Anatomic and Physiologic Determinants of Vessel-Specific Ischemia by Coronary CT

描述（由申请人提供）：本提案的总体目标是整合来自计算机断层血管成像的解剖和生理信息，以精确识别引起缺血的冠状动脉病变。本研究为缺血试验的伴随研究。对于稳定性缺血性心脏病患者，心肌缺血可能是阻塞性冠状动脉疾病（CAD）的结果，这对指导血运重建的决定是有用的。迄今为止，非侵入性压力测试已成为识别缺血的主要方法；这些检查包括超声心动图、磁共振和心肌灌注显像（MPS）。其中，MPS最常用，因为它能够识别阻塞性CAD，重新分类CAD的可能性，并预测不良事件。CT已经成为一种非侵入性方法，可以直接显示CAD，与侵入性冠状动脉造影（ICA）相比，它对阻塞性CAD表现出更高的性能，并预测不良预后。除了狭窄之外，CT还可以评估其他动脉粥样硬化斑块特征（apc），这些特征与侵入性方法高度一致，并可能增加导致缺血的冠状动脉病变的确定。CT的最新发展也允许通过将计算流体动力学应用于典型获取的CT扫描来计算冠状动脉压力和流量，从而实现非侵入性计算分数血流储备（FFRCT），这是一种血管特异性缺血的测量方法。该建议的总体假设是，将解剖APCs与生理性FFRCT相结合，将优化识别导致缺血的冠状动脉病变。我们提出了三个具体目的：目的1：通过CT评估解剖apc的性能，以诊断血管特异性缺血。目的2：评价生理性FFRCT对血管特异性缺血的诊断价值。目的3：直接比较APC-FFRCT综合CT测量与MPS诊断病变特异性缺血的效果。本提案的工作将为一种新的诊断范式提供基本原理，该范式比传统的应激成像测试更准确地识别表现为缺血的患者并确定导致缺血的冠状动脉病变；因此，可以更好地选择个体进行血运重建，并消除不必要的侵入性手术。

DESCRIPTION (provided by applicant): The OVERALL OBJECTIVE of this proposal is to integrate the anatomic and physiologic information derived from computed tomographic angiograms for the precise identification of coronary artery lesions that cause ischemia. This proposal is a companion study to ISCHEMIA Trial. For patients with stable ischemic heart disease, myocardial ischemia may arise as a consequence of obstructive coronary artery disease (CAD) and is useful for guiding decisions of revascularization. To date, non-invasive stress tests have served as a mainstay for identifying ischemia; these tests include echocardiography, magnetic resonance and myocardial perfusion scintigraphy (MPS). Among these, MPS is performed most commonly due to its ability to identify obstructive CAD, reclassify CAD likelihood, and predict adverse events. CT has emerged as a non-invasive method that permits direct visualization of CAD, demonstrates high performance for obstructive CAD compared to invasive coronary angiography (ICA), and predicts adverse prognosis. Beyond stenosis, CT enables evaluation of additional atherosclerotic plaque characteristics (APCs) that demonstrate high agreement to invasive methods and may augment determination of coronary lesions that cause ischemia. Recent developments in CT also permit physiologic assessment of CAD by applying computational fluid dynamics to typically- acquired CT scans for calculation of coronary artery pressure and flow, thus enabling the non-invasive calculation of fractional flow reserve (FFRCT), a measure of vessel-specific ischemia. The OVERALL HYPOTHESIS of this proposal is that integrating anatomic APCs with physiologic FFRCT will optimize identification of coronary lesions that are ischemia-causing. We propose 3 specific aims: AIM 1: To assess performance of anatomic APCs by CT for diagnosis of vessel-specific ischemia. AIM 2: To assess performance of physiologic FFRCT for diagnosis of vessel-specific ischemia. AIM 3: To directly compare an integrated anatomic-physiologic (APC-FFRCT) CT measure to MPS for diagnosis of lesion-specific ischemia. The work in this proposal will provide the rationale for a novel diagnostic paradigm that is more accurate than conventional stress imaging testing for identifying patients who manifest ischemia and pinpointing the coronary lesions that are the cause; thus, allowing for better selection of individuals for revascularization and eliminating unnecessary invasive procedures.