Kueh Shaw Hua, Boroditsky Matthew, Leipsic Jonathon
St Paul's Hospital, Vancouver, Canada.
McMaster University, Ontario, Canada.
Cardiovasc Diagn Ther. 2017 Oct;7(5):463-474. doi: 10.21037/cdt.2017.01.04.
Amongst patients with suspected obstructive coronary artery disease (CAD), less than a third of patients have obstructive disease on invasive coronary angiography (ICA) and fewer still have flow-limiting obstructive disease as determined by invasive fractional flow reserve (FFR). FFR is a powerful tool in guiding revascularization of flow-limiting lesions which in turn improves clinical outcome in those with haemodynamically significant obstructive disease. However FFR is infrequently performed due to the cost, time and patient discomfort the procedure entails. Further advances in non-invasive imaging has allowed FFR to be derived non-invasively by applying computational fluid dynamic (CFD) modeling to the coronary computed tomography angiography (CCTA) dataset without the need to induce hyperemia or modify the standard CCTA acquisition protocol. FFR derived from CCTA has been shown to have excellent correlation with invasive FFR and remains diagnostically robust in presence of reduced signal-to-noise ratio (SNR), coronary calcification and motion artifact. More recently, new data have emerged evaluating the clinical impact of fractional flow reserve computed tomography (FFRCT) on the assessment and management of patients with stable chest pain. One such study is the Prospective LongitudinAl trial of FFRCT: Outcome and Resource IMpacts (PLATFORM) study which showed an improved patient selection for ICA using CCTA-FFRCT approach by increasing the likelihood of identifying obstructive CAD at ICA amongst those intended for invasive testing. CCTA-FFRCT may therefore serve as efficacious gatekeeper to ICA that enriches the ICA population. The utility of FFRCT has also helped deepened our understanding of CAD. Through CFD modeling, it is now recognized that there are mechanistic forces of wall shear stress (WSS) and axial plaque force acting on coronary plaques. This has created further interest in exploring the possible interplay between these mechanistic forces on the development of coronary plaque and vulnerability of these plaques to rupture.
在疑似阻塞性冠状动脉疾病（CAD）的患者中，不到三分之一的患者在有创冠状动脉造影（ICA）检查中存在阻塞性病变，而通过有创血流储备分数（FFR）确定为血流受限性阻塞性病变的患者更少。FFR是指导血流受限性病变血运重建的有力工具，进而改善血流动力学显著阻塞性疾病患者的临床结局。然而，由于该检查的成本、时间以及给患者带来的不适，FFR检查并不常用。无创成像技术的进一步发展使得通过将计算流体动力学（CFD）模型应用于冠状动脉计算机断层扫描血管造影（CCTA）数据集来无创获得FFR成为可能，而无需诱发充血或修改标准CCTA采集方案。已证明从CCTA获得的FFR与有创FFR具有极好的相关性，并且在存在信噪比（SNR）降低、冠状动脉钙化和运动伪影的情况下，诊断仍然可靠。最近，出现了新的数据评估分数流储备计算机断层扫描（FFRCT）对稳定型胸痛患者评估和管理的临床影响。其中一项研究是FFRCT前瞻性纵向试验：结局与资源影响（PLATFORM）研究，该研究表明，使用CCTA-FFRCT方法可改善ICA的患者选择，通过增加在打算进行有创检查的患者中在ICA时识别阻塞性CAD的可能性。因此，CCTA-FFRCT可作为ICA的有效守门人，丰富ICA人群。FFRCT的实用性也有助于加深我们对CAD的理解。通过CFD建模，现在认识到有壁面剪应力（WSS）和轴向斑块力等力学力作用于冠状动脉斑块。这引发了人们对探索这些力学力在冠状动脉斑块形成以及这些斑块破裂易损性方面可能的相互作用的进一步兴趣。
