Differential Impact of Appropriate Use Criteria on the Association between Age and an Abnormal Stress Myocardial Perfusion SPECT.

Abstract

The diagnostic and prognostic value of appropriate use criteria (AUC) for coronary artery disease (CAD) is well established. Whether the diagnostic yield of AUC for predicting CAD is preserved among the elderly is not known. We analyzed a multi-site prospective cohort of 1511 consecutive patients (mean age 59 ±13 years, 57% males) who underwent outpatient, community-based SPECT myocardial perfusion imaging (MPI). Appropriateness of the studies was determined based on the 2013 multimodality AUC for detection and risk assessment of stable ischemic heart disease. An abnormal SPECT MPI was defined by either a summed stress score ≥ 4 or a summed difference score ≥ 2. Abnormal SPECT MPI was present in 190 patients (12.5%), while ischemia on MPI alone was present in 122 (8%). In multivariate logistic regression analysis, age ≥ 60 years, male gender, hypertension, diabetes mellitus, and known CAD were independent predictors of an abnormal SPET MPI, while appropriate indication of testing was not. Age ≥ 60 years was also an independent predictor of inducible myocardial ischemia, while appropriate indication for testing was not. Among elderly (≥ 60 year), regardless of appropriateness of testing, there was no difference in the prevalence of an abnormal SPECT (19% vs. 14%, p=0.14) or prevalence of SPECT ischemia (11% vs. 11%, p=1.00). Among younger patients however, appropriate testing predicted a greater prevalence of an abnormal SPECT (12% vs. 7%, p=0.013). In this multi-site cohort, testing based on AUC did not discriminate the risk of an abnormal SPECT MPI among the elderly. Caution is advised when relying on AUC for referring elderly patients for SPECT MPI.