Randomized Trial of Pulmonary Valve Replacement in TOF

慢性肺动脉返流（PR）是法洛四联症（TOF）术后长期存活者发病和死亡的重要原因。尽管在修复的TOF和严重PR患者中进行肺动脉瓣置换术（PVR）的早期结果表明，手术与极低的死亡率相关，但我们的数据和其他研究者的数据表明，尽管成功恢复了肺动脉瓣功能并消除了RV容量超负荷，但RV功能障碍通常持续存在甚至复发。我们假设，持续存在的不稳定和无动力的右心室壁段，这不是单独的PVR解决，有助于在TOF修复的长期幸存者的持续右心室功能障碍。这项前瞻性、随机、单中心试验旨在比较两种手术策略（单独PVR（标准治疗）与PVR和手术RV重塑）对修复TOF和慢性PR患者的RV力学的影响。根据标准化术前定量心脏MRI标准符合入组条件的患者将被随机分配至单独PVR组或PVR和手术RV重塑组。在两个研究组中，患者将在肺动脉位置接受人工生物瓣膜（标准治疗）。在PVR + RV重塑组中，除PVR外，还将切除RV游离壁的平滑肌和无运动部分，以减小RV尺寸。第一个具体目标是比较两种手术策略对术后6个月RV力学的影响。主要结果变量是通过心脏MRI测量的术后6个月RV射血分数与术前相比的变化。次要结果变量是右心室和左心室容积、质量、质量容积比和可复搏心室搏出量和射血的变化 6个月时测量的次最大多巴酚丁胺应激反应分数（通过心脏MRI） 术后与术前值相比。其他次要结局变量包括功能状态评分（SF-36）、运动能力（平板试验）、肺功能以及心律失常和传导的综合无创评估。第二个具体目的是比较PVR+手术RV重塑组与单纯PVR组的术后不良事件发生率。总样本量为100名患者，将在四年内招募。

Chronic pulmonary regurgitation (PR) is an important cause of morbidity and mortality in long-term survivors of tetralogy of Fallot (TOF) repair. Although early results of pulmonary valve replacement (PVR) in patients with repaired TOF and severe PR have demonstrated that surgery is associated with very low mortality, our data and that of other investigators have demonstrated that despite successful restoration of pulmonary valve competence and elimination of the RV volume overload, RV dysfunction often persists or even worsens. We hypothesize that persistence of aneurysmal and akinetic RV wall segments, which are not addressed by PVR alone, contribute to persistent RV dysfunction in long-term survivors of TOF repair. This prospective, randomized, single-center trial aims to compare the effects of two surgical strategies, PVR alone (standard treatment) vs. PVR and surgical RV remodeling, on RV mechanics in patients with repaired TOF and chronic PR. Patients who are eligible for enrollment based on standardized preoperative quantitative cardiac MRI criteria will be randomly assigned to PVR alone or to PVR and surgical RV remodeling. In both study arms patients will receive a bioprosthetic valve in the pulmonary position (standard treatment). In the PVR + RV remodeling group, the aneurysmal and akinetic portions of the RV free wall will be resected to reduce RV size in addition to PVR. The first specific aim is to compare the effects of the two surgical strategies on RV mechanics six months after surgery. The primary outcome variable is the change in RV ejection fraction six months postoperatively compared with preoperatively as measured by cardiac MRI. Secondary outcome variables are changes in RV and LV volumes, mass, mass-to-volume ratio, and recruitable ventricular stroke volume and ejection fraction in response to submaximal Dobutamine stress (by cardiac MRI) measured six months postoperatively compared with preoperative values. Other secondary outcome variables include a functional status score (SF-36), exercise capacity (treadmill test), pulmonary function, and a comprehensive noninvasive assessment of arrhythmias and conduction. The second specific aim is to compare the incidence of postoperative adverse events occurring in the PVR plus surgical RV remodeling group to those in the PVR alone group. The total sample size is 100 patients, to be recruited over four years.