Department of Mechanical Engineering, University of Malaya, Kuala Lumpur, Malaysia.
Phys Med. 2013 May;29(3):225-32. doi: 10.1016/j.ejmp.2012.03.008. Epub 2012 Jun 14.
Coronary Artery Disease (CAD) is responsible for most of the deaths in patients with cardiovascular diseases. Diagnostic coronary angiography analysis offers an anatomical knowledge of the severity of the stenosis. The functional or physiological significance is more valuable than the anatomical significance of CAD. Clinicians assess the functional severity of the stenosis by resorting to an invasive measurement of the pressure drop and flow. Hemodynamic parameters, such as pressure wire assessment fractional flow reserve (FFR) or Doppler wire assessment coronary flow reserve (CFR) are well-proven techniques to evaluate the physiological significance of the coronary artery stenosis in the cardiac catheterization laboratory. Between the two techniques mentioned above, the FFR is seen as a very useful index. The presence of guide wire reduces the coronary flow which causes the underestimation of pressure drop across the stenosis which leads to dilemma for the clinicians in the assessment of moderate stenosis. In such condition, the fundamental fluid mechanics is useful in the development of new functional severity parameters such as pressure drop coefficient and lesion flow coefficient. Since the flow takes place in a narrowed artery, the blood behaves as a non-Newtonian fluid. Computational fluid dynamics (CFD) allows a complete coronary flow simulation to study the relationship between the pressure and flow. This paper aims at explaining (i) diagnostic modalities for the evaluation of the CAD and valuable insights regarding FFR in the evaluation of the functional severity of the CAD (ii) the role of fluid dynamics in measuring the severity of CAD.
冠状动脉疾病（CAD）是导致心血管疾病患者死亡的主要原因。诊断性冠状动脉造影分析提供了狭窄严重程度的解剖学知识。CAD 的功能或生理意义比解剖学意义更有价值。临床医生通过测量压力降和流量来评估狭窄的功能严重程度。血流动力学参数，如压力导丝评估的血流储备分数（FFR）或多普勒导丝评估的冠状动脉血流储备（CFR），是在心脏导管实验室评估冠状动脉狭窄的生理意义的成熟技术。在上述两种技术中，FFR 被视为非常有用的指标。导丝的存在会降低冠状动脉血流量，从而导致对狭窄处压力降的低估，这使得临床医生在评估中度狭窄时陷入困境。在这种情况下，基础流体力学在开发新的功能严重程度参数（如压力降系数和病变流量系数）方面很有用。由于血流发生在狭窄的动脉中，血液表现为非牛顿流体。计算流体动力学（CFD）允许对完整的冠状动脉血流进行模拟，以研究压力和流量之间的关系。本文旨在解释（i）用于评估 CAD 的诊断方式，以及 FFR 在评估 CAD 功能严重程度方面的有价值的见解；（ii）流体动力学在测量 CAD 严重程度方面的作用。
