Objectives The current substudy of the PACIFIC (Prospective Comparison of Cardiac PET/CT, SPECT/CT Perfusion Imaging and CT Coronary Angiography With Invasive Coronary Angiography) trial explores the impact of computed tomography (CT)–derived unfavorable plaque features on both hyperemic and non-hyperemic flow indices. Background Next to lesion severity, plaque vulnerability as assessed using coronary CT angiography affects fractional flow reserve (FFR), which is associated with imminent acute coronary syndromes. Instantaneous wave-free ratio (iFR) has recently emerged as an alternative for FFR to interrogate coronary lesions for ischemia. It is, however, unknown whether vasodilator-free assessment with iFR is associated with plaque stability similarly as FFR. Methods Of 120 patients (62% men, age 58.3 ± 8.6 years) with suspected coronary artery disease, 257 vessels were prospectively evaluated. Each patient underwent 256-slice coronary CT angiography to assess stenosis severity and plaque features (positive remodeling [PR], low attenuation plaque [LAP], spotty calcification [SC], and napkin ring sign [NRS]), as well as intracoronary pressure measurements (FFR, iFR, Pd/Pa, and pressure ratio during adenosine within the wave-free period [iFRa]). CT-derived plaque characteristics were related to these invasive pressure measurements. Results Atherosclerotic plaques were present in 170 (66%) coronary arteries. On a per-vessel basis, luminal stenosis severity was significantly associated with impaired FFR, iFR, Pd/Pa, and iFRa. Multivariable analysis revealed that FFR and iFR were independently related to ≥70% stenosis (−0.10, p < 0.001 and −0.09, p = 0.003, respectively) and plaque volume (-0.02, p = 0.020 and -0.02, p = 0.030, respectively). Additionally, PR and SC were also independent predictors of an impaired FFR (−0.10, p < 0.001 and −0.07, p = 0.021, respectively), but adverse plaque characteristics were not independently related to the vasodilator-free iFR. Conclusions CT-derived vulnerable plaque characteristics are independently associated with hyperemic flow indices as assessed with FFR and iFRa, but not with non-hyperemic indices such as iFR and Pd/Pa. These findings suggest that the effects of hyperemia on pressure-derived indices might depend not only on hemodynamic stenosis severity but also on plaque characteristics.

中文翻译：

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血斑分数特征与充血分数流量储备和瞬时无浪比比与静止瞬时无浪比更紧密相关

目的PACIFIC（心脏PET / CT，SPECT / CT灌注成像和CT冠状动脉造影与有创冠状动脉造影术的前瞻性比较）试验的当前子研究探讨了计算机断层扫描（CT）引起的斑块对充血性和非充血性的影响-高血流指数。背景技术除病变严重程度外，使用冠状动脉CT血管造影术评估的斑块易损性会影响血流储备（FFR），这与即将来临的急性冠脉综合征相关。瞬时无波速比（iFR）最近已经出现，可以替代FFR来查询缺血性冠状动脉病变。然而，与FFR相似，使用iFR进行无血管扩张剂评估是否与斑块稳定性相关联尚不清楚。方法对120例患者（62％的男性，年龄58.3±8）6年），怀疑有冠状动脉疾病，前瞻性评估了257支血管。每位患者均接受256层冠状动脉CT血管造影，以评估狭窄程度和斑块特征（正重塑[PR]，低衰减斑块[LAP]，斑点钙化[SC]和餐巾环征[NRS]）以及冠状动脉内压测量（FFR，iFR，Pd / Pa和无波周期内的腺苷压力比[iFRa]）。CT衍生的斑块特征与这些侵入性压力测量结果有关。结果170例（66％）冠状动脉中存在动脉粥样硬化斑块。以每个血管为基础，管腔狭窄严重程度与FFR，iFR，Pd / Pa和iFRa受损显着相关。多变量分析显示，FFR和iFR与狭窄度≥70％独立相关（−0.10，p <0.001和-0.09，p = 0.003）和噬菌斑体积（-0.02，p = 0.020和-0.02，p = 0.030）。此外，PR和SC还是FFR受损的独立预测因子（分别为-0.10，p <0.001和-0.07，p = 0.021），但是不良的斑块特征与无血管扩张剂的iFR无关。结论根据FFR和iFRa评估，CT衍生的易损斑块特征与充血流量指数独立相关，但与iFR和Pd / Pa等非充血指数无关。这些发现表明，充血对压力衍生指标的影响可能不仅取决于血流动力学狭窄的严重程度，还取决于斑块的特征。PR和SC还是FFR受损的独立预测因子（分别为-0.10，p <0.001和-0.07，p = 0.021），但是不良的斑块特征与无血管扩张剂的iFR无关。结论根据FFR和iFRa评估，CT衍生的易损斑块特征与充血流量指数独立相关，但与iFR和Pd / Pa等非充血指数无关。这些发现表明，充血对压力衍生指标的影响可能不仅取决于血流动力学狭窄的严重程度，还取决于斑块的特征。PR和SC也是FFR受损的独立预测因子（分别为-0.10，p <0.001和-0.07，p = 0.021），但不良斑块特征与无血管扩张剂的iFR无关。结论根据FFR和iFRa评估，CT衍生的易损斑块特征与充血流量指数独立相关，但与iFR和Pd / Pa等非充血指数无关。这些发现表明，充血对压力衍生指标的影响可能不仅取决于血流动力学狭窄的严重程度，还取决于斑块的特征。结论根据FFR和iFRa评估，CT衍生的易损斑块特征与充血流量指数独立相关，但与iFR和Pd / Pa等非充血指数无关。这些发现表明，充血对压力衍生指标的影响可能不仅取决于血流动力学狭窄的严重程度，还取决于斑块的特征。结论根据FFR和iFRa评估，CT衍生的易损斑块特征与充血流量指数独立相关，但与iFR和Pd / Pa等非充血指数无关。这些发现表明，充血对压力衍生指标的影响可能不仅取决于血流动力学狭窄的严重程度，还取决于斑块的特征。