Division of Clinical Medicine, School of Medicine and Population Health, University of Sheffield, Sheffield, United Kingdom; Insigneo Institute for in Silico Medicine, University of Sheffield, Sheffield, United Kingdom.
Materials & Engineering Research Institute, Sheffield Hallam University, Sheffield, United Kingdom.
Comput Biol Med. 2024 May;173:108299. doi: 10.1016/j.compbiomed.2024.108299. Epub 2024 Mar 18.
Myocardial ischaemia results from insufficient coronary blood flow. Computed virtual fractional flow reserve (vFFR) allows quantification of proportional flow loss without the need for invasive pressure-wire testing. In the current study, we describe a novel, conductivity model of side branch flow, referred to as 'leak'. This leak model is a function of taper and local pressure, the latter of which may change radically when focal disease is present. This builds upon previous techniques, which either ignore side branch flow, or rely purely on anatomical factors. This study aimed to describe a new, conductivity model of side branch flow and compare this with established anatomical models.
The novel technique was used to quantify vFFR, distal absolute flow (Qd) and microvascular resistance (CMVR) in 325 idealised 1D models of coronary arteries, modelled from invasive clinical data. Outputs were compared to an established anatomical model of flow. The conductivity model correlated and agreed with the reference model for vFFR (r = 0.895, p < 0.0001; ＋0.02, 95% CI 0.00 to ＋ 0.22), Qd (r = 0.959, p < 0.0001; -5.2 mL/min, 95% CI -52.2 to ＋13.0) and CMVR (r = 0.624, p < 0.0001; ＋50 Woods Units, 95% CI -325 to ＋2549).
Agreement between the two techniques was closest for vFFR, with greater proportional differences seen for Qd and CMVR. The conductivity function assumes vessel taper was optimised for the healthy state and that CMVR was not affected by local disease. The latter may be addressed with further refinement of the technique or inferred from complementary image data. The conductivity technique may represent a refinement of current techniques for modelling coronary side-branch flow. Further work is needed to validate the technique against invasive clinical data.
心肌缺血是由于冠状动脉血流不足引起的。计算虚拟血流储备分数（vFFR）允许定量分析比例血流损失，而无需进行有创压力导丝检测。在本研究中，我们描述了一种新的侧支血流传导模型，称为“泄漏”。该泄漏模型是锥形和局部压力的函数，当存在局灶性疾病时，后者可能会发生根本变化。这是在先前的技术基础上进行的，这些技术要么忽略侧支血流，要么纯粹依赖于解剖因素。本研究旨在描述一种新的侧支血流传导模型，并将其与已建立的解剖模型进行比较。
使用新的技术在 325 个理想的冠状动脉 1D 模型中量化了 vFFR、远端绝对血流量（Qd）和微血管阻力（CMVR），这些模型是从有创临床数据中建模得到的。输出结果与现有的血流解剖模型进行了比较。传导模型与参考模型在 vFFR（r = 0.895，p < 0.0001；＋0.02，95%CI 0.00 至 ＋0.22）、Qd（r = 0.959，p < 0.0001；-5.2 mL/min，95%CI -52.2 至 ＋13.0）和 CMVR（r = 0.624，p < 0.0001；＋50 Woods 单位，95%CI -325 至 ＋2549）方面具有相关性和一致性。
两种技术之间的一致性最接近 vFFR，而 Qd 和 CMVR 的比例差异较大。传导函数假设血管锥形是为健康状态优化的，并且 CMVR不受局部疾病的影响。后者可以通过进一步改进技术或从补充的图像数据中推断出来来解决。传导技术可能代表了当前侧支血流建模技术的改进。需要进一步的工作来验证该技术与有创临床数据的吻合度。
