Zhang Xiaoya, Kizilski Shannen B, Recco Dominic P, Chaillo Lizarraga Martha D, Kneier Nicholas E, Schulz Noah E, Baird Christopher W, Hammer Peter E, Hoganson David M
Department of Cardiac Surgery, Boston Children's Hospital, 300 Longwood Avenue, Bader, 2nd Floor, Boston, MA, 02215, USA.
Harvard Medical School, Boston, MA, USA.
Cardiovasc Eng Technol. 2023 Dec;14(6):827-839. doi: 10.1007/s13239-023-00690-2. Epub 2023 Nov 16.
Pulmonary valve (PV) monocusp reconstruction in transannular patch (TAP) right ventricular outflow tract (RVOT) repair for Tetralogy of Fallot has variable clinical outcomes across different surgical approaches. The study purpose was to systematically evaluate how monocusp leaflet design parameters affect valve function in-vitro.
A 3D-printed, disease-specific RVOT model was tested under three infant physiological conditions. Monocusps were sewn into models with the native main pulmonary artery (MPA) forming backwalls that constituted 40% and 50% of the reconstructed circumference for z-score zero PV annulus and MPA diameters (native PV z-score - 3.52 and - 2.99 for BSA 0.32m). Various leaflet free edge lengths (FEL) (relative to backwall), positions (relative to PV STJ), and scallop depths were investigated across both models. Pressure gradient, regurgitation, and coaptation were analyzed with descriptive statistics and regression models.
Increasing FEL beyond 100% of the MPA backwall decreased gradient but mildly increased regurgitation to a peak of 25%. Positioning the free edge 2 mm past the STJ mildly increased gradient for each FEL without significantly changing regurgitation compared to STJ placement. Scalloping leaflets trivially affected performance. Pre-folding leaflets improved mobility and slightly reduced gradient.
Balancing gradient, regurgitation, and oversizing for growth, a set of leaflet designs have been selected for pre-clinical evaluation. Designs with leaflet widths 140-160% in the 40% backwall model (110-120% in the 50% backwall), positioned at or 2 mm past the STJ, demonstrated the best results. The next stage of ex-vivo testing will additionally consider native RVOT distensibility, native leaflet interactions, and TAP characteristics.
法洛四联症经环补片（TAP）右心室流出道（RVOT）修复术中肺动脉瓣（PV）单瓣重建在不同手术方式下临床结果各异。本研究旨在系统评估单瓣小叶设计参数如何在体外影响瓣膜功能。
在三种婴儿生理条件下对一个3D打印的、针对特定疾病的RVOT模型进行测试。将单瓣缝入模型，天然主肺动脉（MPA）形成后壁，对于z评分零的PV瓣环和MPA直径（BSA为0.32m²时天然PV的z评分为 -3.52和 -2.99），后壁分别占重建周长的40%和50%。在两个模型中研究了各种小叶游离缘长度（FEL）（相对于后壁）、位置（相对于PV窦管交界[STJ]）和扇形深度。采用描述性统计和回归模型分析压力梯度、反流和贴合情况。
将FEL增加至超过MPA后壁的100%会降低梯度，但会使反流轻度增加至峰值25%。与STJ位置相比，将游离缘置于STJ后方2mm处，每种FEL的梯度会轻度增加，而反流无显著变化。扇形小叶对性能影响极小。预折叠小叶可改善活动性并略微降低梯度。
为平衡梯度、反流和生长时的尺寸过大问题已选择了一组小叶设计用于临床前评估。在40%后壁模型中，小叶宽度为140 - 160%（50%后壁模型中为110 - 120%）、位于STJ处或STJ后方2mm处的设计显示出最佳结果。体外测试的下一阶段将额外考虑天然RVOT的可扩张性、天然小叶相互作用和TAP特征。
