0334: Coronary artery calcium score as a predictor of myocardial ischemia in asymptomatic diabetic patients

Abstract

High coronary artery calcium (CAC) scores were shown to predict a higher likelihood of inducible myocardial ischemia and to be associated with a poor cardio-vascular prognosis. However the predictive value for coronary stenoses (CS) has not been tested in asymptomatic diabetic patients. This study aimed to evaluate the predictive value of a high CAC score for silent myocardial ischemia (SMI) and CS in high risk asymptomatic diabetic patients. CAC score was measured by computed tomography in 150 diabetic patients without cardiac history or symptom, with a normal resting ECG and ≥1 additional risk factors. SMI was assessed using stress myocardial scintigraphy and/or stress echocardiography, and CS using coronary angiography in those with an abnormal SMI test. CAC score was ≥100 Agatston units in 35.3% of the patients. SMI was detected in 27 patients (18.0%). A coronary angiography was performed in 17 of SMI patients and detected significant CS in six of them. CAC score was associated with coronary status (no SMI: median value 14 (range 0-2900); SMI without CS: 101 (23-3230) and SMI with CS: 800 (76-2978); (p<0.01)), and similarly for a CAC score ≥100 (in 37/123 patients without SMI (30.2%), 6/11 with SMI and no CS (54.5%) and 5/6 patients with SMI and CS (83.3%) (p<0.05). A CAC score ≥100 predicted the presence of SMI: 30.2% of patients had SMI vs 11.3% of those with CAC <100 (odds ratio 3.4 [1.4-8.0], p<0.01), with a sensitivity and specificity of 59% and 70%, and positive and negative predictive values of 30 and 87%, respectively. These data suggest that in asymptomatic high risk diabetic patients CAC score is associated with cardiac ischemic status, with a 3.4-fold increased risk of SMI when the score is ≥100. The negative predictive value of CAC score for SMI is an interesting finding. The predictive value for CS remains to be determined in a larger sample of patients with CS.