In Vitro Evaluation of Right Ventricular Outflow Tract Reconstruction With Bicuspid Valved Polytetrafluoroethylene Conduit
In Vitro Evaluation of Right Ventricular Outflow Tract Reconstruction With Bicuspid Valved Polytetrafluoroethylene Conduit
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DOI：
10.1111/j.1525-1594.2010.01136.x
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发表时间：
2010-11-01
影响因子：
2.4
通讯作者：
Pekkan, Kerem
中科院分区：
文献类型：
--
作者：
Dur, Onur;Yoshida, Masahiro;Pekkan, Kerem
可用于右心室流出道（RVOT）重建的导管最终因钙化而变得狭窄和/或不足。为了减少再次手术的发生率，我们开发并使用了带瓣聚四氟乙烯（PTFE）管道进行RVOT重建。本研究的目的是使用小儿体外右心模拟环研究新设计的血流动力学性能。PTFE导管已用于20例紫绀型先天性缺损患者（年龄1.7 ± 6岁）的完全双心室修复。为了解释导管尺寸的较大变异性，使用体外血流回路评价了14、16、22和24 mm导管尺寸，该体外血流回路由心输出量（CO）为1.2-3.2 L/min的脉动泵、二尖瓣RVOT导管、肺动脉、静脉室和血流可视化设置组成。我们记录了静态和脉动设置下的舒张期瓣膜泄漏和导管前后压力。使用高速摄像机和超声流量探头评价体外瓣膜功能和总体血流动力学性能。通过计算流体动力学（CFD）分析计算了不同体内管道曲率和流入状态的三维流场，以进一步帮助管道设计过程。对于所测试的CO范围，带阀导管上的平均压降为0.8 +/-1.7 mm Hg。反流率、峰间压差和有效办公室面积的典型值分别为23 +/-2.1%、13 +/- 2.4 mm Hg和1.56 +/- 0.2 cm（2）。高速视频捕捉到了心脏收缩期瓣膜不对称打开的完整瓣膜运动。CFD模拟证明了基于肺动脉曲率的朝向管道主曲率的流动偏斜。二尖瓣带瓣PTFE管道的体外评价与可接受的早期临床性能（轻度功能不全）一致，压降相对较低，瓣膜运动完整，与管道曲率、方向或瓣膜位置无关，但以舒张期血流返流增加为代价。这些发现为二尖瓣带瓣管道的基线性能提供了基准，并将用于未来的设计，以提高瓣膜性能。
Conduits available for right ventricular outflow tract (RVOT) reconstruction eventually become stenotic and/or insufficient due to calcification. In order to reduce the incidence of reoperations we have developed and used a bicuspid valved polytetrafluoroethylene (PTFE) conduit for the RVOT reconstruction. The purpose of this study is to investigate the hemodynamic performance of the new design using a pediatric in vitro right heart mock loop. PTFE conduit has been used for the complete biventricular repair of 20 patients (age 1.7 +/- 6 years) with cyanotic congenital defects. To account for the large variability of conduit sizes, 14, 16, 22, and 24-mm conduit sizes were evaluated using an in vitro flow loop comprised of a pulsatile pump with cardiac output (CO) of 1.2-3.2 L/min, bicuspid valved RVOT conduit, pulmonary artery, venous compartments, and the flow visualization setup. We recorded the diastolic valve leakage and pre- and postconduit pressures in static and pulsatile settings. In vitro valve function and overall hemodynamic performance was evaluated using high-speed cameras and ultrasonic flow probes. Three-dimensional flow fields for different in vivo conduit curvatures and inflow regimes were calculated by computational fluid dynamics (CFD) analysis to further aid the conduit design process. The average pressure drop over the valved conduits was 0.8 +/- 1.7 mm Hg for the CO range tested. Typical values for regurgitant fraction, peak-to-peak pressure gradient, and effective office area were 23 +/- 2.1%, 13 +/- 2.4 mm Hg, and 1.56 +/- 0.2 cm(2), respectively. Highspeed videos captured the intact valve motion with asymmetrical valve opening during the systole. CFD simulations demonstrated the flow skewness toward the major curvature of the conduit based on the pulmonic curvature. In vitro evaluation of the bicuspid valved PTFE conduit coincides well with acceptable early clinical performance (mild insufficiency), with relatively low pressure drop, and intact valve motion independent from the conduit curvature, orientation or valve location, but at the expense of increased diastolic flow regurgitation. These findings benchmark the baseline performance of the bicuspid valved conduit and will be used for future designs to improve valve competency.