Kizilski Shannen B, Zhang Xiaoya, Kneier Nicholas E, Chaillo Lizarraga Martha D, Schulz Noah E, Hammer Peter E, Hoganson David M
Department of Cardiac Surgery, Boston Children's Hospital, Boston, MA, USA.
Harvard Medical School, Boston, MA, USA.
Cardiovasc Eng Technol. 2023 Apr;14(2):217-229. doi: 10.1007/s13239-022-00648-w. Epub 2022 Dec 1.
Tetralogy of Fallot and other conditions affecting the right ventricular outflow tract (RVOT) are common in pediatric patients, but there is a lack of quantitative comparison among techniques for repairing or replacing the pulmonary valve. The aim of this study was to develop a robust in vitro system for quantifying flow conditions after various RVOT interventions.
An infant-sized mock circulatory loop that includes a 3D-printed RVOT anatomical model was developed to evaluate flow conditions after different simulated surgical repairs. Physiologically correct flow and pressure were achieved with custom compliant tubing and a tunable flow restrictor. Pressure gradient, flow regurgitation, and coaptation height were measured for two monocusp leaflet designs after tuning the system with a 12 mm Hancock valved conduit.
Measurements were repeatable across multiple samples of two different monocusp designs, with the wider leaflet in the 50% backwall model consistently exhibiting lower pressure gradient but higher regurgitation compared to the leaflet in the 40% backwall model. Coaptation height was measured via direct visualization with endoscopic cameras, revealing a shorter area of contact for the wider leaflet (3.3-4.0 mm) compared to the narrower one (4.3 mm).
The 3D-printed RVOT anatomical model and in vitro pulmonary circulatory loop developed in this work provide a platform for planning and evaluating surgical interventions in the pediatric population. Measurements of regurgitation, pressure gradient, and coaptation provide a quantitative basis for comparison among different valve designs and positions.
法洛四联症及其他影响右心室流出道（RVOT）的病症在儿科患者中很常见，但在肺动脉瓣修复或置换技术之间缺乏定量比较。本研究的目的是开发一种强大的体外系统，用于量化各种RVOT干预后的血流状况。
开发了一种婴儿尺寸的模拟循环回路，其中包括一个3D打印的RVOT解剖模型，以评估不同模拟手术修复后的血流状况。通过定制的顺应性管道和可调流量限制器实现生理上正确的流量和压力。在用12毫米汉考克带瓣管道对系统进行调谐后，对两种单叶瓣设计测量了压力梯度、反流和贴合高度。
在两种不同单叶瓣设计的多个样本中测量结果具有可重复性，与40%后壁模型中的瓣叶相比，50%后壁模型中较宽的瓣叶始终表现出较低的压力梯度，但反流较高。通过内窥镜摄像头直接可视化测量贴合高度，结果显示较宽瓣叶的接触面积（3.3 - 4.0毫米）比窄瓣叶（4.3毫米）短。
本研究中开发的3D打印RVOT解剖模型和体外肺循环回路为儿科人群的手术干预规划和评估提供了一个平台。反流、压力梯度和贴合的测量为不同瓣膜设计和位置之间的比较提供了定量基础。
