Centre for Cardiovascular Imaging, UCL Institute of Cardiovascular Science, Great Ormond Street Hospital for Children, London, United Kingdom.
J Thorac Cardiovasc Surg. 2012 May;143(5):1103-7. doi: 10.1016/j.jtcvs.2011.09.039. Epub 2011 Nov 4.
Chronic pulmonary regurgitation (PR) has deleterious effects on right ventricular (RV) function in repaired tetralogy of Fallot (ToF). However, there are little data regarding right ventricular outflow tract (RVOT) contractile dysfunction in response to chronic PR and on both RV and LV volumes and function.
We retrospectively identified consecutive patients with PR who were referred for magnetic resonance imaging quantification of "free PR" detected on echocardiography between 2003 and 2008. Patients had ToF and a transannular patch procedure (n = 30, 25.1 ± 1.2 years) or PR resulting from valvar pulmonary stenosis treated with surgical or percutaneous valvotomy (n = 30, 26.6 ± 1.8 years).
The ToF and the PS groups were well matched for age at scan, age at repair surgery in ToF or initial valvotomy in PS, duration of exposure to PR, body surface area, heart rate, PR fraction, net forward pulmonary artery flow, and main and branch pulmonary artery dimensions. Severe PR fractions were identified in both groups (ToF: 40% ± 1% vs PS: 37% ± 2%, P = .2). Indexed RV and LV end-diastolic volumes were similar for both ToF and PS groups (RV end-diastolic volume index: 137 ± 6 mL/m(2) vs 128 ± 5 mL/m(2), P = .2, and LV end-diastolic volume index: 72 ± 2 mL/m(2) vs 67 ± 2 mL/m(2), P = .1, respectively). RV mass was also similar between groups (95 ± 5 g vs 81 ± 6 g, respectively, P = .08). However, indexed RV and LV end-systolic volumes were consistently higher in ToF when compared with PS (RV end-systolic volume index: 70 ± 5 mL/m(2) vs 54 ± 3 mL/m(2), P < .01, and LV end-systolic volume index: 29 ± 1 mL/m(2) vs 22 ± 1 mL/m(2), P < .01, respectively). These changes were reflected in lower biventricular systolic function in patients with ToF when compared with PS (RV ejection fraction: 52% ± 1.5% vs 59% ± 1%, P < .001, and LV ejection fraction: 61% ± 1% vs 67 ± 1%, P < .001, respectively). Although RV transannular plane systolic excursion was not significantly different between the groups (P = .86), the RV outflow tract was considered contractile in only 50% of patients with ToF compared with 93% of patients with PS (P = .0004). RV volumes and function were similar when only patients with contractile RV outflow tracts were compared.
RV outflow tract patch dysfunction in repaired ToF is responsible for higher end-systolic volumes and thus lower global measures of ventricular systolic function. These findings were not evident in cases of PS treated with valvotomy with comparable amount of PR. These observations highlight the importance of the initial repair surgery in ToF for late outcomes.
慢性三尖瓣反流（PR）对修复后的法洛四联症（ToF）的右心室（RV）功能有不良影响。然而，关于慢性 PR 时 RV 流出道（RVOT）收缩功能障碍以及 RV 和 LV 容积和功能的相关数据却很少。
我们回顾性地确定了在 2003 年至 2008 年间接受超声心动图检测到的“自由 PR”定量磁共振成像检查的连续 PR 患者。患者均患有 ToF 和跨环补片术（n=30，25.1±1.2 岁）或由于瓣膜性肺动脉狭窄而接受手术或经皮瓣膜切开术治疗的 PR（n=30，26.6±1.8 岁）。
ToF 和 PS 两组患者在扫描时的年龄、ToF 修复手术时的年龄或 PS 初始瓣膜切开术时的年龄、暴露于 PR 的时间、体表面积、心率、PR 分数、净肺动脉前向流量、主肺动脉和分支肺动脉的尺寸方面均匹配良好。两组患者均存在严重的 PR 分数（ToF：40%±1%vs PS：37%±2%，P=0.2）。两组的 RV 和 LV 舒张末期容积指数相似（RV 舒张末期容积指数：137±6mL/m2vs 128±5mL/m2，P=0.2，LV 舒张末期容积指数：72±2mL/m2vs 67±2mL/m2，P=0.1）。RV 质量在两组之间也相似（分别为 95±5g 和 81±6g，P=0.08）。然而，与 PS 相比，ToF 的 RV 和 LV 收缩末期容积指数始终较高（RV 收缩末期容积指数：70±5mL/m2vs 54±3mL/m2，P<0.01，LV 收缩末期容积指数：29±1mL/m2vs 22±1mL/m2，P<0.01）。与 PS 相比，这些变化反映了 ToF 患者的双心室收缩功能较低（RV 射血分数：52%±1.5%vs 59%±1%，P<0.001，LV 射血分数：61%±1%vs 67±1%，P<0.001）。尽管两组的 RV 跨环平面收缩期位移没有显著差异（P=0.86），但与 PS 组 93%的患者相比，仅 50%的 ToF 患者的 RV 流出道被认为具有收缩功能（P=0.0004）。当仅比较具有收缩性 RV 流出道的患者时，RV 容积和功能相似。
修复后的 ToF 的 RV 流出道补片功能障碍导致收缩末期容积较高，从而导致心室整体收缩功能降低。在接受瓣膜切开术治疗的 PS 患者中，并未出现与 PR 量相当的情况。这些发现突出了初始修复手术在 ToF 后期结果中的重要性。
