Department of Cardiology, Academic Medical Center of Amsterdam, Cardiology, Amsterdam, the Netherlands; Department of Cardiology, Universitair Ziekenhuis Brussel, Brussels, Belgium.
Thoraxcenter, Erasmus Medical Center, Rotterdam, the Netherlands.
J Am Coll Cardiol. 2018 Jun 19;71(24):2756-2769. doi: 10.1016/j.jacc.2018.02.053. Epub 2018 May 22.
The functional SYNTAX score (FSS) has been shown to improve the discrimination for major adverse cardiac events compared with the anatomic SYNTAX score (SS) while reducing interobserver variability. However, evidence supporting the noninvasive FSS in patients with multivessel coronary artery disease (CAD) is scarce.
The purpose of this study was to assess the feasibility of and validate the noninvasive FSS derived from coronary computed tomography angiography (CTA) with fractional flow reserve (FFR) in patients with 3-vessel CAD.
The CTA-SS was calculated in patients with 3-vessel CAD included in the SYNTAX II (SYNergy between percutaneous coronary intervention with TAXus and cardiac surgery II) study. The noninvasive FSS was determined by including only ischemia-producing lesions (FFR ≤0.80). SS derived from different imaging modalities were compared using the Bland-Altman and Passing-Bablok method, and the agreement on the SS tertiles was investigated with Cohen's Kappa. The risk reclassification was compared between the noninvasive and invasive physiological assessment, and the diagnostic accuracy of FFR was assessed by the area under the receiver-operating characteristic curve using instantaneous wave-free ratio as a reference.
The CTA-SS was feasible in 86% of patients (66 of 77), whereas the noninvasive FSS was feasible in 80% (53 of 66). The anatomic SS was overestimated by CTA compared with conventional angiography (27.6 ± 6.4 vs. 25.3 ± 6.9; p < 0.0001) whereas the calculation of the FSS yielded similar results between the noninvasive and invasive imaging modalities (21.6 ± 7.8 vs. 21.2 ± 8.8; p = 0.589). The noninvasive FSS reclassified 30% of patients from the high- and intermediate-SS tertiles to the low-risk tertile, whereas invasive FSS reclassified 23% of patients from the high- and intermediate-SS tertiles to the low-risk tertile. The agreement on the classic SS tertiles based on Kappa statistics was slight for the anatomic SS (Kappa = 0.19) and fair for the FSS (Kappa = 0.32). The diagnostic accuracy of FFR to detect functional significant stenosis based on an instantaneous wave-free ratio ≤0.89 revealed an area under the receiver-operating characteristics curve of 0.85 (95% CI: 0.79 to 0.90) with a sensitivity of 95% (95% CI: 89% to 98%), specificity of 61% (95% CI: 48% to 73%), positive predictive value of 81% (95% CI: 76% to 86%), and negative predictive value of 87% (95% CI: 74% to 94%).
Calculation of the noninvasive FSS is feasible and yielded similar results to those obtained with invasive pressure-wire assessment. The agreement on the SYNTAX score tertile classification improved with the inclusion of the functional component from slight to fair agreement. FFR has good accuracy in detecting functionally significant lesions in patients with 3-vessel CAD. (A Trial to Evaluate a New Strategy in the Functional Assessment of 3-Vessel Disease Using SYNTAX II Score in Patients Treated With PCI; NCT02015832).
与解剖学 SYNTAX 评分（SS）相比，功能 SYNTAX 评分（FSS）在提高主要不良心脏事件的区分能力的同时，还降低了观察者间的变异性。然而，在多支血管冠状动脉疾病（CAD）患者中，支持无创 FSS 的证据很少。
本研究旨在评估基于冠状动脉计算机断层血管造影术（CTA）与血流储备分数（FFR）的无创 FSS 在 3 支血管 CAD 患者中的可行性并验证其准确性。
在 SYNTAX II 研究中纳入的 3 支血管 CAD 患者中计算 CTA-SS。通过仅包括产生缺血的病变（FFR≤0.80）来确定无创 FSS。使用 Bland-Altman 和 Passing-Bablok 方法比较不同成像方式的 SS，并使用 Cohen's Kappa 研究 SS 三分位数的一致性。比较无创和有创生理评估之间的风险重新分类，并使用瞬时无波比评估 FFR 的诊断准确性，以参考作为参考。
CTA-SS 在 86%的患者（77 例中的 66 例）中是可行的，而无创 FSS 在 80%的患者（66 例中的 53 例）中是可行的。与常规血管造影相比，CTA 高估了解剖学 SS（27.6±6.4 与 25.3±6.9；p<0.0001），而 FSS 的计算结果在无创和有创成像方式之间相似（21.6±7.8 与 21.2±8.8；p=0.589）。无创 FSS 将 30%的高和中 SS 三分位数患者重新分类为低风险三分位数，而有创 FSS 将 23%的高和中 SS 三分位数患者重新分类为低风险三分位数。基于 Kappa 统计的经典 SS 三分位数的一致性，解剖学 SS 的一致性为轻微（Kappa=0.19），而 FSS 的一致性为中等（Kappa=0.32）。基于瞬时无波比≤0.89 的 FFR 检测功能显著狭窄的诊断准确性显示出受试者工作特征曲线下面积为 0.85（95%置信区间：0.79 至 0.90），灵敏度为 95%（95%置信区间：89%至 98%），特异性为 61%（95%置信区间：48%至 73%），阳性预测值为 81%（95%置信区间：76%至 86%），阴性预测值为 87%（95%置信区间：74%至 94%）。
计算无创 FSS 是可行的，并且与有创压力导丝评估得出的结果相似。SYNTAX 评分三分位数分类的一致性随着功能成分的纳入而从轻微改善到中等一致。FFR 在检测 3 支血管 CAD 患者中功能显著病变方面具有良好的准确性。（一项使用 SYNTAX II 评分评估经 PCI 治疗的患者中 3 支血管疾病的新策略的功能评估的试验；NCT02015832）。
