Biomedical Engineering Program, University of South Carolina, Columbia, SC, USA.
Biomedical Engineering Department, Georgia Institute of Technology, Atlanta, GA, USA.
Cardiovasc Eng Technol. 2023 Jun;14(3):404-418. doi: 10.1007/s13239-023-00661-7. Epub 2023 Feb 24.
Premature coronary artery bypass graft (CABG) failure has been linked to geometric, mechanical, and compositional discrepancies between host and graft tissues. Acute hemodynamic disturbances and the introduction of wall stress gradients trigger a myriad of mechanobiological processes at the anastomosis that can be associated with restenosis and graft failure. Although the origins of coronary artery disease dictate the anastomotic target, an opportunity exists for graft-vessel optimization through rationale graft selection.
Here we explored the four distinct regions of the left (L) and right (R) ITA (1 = proximal, 2 = submuscular, 3 = middle, 4 = distal), and four common target vessels in the coronary circulation including the proximal and distal left anterior descending (PLAD & DLAD), right coronary (RCA), and left circumflex (LCX) arteries. Benchtop biaxial mechanical data was used to acquire constitutive model parameters of these tissues and enable vessel-specific computational models to elucidate the mechanical consequences of 32 unique graft-target combinations.
Simulations revealed the maximum principal wall stresses for the PLAD, RCA, and LCX occurred when anastomosed with LITA, and the maximum flow-induced shear stress occurred with LITA. The DLAD, on the other hand, reached stress maximums when anastomosed to LITA. Using a normalized objective function of simulation output variables, we found LITA to be the best graft choice for both LADs, RITA for the RCA, and LITA for the LCX.
Although mechanical compatibility is just one of many factors determining bypass graft outcomes, our data suggests improvements can be made to the grafting process through vessel-specific regional optimization.
过早的冠状动脉旁路移植（CABG）失败与宿主和移植物组织之间的几何形状、机械和组成差异有关。急性血流动力学紊乱和壁面应力梯度的引入会在吻合口引发一系列的机械生物学过程，这些过程可能与再狭窄和移植物失败有关。尽管冠状动脉疾病的起源决定了吻合的靶标，但通过合理的移植物选择，仍然存在优化移植物的机会。
在这里，我们探索了左（L）和右（R）ITA 的四个不同区域（1=近端，2=肌内，3=中段，4=远端），以及冠状动脉循环中的四个常见靶血管，包括左前降支（PLAD & DLAD）近端和远端、右冠状动脉（RCA）和左回旋支（LCX）。使用台式双向力学数据来获取这些组织的本构模型参数，并使血管特异性计算模型能够阐明 32 种独特的移植物-靶标组合的力学后果。
模拟结果表明，PLAD、RCA 和 LCX 的最大主壁应力发生在与 LITA 吻合时，最大血流诱导的剪切应力发生在 LITA 上。另一方面，当与 LITA 吻合时，DLAD 达到了最大的应力。通过对模拟输出变量的归一化目标函数的使用，我们发现 LITA 是 LAD 的最佳移植物选择，RITA 是 RCA 的最佳选择，而 LITA 是 LCX 的最佳选择。
尽管机械相容性只是决定旁路移植结果的众多因素之一，但我们的数据表明，通过血管特异性的区域优化，可以改进移植过程。
