Palliative reconstruction of right ventricular outflow tract in tetralogy with hypoplastic pulmonary arteries.

Twenty-five symptomatic patients with tetralogy of Fallot underwent palliative reconstruction of the right ventricular outflow tract without closure of the ventricular septal defect. Their ages ranged from 5 months to 20 years (mean age, 3.5 years). Eight patients had had 13 prior systemic-pulmonary arterial shunts. There were six hospital deaths (24%). Three patients needed a repeat right ventricular outflow reconstruction. There was one late death. The other patients manifested clinical improvement; hematocrit decreased from 0.54 to 0.43 (p less than 0.01) and arterial oxygen saturation increased from 63.0% to 83.2% (p less than 0.01). The size of the pulmonary artery, defined as the ratio of the sum of the diameter of the right and left pulmonary arteries to the diameter of the descending aorta, increased from 0.72 to 2.06 (p less than 0.01). Sixteen patients underwent a corrective operation 2.4 years after palliation. The results of palliative right ventricular outflow tract reconstruction suggest that it may be an optional strategy for the treatment of symptomatic patients who have tetralogy of Fallot with severely hypoplastic pulmonary arteries.     

右心室流出道的处理方法与法洛四联症矫治术后右心室功能的相关分析

目的 评价法洛四联症(TOF)右心室流出道(RVOT)处理方法与矫治术后右心功能变化的关系,以期提高矫治手术的中、远期效果.方法 2003年1月至2006年1月,125例TOF患儿接受矫治手术,其中男66例,女59例;手术年龄1～5岁,平均(3.4±1.1)岁;体质量7～26 kg,平均(15.2±5.7)kg.对照组选择20例同龄健康儿童.RVOT处理方法包括跨肺动脉瓣环补片加宽(M1组)67例,右心室漏斗部补片加宽(M2组)6例,经右心室切口非补片修复(M3组)18例,经右心房-肺动脉切口非补片修复(M4组)34例.采用脉冲多普勒(PDE)和组织多普勒超声心动图(TDI)评价右心室功能,选择三尖瓣环收缩期移位(TAPSE)、右心室心肌作功指数(MPI)作为右心室收缩功能指标,测定的三尖瓣瓣环处舒张早期峰速(Em),舒张晚期峰速(Am),计算Em/Am和E/Em比值作为右心室舒张功能指标.计量资料采用单因素方差分析,单因素分析有统计学意义的变量纳入logistic回归分析.计数资料采用x2检验.结果 术后5年随访检查心脏超声发现,M1和M2组的MPI和E/Em显著高于M3和M4组.单因素分析显示,术前Nakata指数、既往分流手术、手术方式、肺动脉瓣反流和术后QRS时间是影响术后MPI的危险因素;术前Nakata指数、手术方式、肺动脉瓣反流和术后QRS时间是影响术后E/Em的危险因素.二元logistic逐步回归分析结果显示,手术方式和术后QRS时间是影响术后MPI的独立因素;术后肺动脉瓣反流是影响术后E/Em的独立因素.结论 TOF术后右心室功能降低与RVOT处理方法有关,舒张功能的降低与术后肺动脉瓣的反流有明显的相关性,收缩功能的降低与手术中应用补片加宽右心室流出道和术后的QRS时间有明显的相关性.心脏超声多普勒技术在测定TOF术后右心室功能和评价术后中、长期疗效有重要的指导意义.     

The indication and effects of palliative right ventricular outflow tract reconstruction for tetralogy of Fallot with pulmonary atresia]

Palliative right ventricular outflow reconstruction (RVOT) in 5 cases with tetralogy of Fallot with valvular pulmonary atresia and 5 cases with truncal pulmonary atresia were studied regarding indication and postoperative development of pulmonary artery. In 4 cases with valvular atresia, RVOT was performed following previous palliation such as Blalock-Taussig shunt, and resulted in improvement in clinical symptoms and in significant increase in postoperative PA-index from 105.4 mm2/m2 before operation to 159.4 mm2/m2. In one case, RVOT was performed as the first stage palliation and symmetrical development of pulmonary arteries were observed. All underwent successful total correction later. However, in 5 cases with the truncal atresia, 2 died after RVOT and postoperative development of pulmonary artery was insignificant. RVOT is indicated for cases with poor pulmonary arterial development despite of palliation, and in future, RVOT as an initial palliation will be indicated in infants with hypoplastic pulmonary artery.     

Evidence for palliative enlargement of the right ventricular outflow tract in severe tetralogy of Fallot

Objective: If the pulmonary artery (PA) tree in patients with Fallot's tetralogy (TOF) is extremely hypoplastic, a shunt procedure may be difficult and not desirable because of side-effects. Moreover, the failing catch-up growth of the pulmonary annulus is well known. In patients with a severe form of TOF, we performed palliative transannular patching of the right ventricular outflow tract. The early and long-term follow-up was evaluated. Methods: Eleven patients (93 days (10–245 days); 3.5±0.7 kg (2.5–4.3 kg)) had highly symptomatic TOF (Hb: 18±2 g/dl, SO₂: 68±11%); angiographic diameters: RPA: 4.1 mm (2.5–6.4 mm), LPA: 3.4 mm (1.6–7.0 mm), PA trunc: 4.4 mm (2.5–7.0 mm). All 11 underwent transannular enlargement of the right ventricular outflow tract without closure of the ventricular septum defect. A PA index (cross-sectional area of the pulmonary arteries to BSA) was used to compare pre- and postoperative data. For follow-up, the patients were repetitively examined clinically and echocardiographically. Results: Preoperative PA index was 87±40 mm²/m² (normal: 330±35 mm²/m²). Postpalliation angiograms (age: 10–14 months) demonstrated a significant catch-up growth in nine patients (PA index from 99±40 to 310±54 mm²/m²) and inadequate growth in two patients (PA index 63 and 115 mm²/m²). Perioperative mortality was zero. Ten patients (43 months; 6–105 months) underwent elective repair. Six patients received pulmonary homograft valves (6–15 years after repair) because of severe pulmonary valve insufficiency and severe RV dilation. Complications: One patient died 10 months postpalliation due to pneumonia, one patient received a pacemaker after repair and died (2 months post-repair) due to pacemaker failure, a 5-year-old patient died 1 month after repair due to sepsis. All eight long-term survivors (12–17years) are in excellent clinical condition. Echocardiography revealed good RV function and near normal diameters at peak systolic pressures between 25 and 50 mmHg. Only one patient developed brady-arrhythmia; a pacemaker was implanted 8 years after repair and 2 years after homograft implantation. Conclusions: In a very severe form of TOF, palliative right ventricular outflow tract construction may provide the potential for complete repair. In the presented high-risk patient group, mortality was not related to the hypoplastic pulmonary arteries. Obviously, all patients need pulmonary valve implantation in the long run.     

食管超声心动图评价围术期儿童法洛四联症的右室流出道

目的 运用经食管超声心动图（TEE）对儿童法洛四联症（TOF）的右室流出道（RVOT）情况进行围术期评价。方法 32例TOF病儿体外循环前后分别进行TEE检查，年龄4个月～15岁8个月，平均4．0岁。结果 术前32例均TEE诊断为TOF。31例行根治术，1例行B-T分流术。RVOT扩大补片15例；跨肺动脉瓣环补片（TAP）16例，包括4例切除肺动脉瓣，2例带瓣移植物重建RVOT。术后TEE诊断RVOT残余梗阻5例（16．1％），与是否采用TAP无关（X^2=1．115，P=0．291）。肺动脉反流（PR）16例（51．6％），采用TAP比扩大补片术后更易出现PR（X^2=14．212，P=0．000）。保留原肺动脉瓣可减轻术后PR程度（X^2=5．915，P=0．015）。带瓣移植物重建RVOT可减少术后PR（X^2=8．163，P=0．004）。结论 术前TEE可明确诊断TOF，术后TEE可评价不同手术方法对于RVOT的效果。     

法乐四联症右室流出道心肌超微结构特点及其临床意义

目的 研究不同年龄组法乐四联症（TOF）右室流出道心肌超微结构特点。方法 取31例TOF右室流出道心肌组织，按年龄分为1岁以下组、1～3岁组和3岁以上组，取12例其他心脏病患者右室流出道心肌作为对照组，分别用光学显微镜和透射电镜对心肌组织进行超微结构的观察。结果 1～3岁TOF组和3岁以上TOF组心肌肌原纤维排列方向紊乱，同向性丧失，大量小线粒体增生堆积，分布不均匀，基质密度增加，z线粗细不等、缺失、断裂；1岁以下TOF组超微结构改变较轻微。对照组可见心肌结构正常。结论 TOF右室流出道存在许多心肌超微结构异常的心肌细胞，TOF病人应尽量在1岁以内进行手术，可避免心肌超微结构变化对心功能的不良影响。     

Right ventricular outflow tract reconstruction for pulmonary regurgitation after repair of tetralogy of Fallot. Preliminary results.

BACKGROUND: Pulmonary regurgitation after tetralogy of Fallot (ToF) repair is associated with right ventricular dilatation, failure and arrhythmia. Timing and technique for re-intervention remain controversial. METHODS: Our recent approach is to reconstruct the dilated right ventricle outflow tract (RVOT) as a fibro-muscular sleeve to support a pulmonary homograft valve conduit in orthotopic position. Indication is based on clinical and magnetic resonance (MR) criteria. We reviewed all patients who underwent RVOT reconstruction between January 2004 and February 2005. There were seven children (mean age 14+/-2 years) operated 13+/-2 years after ToF repair, and 12 adults (mean age 30+/-15 years) operated 23+/-10 years after ToF repair. Exercise testing and MR evaluation prior to surgery and at 1 year postoperative follow-up were compared. RESULTS: There was no operative mortality. At 1 year, pulmonary regurgitation was mild or less in 16/19 patients. Right ventricular (RV) end-diastolic (158+/-51 to 103+/-36ml/m(2), p<0.001) and end-systolic volumes (85+/-42 to 49+/-24ml/m(2), p=0.001) fell significantly. Importantly, effective RV stroke volume (43+/-10 to 48+/-7ml/m(2), p=0.019) and left ventricular (LV) stroke volume (43+/-7 to 47+/-7ml/m(2), p=0.009) increased significantly. The mean RV/LV end-diastolic volume ratio fell markedly in both children and adults (2.22+/-0.62 to 1.38+/-0.52). However, no improvement in maximal VO(2) on exercise was noted in either group. CONCLUSIONS: RVOT reconstruction restored valve function, improved RV dimensions and left and right stroke volumes. Maximal exercise capacity did not improve in either children or adults.     

Prediction of severe obstruction to right ventricular outflow after repair of tetralogy of Fallot and pulmonary atresia

Cineangiograms were available for a quantitative retrospective study along with complete clinical information in 96 patients who underwent intracardiac repair of tetralogy of Fallot with pulmonary atresia. Multivariate analysis determined that the risk factors for too high a ratio (greater than or equal to 1) between the peak pressure in the right ventricle and that in the left, in the operating room about 30 minutes after repair, were as follows: size of the patient, small size of the right and left pulmonary arteries, and a larger number of large aortopulmonary collateral arteries. When, according to the multivariate equation, the predicted probability of this ratio being equal to or greater than 1 is 50% or more, consideration may be given to preliminary operations before repair; when the predicted probability is 70% or more, complete repair at that stage may be unwise.     

The Contegra conduit in the right ventricular outflow tract induces supravalvular stenosis

OBJECTIVE: We sought to evaluate the incidence and nature of pulmonary stenosis after implantation of the bovine jugular vein graft (Contegra; Medtronic, Inc, Minneapolis, Minn) in the right ventricular outflow tract. METHODS: Between May 2000 and September 2002, 58 Contegra conduits (8-22 mm) were implanted during primary (n = 27) or redo operations (n = 31) in 57 patients, with ages ranging from 2 days to 48 years (mean, 9 years). Indications were truncus arteriosus (n = 16), tetralogy of Fallot (n = 28), pulmonary replacement in the Ross operation (n = 10), and Rastelli-type repair for double-outlet right ventricle (n = 4). Echocardiography was prospectively performed by a fixed team of investigators during follow-up (mean, 22.7 +/- 10 months). A peak gradient of greater than 50 mm Hg was considered severe stenosis. RESULTS: Two patients died from Staphylococcus aureus -induced septicemia and enterococcal endocarditis after 12 days and 12 weeks, respectively. One patient died of heart failure caused by endocardial fibroelastosis after 1 year. Freedom from severe stenosis at the distal anastomosis was 91% +/- 3% at 3 months, 68% +/- 6% at 12 months, and 49% +/- 8% at 24 months. The risk of development of stenosis does not change over time. Younger age and its derivatives (graft size and indication) are significantly related to the occurrence of severe stenosis ( P < .0001). Seventeen (29%) conduits required an endovascular intervention (balloon dilatation or stent). Seven (12%) conduits were explanted (endocarditis, 2; stenosis, 5). Histologic analysis of the explanted conduits showed excessive proliferation of neointima at the level of the distal anastomosis. Valve regurgitation was observed in 9 (16%) conduits and was always secondary to dilatation in the presence of severe distal stenosis. CONCLUSION: The Contegra conduit induces a neointimal proliferation at the level of the pulmonary anastomosis. This leads to a high incidence of severe stenosis at intermediate-term follow-up.