Repeat right ventricular outflow tract reconstruction using the Medtronic Freestyle porcine aortic root

BACKGROUND AND AIM OF THE STUDY: A variety of valve substitutes are used for right ventricular outflow tract (RVOT) reconstruction in children and young adults after previous RVOT surgery that has led to significant pulmonary insufficiency and/or stenosis. Herein, the authors' experience with pulmonary valve replacement (PVR) using a porcine valved conduit late after previous RVOT surgery was reviewed. METHODS: Between August 2002 and April 2005, 31 patients (mean age 14.5 +/- 9.5 years; range: 1.2-33.1 years) underwent PVR using the Medtronic Freestyle porcine aortic root. These patients averaged two prior operations (range: 1-5) for the following diagnoses: tetralogy of Fallot +/- pulmonary atresia (n = 21); persistent truncus arteriosus (n = 5); aortic stenosis (Ross-Konno procedure) (n = 2); pulmonary atresia with intact ventricular septum; (n = 1); congenital pulmonary stenosis (n = 1); and transposition of the great arteries (n = 1). Of these patients, 29 (93.5%) underwent additional procedures at the time of pulmonary valve insertion including: branch pulmonary artery reconstruction (n = 21), atrial septal defect closure (n = 5), ascending aorta replacement (n = 4), pacemaker or defibrillator placement (n = 3), tricuspid valve repair (n = 2), ventricular septal defect closure (n = 2), and other procedures (n = 2). RESULTS: There were no early or late deaths. The mean hospital stay was 8.3 +/- 5.9 days (range: 4-25 days). One patient had a subarachnoid hemorrhage with transient left hemiparesis, and two patients had acute tubular necrosis with temporary dialysis treatment. All patients were well at a mean follow up of 13 +/- 9.3 months (range: 0.5-31 months). Echocardiography showed trivial or no pulmonary insufficiency in 30 patients (96.7%). The calculated mean peak systolic RVOT gradient by echocardiography was 23.4 +/- 7.6 mmHg. CONCLUSION: The Medtronic Freestyle bioprostheses demonstrated excellent short-term results for repeat RVOT reconstruction. This valve's hemodynamic characteristics are comparable to those of homografts, and it is an attractive alternative given the limited availability of homograft valves. A lack of availability in sizes smaller than 19 mm limits use of this valve in pediatric patients, and long-term results remain to be determined.     

新型无支架生物瓣带瓣管道用于右室流出道重建

目的:验证新型无支架生物瓣带瓣管道应用于右室流出道重建术中的有效性和安全性。方法:2007年11月～2008年5月,全组7例复杂先天性心脏病患者使用了新型无支架牛心包带瓣管道重建右室流出道,其中Rastelli手术6例、Nikaidoh手术1例。通过术后不同时期超声检查结果,记录肺动脉压、血流速度、新建肺动脉瓣跨瓣压差及开口面积和返流情况,了解肺动脉管道直径、有无瘤样扩张以及远端吻合口压差等,对移植的无支架生物瓣带瓣管道的临床性能进行评价。结果:所有患者住院期间均无吻合口渗血、心内膜炎、血栓栓塞等带瓣管道相关并发症发生,恢复顺利,均治愈出院。术后1～4月和6月以上超声检查均提示移植的管道通畅,管壁无变薄、钙化,无瘤样扩张,无明显肺动脉瓣返流等。结论:新型无支架生物瓣带瓣管道具有管壁弹性好、易于缝合、术后排斥反应少等优点,且有良好抗返流作用,早期疗效满意。     

Reconstruction of the right ventricular outflow tract using a Medtronic Freestyle aortic root bioprosthesis

Uncorrected, long-term pulmonary regurgitation leads to right ventricular dilatation and dysfunction in a significant percentage of patients. We used magnetic resonance imaging (MRI) before and after surgery to assess the effect of pulmonary valve replacement with the Medtronic Freestyle bioprosthesis on right ventricular function and volume in nine patients with pulmonary regurgitation or stenosis. Mean follow-up time was 26 (10) months. We observed a decrease in mean end-diastolic volume from 143.6 (85.1) mL/m2 to 74.1 (12.6) mL/m2 (P=.018) and, in end-systolic volume from 88.0 (50.3) mL/m2 to 35.8 (19.3) mL/m2 (P=.016). In pulmonary valve disease, extensive follow-up by MRI is essential for timely evaluation of the degree of right ventricular dilation or dysfunction and for selecting a suitable time for valve replacement. The Medtronic Freestyle bioprosthesis is a good surgical choice for pulmonary valve replacement as its use is associated with low morbidity and mortality and the successful normalization of ventricular volumes.     

Percutaneous pulmonary valve implantation for reconstruction of a patch‐repaired right ventricular outflow tract

Percutaneous pulmonary valve implantation (PPVI) is nowadays an accepted treatment option to repair post‐surgical conduit dysfunction of the right ventricular outflow tract (RVOT). In addition, many patients need a pulmonary valve to reconstruct a hemodynamically incompetent native or conduit free outflow tract. Based on our experience with percutaneous stent‐valve placement in a cohort of 125 patients, we report here transvenous reconstruction of a conduit‐free, patch repaired outflow tract by utilizing balloon‐expandable stent‐valves in 23 patients with a median age of 22 years (5‐60 years). In 20 patients, the step‐by‐step procedure was performed uneventful with the aimed success. Severe RVOT dysfunction in term of a clinical relevant regurgitation could be changed to mild, as it was confirmed by follow‐up color Doppler echocardiography. In a 5‐year‐old girl a Melody® valve was placed as a surgical‐interventional hybrid approach. In one patient, the procedure was complicated by stent embolization during preparation of the RVOT for stent‐valve implantation. Reposition of the embolized stent was nevertheless successful for finishing percutaneous valve‐implantation. In one patient, surgical approach became necessary because of the inability to advance the balloon‐mounted stent‐valve through a pre‐stented RVOT. Considering the current available balloon‐expandable stent‐valves, transvenous pulmonary valve implantation is feasible to treat even an incompetent conduit‐free RVOT. However, preparation of the RVOT by pre‐stenting, in most patients with more than two stents in telescope technique remains challenging. Reconstruction of RVOT by the current available valves is promising only for a carefully selected group of patients.     

Long-term performance of beta-propiolactone-treated nonviable homograft for aortic valve replacement and right ventricular outflow tract reconstruction

Summary The long-term performance of beta-propiolactone-treated homografts was clearly different between operative survivors of aortic valve replacement (n=27) and those of right ventricular outflow tract reconstruction (n=11). The reoperation-free survival rate at 20 years was 14.8±6.8 (standard error)% in the former and 77.8±13.9% in the latter. Even a nonviable aortic homograft can be favorably accepted as a material for right ventricular outflow tract reconstruction in contrast to the aortic position.     

Percutaneous pulmonary valve implantation in the native right ventricular outflow tract

Percutaneous pulmonary valve implantation into dysfunctional right ventricular (RV) to pulmonary artery conduits is being increasingly performed in many European and North American centers with satisfactory results and low‐complication rates. We report the first application of this elaborate technique in the native RV outflow tract of a young patient who developed severe supravalvular pulmonary stenosis following an arterial switch operation for transposition of the great arteries. The procedure may be used as an alternative to surgical repair for the treatment of selected patients with supravalvular pulmonary stenosis complicating congenital heart surgery. © 2011 Wiley Periodicals, Inc.     

膨体聚四氟乙烯片作肺动脉单瓣重建右室流出道的近期疗效评价

目的评价膨体聚四氟乙烯片(Gore-Tex片)作肺动脉单瓣重建右室流出道(RVOT)的近期疗效。方法 2002年6月至2013年6月对91例先天性心脏病合并肺动脉狭窄或闭锁的患者施行矫治手术,其中男51例,女40例。法洛四联症合并肺动脉狭窄67例,法洛四联症合并Ⅰ型肺动脉闭锁12例,法洛四联症合并肺动脉瓣缺如5例,右心室双出口合并肺动脉狭窄3例,完全大动脉转位2例,肺动脉狭窄及室间隔缺损各1例。结果术中采用厚度0.1 mm的Gore-Tex片作肺动脉单瓣的Dacron血管片重建RVOT,术后血氧饱和度为96%~100%,动脉血氧分压82~207 mm Hg,右室/左室收缩压比值0.22~0.70,右室与左、右肺动脉间的压力阶差小于10 mm Hg。左室射血分数0.53~0.80,右室射血分数0.52~0.71,左室舒张末期容积指数0.28~0.62 ml/m2。术后早期并发症:心包积液10例,低氧血症(氧合指数<150)8例,心律失常7例,低心排血量综合征5例,残余室间隔缺损4例。术后随访3~48个月,无死亡和并发症的发生,其中76例RVOT早期瓣膜活动功能正常,15例单瓣固定在开放状态;87例无肺动脉单瓣狭窄,4例单瓣轻度狭窄;23例肺动脉瓣轻度反流,6例中度反流。结论采用厚度0.1 mm的Gore-Tex片作单瓣重建RVOT,可获得满意的临床和血流动力学效果,近期效果良好。     

Late results of right ventricular outflow tract reconstruction with Bj?rk-Shiley valved conduits

Between 1971 and December 1976, 27 children with congenital heart disease underwent right ventricular outflow tract reconstruction with conduits incorporating a Bj?rk-Shiley valve. The conditions corrected were pulmonary atresia with ventricular septal defect (14 patients), truncus arteriosus (6 patients), and complex disease (7 patients). At operation the children were aged from 12 days to 16 years (five patients were less than one year old). Overall mortality for the group was high (52%). There were nine early deaths and five late ones. Actuarial survival till death or reoperation was 55% at four years, 35% at eight years, and 28% at 12 years. Ten children subsequently underwent reoperation for conduit stenosis caused by neointimal proliferation and valve obstruction. The new conduits incorporated a biological valve. Mortality was highest in patients aged less than one year, and in those with truncus arteriosus, severe pulmonary hypertension, or complex heart disease. Mechanical valves should be avoided in conduit reconstruction of the right ventricular outflow tract for congenital heart disease.     

Current status of the Contegra conduit for pediatric right ventricular outflow tract reconstruction

Reconstruction of the right ventricular outflow tract (RVOT) is needed in a wide variety of congenital heart diseases at the time of primary repair, or later for replacement of existing valves or conduits. Ideally, the conduit or valve needed for such reconstruction should be formed of autologous tissue that grows, resists infection, lasts for the life span of the patient, and is readily available in all sizes. Such a conduit is not available, though several alternatives have been used, none of which is without potential drawbacks. One alternative--the Contegra bovine jugular vein conduit (Medtronic, Inc., Minneapolis, MN, USA)--was introduced in 1999 and has gained widespread application, with increasing enthusiasm for its use. The Contegra conduit consists of a bovine jugular vein with an incorporated trileaflet valve. The conduit tissue is extremely pliable and offers optimal conditions for surgical handling. Moreover, the proximal tubular segment allows construction of the proximal anastomosis to the right ventricle, without the use of additional material. Increasingly, experience with the Contegra conduit is being published; hence, a literature search was conducted to evaluate available evidence on current use of the device in pediatric RVOT reconstruction.     

Late results of right ventricular outflow tract reconstruction with Bj?rk-Shiley valved conduits.

Between 1971 and December 1976, 27 children with congenital heart disease underwent right ventricular outflow tract reconstruction with conduits incorporating a Björk-Shiley valve. The conditions corrected were pulmonary atresia with ventricular septal defect (14 patients), truncus arteriosus (6 patients), and complex disease (7 patients). At operation the children were aged from 12 days to 16 years (five patients were less than one year old). Overall mortality for the group was high (52%). There were nine early deaths and five late ones. Actuarial survival till death or reoperation was 55% at four years, 35% at eight years, and 28% at 12 years. Ten children subsequently underwent reoperation for conduit stenosis caused by neointimal proliferation and valve obstruction. The new conduits incorporated a biological valve. Mortality was highest in patients aged less than one year, and in those with truncus arteriosus, severe pulmonary hypertension, or complex heart disease. Mechanical valves should be avoided in conduit reconstruction of the right ventricular outflow tract for congenital heart disease.     

Experimental right ventricular outflow tract reconstruction with a composite Mitrathane monocusp patch: preliminary results

Twenty large white pigs underwent normothermic right ventricular bypass, pulmonary artery valve excision and right ventricular outflow tract (RVOT) reconstruction using a synthetic material (Mitrathane). The animals were divided in two groups (ten for each group) for the RVOT reconstruction model: Group I with a composite monocusp patch (with a new design geometrically related to pulmonary artery circumference) and Group II without a valve mechanism. Four early postoperative deaths occurred in Group I (unrelated to monocusp patch function) and seven in Group II (due to acute right ventricular failure). Follow up of the six animals of Group I was 600-630 (average 617.5) days and of the three Group II animals was 95-110 (average 101.6) days. In Group I haemodynamic studies showed no significant difference from preoperative values at 5 months while at 20 months there was a moderate valve insufficiency in all animals. In Group II severe right ventricular insufficiency was present in all animals and spontaneous death occurred after about 3 months. In Group I angiographic studies disclosed no evidence of graft calcification or stenosis while in Group II there was a moderate pulmonary trunk dilatation. Post mortem examination showed no signs of degeneration in any graft. Microscopic studies of both groups revealed an acellular layer of fibrin on the external surface and fibrous deposit on the inner part of the suture with the right ventricle. In Group I there were leukocyte and histocyte infiltration of the grafts. In these experiments our synthetic monocusp model showed good function and durability in comparison to a RVOT reconstruction without a valve mechanism.     

Double freestyle valve replacement in a patient with a prior Ross procedure

Following a Ross procedure, patients may require reintervention for valvular stenosis or insufficiency of either the pulmonary autograft or the pulmonary homograft. Herein is reported a double use of the Medtronic Freestyle stentless bioprosthesis in a patient who previously had undergone a Ross procedure.     

Midterm outcomes of right ventricular outflow tract reconstruction using the Freestyle xenograft

Objective: Various options exist for right ventricular outflow tract (RVOT) recon‐struction in congenital heart disease. The Freestyle porcine aortic root may be usedbut its longevity is not well defined.
Design: We performed a retrospective review of all non‐Ross RVOT reconstructionsusing the Freestyle root in our institution. Survival and reintervention, either by sur‐gery, transcatheter valve implantation, balloon valvuloplasty, or bare metal stent placement, were recorded. Factors associated with reintervention were assessedusing Cox regression.
Results: Between January 2002 and December 2015, there were 182 patients identi‐fied. Sixteen patients were lost to follow‐up and 3 patients died, unrelated to cardiacsurgery. Of the remaining 163 patients, the median age was 12.2 years (interquartilerange 6.4‐16.4), median weight was 39.0 kg (interquartile range 19.9‐59.3), and themedian body surface area was 1.23 m² (interquartile range 0.79‐1.64). Ninety‐three(57%) patients had tetralogy of Fallot. The median follow‐up was 5.4 years (inter‐quartile range 2.9‐8 years). There were no operative or cardiac‐related deaths. Thirty‐eight patients (23%) required reintervention. The rate of freedom from rein‐tervention was 93.2% (95% CI 86.7%‐96.6%) at 5 years and 48.4% (95% CI34.9%‐60.6%) at 10 years. Age < 10 years, weight < 39 kg, and body surface area<1.2 m2 at the time of valve placement, as well as valve size ≤25 mm were signifi‐cantly associated with need for earlier reintervention.
Conclusions: The Freestyle root in the RVOT is associated with excellent survival andlow midterm need for reintervention. Its longevity is comparable to published data on homografts and other bioprosthetic valves.     

Left ventricular function improves after pulmonary valve replacement in patients with previous right ventricular outflow tract reconstruction and biventricular dysfunction

Congenital heart defects that have a component of right ventricular outflow tract obstruction, such as tetralogy of Fallot, are frequently palliated in childhood by disruption of the pulmonary valve. Although this can provide an initial improvement in quality of life, these patients are often left with severe pulmonary valve insufficiency. Over time, this insufficiency can lead to enlargement of the right ventricle and to the deterioration of right ventricular systolic and diastolic function. Pulmonary valve replacement in these patients decreases right ventricular volume overload and improves right ventricular performance. To date, few studies have examined the effects of pulmonary valve replacement on left ventricular function in patients with biventricular dysfunction. We sought to perform such an evaluation.Records of adult patients who had undergone pulmonary valve replacement from January 2003 through November 2006 were analyzed retrospectively. We reviewed preoperative and postoperative echocardiograms and calculated left ventricular function in 38 patients.In the entire cohort, the mean left ventricular ejection fraction increased by a mean of 0.07 after pulmonary valve replacement, which was a statistically significant change (P < 0.01). In patients with preoperative ejection fractions of less than 0.50, mean ejection fractions increased by 0.10.We conclude that pulmonary valve replacement in patients with biventricular dysfunction arising from severe pulmonary insufficiency and right ventricular enlargement can improve left ventricular function. Prospective studies are needed to verify this finding.     

Abnormal cardiac autonomic nervous activity after right ventricular outflow tract reconstruction

BACKGROUND: There are few studies of cardiac autonomic nervous activity (CANA) in patients with congenital heart disease. Methods and Results-We evaluated CANA in 54 patients after closure of an atrial/ventricular septal defect (group A), 54 patients after successful right ventricular outflow tract reconstruction (RVOTR) (group B1), 35 RVOTR patients with residual stenosis (group B2), and 47 controls. Cardiac parasympathetic nervous activity (PSNA) was estimated by heart rate (HR) change after cholinergic blockade, HR variability, and arterial baroreflex sensitivity (BRS). Cardiac sympathetic nervous activity was estimated by the heart-to-mediastinum (123)I-metaiodobenzylguanidine activity ratio (H/M) and HR increase after isoproterenol infusion (ss). HR response (DeltaHR) and peak oxygen uptake (VO(2)) were measured by exercise test. There was no difference in ss among study groups. Group A exhibited mildly impaired PSNA, which recovered 1 year after surgery, and no change in H/M. Impaired PSNA and low H/M were found in groups B1 and B2 compared with controls (P<0.001), although the PSNA tended to recover 1 year after re-RVOTR. In group B1, PSNA and ss were related to DeltaHR, and BRS correlated inversely with the number of surgical procedures and age at RVOTR and positively correlated with the follow-up period, whereas DeltaHR correlated with peak VO(2) (P<0.01 to 0.001). CONCLUSIONS: After RVOTR, postsynaptic ss-sensitivity is maintained and is important in DeltaHR during exercise, as is PSNA, although ventricular sympathetic denervation is common. Impaired PSNA immediately after RVOTR improves with improved DeltaHR and results in future amelioration of aerobic capacity, whereas ventricular sympathetic reinnervation is uncertain.     

Post-traumatic aneurysm of the right ventricular outflow tract with concomitant tricuspid valve insufficiency

Right ventricular aneurysms of different etiology are rare findings. Aneurysms of traumatic origin after penetrating accidents are reported. After nonpenetrating traumas formation of a right ventricular aneurysm, however, has not yet been reported. This case report deals with a 25-year-old patient who developed an aneurysm of the right ventricular outflow tract and tricuspid regurgitation after a nonpenetrating chest trauma. Clinical, hemodynamic, and echocardiographic findings with a follow up for 18 months demonstrate excellent adaptation to the traumatic changes. Therapeutic consequences are discussed with respect to the literature and prognosis.     

特发性右心室流出道室性心动过速

特发性右心室流出道室性心动过速（RVOT-VT）是起源于右心室流出道的特发性室性心动过速,即起源于右心室流出道的没有明显的器质性心脏病及致心律失常因素基础上的室性心动过速（VT）.RVOT-VT在国外约占全部特发性室性心动过速的80%左右,在国内也不少见.