Use of Myocardial Perfusion Imaging to Guide Prognosis and Management in Older Adults: Is There an Age Limit?

BACKGROUND: Myocardial perfusion imaging is used to guide risk stratification and revascularization decisions. We aimed to determine whether the prognostic value of ischemia on myocardial perfusion imaging and the association with early revascularization (ER) and outcomes differ across age groups. METHODS: We included 73 038 patients who underwent single photon emission computed tomography (n=45 252) or positron emission tomography (n=27 786) myocardial perfusion imaging across 20 sites from 2009 to 2024. ER was defined as revascularization within 90 days post-myocardial perfusion imaging. Propensity score-adjusted Cox models evaluated the interaction between age, ischemic burden (myocardial flow reserve for positron emission tomography), and ER for the primary outcome of all-cause death or nonfatal myocardial infarction. RESULTS: Median age was 66 years; 45.3% were <65, 31.5% were 65 to 74, 19.1% were 75 to 84, and 4.2% were ≥85. ER was performed in 6.1%, rising to 7.0% in those aged 75 to 84 years and decreasing to 6.5% in those aged ≥85 years. During a median follow-up of 3.7 years, 10 757 deaths/myocardial infarctions occurred. Increasing ischemia was associated with lower event rates after ER versus medical therapy across most age groups, with no significant continuous age-ischemia-ER interaction (P=0.748). In an exploratory analysis of 3031 patients aged ≥85 years, this association appeared attenuated (hazard ratio for ischemia >10%: 0.90 [0.64-1.26]), although precision was limited, likely reflecting, in part, the small number of patients undergoing ER (n=198). Among positron emission tomography patients, the myocardial flow reserve×ER association did not vary with age (3-way interaction P=0.689). In analyses excluding patients with ER, ischemia remained prognostic in all age groups, though its associated risk declined with advancing age. CONCLUSIONS: Ischemia remains prognostic across all ages and may help identify candidates who have improved outcomes with ER. In an exploratory analysis, this association appeared attenuated in patients aged ≥85 years, a hypothesis-generating observation. Positron emission tomography-derived myocardial flow reserve may provide complementary physiological information for treatment selection in older adults.