Burkhardt Barbara E U, Velasco Forte Marí Nieves, Durairaj Saravanan, Rafiq Isma, Valverde Israel, Tandon Animesh, Simpson John, Hussain Tarique
Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, TX, USA; Pediatric Heart Center, University Children's Hospital Zurich, Zurich, Switzerland.
Division of Imaging Sciences and Biomedical Engineering, King's College London , London , UK.
Front Pediatr. 2017 Feb 28;5:39. doi: 10.3389/fped.2017.00039. eCollection 2017.
Patients with Tetralogy of Fallot (TOF) and pulmonary insufficiency and a dilated right ventricle (RV) may suffer from a reduction in left ventricular (LV) performance. It is not clear whether timely pulmonary valve replacement (PVR) preserves LV mechanics.
Ten TOF patients who underwent PVR were identified from hospital records, and pre- and postoperative cardiac magnetic resonance images were post-processed with a semi-automatic tissue tracking software. LV circumferential strain, time to peak strain, and torsion were compared before and after PVR. A control group of 10 age-matched normal volunteers was assessed as a comparison.
LV circumferential strain did not change before vs. after PVR (basal -18.3 ± 3.7 vs. -20.5 ± 3%, = 0.082; mid-ventricular -18.4 ± 3.6 vs. -19.1 ± 2%, = 0.571; apical -22.7 ± 5.2 vs. -22.1 ± 4%; = 0.703). There was also no difference seen between the baseline strain and normal controls (control basal -18.2 ± 3.3%, = 0.937; mid -18 ± 3.2%, = 0.798; apex -24.1 ± 5%, = 0.552). LV torsion remained unchanged from baseline to post PVR [systolic 2.75 (1.23-9.51) °/cm vs. 2.3 ± 1.2°/cm, = 0.285; maximum 5.5 ± 3.5°/cm vs. 2.34 (1.37-8.07) °/cm, = 0.083]. There was no difference in time to measured peak LV circumferential strain before vs. after PVR (basal 0.44 ± 0.1 vs. 0.43 ± 0.05, = 0.912; mid-ventricular 0.42 ± 0.08 vs. 0.38 ± 0.06, = 0.186; apical 0.40 ± 0.08 vs. 0.40 ± 0.06, = 0.995). At the same time, pulmonary regurgitation and RV end-diastolic and end-systolic volume indices decreased and LV end-diastolic volume increased after PVR. RV and LV ejection fractions remained constant.
PVR allows for favorable remodeling of both ventricular volumes for TOF patients with significant pulmonary regurgitation. In this cohort, LV myocardial functional parameters such as circumferential strain, time to peak strain, and LV torsion were normal at baseline and remain unchanged after PVR.
法洛四联症（TOF）合并肺动脉瓣关闭不全及右心室（RV）扩张的患者，左心室（LV）功能可能会降低。目前尚不清楚及时进行肺动脉瓣置换术（PVR）是否能保留左心室力学功能。
从医院记录中识别出10例行PVR的TOF患者，并使用半自动组织追踪软件对术前和术后的心脏磁共振图像进行后处理。比较PVR前后左心室圆周应变、应变峰值时间和扭转情况。选取10名年龄匹配的正常志愿者作为对照组进行评估。
PVR前后左心室圆周应变无变化（基底段-18.3±3.7%对-20.5±3%，P = 0.082；心室中段-18.4±3.6%对-19.1±2%，P = 0.571；心尖段-22.7±5.2%对-22.1±4%，P = 0.703）。基线应变与正常对照组之间也无差异（对照组基底段-18.2±3.3%，P = 0.937；心室中段-18±3.2%，P = 0.798；心尖段-24.1±5%，P = 0.552）。从基线到PVR后，左心室扭转保持不变[收缩期2.75（1.23 - 9.51）°/cm对2.3±1.2°/cm，P = 0.285；最大值5.5±3.5°/cm对2.34（1.37 - 8.0—— 此处原文有误，应为8.07）°/cm，P = 0.083]。PVR前后测量左心室圆周应变峰值的时间无差异（基底段0.44±0.1对0.43±0.05，P = 0.912；心室中段0.42±0.08对0.38±0.06，P = 0.186；心尖段0.40±0.08对0.40±0.06，P = 0.995）。同时，PVR后肺动脉反流以及右心室舒张末期和收缩末期容积指数降低，左心室舒张末期容积增加。右心室和左心室射血分数保持不变。
对于有严重肺动脉反流的TOF患者，PVR可使两个心室容积得到良好重塑。在该队列中，左心室心肌功能参数如圆周应变、应变峰值时间和左心室扭转在基线时正常，PVR后保持不变。
