The Performance of Hancock Porcine-Valved Dacron Conduit for Right Ventricular Outflow Tract Reconstruction

Outcomes after Biventricular Repair Using a Conduit between the Right Ventricle and Pulmonary Artery in Infancy

Background

This study investigated the outcomes of biventricular repair using right ventricle to pulmonary artery (RV-PA) conduit placement in patients aged <1 year.

Methods

Patients aged <1 year who underwent biventricular repair using an RV-PA conduit between 2011 and 2020 were included in this study. The outcomes of interest were death from any cause, conduit reintervention, and conduit dysfunction (peak velocity of ≥3.5 m/sec or moderate or severe regurgitation).

Results

In total, 141 patients were enrolled. The median age at initial conduit implantation was 6 months. The median conduit diameter z-score was 1.3. The overall 5-year survival rate was 89.6%. In the multivariable analysis, younger age (p=0.006) and longer cardiopulmonary bypass time (p=0.001) were risk factors for overall mortality. During follow-up, 61 patients required conduit reintervention, and conduit dysfunction occurred in 68 patients. The 5-year freedom from conduit reintervention and dysfunction rates were 52.9% and 45.9%, respectively. In the multivariable analysis, a smaller conduit z-score (p<0.001) was a shared risk factor for both conduit reintervention and dysfunction. Analysis of variance demonstrated a nonlinear relationship between the conduit z-score and conduit reintervention or dysfunction. The hazard ratio was lowest in patients with a conduit z-score of 1.3 for reintervention and a conduit z-score of 1.4 for dysfunction.

Conclusion

RV-PA conduit placement can be safely performed in infants. A significant number of patients required conduit reintervention and had conduit dysfunction. A slightly oversized conduit with a z-score of 1.3 may reduce the risk of conduit reintervention or dysfunction.

In Vitro Proof of Concept of a First-Generation Growth-Accommodating Heart Valved Conduit for Pediatric Use

Currently available heart valve prostheses have no growth potential, requiring children with heart valve diseases to endure multiple valve replacement surgeries with compounding risks. This study demonstrates the in vitro proof of concept of a biostable polymeric trileaflet valved conduit designed for surgical implantation and subsequent expansion via transcatheter balloon dilation to accommodate the growth of pediatric patients and delay or avoid repeated open-heart surgeries. The valved conduit is formed via dip molding using a polydimethylsiloxane-based polyurethane, a biocompatible material shown here to be capable of permanent stretching under mechanical loading. The valve leaflets are designed with an increased coaptation area to preserve valve competence at expanded diameters. Four 22 mm diameter valved conduits are tested in vitro for hydrodynamics, balloon dilated to new permanent diameters of 23.26 ± 0.38 mm, and then tested again. Upon further dilation, two valved conduits sustain leaflet tears, while the two surviving devices reach final diameters of 24.38 ± 0.19 mm. After each successful dilation, the valved conduits show increased effective orifice areas and decreased transvalvular pressure differentials while maintaining low regurgitation. These results demonstrate concept feasibility and motivate further development of a polymeric balloon-expandable device to replace valves in children and avoid reoperations.

Application of Homograft Valved Conduit in Cardiac Surgery

Valved conduits often correct the blood flow of congenital heart disease by connecting the right ventricle to the pulmonary artery (RV-PA). The homograft valved conduit was invented in the 1960s, but its wide application is limited due to the lack of effective sterilization and preservation methods. Modern cryopreservation prolongs the preservation time of homograft valved conduit, which makes it become the most important treatment at present, and is widely used in Ross and other operations. However, homograft valved conduit has limited biocompatibility and durability and lacks any additional growth capacity. Therefore, decellularized valved conduit has been proposed as an effective improved method, which can reduce immune response and calcification, and has potential growth ability. In addition, as a possible substitute, commercial xenograft valved conduit has certain advantages in clinical application, and tissue engineering artificial valved conduit needs to be further studied.

Pediatric tri-tube valved conduits made from fibroblast-produced extracellular matrix evaluated over 52 weeks in growing lambs

There is a need for replacement heart valves that can grow with children. We fabricated tubes of fibroblast-derived collagenous matrix that have been shown to regenerate and grow as a pulmonary artery replacement in lambs and implemented a design for a valved conduit consisting of three tubes sewn together. Seven lambs were implanted with tri-tube valved conduits in sequential cohorts and compared to bioprosthetic conduits. Valves implanted into the pulmonary artery of two lambs of the first cohort of four animals functioned with mild regurgitation and systolic pressure drops <10 mmHg up to 52 weeks after implantation, during which the valve diameter increased from 19 mm to a physiologically normal ~25 mm. In a second cohort, the valve design was modified to include an additional tube, creating a sleeve around the tri-tube valve to counteract faster root growth relative to the leaflets. Two valves exhibited trivial-to-mild regurgitation at 52 weeks with similar diameter increases to ~25 mm and systolic pressure drops of <5 mmHg, whereas the third valve showed similar findings until moderate regurgitation was observed at 52 weeks, correlating to hyperincrease in the valve diameter. In all explanted valves, the leaflets contained interstitial cells and an endothelium progressing from the base of the leaflets and remained thin and pliable with sparse, punctate microcalcifications. The tri-tube valves demonstrated reduced calcification and improved hemodynamic function compared to clinically used pediatric bioprosthetic valves tested in the same model. This tri-tube valved conduit has potential for long-term valve growth in children.

Morphological changes and number of candidates for transcatheter pulmonary valve implantation in conduits involving heterograft and artificial material

Heterograft and artificial materials have been used for extracardiac conduit implantation to create right ventricular (RV) to pulmonary artery (PA) continuity for biventricular repair in Japan because of the limited availability of homograft valves. However, few studies have examined morphological changes and number of candidates for transcatheter pulmonary valve implantation (TPVI) in which the conduit includes more than one type of material. Overall, 88 patients who underwent biventricular repair with an external conduit were included in this evaluation. Based on catheterization data and surgical records, we estimated morphological change in the RV outflow tract for each material and the number of candidates for Melody valve implantation based on premarket approval application criteria established by the U.S. Food and Drug Administration. There were 63 candidates for TPVI (72%, 63/88). Median anteroposterior and lateral diameter of the RV outflow tract was 20.4 mm (range 9.0-41.5) and 17.8 mm (range 9.5-34.9), respectively. Bovine pericardium tended to dilate by 11.2%. Polytetrafluoroethylene (ePTFE), homograft, and Dacron polyethylene terephthalate (PET) tended to become stenotic by 11.1%, 28.0%, and 13.4%, respectively. While ePTFE (27/33, 82%) and Dacron PET (2/2, 100%) were highly suitable for TPVI, bovine pericardium (32/48, 67%) was less suitable. In Japan, many patients with hemodynamic indications for TPVI following extracardiac conduit implantation to create RV to PA continuity may also meet the morphological indications.

Four right ventricle to pulmonary artery conduit types

OBJECTIVE

The most durable valved right ventricle to pulmonary artery conduit for the repair of congenital heart defects in patients of different ages, sizes, and anatomic substrate remains uncertain.

METHODS

We performed a retrospective analysis of 4 common right ventricle to pulmonary artery conduits used in a single institution over 30 years, using univariable and multivariable models of time-to-failure to analyse freedom from conduit dysfunction, reintervention, and replacement.

RESULTS

Between 1988 and 2018, 959 right ventricle to pulmonary artery conduits were implanted: 333 aortic homografts, 227 pulmonary homografts, 227 composite porcine valve conduits, and 172 bovine jugular vein conduits. Patients weighed 1.6 to 98.3 kg (median 15.3 kg), and median duration of follow-up was 11.4 years, with 505 (52.2%) conduits developing dysfunction, 165 (17.2%) requiring catheter intervention, and 415 (43.2%) being replaced. Greater patient weight, conduit z-score, type and position, as well as catheter intervention were predictors of freedom from replacement. Multivariable analysis demonstrated inferior durability for smaller composite porcine valve conduits, with excellent durability for larger diameter conduits of the same type. Bovine jugular vein conduit longevity was inferior to that of homografts in all but the smallest patients. Freedom from dysfunction at 8 years was 60.7% for aortic homografts, 72% for pulmonary homografts, 51.2% for composite porcine valve conduits, and 41.3% for bovine jugular vein conduits. Judicious oversizing of the conduit improved conduit durability in all patients, but to the greatest extent in patients weighing 5 to 20 kg.

CONCLUSIONS

Pulmonary and aortic homografts had greater durability than xenograft conduits, particularly in patients weighing 5 to 20 kg. Judicious oversizing was the most significant surgeon-modifiable factor affecting conduit longevity.

Right Ventricular Outflow Tract Reconstruction in Infant Truncus Arteriosus: A 37-year Experience

BACKGROUND

Multiple conduits for right ventricular outflow tract reconstruction exist, although the ideal conduit that maximizes outcomes remains controversial. We evaluated long-term outcomes and compared conduits for right ventricular outflow tract reconstruction in children with truncus arteriosus.

METHODS

Records of patients who underwent truncus arteriosus repair at our institution between 1981 and 2018 were retrospectively reviewed. Primary outcomes included survival and freedom from catheter reintervention or reoperation. Secondary analyses evaluated the effect of comorbidity, operation era, conduit type, and conduit size.

RESULTS

One hundred patients met inclusion criteria. Median follow-up time was 15.6 years (interquartile range, 5.3-22.2). Actuarial survival at 30 days, 5 years, 10 years, and 15 years was 85%, 72%, 72%, and 68%, respectively. Early mortality was associated with concomitant interrupted aortic arch (hazard ratio, 5.4; 95% confidence interval, 1.7-17.4; P = .005). Median time to surgical reoperation was 4.6 years (interquartile range, 2.9-6.8; n = 58). Right ventricle to pulmonary artery continuity was established with an aortic homograft (n = 14), pulmonary homograft (n = 41), or bovine jugular vein conduit (n = 36) in most cases. Multivariate analysis revealed longer freedom from reoperation with the bovine jugular vein conduit compared with the aortic homograft (hazard ratio, 3.1; 95% confidence interval, 1.3-7.7; P = .02) with no difference compared with the pulmonary homograft. Larger conduit size was associated with longer freedom from reoperation (hazard ratio, 0.7; 95% confidence interval, 0.6-0.9; P < .001).

CONCLUSIONS

The bovine jugular vein conduit is a favorable conduit for right ventricular outflow tract reconstruction in patients with truncus arteriosus. Concomitant interrupted aortic arch is a risk factor for early mortality.

Three-Year Outcomes From the Harmony Native Outflow Tract Early Feasibility Study

Background:

The Harmony transcatheter pulmonary valve (TPV) was designed for treatment of postoperative pulmonary valve regurgitation in patients with repaired right ventricular outflow tracts.

Methods:

The Native TPV EFS (Early Feasibility Study) is a prospective, multicenter, nonrandomized feasibility study. Three-year outcomes are reported.

Results:

Of 20 implanted patients, 17 completed 3-year follow-up (maximum: 4.1 years). There were no deaths and 2 early explants. One patient did not complete the 3-year visit. In patients with available 3-year echocardiographic data, 1 had a mild paravalvular leak and the rest had none/trace; 1 patient had mild pulmonary valve regurgitation and the remainder had none/trace. The 3-year mean right ventricular outflow tract echocardiographic gradient was 15.7±5.5 mm Hg. Radiographically, no late frame fractures or erosions were identified. At 2 years, 2 patients presented with an increased echocardiographic outflow gradient (1 mixed lesion with moderate/severe pulmonary valve regurgitation). Computed tomography scans identified neointimal tissue ingrowth within the stent frame in both patients, and they were treated successfully with a transcatheter valve-in-valve procedure (Melody TPV). Additional follow-up computed tomography scans performed at 3.2±0.5 years after implant were obtained in 16 patients and revealed luminal tissue thickening at the inflow and outflow portion of the frame with no significant alteration of the valve housing.

Conclusions:

Three-year results from the Native TPV EFS revealed stable Harmony TPV device position, good valve function in most, and the absence of moderate/severe paravalvular leak and significant late frame fractures. Two patients developed significant neointimal proliferation requiring valve-in-valve treatment, while all others had no clinically significant right ventricular outflow tract obstruction.

Clinical Trial Registration:

URL: https://www.clinicaltrials.gov . Unique identifier: NCT01762124.

Outcome of 40 consecutive cases of modified Ross procedure using novel Dacron valved conduit

OBJECTIVE

The Ross procedure is an established option for aortic valve disease in children. Due to limited availability of pulmonary homograft, we devised a novel technique for right ventricular outflow tract (RVOT) reconstruction by preparing indigenous Dacron valved conduit.

METHODS

Forty consecutive cases of modified Ross procedure done at our center (2013-2018) were analyzed. Thirty-seven patients (95%) were followed up with median duration of 2.5 (0.08-5.5) years. Median age was 12 (5-39) years. Nineteen (47.5%) patients had rheumatic aortic valve disease, while 19 (47.5%) had congenital aortic valve disease. Aortic root replacement with pulmonary autograft was performed in all patients. Dacron conduit for RVOT reconstruction was used with on table sewn bileaflet valve using Dacron patch (n = 22), expanded polytetrafluoroethylene (ePTFE) membrane (n = 10), bioprosthetic valve (n = 4), and pericardium (n = 4). Additional surgical procedures included mitral valve repair (n = 10), septal myectomy (n = 2), ascending aorta replacement (n = 1), ruptured sinus of valsalva (RSOV) repair (n = 1), and ventricular septal defect (VSD) closure (n = 1).

RESULTS

There was one in-hospital mortality while one late death occurred at 3.5 years postoperatively. The neo-aortic valve regurgitation on echocardiographic evaluation at last follow-up was trivial (n = 28), mild (n = 7), and moderate (n = 2). Mild RVOT obstruction was present in 8 patients while 18 patients had mild pulmonary regurgitation. No patient required reintervention during follow-up.

CONCLUSION

Our early results of modified Ross procedure are encouraging, however, long-term follow-up is required.

Evaluation of Hybrid Surgical Access Approaches for Pulmonary Valve Implantation in an Acute Swine Model

Percutaneous implantation of the pulmonary valve through peripheral vascular access can be limited due to poor venous access, low patient weight, hemodynamic or rhythmic instability, and size constraints related to the valve. In such cases, hybrid procedures may provide alternatives. Because the most commonly used median sternotomy is unsuitable for chronic trials in large animals, we evaluated several hybrid approaches for pulmonary valve replacement in a swine model. We tested the feasibility of hybrid pulmonary valve implantation in pigs by using inhouse-generated valves containing bare-metal or nitinol stents. Valves consisted of bovine jugular veins, bovine pericardial valves, or sprayed polyurethane valves. Access was achieved through median sternotomy, lower partial sternotomy, transverse sternotomy, or right lateral thoracotomy. The delivery device was introduced in a transventricular manner. Implantation took place under fluoroscopic and epicardial echocardiographic guidance. We achieved implantation of the stented valve in 12 (92.3%) pigs, of which 5 (41.7%) of the implanted valves were in an optimal position. Paravalvular leakage occurred in 2 trials (16.7%). Lower partial sternotomy provided the best trade-off between feasibility and minimized trauma for long-term animal trials. Here we describe our experience with hybrid pulmonary valve implantation in an acute large-animal (swine) model. We demonstrate the feasibility of the procedure in terms of surgical technique and the perioperative management and preparation of the field for a chronic trial.

Transcatheter Pulmonary Valve Replacement in Congenital Heart Disease

Patients with dysfunctional right ventricular outflow tracks comprise a large portion of patients with severe congenital heart disease. Transcatheter pulmonary valve replacement in patients with dysfunctional right ventricular outflow tracks is feasible, safe, and efficacious. This article reviews current transcatheter valve replacement technology for dysfunctional right ventricular outflow tract and pulmonary valvular disease and its applications to patients with congenital heart disease. Discussed are the approach and preprocedural planning, current options, and applications of transcatheter pulmonary valve therapy. Also considered are future directions in this field as the technologies begin to develop further.

Polymer-Based Reconstruction of the Inferior Vena Cava in Rat: Stem Cells or RGD Peptide?

As part of a program targeted at developing a resorbable valved tube for replacement of the right ventricular outflow tract, we compared three biopolymers (polyurethane [PU], polyhydroxyalkanoate (the poly(3-hydroxybutyrate-co-3-hydroxyvalerate-co-4-hydroxyvalerate) [PHBVV]), and polydioxanone [PDO]) and two biofunctionalization techniques (using adipose-derived stem cells [ADSCs] or the arginine-glycine-aspartate [RGD] peptide) in a rat model of partial inferior vena cava (IVC) replacement. Fifty-three Wistar rats first underwent partial replacement of the IVC with an acellular electrospun PDO, PU, or PHBVV patch, and 31 nude rats subsequently underwent the same procedure using a PDO patch biofunctionalized either by ADSC or RGD. Results were assessed both in vitro (proliferation and survival of ADSC seeded onto the different materials) and in vivo by magnetic resonance imaging (MRI), histology, immunohistochemistry [against markers of vascular cells (von Willebrand factor [vWF], smooth muscle actin [SMA]), and macrophages ([ED1 and ED2] immunostaining)], and enzyme-linked immunosorbent assay (ELISA; for the expression of various cytokines and inducible NO synthase). PDO showed the best in vitro properties. Six weeks after implantation, MRI did not detect significant luminal changes in any group. All biopolymers were evenly lined by vWF-positive cells, but only PDO and PHBVV showed a continuous layer of SMA-positive cells at 3 months. PU patches resulted in a marked granulomatous inflammatory reaction. The ADSC and RGD biofunctionalization yielded similar outcomes. These data confirm the good biocompatibility of PDO and support the concept that appropriately peptide-functionalized polymers may be successfully substituted for cell-loaded materials.

Which type of conduit to choose for right ventricular outflow tract reconstruction in patients below 1 year of age?†

OBJECTIVES

Reconstruction of the right ventricular outflow tract (RVOT) with a conduit in patients below 1 year of age remains a matter of concern due to limited availability and durability of conduits. We sought to analyse the freedom from conduit exchange in this subgroup of patients by comparing different conduits.

METHODS

Data of 145 consecutive patients below 1 year of age, requiring a conduit for RVOT reconstruction between 1994 and 2011 were reviewed. The endpoints of the study were defined as: 'conduit exchange for any reason', 'at least moderate conduit stenosis' and 'at least moderate insufficiency'.

RESULTS

Homografts, bovine jugular vein conduits (Contegra) and porcine-valved Dacron conduits (Hancock) were implanted in 62 (43%), 35 (24%) and 48 (33%) patients, respectively. The mean conduit diameter was 12.9 ± 1.3 mm. A conduit exchange was necessary in 72 patients (55%) at a median time of 5.9 years [1.1-10.8]. The rate of freedom from conduit exchange at 5 years was 69.4 ± 6.6, 59.4 ± 8.7 and 53.8 ± 7.4%, respectively (P = 0.4). The rate of freedom from at least moderate stenosis was 85.4 ± 5.6, 75.1 ± 9.1 69.1 ± 7.9% at 5 years and 59.2 ± 11.1, 35.8 ± 12.0, 49.7 ± 10.1% at 10 years, for homografts, Contegra and Hancock conduits, respectively. The rate of freedom from at least moderate conduit insufficiency was 91.7 ± 4, 74.6 ± 9.1, 86.9 ± 7.4% at 5 years and 64.8 ± 14.1, 44.2 ± 13.7, 52.1 ± 14.2% at 10 years, for homografts, Contegra and Hancock conduits, respectively. Patients with a Contegra conduit developed moderate conduit stenosis or insufficiency faster than patients with a homograft (P = 0.01). Age below 1 month and heterotopic implantation of the conduit emerged as risk factors for conduit exchange in the univariate analysis (P = 0.05, P = 0.02, respectively). There was no significant influence of the conduit type, conduit size, z-score or the body surface area. In the multivariate analysis, heterotopic implantation emerged as the only risk factor for conduit exchange (P = 0.02, hazard ratio = 1.6, 95% confidence interval = 1.0-2.7).

CONCLUSIONS

Homografts, bovine jugular vein conduits and porcine-valved Dacron conduits exhibit equal durability after implantation in patients below 1 year of age independent of their size. Nonetheless, moderate conduit stenosis or insufficiency develops earlier in patients with a Contegra conduit. Conduit placement in the neonatal period and implantation in a heterotopic position shortens the durability.

New technologies for surgery of the congenital cardiac defect

The surgical repair of complex congenital heart defects frequently requires additional tissue in various forms, such as patches, conduits, and valves. These devices often require replacement over a patient's lifetime because of degeneration, calcification, or lack of growth. The main new technologies in congenital cardiac surgery aim at, on the one hand, avoiding such reoperations and, on the other hand, improving long-term outcomes of devices used to repair or replace diseased structural malformations. These technologies are: 1) new patches: CorMatrix® patches made of decellularized porcine small intestinal submucosa extracellular matrix; 2) new devices: the Melody® valve (for percutaneous pulmonary valve implantation) and tissue-engineered valved conduits (either decellularized scaffolds or polymeric scaffolds); and 3) new emerging fields, such as antenatal corrective cardiac surgery or robotically assisted congenital cardiac surgical procedures. These new technologies for structural malformation surgery are still in their infancy but certainly present great promise for the future. But the translation of these emerging technologies to routine health care and public health policy will also largely depend on economic considerations, value judgments, and political factors.

Novel use of extracellular matrix graft for creation of pulmonary valved conduit

We report the use of a commercially available graft material to create a trileaflet pulmonary valved conduit, which was implanted in a 12-year-old girl with mixed aortic valve disease as part of a Ross procedure. The patient presented with severe aortic insufficiency and left ventricular dilatation following balloon valvuloplasty. The patient lives in Ecuador, where most commonly used replacements for the pulmonary valve are either unavailable or unaffordable. Our technique involves the use of porcine small intestinal submucosal extracellular matrix (SIS-ECM), commercially available as CorMatrix ECM (CorMatrix Cardiovascular, Inc, Tallahassee, Florida) to create a trileaflet-valved conduit.

Right ventricle to pulmonary artery conduit reoperations in patients with tetralogy of fallot or pulmonary atresia associated with ventricular septal defect

The short lifespan of right ventricle-to-pulmonary artery (RV-PA) conduits used in repairs of complex congenital heart defects makes future surgical replacement inevitable. Percutaneous pulmonary valve implantation (PPVI) now offers an attractive alternative to surgery in some patients. The objectives of this study were to examine the pattern of conduit reoperations, the factors affecting conduit longevity, and to discuss the role of PPVI in these patients. Forty-nine patients (mean age 27 ± 8 years) with pulmonary atresia or pulmonary stenosis with tetralogy of Fallot who underwent surgery for RV-PA conduits from September 1974 to October 2011 were reviewed. A total of 106 RV-PA conduits were implanted, 57 of which were replacements. Second, third, and fourth conduits were required during the follow-up period in 39, 16, and 2 patients, respectively. Freedom from reoperation at 10 years for the first, second, and third conduits was 50%, 74%, and 86%, respectively. Significant independent predictors of shorter conduit longevity included smaller conduit and conduit type (homograft and other vs Dacron). Furthermore, a significant proportion (32 of 57 [56%]) of conduit replacements took place from ages 9 to 18 years. There were 37 adults whose current existing conduits had not yet failed, with 73% (27 of 37) potentially suitable in the future for PPVI on the basis of conduit size of 16 to 27 mm. In conclusion, multiple RV-PA conduit revisions were required in patients who survived to adulthood, with many replacements taking place during adolescence. Most conduits in this adult cohort met size criteria for PPVI, thereby offering these patients a potential alternative to surgical intervention for conduit failure.

Safe surgical strategy for extracardiac conduit replacement in common arterial trunk

Repair of common arterial trunk using an extracardiac right ventricular to pulmonary arterial conduit is the preferred method in most cardiac surgical centres. Reoperation is a fact of life for survivors of common arterial trunk and related cardiac lesions who have undergone such repairs. Long-term survivors may require periodic conduit revisions, with a potentially escalating technical difficulty and risk. Herein we present an analysis of the currently available choices for extracardiac conduits, and outline what we consider to be a safe and reliable surgical strategy for conduit revision.

Valve replacement in children: a challenge for a whole life

Valvular pathology in infants and children poses numerous challenges to the paediatric cardiac surgeon. Without question, valvular repair is the goal of intervention because restoration of valvular anatomy and physiology using native tissue allows for growth and a potentially better long-term outcome. When reconstruction fails or is not feasible, valve replacement becomes inevitable. Which valve for which position is controversial. Homograft and bioprosthetic valves achieve superior haemodynamic results initially but at the cost of accelerated degeneration. Small patient size and the risk of thromboembolism limit the usefulness of mechanical valves, and somatic outgrowth is an universal problem with all available prostheses. The goal of this article is to address valve replacement options for all four valve positions within the paediatric population. We review current literature and our practice to support our preferences. To summarize, a multitude of opinions and surgical experiences exist. Today, the valve choices that seem without controversy are bioprosthetic replacement of the tricuspid valve and Ross or Ross-Konno procedures when necessary for the aortic valve. On the other hand, bioprostheses may be implanted when annular pulmonary diameter is adequate; if not or in case of right ventricular outflow tract discontinuity, it is better to use a pulmonary homograft with the Ross procedure. Otherwise, a valved conduit. Mitral valve replacement remains the most problematic; the mechanical prosthesis must be placed in the annular position, avoiding oversizing. Future advances with tissue-engineered heart valves for all positions and new anticoagulants may change the landscape for valve replacement in the paediatric population.

Long term results of right ventricular outflow tract reconstruction with homografts

Background

Homograft cardiac valves and valved-conduits have been available in our institute since 1992. We sought to determine the long-term outcome after right ventricular outflow tract (RVOT) reconstruction using homografts, and risk factors for reoperation were analyzed.

Materials and Methods

We retrospectively reviewed 112 patients who had undergone repair using 116 homografts between 1992 and 2008. Median age and body weight at operation were 31.2 months and 12.2 kg, respectively. The diagnoses were pulmonary atresia or stenosis with ventricular septal defect (n=93), congenital aortic valve diseases (n=15), and truncus arteriosus (N=8). Mean follow-up duration was 79.2±14.8 months.

Results

There were 10 early and 4 late deaths. Overall survival rate was 89.6%, 88.7%, 86.1% at postoperative 1 year, 5 years and 10 years, respectively. Body weight at operation, cardiopulmonary bypass (CPB) time and aortic cross-clamping (ACC) time were identified as risk factors for death. Forty-three reoperations were performed in thirty-nine patients. Freedom from reoperation was 97.0%, 77.8%, 35.0% at postoperative 1 year, 5 years and 10 years respectively. Small-sized graft was identified as a risk factor for reoperation.

Conclusion

Although long-term survival after RVOT reconstruction with homografts was excellent, freedom from reoperation was unsatisfactory, especially in patients who had small grafts upon initial repair. Thus, alternative surgical strategies not using small grafts may need to be considered in this subset.