Predicting Significant Coronary Obstruction in a Population with Suspected Coronary Disease and Absence of Coronary Calcium: CORE-64 / CORE320 Studies

Abstract Background Coronary artery calcium (CAC) scanning can be performed using non-contrast computed tomography to predict cardiovascular events, but has less value for risk stratification in symptomatic patients. Objective To identify and validate predictors of significant coronary obstruction (SCO) in symptomatic patients without coronary artery calcification. Methods A total of 4,258 participants were screened from the CORE64 and CORE320 studies that enrolled patients referred for invasive angiography, and from the Quanta Registry that included patients referred for coronary computed tomography angiography (CTA). Logistic regression models evaluated associations between cardiovascular risk factors, CAC, and SCO. An algorithm to assess the risk of SCO was proposed for patients without CAC. Significance level of 5% was used in the analyses. Results Of the 509 participants of the CORE study, 117 (23%) had zero coronary calcium score; 13 (11%) patients without CAC had SCO. Zero calcium score was related to younger age, female gender, lower body mass index, no diabetes, and no dyslipidemia. Being a current smoker increased ~3.5 fold the probability of SCO and other CV risk factors were not significantly associated. Considering the clinical findings, an algorithm to further stratify zero calcium score patients was proposed and had a limited performance in the validation cohort (AUC 58; 95%CI 43, 72). Conclusion A lower cardiovascular risk profile is associated with zero calcium score in a setting of high-risk patients. Smoking is the strongest predictor of SCO in patients without CAC.

摘要：
背景：冠状动脉钙化（Coronary artery calcium, CAC）扫描可通过非增强计算机断层扫描实施，用于预测心血管事件，但对有症状患者的危险分层价值有限。
研究目的：本研究旨在识别并验证无冠状动脉钙化的有症状患者中显著冠状动脉阻塞（significant coronary obstruction, SCO）的预测因子。
研究方法：本研究从纳入接受有创血管造影患者的CORE64与CORE32研究，以及纳入接受冠状动脉计算机断层血管造影（coronary computed tomography angiography, CTA）患者的Quanta登记研究中，共筛选出4258名受试者。采用Logistic回归模型评估心血管危险因素、CAC与SCO的关联，并为无CAC的患者提出了一种评估SCO风险的算法。本分析采用5%的检验水准。
研究结果：在CORE研究的509名受试者中，117名（23%）的冠状动脉钙化评分为0；其中13名（11%）无CAC的患者存在SCO。冠状动脉钙化评分为0与更年轻的年龄、女性性别、更低的体质量指数、无糖尿病及无血脂异常相关。当前吸烟可使SCO发生概率升高约3.5倍，其余心血管危险因素未显示出显著关联。结合临床特征，本研究提出了一种用于进一步分层无钙化评分患者的算法，该算法在验证队列中仅表现有限（受试者工作特征曲线下面积（Area Under the Curve, AUC）=0.58；95%置信区间（Confidence Interval, CI）：0.43~0.72）。
研究结论：在高危患者队列中，更低的心血管风险特征与无冠状动脉钙化评分相关。在无CAC的患者中，吸烟是SCO最强的预测因子。