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

描述(由申请人提供)：这项建议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，以精确识别导致缺血的冠状动脉病变。这项建议是对缺血试验的配对研究。对于稳定性的缺血性心脏病患者，心肌缺血可能是阻塞性冠状动脉疾病(CAD)的结果，并有助于指导血运重建的决策。到目前为止，无创负荷试验一直是识别缺血的主要手段；这些试验包括超声心动图、磁共振和心肌灌注闪烁成像(MPS)。其中，MPS最常用于识别梗阻性CAD、重新分类CAD可能性和预测不良事件。CT是一种非侵入性方法，可以直接显示CAD，与有创冠状动脉造影术(ICA)相比，它对阻塞性CAD显示出更高的性能，并能预测不良的预后。除了狭窄，CT还可以评估其他动脉粥样硬化斑块特征(APC)，这些特征表明与侵入性方法高度一致，并可能增强对导致缺血的冠状动脉病变的确定。CT的最新发展也使得对CAD的生理学评估成为可能，方法是将计算流体动力学应用于通常获得的CT扫描，以计算冠状动脉压力和流量，从而能够无创性地计算血流储备分数(FFRCT)，这是一种测量血管特异性缺血的指标。这一建议的总体假设是，将解剖APC与生理性FFRCT相结合将优化对导致缺血的冠状动脉病变的识别。我们提出了三个具体的目标：目标1：评估解剖APC在CT诊断血管特异性缺血中的表现。目的：评价生理性FFRCT对血管特异性缺血的诊断价值。目的：直接比较解剖-生理学综合CT(APC-FRCT)和MPS对病变特异性缺血的诊断价值。这项提议中的工作将为一种新的诊断范式提供理论基础，该范式比传统的负荷成像测试更准确地识别表现为缺血的患者，并准确地定位导致缺血的冠状动脉病变；因此，允许更好地选择个体进行血运重建，并消除不必要的侵入性程序。

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.