Tasca Giordano, Selmi Matteo, Votta Emiliano, Redaelli Paola, Sturla Francesco, Redaelli Alberto, Gamba Amando
Cardiovascular Department, Operative Unit of Cardiac Surgery, Ospedale "A. Manzoni" di Lecco, Lecco, Italy; Department of Electronics, Information, and Bioengineering, Politecnico di Milano, Milano, Italy.
Department of Electronics, Information, and Bioengineering, Politecnico di Milano, Milano, Italy; Division of Cardiovascular Surgery, Università degli Studi di Verona, Italy.
Ann Thorac Surg. 2017 May;103(5):1451-1459. doi: 10.1016/j.athoracsur.2016.08.003. Epub 2016 Oct 15.
Aortic root aneurysm can be treated with valve-sparing procedures. The David and Yacoub techniques have shown excellent long-term results but are technically demanding. Recently, a new and simpler procedure, the Sleeve technique, was proposed with encouraging results. We aimed to quantify the biomechanics of the initially aneurysmal aortic root (AR) after the Sleeve procedure to assess whether it induces abnormal stresses, potentially undermining its durability.
Two finite element (FE) models of the physiologic and aneurysmal AR were built, accounting for the anatomical asymmetry and the nonlinear and anisotropic mechanical properties of human AR tissues. On the aneurysmal model, the Sleeve and David techniques were simulated based on the corresponding published technical features. Aortic root biomechanics throughout 2 consecutive cardiac cycles were computed in each simulated configuration.
Both sparing techniques restored physiologic-like kinematics of aortic valve (AV) leaflets but induced different leaflets stresses. The time course averaged over the leaflets' bellies was 35% higher in the David model than in the Sleeve model. Commissural stresses, which were equal to 153 and 318 kPa in the physiologic and aneurysmal models, respectively, became 369 and 208 kPa in the David and Sleeve models, respectively.
No intrinsic structural problems were detected in the Sleeve model that might jeopardize the durability of the procedure. If corroborated by long-term clinical outcomes, the results obtained suggest that using this new technique could successfully simplify the surgical repair of AR aneurysms and reduce intraoperative complications.
主动脉根部动脉瘤可采用保留瓣膜的手术方法进行治疗。大卫（David）技术和亚库布（Yacoub）技术已显示出优异的长期效果，但技术要求较高。最近，一种新的、更简单的手术方法——袖套技术被提出，且取得了令人鼓舞的结果。我们旨在量化袖套手术后最初动脉瘤性主动脉根部（AR）的生物力学特性，以评估其是否会引发异常应力，从而可能影响其耐久性。
构建了生理状态和动脉瘤性AR的两个有限元（FE）模型，考虑了人体AR组织的解剖学不对称性以及非线性和各向异性力学特性。在动脉瘤模型上，根据相应已发表的技术特征模拟了袖套技术和大卫技术。在每个模拟构型中计算了连续两个心动周期内的主动脉根部生物力学特性。
两种保留技术均恢复了主动脉瓣（AV）瓣叶类似生理状态的运动学，但诱导产生了不同的瓣叶应力。大卫模型中瓣叶腹侧的时间平均应力比袖套模型高35%。生理模型和动脉瘤模型中分别为153和318 kPa的连合处应力，在大卫模型和袖套模型中分别变为369和208 kPa。
在袖套模型中未检测到可能危及该手术耐久性的内在结构问题。如果长期临床结果得到证实，所获得的结果表明，使用这种新技术可以成功简化AR动脉瘤的手术修复并减少术中并发症。
