Abstract 10484: Carotid Plaque Score Adds Discriminatory Benefit to the Stress Echo for Major Adverse Cardiovascular Events in Low-Intermediate Risk Cardiac Patients

Introduction: Carotid plaque is recommended for cardiac risk stratification for intermediate risk patients but has not been integrated into cardiology community clinics to help refine testing and reduce risk for major adverse cardiovascular events (MACE). The purpose was to determine the clinical usefulness of carotid plaque score (PS) to guide management of low-intermediate risk patients. Methods: Patients 40-75 years who received a carotid ultrasound were followed up to 10 years for MACE (cardiovascular death, myocardial infarction, stroke). Low-intermediate risk participants (n = 9,114) with no known cardiovascular disease were included. Administrative data holdings housed at IC/ES were used for event follow-up. Kaplan-Meier curves and Cox proportional hazard ratios determined relative risk. Combining plaque score (Rotterdam method, plaque presence within carotid segments, PS 0 to 6) with stress echo (SE) was assessed in a subset of participants (n = 624). Results: The optimum threshold for PS = 2 for 1-year MACE (AUC = 0.738). The population rate of MACE over 10 years was 4%. In participants referred for SE, PS of <2 was associated with an excellent 5-year outcome irrespective of the SE result (PS<2 = 0.9% MACE, normal SE = 1.6% MACE). A PS of ≥2 and an abnormal SE was associated with increased risk (MACE = 11%). The hazard ratio for MACE increased with PS from 1.08 to 9.86 (PS = 1 and 6; reference PS=0). Combining SE with PS (either test positive) increased the sensitivity of the SE from 36% to 71%, with an excellent specificity (SE alone = 94% vs SE+PS = 87%). Conclusions: In low-intermediate risk patients, if a PS is <2, cardiac testing for atherosclerotic risk is not required for up to 5 years. However, patients with a PS of ≥2 should undergo a stress echo. Combining SE with PS adds discriminatory benefit in identifying risk for MACE. This simple stratification parameter can be easily integrated in community cardiology clinics to prioritize patients requiring further testing.