Characteristics of coronary artery calcium in Chinese patients with suspected coronary artery disease and its relationship with myocardial ischemia

Objectives The aim of this study was to investigate the characteristics of coronary artery calcium (CAC) in Chinese population with suspected coronary artery disease (CAD) and its relationship with myocardial ischemia.

Methods 1) We analyzed 205 Chinese patients with suspected CAD undergoing combined CAC scoring and myocardial perfusion imaging (MPI) on a hybrid SPECT/CT scanner. Based on their CAC score (CACS), we assigned these patients into non-CAC group (CACS=0) and CAC group (CACS> 0), and further assigned the latter into groups with CACS of 1~399 and 蠅400. 2) We semi-quantitatively interpreted each MPI image with a 17-segment model of left ventricular, and calculated the summed stress score (SSS), summed rest score (SRS) and summed difference score (SDS=SSS-SRS). Patients with SSS 蠅4 and SDS蠅2 were defined as myocardial ischemia. 3) We assessed the correlation between CACS and ischemic MPI and investigated the characteristics of CACS in Chinese patients with suspected CAD.

Results 1) Among the 205 patients with suspected CAD, 132 (64.3%) had CACS=0 and 73 (35.6%) had CACS>0, of the latter, 58 (28.3%) had CACS of 1~399 and 15 (7.3%) had CACS蠅400; 2) The prevalence of CAC and CACS increased significantly with age (P<0.05); 3) Multivariate Logistic regression analysis indicated that age and hypertension were independent risk factors for CAC; 4) The incidence of ischemic MPI was 10.6% (14/132), 19.0% (11/58) and 33.3% (5/15) for patients with CCS=0, of 1~399 and 蠅400, respectively, showing significant difference (χ^2=6.784, P=0.034), and significantly increased with CACS increasing (χ^2=6.550, P=0.010). 5) Comparison of SDS with natural logarithm transformed CACS revealed a weak, but significant correlation (r=0.171, P=0.014).

Conclusions 1) Compared with Western populations, the prevalence of CAC and CACS in Chinese population with intermediate likelihood of CAD was low and increased significantly with age and age and hypertension were independent risk factors of CAC; 2) CACS was weakly correlated with myocardial ischemia, and the incidence of myocardial ischemia on MPI also increased with CACS increasing.