3D and Computer Simulation Laboratory, IRCCS Policlinico San Donato, San Donato Milanese, Italy.
Department of Electronics Information and Bioengineering, Politecnico di Milano, Milano, Italy.
J Endovasc Ther. 2023 Oct;30(5):756-768. doi: 10.1177/15266028221095403. Epub 2022 May 19.
Displacement forces (s) identify hostile landing zones for stent graft deployment in thoracic endovascular aortic repair (TEVAR). However, their use in TEVAR planning is hampered by the need for time-expensive computational fluid dynamics (CFD). We propose a novel fast-approximate computation of s merely exploiting aortic arch anatomy, as derived from the computed tomography (CT) and a measure of central aortic pressure.
We tested the fast-approximate approach against CFD gold-standard in 34 subjects with the "bovine" aortic arch variant. For each dataset, a 3-dimensional (3D) model of the aortic arch lumen was reconstructed from computed tomography angiography and CFD then employed to compute s within the aortic proximal landing zones. To quantify fast-approximate s, the wall shear stress contribution to the was neglected and blood pressure space-distribution was averaged on the entire aortic wall to reliably approximate the patient-specific central blood pressure. Also, values were normalized on the corresponding proximal landing zone area to obtain the equivalent surface traction ().
Fast-approximate approach consistently reflected (r=0.99, p<0.0001) the pattern obtained by CFD, with a -1.1% and 0.7° bias in s magnitude and orientation, respectively. The normalized progressively increased (p<0.0001) from zone 0 to zone 3 regardless of the type of arch, with proximal landing zone 3 showing significantly greater forces than zone 2 (p<0.0001). Upon DF normalization to the corresponding aortic surface, fast-approximate was decoupled in blood pressure and a dimensionless shape vector (S) reflecting aortic arch morphology. showed a zone-specific pattern of orientation and proved a valid biomechanical blueprint of impact on the thoracic aortic wall.
Requiring only a few seconds and quantifying clinically relevant biomechanical parameters of proximal landing zones for arch TEVAR, our method suits the real preoperative decision-making process. It paves the way toward analyzing large population of patients and hence to define threshold values for a future patient-specific preoperative TEVAR planning.
在胸主动脉腔内修复术（TEVAR）中，位移力（s）可识别支架移植物植入的敌对着陆区。然而，由于需要耗时的计算流体动力学（CFD），其在 TEVAR 规划中的应用受到了阻碍。我们提出了一种仅利用从计算机断层扫描（CT）和中央主动脉压力测量中得出的主动脉弓解剖结构来快速近似计算 s 的新方法。
我们在 34 名具有“牛”型主动脉弓变异的受试者中对快速近似方法进行了测试，该方法与 CFD 金标准进行了对比。对于每个数据集，从计算机断层血管造影术重建主动脉弓管腔的 3 维（3D）模型，然后在主动脉近端着陆区内部使用 CFD 计算 s。为了量化快速近似 s，忽略了壁面切应力对 s 的贡献，并对整个主动脉壁的血压空间分布进行平均，以可靠地近似患者特定的中央血压。此外，将 s 值归一化到相应的近端着陆区面积上，以获得等效的表面牵引力（）。
快速近似方法始终反映了 CFD 获得的 s 模式（r=0.99，p<0.0001），其在 s 幅度和方向上的偏差分别为-1.1%和 0.7°。无论弓的类型如何，归一化 s 都逐渐增加（p<0.0001），从区 0 增加到区 3，近端着陆区 3 显示出的力明显大于区 2（p<0.0001）。在 DF 归一化到相应的主动脉表面后，快速近似 s 与血压解耦，并形成反映主动脉弓形态的无量纲形状向量（S）。 S 呈现出区特异性的取向模式，并且是对胸主动脉壁的影响的有效生物力学蓝图。
该方法仅需几秒钟即可量化弓 TEVAR 近端着陆区的临床相关生物力学参数，适合实际的术前决策过程。它为分析大量患者并为未来的患者特异性 TEVAR 术前规划定义阈值铺平了道路。
