Early failure of the Shelhigh pulmonary valve conduit in infants

BACKGROUND: The ideal valved conduit for right-sided (pulmonary) reconstruction in infants and children remains elusive. Desired characteristics include availability, ease of implantation, and longevity. Cryopreserved homografts are most commonly used, but availability of small sizes and limited durability remain problematic. The Shelhigh porcine-valved conduit (SPVC) with its No-React anticalcification properties was developed as a potential alternative to homografts. METHODS: During a 10-month period, 8 patients underwent seven successful SPVC implantations. Median age was 9.5 days. Six conduits were less than 12 mm in diameter (range, 9 to 19 mm). RESULTS: The early and late survival rates were 100%. During a mean follow-up of 18 months, five conduits were replaced at 6, 10, 12, 12, and 13 months for severe obstruction. Actuarial conduit failure at 12 months was 72%. Explanted SPVCs demonstrated marked pseudointimal peel formation along the original intima with an intense granulomatous inflammatory reaction. The intimal reaction was severely fibrogenic, but calcification was not present. For comparison, we retrospectively reviewed the cases of 23 infants receiving cryopreserved homografts during an overlapping period. Twelve patients, 6 of them neonates, were less than 90 days old. Mean homograft size was 13 mm (range, 8 to 15 mm), with nine less than 13 mm. During a mean follow-up of 26 months, six conduits were replaced at 7, 12, 12, 16, 20, and 35 months (sizes 13, 17, 14, 12, 10, and 12 mm, respectively). Only three of nine homografts less than 13 mm in size were replaced during a mean follow-up of 12 months. The overall homograft replacement rate was 17% at 22 months (p = 0.005) compared with the SPVC). CONCLUSIONS: Although the SPVC appears to resist calcification, a marked foreign-body type of reaction results in pseudointimal peel formation and early conduit stenosis. In its present configuration, the SPVC in not a suitable valved conduit for use in infants. Although not ideal, the cryopreserved homograft has superior longevity to the SPVC.     

Right ventricular outflow tract reconstruction using Contegra valved conduit: natural history and conduit performance under pressure.

OBJECTIVE: To assess the performance of the bovine Contegra valved conduit used for right ventricular (RV) outflow tract reconstruction, particularly in relation to post-operative RV pressure. METHODS: Follow-up study of 64 consecutive right ventricular to pulmonary artery-conduit implants in 62 patients between January 2000 and April 2003. The majority of cases were forms of pulmonary atresia/VSD (n=24, 39%) or Fallot's tetralogy (n=13, 21%). Thirteen cases (21%) had aortic atresia, truncus arteriosus or discordant connections with pulmonary atresia/VSD. Twelve cases (19%) were conduit replacements. Echocardiography was performed for a median follow-up of 14 months (range 0-38 months). RESULTS: Median age at implantation was 13.8 months (range 0.1-244 months) and median weight was 8.9 kg (range 2.1-84.1 kg). Thirty-eight patients (59.4%) were <10 kg at the time of surgery. Early mortality was 6.4% (n=4). During follow-up there were four explantations (one for endocarditis and three for conduit dilatation) and 16 (28.6%) catheter interventions. Overall freedom from intervention at 1 and 3 years was 71+/-6% and 53+/-11%, respectively. Freedom from conduit-specific reintervention was 66+/-11% at the end of the study period. Reintervention was associated with small conduits (p=0.04), age <1 year (p=0.04) and with high RV/LV pressure ratio in the immediate post-operative period (p=0.0003). On multivariate analysis, the RV/LV pressure ratio was the strongest single factor predicting the overall reintervention (OR 5.45). Acquired distal conduit stenosis at suture line was the commonest indication for conduit-specific reintervention and was associated with the smaller conduits. The conduits explanted for dilatation showed neointimal proliferation, thrombosis, calcification and chronic inflammation. CONCLUSIONS: The Contegra conduit is widely applicable to RVOT reconstruction with satisfactory mid-term results. However, there is a significant incidence of conduit-related complications, particularly with the smaller conduits. Adverse performance was strongly associated with high RV/LV pressure ratio at completion of surgery. We would recommend cautious use of the conduits in patients with predicted high RV/LV pressure ratios, where careful monitoring of conduit performance is crucial. There is some element of unpredictability, which adds to the importance of close follow-up. Further studies are needed to explore the issues of thrombogenicity, degeneration, possible 'rejection', and the potential role of anti-platelet and anti-inflammatory modulation.     

Valved and nonvalved right ventricular--pulmonary arterial extracardiac conduits. An experimental comparison

Extracardiac conduits are essential in operations for congenital discontinuity between the right ventricle and the pulmonary artery. The disturbing degree of obstruction reported in clinical series of extracardiac conduits containing porcine valves has been attributed in part to early valve deterioration and the development of a thick neonintimal lining within the Dacron graft. This study compares the hemodynamic differences and the thickness of the neointimal lining in right ventricular extracardiac conduits with and without a porcine valve. Woven Dacron conduits (16 mm) were implanted in 15 adult mongrel dogs, and then the proximal pulmonary artery was occluded with Dacron tape. In six dogs, the extracardiac conduit contained a porcine valve, whereas in the other nine it did not. Cardiac output, transconduit gradient, and resistance were measured at operation and 6 and 12 months postoperatively in both groups. No hemodynamic differences were noted. After 1 year, the thickness of the neointimal lining was threefold greater in valved conduits (1,370 +/- 313.1 mu versus 367 +/- 28.07 mu, p less than 0.005). The neointima along the Dacron graft was thickest proximal and distal to the porcine valve. The luminal peel in valved conduits contained fenestrations and intimal flaps, similar to those observed clinically. In our model, a porcine valve in a right ventricular extracardiac conduit is associated with intimal hyperplasia not seen in nonvalved conduits. If the pulmonary vascular resistance is normal, then the absence of a valve within the conduit does not significantly change hemodynamics and may warrant clinical application to prevent late conduit obstruction.     

Bovine valved venous xenografts for RVOT reconstruction: results after 71 implantations.

BACKGROUND: Pediatric right ventricular outflow tract (RVOT) reconstruction with homo- or porcine xenografts is problematic because of limited availability, lack of material for reconstruction, early degeneration, and tissue ingrowth. Contegra, a bovine jugular vein graft, might be an interesting alternative to overcome these problems. PATIENTS AND METHODS: Within a Federal Drug Administration controlled study, we implanted 71 Contegra pulmonary valved conduits from May 1999 to September 2001 in 71 patients (male/female 33/38) in the age range 2 days-17.4 years, median 1.2 years. Twenty five were primary repairs, 22 had previous graft implantations, and 24 had other repairs/palliations. Preoperative diagnoses: truncus arteriosus communis (19 patients), tetralogy of Fallot (32), double outlet right ventricle (13), transposition of the great arteries (5), and two rare complex malformations. The size of implanted Contegra conduits ranged from 12 to 22 mm. Echocardiography was performed at 1 and 3 months, and then every 3 months postoperatively. Follow-up time was 27 months (maximal), 80 years in total. Results were compared with our 52 homograft- and 30 Tissuemed porcine xenograft recipients. RESULTS: Contegra enables the surgeon to perform all anastomoses without additional material. Its tissue is very apt for suturing and its insufficiencies are common, but without clinical significance or tendency to increase. We saw no sign of conduit or valve degeneration during the whole follow-up up to 27 months. There were no device related adverse events. Redos: five for peripheral pulmonary arteries, two residual ventricular septum defect (VSD) closures. There were six deaths (five early, one late). The maximal transvalvular gradients of 25-42 mmHg were measured in seven patients; these gradients did not increase further during the follow-up. Six patients with completely intact Contegra conduits developed pressure gradients of more than 70 mmHg immediately distal from the conduit. At 27 months, Contegra grafts were advantageous compared to homografts with respect to survival and freedom from explantation. Right ventricle to left ventricle (RV/LV) ratio development and freedom from explantation/redo were equal for Contegra conduits and homografts. Porcine Tissuemed xenografts were significantly inferior. CONCLUSION: The Contegra conduit offers unique tailoring and suturing options for primary and redo RVOT reconstruction. At 27 months, its durability seems at least equivalent to homografts and is superior to porcine Tissuemed xenografts.     

Long-term outcome of right ventricular outflow tract reconstruction using a handmade tri-leaflet conduit.

OBJECTIVE: Since 1985, we have implanted handmade tri-leaflet conduits made of heterologous pericardium or expanded polytetrafluoroethylene (ePTFE), as an alternative to homograft for right ventricular outflow tract reconstruction. This report assesses the long-term outcome of these prostheses. METHODS: From 1985 to 2003, 216 handmade tri-leaflet conduits were implanted in 191 patients. Forty-two patients had previous conduit repairs. The mean age at operation was 8.1+/-7.7 years (range: 15 days-44 years). The underlying diagnoses were pulmonary atresia with ventricular septal defect in 83 patients, atrioventricular discordance in 36, transposition of the great arteries in 26, double outlet right ventricle in 14, and truncus arteriosus in 17. Whole heterologous pericardial tri-leaflet conduits were implanted in 169 patients, in the early series (porcine: 85; equine: 58; bovine: 26); bovine pericardial conduits containing ePTFE leaflets were implanted in 26 patients since 1996; whole ePTFE tri-leaflet rolls were employed in the most recent 21 patients. The conduit size was 21.1+/-3.1mm (range: 12-27 mm), 147.4+/-21.4% (range: 82.6-202.6%) of the anticipated diameter of the pulmonary valve. Follow-up was complete. RESULTS: There were 28 early deaths and 24 late deaths. The indication for conduit replacement was a peak instantaneous pressure gradient of greater than 50 mmHg. Sixty-five conduits required reoperation for conduit obstruction at 8.6+/-3.3 years after implantation. The freedom from reoperation at 5, 10, and 15 years was 93.9+/-1.9, 61.4+/-4.5, and 35.5+/-5.6%, respectively. Patients with smaller conduit size and young age at operation were predisposed to reoperation. None of the 47 ePTFE tri-leaflet conduits developed significant obstruction. The freedom from important pulmonary valve regurgitation (PR) as assessed by echocardiography was 68.3+/-3.7% at 5 years, 33.0+/-4.5% at 10 years, and 21.6+/-4.9% at 15 years. No patient required reoperation due to PR or right ventricular dysfunction. CONCLUSIONS: Handmade tri-leaflet conduits provide a reliable alternative for RVOT reconstruction in children, yielding as good a long-term outcome as do homografts. Longer follow-up is needed to determine how well ePTFE leaflets will fare.     

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.     

Pericardial tissue valves and Gore-Tex conduits as an alternative for right ventricular outflow tract replacement in children

BACKGROUND: There is still no perfect conduit for reconstruction of the right ventricular outflow tract (RVOT) in children. Homografts are not always available in the appropriate size, and degenerate in a few years. This study evaluates the pericardial valve with Gore-Tex conduit as an alternative for RVOT construction. METHODS: From January 1, 1993, to September 30, 1999, a pericardial tissue valve was inserted in all patients undergoing RVOT reconstruction or pulmonary valve replacement (PVR) who were large enough to accommodate a tissue valve. In patients without a native main pulmonary artery, a new technique was used to construct an RV-PA conduit out of a flat sheet of Gore-Tex, as Dacron frequently leads to stenosis. Data were collected by retrospective review, follow-up echocardiograms, and assessment by a single cardiologist. RESULTS: There were 48 patients, 22 undergoing a PVR alone and 26 a RV-PA valved Gore-Tex conduit. Diagnosis included tetralogy of Fallot (n = 25); truncus arteriosis (n = 9); ventricular septal defect with PA (n = 5); DORV (n = 4); D-TGA with PS (n = 2); and 1 each IAA with sub AS, VSD with PI, and PS s/p Ross procedure. Patient age ranged from 3 to 33 years and 98% were reoperations. The valve sizes ranged from 19 to 33 mm and the median hospital length of stay was 4 days. There were 2 (4.2%) perioperative and 1 (2.1%) late deaths, none related to the valve or Gore-Tex conduit. At a follow-up of 15 to 86 months (mean 43 +/- 16 months), all remaining 45 patients are New York Heart Association class I, all valves are functional, and no patient has required valve or conduit replacement or revision; more importantly, echocardiogram revealed no significant valve or conduit stenosis (mean gradient 16 +/- 8 mm Hg) and no evidence of regurgitation or structural degeneration. CONCLUSIONS: A pericardial tissue valve and Gore-Tex conduit provides a reliable alternative for RVOT reconstruction in pediatric patients. It is readily available, molds in the limited retrosternal space, and has outstanding intermediate results with no evidence of failure or deterioration up to 7 years after insertion.     

Experimental evaluation of porcine-valved conduits processed with a calcium-retarding agent (T6)

The effectiveness of a water-soluble C-12 alkyl sulfate (T6) (U.S. Patent No. 4,323,358) in retarding bioprosthetic calcification was evaluated in 23 porcine-valved conduits (13 T6-treated conduits and 10 controls) implanted in young sheep between the right ventricle and the pulmonary trunk. The grafts were divided into three groups according to the period of function: Group I, less than 2 months; Group II, 2 to 4 months; and Group III, 5 to 7 months. In Group I (four T6 and four controls), endocarditis occurred in five cases. In Group II (three T6 and three controls), four conduits showed severe fibrous peel ingrowth. In Group III (six T6 and three controls), fibrous peel was the main feature in four conduits and calcium deposits occurred in the porcine aortic wall in all cases, with cusp involvement in two; in both T6-treated and control conduits, chemical analysis showed a much lower calcium content of the cusps (8.45 +/- 80 versus 2.95 +/- 1.52 mg/gm dry weight, respectively) than that reported in other animal or human explants. The grade of calcification in control and T6-treated conduits was equal on x-ray analysis, and no differences in calcification patterns were noted on electron microscopy. This experimental model shows a low degree of cusp calcification and no significant differences between T6-treated and control conduits. Peel formation markedly interferes with performance of the porcine-valved conduit. The results of this analysis indicate that valved conduits are not the optimum model for evaluating calcium-retardant agents in biological valves.     

Early results of right ventricular-pulmonary artery conduits in patients under 1 year of age.

OBJECTIVES: Management strategies for the repair of many complex heart defects require the implantation of a valved conduit between the right ventricle (RV) and the pulmonary artery (PA), often using aortic or pulmonary homograft valves. Their limited availability, however, has led to the development and use of new conduits. We retrospectively compared our experience with small homografts in patients of less than 1 year of age with the TissueMed bioprosthetic valved conduit. METHODS: From March 1994 to November 1997 29 patients in their first year of life underwent conduit implantation for complex heart defects. These were retrospectively reviewed in order to determine the incidence of death or conduit stenosis. Seventeen patients received homografts and 12 TissueMed conduits. RESULTS: Diagnoses and operative details including conduit size were similar in the two groups and in all cases complete repair of the underlying defect was carried out. Early post-operative mortality was 4/17 (23.5%) in the homograft group and 3/12 (25%) in the TissueMed group. Echo Doppler evaluation within 1 month of operation showed no right ventricular outflow tract (RVOT) obstruction in any of the survivors. In the TissueMed group 8/9 (77%) survivors have gone on to develop significant RVOT obstruction within 12 months of operation. There have been three late deaths in this group all related to severe RVOT obstruction. Two patients died during an attempt at balloon dilatation and one patient died of progressive right heart failure. Five patients had successful replacement of the TissueMed conduit. One child remains well with no evidence of RVOT obstruction. At operation to replace conduit, or at autopsy, the stenoses were related to the deposition of fibrous tissue at the anastomotic suture lines. In the homograft group none of the survivors developed RVOT obstruction during the first 12 months post-operatively. There was one late death (non-cardiac in origin) and one child is awaiting conduit replacement 40 months after initial implantation for obstruction. CONCLUSIONS: The homograft is a satisfactory conduit for re-establishment of RV-PA continuity in infancy. Further work needs to be undertaken in order to elucidate the mechanisms of early graft failure in bioprosthetic conduits if these are to be a suitable alternative for RV outflow reconstruction in infants.     

Composite lengthened arterial conduits: long-term angiographic results of an uncommon surgical strategy

BACKGROUND: We sought to evaluate the long-term patency rate of composite lengthened conduits. METHODS AND RESULTS: From December 1991 to April 2000, 43 patients had a composite lengthened arterial conduit. There was a mean of 2.83 +/- 1.23 anastomoses per patient. No 30-day mortality occurred. Five patients died from 3 to 84 months after the operation (mean, 38.6 +/- 34.6 months). After a mean follow-up of 57.0 +/- 32.3 months (range, 3-99 months), all the survivors are asymptomatic. The only cardiac major events recorded were 2 (4.6%) late acute myocardial infarctions in the patients who died. Eight-year survival and event-free survival were both 80.4% +/- 9.1% (range, 3%-93%). In the early period (13.5 +/- 4.8 days) in 26 patients, 26 arterial composite lengthened conduits and 37 distal anastomoses had postoperative angiographic control; all the anastomoses were rates as grade A, according to Fitzgibbon classification. In the late period (29 +/- 30 months) in 23 patients, 23 arterial composite lengthened conduits and 34 distal anastomoses were checked; the patency rate was 22 (95.6%) of 23 for the composite lengthened conduits and 33 (97%) of 34 for the distal anastomoses. CONCLUSIONS: In particular situations, when the length of an arterial conduit is not enough to allow a correct use of the graft, lengthening of an arterial conduit can be a safe and effective technique.     

Xenograft transplantation in congenital cardiac surgery at Baskent University: midterm results

OBJECTIVE: Xenograft valved conduits have been used in several cardiac pathologies. In this study we have presented our midterm results of pediatric patients pathologies who were operated with xenograft conduits. PATIENTS AND METHODS: Between January 1999 and January 2005, 134 patients underwent open heart surgery with xenograft conduits. The conduits were used to establish the continuity of the right ventricle to the pulmonary artery or aorta, the left ventricle to the pulmonary artery, or aorta due to various types of complex cardiac anomalies. Patients were evaluated by transthoracic echocardiography (ECHO) at 6-month follow-ups. Cardiac catheterization was performed when ECHO demonstrated significant conduit failure. RESULTS: Hospital mortality was observed in 28 patients (20.1%), and 13 patients died upon follow-up (9.7%). Mean follow-up was 24.6 +/- 4 months (range, 13 to 85 months). Among 93 survivors 20 patients (21.5%) were reoperated due to conduit failure. The main reasons for conduit failure were stenosis (n=13), valvular regurgitation (n=2), or both conditions in 5 cases. Mean pulmonary gradient before conduit re-replacement was 47.7 +/- 30.1 mmHg. The 1-, 3-, and 6-year actuarial survival rates were 95 +/- 2%, 91 +/- 3%, and 86 +/- 5%. The 1-, 3-, and 6-year actuarial freedom rates from reoperation were 95 +/- 1%, 90 +/- 3%, and 86 +/- 4%. An increased gradient between the pulmonary artery and the right ventricle and prolonged cardiopulmonary bypass times were observed to be significant risk factors for reoperation. There was no mortality among reoperated patients. CONCLUSION: Xenograft conduits should be closely followed for calcification and stenosis. Conduit stenosis is the major risk factor for reoperation. In these patients, reoperation for conduit replacement can be performed safely before deterioration of cardiac performance.     

Externally stented polytetrafluoroethylene valved conduits for right heart reconstruction. An experimental comparison with Dacron valved conduits

Valve-containing conduits have made possible the repair of many congenital anomalies that involve right ventricular-pulmonary arterial discontinuity. The distressing problem of neointimal peel formation with eventual conduit obstruction in patients with Dacron valved conduits has led to the need for premature replacement in many patients. Externally stented polytetrafluorethylene has demonstrated superior patency in the venous system experimentally and clinically and was believed to have potential advantages over Dacron for conduit construction. This study compares the transconduit resistance and the thickness of the neointimal peel in right ventricular-pulmonary arterial conduits constructed of externally stented polytetrafluoroethylene with those of woven Dacron. The 19 mm externally stented polytetrafluoroethylene conduits (Impra, Inc.) containing a Hancock porcine valve (Extracorporeal Inc.) were implanted in six adult mongrel dogs followed by proximal occlusion of the pulmonary artery. In six additional animals, a Dacron valved conduit of similar size and length was inserted. Cardiac output, transconduit gradient, and resistance were measured at operation and at 3 months. All conduits were subsequently explanted, opened longitudinally, and the thickness of the neointimal peel (excluding suture lines) measured. No hemodynamic differences were noted during the 3 month follow-up. However, the thickness of the neointimal peel was fourfold greater in Dacron conduits (609 +/- 144 mu) than in the conduits constructed of externally stented polytetrafluoroethylene (156 +/- 50 mu) (p less than 0.01). The thick peel in Dacron conduits extended into the outflow portion of the porcine valve cusps and prevented their full excision. The neointima in externally stented polytetrafluoroethylene conduits was thin and uniform and did not extend onto the leaflets or limit their mobility. This study demonstrated that the early hemodynamic performance of externally stented polytetrafluoroethylene conduits was comparable to that of Dacron conduits; Dacron conduits were subject to an accelerated rate of peel formation that affected leaflet mobility and may be a factor in early valve degeneration; a thin neointima formed in externally stented polytetrafluoroethylene conduits and valve leaflet motion was preserved. This study showed that externally stented polytetrafluoroethylene conduits offer advantages over Dacron valved conduits and warrant clinical application.     

同种带瓣管道应用的远期效果

目的　评价同种带瓣管道应用后的远期效果。方法　1988年1月至1997年12月的10年间应用同种带管道瓣治疗165例多种复杂先天性心脏病(先心病)，其中主动脉带瓣管道136例、肺动脉带瓣管道29例。病人年龄1.3～22.0岁，平均7.6岁。体重9.5～58.0kg，平均22.0kg。管道直径17～22mm，平均19mm。结果　术后早期（30d内）死亡40例，死亡率为24%。术后随访10个月～12.1年，平均(37.0±8.6)个月。病人术后5、10年生存率分别为94.6%、83.8%，带瓣管道完好率分别为83%、58%。结论　应用同种带瓣管道治疗复杂先心病，远期疗效比较满意。     

Results with the freestyle porcine aortic root for right ventricular outflow tract reconstruction in children

BACKGROUND: The ideal choice for valved reconstruction of the right ventricular outflow tract (RVOT) in children is undetermined. This study explores the Freestyle porcine aortic root for these patients. METHODS: From January 1998 to December 2002, 56 patients ages 1.6 to 29.9 years old (mean 11.8 years old) underwent RVOT reconstruction using a Freestyle porcine aortic root. The patients averaged 1.9 prior operations (range 0 to 5) for tetralogy of Fallot +/- pulmonary atresia (28 patients), critical pulmonary stenosis (10 patients), Ross procedure (5 patients), pulmonary atresia/intact ventricular septum (4 patients), complete atrioventricular septal defect +/- tetralogy of Fallot (4 patients), and others (5 patients). At time of RVOT reconstruction, 42 patients (75%) had additional procedures including the following: tricuspid or mitral repair (24 patients), pulmonary arterioplasty +/- Glenn (12 patients), ventricular septal defect closure (5 patients), aortic valve replacement (3 patients), placement of a cardioverter/defibrillator or pacemaker (3 patients), and others (8 patients). RESULTS: One patient developed mediastinitis; another was treated for Candida endocarditis (his excised homograft unexpectedly grew Candida). All patients are well on follow-up from 2 to 60 months (mean 30 +/- 20 months) with no deaths. The patient with endocarditis underwent conduit replacement for recurrent pulmonary stenosis 3.5 years postoperatively. Echocardiography revealed mild or no pulmonary insufficiency in 93%. The calculated mean peak systolic RVOT gradient by echocardiography was 19.7 +/- 15.4 mm Hg. CONCLUSIONS: These data demonstrate excellent results with the Freestyle bioprosthesis for RVOT reconstruction in children. This valve may serve as a readily available alternative to homograft valves in RVOT reconstruction, particularly since early insufficiency seems to be less problematic. Questions of long-term durability and significance of echocardiographic stenosis remain unanswered.     

Homograft conduit failure in infants is not due to somatic outgrowth

OBJECTIVE: It has been assumed that the need for homograft replacement is due to somatic outgrowth, but this has not been adequately studied. Our objective was to identify reasons for homograft conduit failure. METHODS: The records and imaging studies of 40 patients undergoing homograft conduit replacement of the right ventricular outflow tract from 1996 to 2000 were retrospectively reviewed. RESULTS: The majority of patients had a diagnosis of tetralogy of Fallot (n = 20) and truncus arteriosus (n = 13). The median age at the initial operation was 8 months (0.25-108 months). The initial homograft sizes ranged from 9 to 22 mm, and 28 conduits were of pulmonary origin. When comparing size of the initial homograft with patients' expected pulmonary valve diameter (z = 0), oversizing was noted to be +3 (range, 0.83-5.4). Median interval to conduit failure was 5.3 years (0.83-11.3 years). At homograft replacement, only 12 patients had an existing conduit that was 1 SD below the homograft conduit size needed (z < or = -1). Most conduits had important regurgitation, but this was rarely a primary reason for reintervention (n = 1). Reoperation was usually required for stenosis, with a median gradient of 53 mm Hg (20-140 mm Hg). Stenosis was further categorized angiographically as follows: homograft valvular stenosis (shrinkage; 21/40 [53%]), distal anastomotic stenosis (4/40 [10%]), conduit kinking (3/40 [8%]), sternal compression (3/40 [8%]), posterior shelf impingement (2/40 [5%]), and somatic outgrowth (3/40 [8%]). Replacement in 2 patients was for proximal hood aneurysm. Several patients (7/40 [18%]) had stenosis at multiple levels. The average decrease in conduit diameter was 47% (28%-73%). CONCLUSIONS: Somatic outgrowth is seldom a primary reason for homograft conduit replacement of the right ventricular outflow tract. The most common cause for failure is conduit obstruction with thickening and shrinkage at the annular area. Conduit stenosis was responsible for failure in 53% of patients, technical issues were responsible for 30%, and only 8% failed as a result of somatic outgrowth. Placement of a smaller homograft (z = 0) at the initial operation may decrease the incidence of conduit kinking, sternal compression, and posterior shelf impingement.     

Use of bovine jugular vein to reconstruct the right ventricular outflow tract: early results

OBJECTIVE: We evaluate early results of bovine jugular vein conduits in the pulmonary outflow. METHODS: Between April 2000 and September 2001, 31 conduits were placed in the outflow of the right ventricle. Patients who received a conduit as a staged surgical procedure were excluded (n = 3). Implantation age ranged from 0 to 21 years (median, 3.4 years). Conduit diameter ranged from 12 to 20 mm (median, 14 mm). Transthoracic echocardiography was performed at discharge and 3 months after surgery. Patients with significant pulmonary regurgitation and/or stenosis underwent cardiac catheterization. RESULTS: Four patients died during the follow-up period. Three deaths were unrelated to the conduit. One death was related to the complete thrombosis of the conduit. At 3 months evaluation, pulmonary valve regurgitation was absent or trivial in 19, mild in 2 and severe in 3 of 24 survivors. Four patients had nonfatal conduit-related complications. A transient thrombus formation within 1 leaflet was noted postoperatively in a patient with a moderate pulmonary regurgitation. Three patients required reoperation 3 to 5.8 months after the implantation for conduit failure (mean, 4.3 months). Cardiac catheterization before replacement revealed an aneurysmal dilation of the conduit below a severe stenosis of the pulmonary bifurcation due to important neointimal proliferation. CONCLUSIONS: Early failure of bovine jugular vein valved conduits can occur because of exaggerated intimal proliferation or thrombotic process within the conduit. Because of these complications, close echocardiographic follow-up is mandatory during the first weeks after implantation.     

Late results of right ventricular outflow tract reconstruction with a bicuspid expanded polytetrafluoroethylene valved conduit

Background and Aim to Read

We report the results of a bicuspid expanded polytetrafluoroethylene (ePTFE) valved conduit used for right ventricular outflow tract reconstruction (RVOTR).

Methods

Between November 2005 and February 2009, 12 conduits were used for RVOTR. The mean age and weight of patients were 43.5 ± 46.4 months and 13.4 ± 8.6 kg. The main diagnosis was tetralogy of Fallot with pulmonary atresia in eight patients. The most common conduit size was 18 mm. The mean follow‐up was 88.0 ± 35.9 months.

Results

There were no operative and late mortalities. At discharge, the mean peak systolic pressure gradient across the RVOT was 14.1 ± 11.3 mmHg. There was no conduit valve regurgitation in nine patients. At the latest echocardiography (mean follow‐up: 84.3 ± 35.5 months), the mean peak systolic pressure gradient across the RVOT was 59.7 ± 20.2 mmHg, and there was no conduit valve regurgitation in six patients. Freedom from conduit malfunction was 100% and 83.3%, at 1 and 8 years, respectively. Two conduits were explanted due to sternal compression and four from conduit malfunction. Freedom from explantation was 83.3% and 74.2% at 2 and 8 years, respectively.

Conclusions

ePTFE bicuspid valved conduit has good late function in terms of valve regurgitation, but the pressure gradient across the conduit increases with time, which is the main cause of conduit failure and explantation.     

Porcine-valved Dacron conduits in Fontan procedures

From a series of 52 Fontan procedures between 1976 and 1984, the cases of the 27 consecutive patients who received a porcine-valved conduit were reviewed. There were 5 hospital deaths among these 27 patients. Follow-up ranges from 11 years 9 months to 3 years 9 months. At follow-up, no conduit-related complications could be demonstrated. There were no signs of valvular stenosis, exuberant peel formation, or calcification of the conduit in any of the patients. To date, there has been no need to replace any of the porcine-valved conduits. Cumulative survival (including hospital deaths) is 71% at 10 years. In conclusion, we believe that the porcine-valved conduits have functioned very satisfactorily over time.     

儿童永存动脉干的外科治疗

目的　总结儿童永存动脉干外科治疗经验。　方法　近９ 年来共收治永存动脉干５例,年龄３～１２ 岁,平均６－３ 岁。Ⅰ型２ 例（肺动脉均起于动脉干远侧）,Ⅱ型２ 例, Ⅳ型１ 例。肺循环时间和肺动脉排空时间均无明显延长。手术在体外循环心内直视下进行,室间隔缺损（ＶＳＤ） 补片缝合于动脉干瓣环并使其环缩。右心外管道采用缝制自体新鲜心包瓣涤纶人工血管４ 例,同种异体主动脉１ 例。　结果　术毕肺动脉压均明显下降,跨外管道压差７～３５ ｍｍ Ｈｇ。２ 例术后早期死亡与肺动脉病变无关。存活３ 例中１ 例并发低心排出量和呼吸功能不全,２ 例术后恢复顺利。分别随访１１４、９６ 和３４ 个月,心功能均为Ⅰ级,１ 例术后８ 年死于外管道梗阻。　结论　儿童永存动脉干仍可有手术指征; 带自体心包瓣人工血管远期效果良好; 纠正动脉干瓣关闭不全,防止ＶＳＤ 残余漏,避免过大的跨外管道压差和缩短手术时间,可提高手术成功率和远期效果     

Jugular venous valved conduit (Contegra) matches allograft performance in infant truncus arteriosus repair

Objective: Limited availability and durability of allograft conduits require that alternatives be considered. We compared bovine jugular venous valved (JVV) and allograft conduit performance in 107 infants who survived truncus arteriosus repair. Methods: Children were prospectively recruited between 2003 and 2007 from 17 institutions. The median z-score for JVV (n = 27, all 12 mm) was +2.1 (range +1.2 to +3.2) and allograft (n = 80, 9–15 mm) was +1.7 (range −0.4 to +3.6). Propensity-adjusted comparison of conduit survival was undertaken using parametric risk-hazard analysis and competing risks techniques. All available echocardiograms (n = 745) were used to model deterioration of conduit function in regression equations adjusted for repeated measures. Results: Overall conduit survival was 64 ± 9% at 3 years. Conduit replacement was for conduit stenosis (n = 16) and/or pulmonary artery stenosis (n = 18) or regurgitation (n = 1). The propensity-adjusted 3-year freedom from replacement for in-conduit stenosis was 96 ± 4% for JVV and 69 ± 8% for allograft (p = 0.05). The risk of intervention or replacement for branch pulmonary artery stenosis was similar for JVV and allograft. Smaller conduit z-score predicted poor conduit performance (p < 0.01) with best outcome between +1 and +3. Although JVV conduits were a uniform diameter, their z-score more consistently matched this ideal. JVV exhibited a non-significant trend towards slower progression of conduit regurgitation and peak right ventricular outflow tract (RVOT) gradient. In addition, catheter intervention was more successful at slowing subsequent gradient progression in children with JVV versus those with allograft (p < 0.01). Conclusions: JVV does match allograft performance and may be advantageous. It is an appropriate first choice for repair of truncus arteriosus, and perhaps other small infants requiring RVOT reconstruction.