence of MACE at follow-up (hazard ratio 0.46 ; 95% confidence interval: 0.34 to 0.62 ; p < 0.001) (Figure 1A) and all-cause mortality (hazard ratio 0.67 ; 95% confidence interval: 0.45 to 0.97 ; p = 0.037).
When patients with early coronary revascularization (within 30 days of CMR) were censored on the day of revascularization, both presence of inducible ischemia and ischemia extent per segment maintained a strong association with MACE. Using Kaplan-Meier analyses, the presence of myocardial ischemia identified the occurrence of future CV events (p < 0.001). Moreover, the absence of inducible ischemia was a predictor of a lower incidence of MACE less significant in men than in women (p < 0.01) (Figure 1B).
Stress CMR is safe and has discriminative prognostic value in very elderly patients, with a very low negative event rate in patients without ischemia or infarction. Among elderly patients without known CAD, the presence of myocardial ischemia on vasodilator stress CMR was predictive of future CV event or death.