Additional value of the coronary artery calcium score in patients for whom myocardial perfusion imaging is challenging.

BACKGROUND Determination of prognosis based on ischemia detection, using single-photon emission computed tomography myocardial perfusion imaging (SPECT-MPI), can be challenging in patients with multiple affected coronary arteries. AIMS The aim of the study was to examine the outcomes of SPECT-MPI combined with the coronary artery calcium score (CACS) to identify predictors of adverse cardiac events (ACEs) in patients for whom ischemia detection may be difficult using SPECT-MPI. METHODS The study group included 195 patients with a history of chronic kidney disease, suspected ischemic cardiomyopathy, or left bundle branch block. All patients underwent SPECT-MPI and CACS evaluation. During the follow-up, ACEs were recorded. Perfusion and functional parameters as well as the CACS were analyzed to find the predictors of ACEs. RESULTS The ACEs were recorded in 58 individuals (29.7%) and were significantly associated with ischemia (P <0.001), abnormal functional parameters (P = 0.04), and higher CACSs (P <0.001). The optimal cutoff value of the CACS to predict an ACE was 530. Cox proportional hazards models revealed that age, mild and severe ischemia, functional abnormalities, and a CACS of 530 or higher were significant predictors of ACEs. In the subgroup of individuals without ischemia, a CACS of 530 or higher was significantly associated with poor outcome, while we recorded only 3 ACEs in these patients when the CACS was lower than 530. CONCLUSIONS The addition of the CACS to SPECT-MPI improves the identification of patients at higher risk for ACEs, even in individuals for whom SPECT-MPI is challenging.