School of Mechanical Engineering, Shiraz University, Shiraz, Iran.
Center of Excellence in Energy Conversion, School of Mechanical Engineering, Sharif University of Technology, Tehran, Iran.
Comput Biol Med. 2021 Dec;139:104958. doi: 10.1016/j.compbiomed.2021.104958. Epub 2021 Oct 19.
Nitric Oxide (NO) provides myocardial oxygen demands of the heart during exercise and cardiac pacing and also prevents cardiovascular diseases such as atherosclerosis and platelet adhesion and aggregation. However, the direct in vivo measurement of NO in coronary arteries is still challenging. To address this matter, a mathematical model of dynamic changes of calcium and NO concentration in the coronary artery was developed for the first time. The model is able to simulate the effect of NO release in coronary arteries and its impact on the hemodynamics of the coronary arterial tree and also to investigate the vasodilation effects of arteries during cardiac pacing. For these purposes, flow rate, time-averaged wall shear stress, dilation percent, NO concentration, and Calcium (Ca2+) concentration within coronary arteries were obtained. In addition, the impact of hematocrit on the flow rate of the coronary artery was studied. It was seen that the behavior of flow rate, wall shear stress, and Ca2+ is biphasic, but the behavior of NO concentration and the dilation percent is triphasic. Also, by increasing the Hematocrit, the blood flow reduces slightly. The results were compared with several experimental measurements to validate the model qualitatively and quantitatively. It was observed that the presented model is well capable of predicting the behavior of arteries after releasing NO during cardiac pacing. Such a study would be a valuable tool to understand the mechanisms underlying vessel damage, and thereby to offer insights for the prevention or treatment of cardiovascular diseases.
一氧化氮（NO）在运动和心脏起搏时提供心肌的氧气需求，还可以预防心血管疾病，如动脉粥样硬化、血小板黏附和聚集。然而，直接在冠状动脉中测量 NO 仍然具有挑战性。为了解决这个问题，我们首次建立了冠状动脉中钙和 NO 浓度动态变化的数学模型。该模型能够模拟冠状动脉中 NO 释放的效果及其对冠状动脉树血流动力学的影响，还可以研究心脏起搏时动脉的舒张效果。为此，我们获得了冠状动脉中的血流速度、时均壁切应力、舒张百分比、NO 浓度和 Ca2+浓度。此外，还研究了血细胞比容对冠状动脉血流速度的影响。结果表明，血流速度、壁切应力和 Ca2+的行为呈双相，但 NO 浓度和舒张百分比的行为呈三相。另外，随着血细胞比容的增加，血流略有减少。我们将结果与几项实验测量进行了比较，以定性和定量地验证模型。结果表明，所提出的模型能够很好地预测心脏起搏时释放 NO 后动脉的行为。这种研究将是理解血管损伤机制的有价值的工具，从而为心血管疾病的预防或治疗提供新的思路。
