Department of Biomedical Engineering, Medical College of Wisconsin and Marquette University, 8701 W Watertown Plank Road, Milwaukee, WI 53226.
Division of Cardiovascular Medicine, Department of Medicine, Medical College of Wisconsin, 8701 W Watertown Plank Road, Milwaukee, WI 53226.
J Biomech Eng. 2021 May 1;143(5). doi: 10.1115/1.4049746.
This study computationally assesses the accuracy of an instantaneous wave-free ratio (iFR) threshold range compared to standard modalities such as fractional flow reserve (FFR) and coronary flow reserve (CFR) for multiple intermediate lesions near the left main (LM) coronary bifurcation. iFR is an adenosine-independent index encouraged for assessment of coronary artery disease (CAD), but different thresholds are debated. This becomes particularly challenging in cases of multivessel disease when sensitivity to downstream lesions is unclear. Idealized LM coronary arteries with 34 different intermediate stenoses were created and categorized (Medina) as single and multiple lesion groups. Computational fluid dynamics modeling was performed with physiologic boundary conditions using an open-source software (simvascular1) to solve the time-dependent Navier-Stokes equations. A strong linear relationship between iFR and FFR was observed among studied models, indicating computational iFR values of 0.92 and 0.93 are statistically equivalent to an FFR of 0.80 in single and multiple lesion groups, respectively. At the clinical FFR value (i.e., 0.8), a triple-lesion group had smaller CFR compared to the single and double lesion groups (e.g., triple = 3.077 versus single = 3.133 and double = 3.132). In general, the effect of additional intermediate downstream lesions (minimum lumen area > 3 mm2) was not statistically significant for iFR and CFR. A computational iFR of 0.92 best predicts an FFR of 0.80 and may be recommended as threshold criteria for computational assessment of LM stenosis following additional validation using patient-specific models.
这项研究通过计算评估了瞬时无波比（iFR）阈值范围的准确性，与分数流量储备（FFR）和冠状动脉血流储备（CFR）等标准模式相比，该范围适用于左主干（LM）冠状动脉分叉附近的多个中间病变。iFR 是一种腺苷非依赖性指数，用于评估冠状动脉疾病（CAD），但不同的阈值存在争议。在多血管疾病的情况下，当下游病变的敏感性不明确时，这尤其具有挑战性。用 34 种不同的中间狭窄创建并分类了理想化的 LM 冠状动脉（Medina）为单一病变组和多病变组。使用生理边界条件对计算流体动力学模型进行了建模，并使用开源软件（simvascular1）求解时变纳维-斯托克斯方程。在所研究的模型中，iFR 和 FFR 之间观察到很强的线性关系，表明计算 iFR 值为 0.92 和 0.93 在统计学上等同于单病变组和多病变组的 FFR 分别为 0.80。在临床 FFR 值（即 0.8）下，三病变组的 CFR 小于单病变组和双病变组（例如，三病变组 = 3.077 比单病变组 = 3.133 和双病变组 = 3.132）。一般来说，对于 iFR 和 CFR，额外的中间下游病变（最小管腔面积 > 3mm2）的影响没有统计学意义。计算 iFR 值为 0.92 可最佳预测 FFR 值为 0.80，并且可能被推荐为在使用特定于患者的模型进行进一步验证后，用于计算评估 LM 狭窄的阈值标准。
