High prevalence of coronary artery calcification in Saudi patients with normal myocardial perfusion

Abstract

BACKGROUND: Normal single-photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI) has a high negative predictive value for ischemic heart disease. Thus, the presence of subclinical coronary atherosclerosis detected by coronary artery calcification (CAC) score in patients who have undergone SPECT MPI is unknown. OBJECTIVES: Determine the prevalence of coronary artery calcification (CAC) in patients with normal SPECT MPI and examine the association of CAC with conventional coronary artery disease (CAD) risk factors. DESIGN: Cross-sectional analytical study using medical records from February 2010 to April 2016. SETTINGS: Single tertiary-care center. PATIENTS AND METHODS: We studied patients referred from the outpatient clinical services for clinically indicated noninvasive CAD diagnosis with MPI SPECT. CAC scoring was subsequently performed within 3 months after a normal MPI. We excluded patients with chest pain or decompensated heart failure or patients with a history of CAD. The study population was divided into three groups: patients with a CAC score of 0, a CAC score from 1 to 300, and a CAC score more than 300. The groups were analyzed by age and other demographic and clinical characteristics. MAIN OUTCOME MEASURE(S): Prevalence of CAC in patients with normal MPI. RESULTS: The prevalence of CAC was 55% (n=114) in 207 patients with a mean (SD) age of 57.1 (10.4) years. Twelve percent had severe coronary atherosclerosis (CAC score >300). All patients had a normal MPI SPECT. CAC scores were 0 for 93 patients (45%), 1 to 300 for 89 (43%), and more than 300 for 24 (12%). There was a strong association between CAC score and age (P<.0001), male sex (P<.0001), and diabetes mellitus (P=.042), but no association between CAC score and hypertension (P=.153), family history of CAD (P=.23), obesity (P=.31), hypercholesterolemia (P=.071), or smoking (P=.308). CONCLUSIONS: The prevalence of CAC is high in this study population of patients with normal SPECT MPI. Age, male sex and diabetes were risk factors associated with CAC. LIMITATIONS: Single center and small study population.