Division of Pediatric Cardiology, University of Utah, Salt Lake City, Utah 84113, USA.
J Am Soc Echocardiogr. 2011 Aug;24(8):826-33. doi: 10.1016/j.echo.2011.05.008. Epub 2011 Jun 15.
Improved early survival has led many centers to use the right ventricle-to-pulmonary artery (RVPA) conduit instead of the modified Blalock-Taussig shunt for Norwood palliation of hypoplastic left-heart syndrome. However, there is concern regarding the potential deleterious effects of the required right ventriculotomy for placement of the RVPA conduit on global and regional right ventricular (RV) function. The purpose of this study was to investigate global and regional RV wall motion abnormalities after Norwood palliation with RVPA conduit using Velocity Vector Imaging (VVI).
Thirty consecutive patients with hypoplastic left-heart syndrome who underwent stage 2 palliation between January 2007 and December 2009 were identified from the surgical database. VVI was performed on two-dimensional echocardiographic images obtained before second-stage palliation. Peak systolic circumferential and radial velocity, strain, and strain rate were measured from parasternal short-axis and apical four-chamber views. RV ejection fraction was measured using the biplane modified Simpson's rule. Regional RV systolic deformations were compared between different RV segments. VVI measures were also compared with RV systolic function. In a subgroup (n = 14), VVI was repeated on follow-up after stage 2 palliation to evaluate changes in regional and global RV deformation.
A total of 30 patients (20 males) were studied. The median age at the time of interstage echocardiography was 12 weeks (range, 8-18 weeks). In the short axis, average peak systolic circumferential strain values for the anterior, posterior, septal, and RV free wall segments were 3.79 ± 2.52%, 11.4 ± 5.2%, 13.3 ± 6.5%, and 11.1 ± 5.0%, respectively. From the short-axis view, the anterior RV segment (ventriculotomy site) exhibited significantly reduced circumferential velocity, peak systolic strain, and strain rate (P < .0001). Mean global VVI measurements were correlated with RV ejection fraction. On follow-up after stage 2 palliation, the ventriculotomy region showed persistently reduced velocity, peak systolic strain, and strain rate compared with all other segments.
In patients with hypoplastic left-heart syndrome after Norwood palliation with RVPA conduit, RV myocardial deformation was significantly reduced at the ventriculotomy site, which persisted after stage 2 palliation. VVI-derived measures demonstrating impairment of global systolic myocardial deformation were correlated with RV systolic function. Long-term multicenter studies to evaluate the effects of ventriculotomy scar on single systemic right ventricle are required.
早期存活率的提高促使许多中心采用右心室-肺动脉（RVPA）管道代替改良的 Blalock-Taussig 分流术，对左心发育不全综合征进行 Norwood 姑息治疗。然而，对于为放置 RVPA 管道而必需的右心室切开术对整体和局部右心室（RV）功能的潜在有害影响存在担忧。本研究旨在使用速度向量成像（VVI）研究使用 RVPA 管道进行 Norwood 姑息治疗后 RV 壁运动异常。
从手术数据库中确定了 2007 年 1 月至 2009 年 12 月间接受第二期姑息性治疗的 30 例左心发育不全综合征患者。在第二期姑息性治疗前，对二维超声心动图图像进行 VVI 检查。从胸骨旁短轴和心尖四腔心视图测量收缩期圆周和径向速度、应变和应变速率。使用双平面改良 Simpson 法则测量 RV 射血分数。比较不同 RV 节段的 RV 收缩期变形。还将 VVI 测量值与 RV 收缩功能进行了比较。在亚组（n = 14）中，在第二期姑息性治疗后进行了 VVI 重复检查，以评估局部和整体 RV 变形的变化。
共研究了 30 例患者（20 例男性）。行中期超声心动图检查时的中位年龄为 12 周（范围为 8-18 周）。在短轴上，前壁、后壁、室间隔和 RV 游离壁节段的平均收缩期圆周应变值分别为 3.79 ± 2.52%、11.4 ± 5.2%、13.3 ± 6.5%和 11.1 ± 5.0%。从短轴观来看，前 RV 节段（心室切开部位）的圆周速度、收缩期峰值应变和应变速率明显降低（P<0.0001）。平均整体 VVI 测量值与 RV 射血分数相关。在第二期姑息性治疗后随访时，与所有其他节段相比，心室切开部位的速度、收缩期峰值应变和应变速率持续降低。
在接受 RVPA 管道进行 Norwood 姑息治疗的左心发育不全综合征患者中，RV 心肌变形在心室切开部位明显减少，在第二期姑息性治疗后仍然存在。显示整体收缩性心肌变形受损的 VVI 测量值与 RV 收缩功能相关。需要进行长期多中心研究，以评估心室切开疤痕对单个系统性右心室的影响。
