Department of Mechanical Engineering, University of Texas at San Antonio, One UTSA Circle, San Antonio, TX, 78249, USA.
Department of Mechanical Engineering, Istinye University, Istanbul, Turkey.
Ann Biomed Eng. 2021 Dec;49(12):3465-3480. doi: 10.1007/s10439-021-02884-y. Epub 2021 Nov 19.
Pulmonary hypertension (PH) is a progressive disease characterized by elevated pressure and vascular resistance in the pulmonary arteries. Nearly 250,000 hospitalizations occur annually in the US with PH as the primary or secondary condition. A definitive diagnosis of PH requires right heart catheterization (RHC) in addition to a chest computed tomography, a walking test, and others. While RHC is the gold standard for diagnosing PH, it is invasive and posseses inherent risks and contraindications. In this work, we characterized the patient-specific pulmonary hemodynamics in silico for diverse PH WHO groups. We grouped patients on the basis of mean pulmonary arterial pressure (mPAP) into three disease severity groups: at-risk ([Formula: see text], denoted with A), mild ([Formula: see text], denoted with M), and severe ([Formula: see text], denoted with S). The pulsatile flow hemodynamics was simulated by evaluating the three-dimensional Navier-Stokes system of equations using a flow solver developed by customizing OpenFOAM libraries (v5.0, The OpenFOAM Foundation). Quasi patient-specific boundary conditions were implemented using a Womersley inlet velocity profile and transient resistance outflow conditions. Hemodynamic indices such as spatially averaged wall shear stress ([Formula: see text]), wall shear stress gradient ([Formula: see text]), time-averaged wall shear stress ([Formula: see text]), oscillatory shear index ([Formula: see text]), and relative residence time ([Formula: see text]), were evaluated along with the clinical metrics pulmonary vascular resistance ([Formula: see text]), stroke volume ([Formula: see text]) and compliance ([Formula: see text]), to assess possible spatiotemporal correlations. We observed statistically significant decreases in [Formula: see text], [Formula: see text], and [Formula: see text], and increases in [Formula: see text] and [Formula: see text] with disease severity. [Formula: see text] was moderately correlated with [Formula: see text] and [Formula: see text] at the mid-notch stage of the cardiac cycle when these indices were computed using the global pulmonary arterial geometry. These results are promising in the context of a long-term goal of identifying computational biomarkers that can serve as surrogates for invasive diagnostic protocols of PH.
肺动脉高压（PH）是一种以肺动脉压力和血管阻力升高为特征的进行性疾病。美国每年有近 25 万人因 PH 作为主要或次要疾病住院。除胸部计算机断层扫描、步行测试等外，还需要进行右心导管检查（RHC）才能明确 PH 的诊断。虽然 RHC 是诊断 PH 的金标准，但它具有侵入性，并存在固有风险和禁忌症。在这项工作中，我们对不同 PHWHO 组的患者特定肺血液动力学进行了计算机模拟。我们根据平均肺动脉压（mPAP）将患者分为三组疾病严重程度：高危（[Formula: see text]，表示为 A）、轻度（[Formula: see text]，表示为 M）和重度（[Formula: see text]，表示为 S）。通过使用定制的 OpenFOAM 库（v5.0，OpenFOAM 基金会）开发的流求解器评估三维纳维-斯托克斯方程组来模拟脉动流血液动力学。使用沃默斯利入口速度分布和瞬态阻力流出条件实现准患者特定边界条件。评估了空间平均壁面剪切应力（[Formula: see text]）、壁面剪切应力梯度（[Formula: see text]）、时均壁面剪切应力（[Formula: see text]）、振荡剪切指数（[Formula: see text]）和相对驻留时间（[Formula: see text]）等血流动力学指标，以及临床指标肺血管阻力（[Formula: see text]）、每搏量（[Formula: see text]）和顺应性（[Formula: see text]），以评估可能的时空相关性。我们观察到随着疾病严重程度的增加，[Formula: see text]、[Formula: see text]和[Formula: see text]显著降低，[Formula: see text]和[Formula: see text]增加。当使用全局肺动脉几何形状计算这些指数时，[Formula: see text]与[Formula: see text]和[Formula: see text]在心脏周期的中切迹阶段具有中度相关性。这些结果在识别可作为 PH 侵入性诊断方案替代物的计算生物标志物的长期目标方面具有很大的希望。
