Role of coronary artery calcium score for risk stratification in patients with non significant perfusion defects by myocardial perfusion single photon emission computed tomography

Background: Myocardial perfusion scintigraphy (MPS) is an important diagnostic tool in the management of patients with suspected coronary artery disease (CAD). However, the presence of mild-moderate perfusion defects can be challenging and may lead to unnecessary cardiac catheterization. The coronary artery calcium (CAC) score is a method with excellent negative predictive value in the evaluation of CAD, but its role in this setting of patients has not been fully defined. This study aims to assess the potential of CAC in the prediction of cardiac adverse events in patients with suspected CAD with mild-moderate perfusion by MPS . Methods and results : We conducted a cohort study in 292 patients presenting with mild-moderate perfusion defects by MPS undergoing a CAC measurement. The patients were followed for a mean of 34 months for occurrence of major cardiac adverse events (MACE). The majority of the patients (64.7%) were male, mean age of 57.9 ± 12.6 years. During the follow-up there were 37 MACE. In multivariate Cox proportional hazards model, hypertension and CAC were independent predictors of MACE. The patients who presented a CAC score of ≥ 400 had a high risk of MACE (HR 20.9; 95% CI 4.79–91.42; p < 0.001). Kaplan-Meier curve showed a significant difference (log-rank c 2 ; p< 0.001) using CAC scores in predicting MACE. Conclusions: CAC score carries a powerful prognostic value in predicting adverse events in patients with suspected CAD and MPS with mild-moderate perfusion defects and may be useful in risk stratification of these patients.