Contegra versus pulmonary homograft for right ventricular outflow tract reconstruction in newborns

Valved Conduits for Right Ventricular Outflow Tract Reconstruction: A Review of Current Technologies and Future Directions

The need for right ventricular outflow tract reconstruction is common and growing in congenital heart surgery given expanding indications for the repair of congenital as well as acquired heart disease. Various valved conduit options currently exist including homografts, xenograft pulmonary valved conduits (Contegra™), and porcine valved conduits. The major limitation for all conduits is implant durability, which requires reoperation. Currently, cryopreserved homografts are often used given their superiority shown in long-term data. Significant limitations remain in the cost and availability of the graft, particularly for smaller sizes. Contegra conduits are available in a variety of sizes. Nonetheless, the data regarding long-term durability are less robust and studies comparing durability with homografts have been conflicting. Additionally, there is concern for increased rates of late endocarditis in this conduit. Porcine valved conduits offer a reliable option but are limited by structural valve degeneration associated with all types of bioprosthetic heart valve replacements. New developments in the field of tissue engineering have produced promising bio-restorative valved conduits that may overcome many of the limitations of previous conduit technologies. These remain in the early stages of clinical testing. This review summarizes the clinical data surrounding the conduits used most commonly in clinical practice today and explores emerging technologies that may bring us closer to developing the ideal conduit.

Epoxy- versus Glutaraldehyde-Treated Bovine Jugular Vein Conduit for Pulmonary Valve Replacement: A Comparison of Morphological Changes in a Pig Model

Valved conduits are often required to replace pulmonary arteries (PA). A widely used Contegra device is made of bovine jugular vein (BJV), preserved with glutaraldehyde (GA) and iso-propanol. However, it has several drawbacks that may be attributed to its chemical treatment. We hypothesized that the use of an alternative preservation compound may significantly improve BJV conduit performance. This study aimed to compare the macroscopic and microscopic properties of the BJV treated with diepoxide (DE) and GA in a porcine model. Twelve DE-BJVs and four Contegra conduits were used for PA replacement in minipigs. To assess the isolated influence of GA, we included an additional control group-BJV treated with 0.625% GA (n = 4). The animals were withdrawn after 6 months of follow-up and the conduits were examined. Explanted DE-BJV had a soft elastic wall with no signs of thrombosis or calcification and good conduit integration, including myofibroblast germination, an ingrowth of soft connective tissue formations and remarkable neoangiogenesis. The inner surface of DE-BJVs was covered by a thin neointimal layer with a solid endothelium. Contegra grafts had a stiffer wall with thrombosis on the leaflets. Calcified foci, chondroid metaplasia, and hyalinosis were observed within the wall. The distal anastomotic sites had hyperplastic neointima, partially covered with the endothelium. The wall of GA-BJV was stiff and rigid with degenerative changes, a substantial amount of calcium deposits and dense fibrotic formations in adventitia. An irregular neointimal layer was presented in the anastomotic sites without endothelial cover in the GA BJV wall. These results demonstrate that DE treatment improves conduit integration and the endothelialization of the inner surface while preventing the mineralization of the BJV, which may reduce the risk of early conduit dysfunction.

20-Year follow-up and comparison of valved conduits used for right ventricular outflow tract reconstruction: single-centre, propensity score match analysis

OBJECTIVES

Surgical repair of complex congenital heart defects with hypoplasia or atresia of the right ventricular outflow tract (RVOT) may require pulmonary valve implantation or replacement during the primary repair or reoperation. The purpose of this study is to evaluate the outcomes of cryopreserved homografts, bovine jugular vein conduits and decellularized Matrix P Plus N conduits in patients undergoing RVOT reconstruction at a single centre.

METHODS

Retrospective, single-centre review of 173 patients with 199 conduits undergoing right ventricle-to-pulmonary artery reconstruction with valved conduit from 2002 to 2022.

RESULTS

A total of 199 conduits were implanted in 173 patients (62.8% male), with a mean age of 8.97 ± 8.5 years. The following 3 types of conduits were used: homografts 129 (64.8%), bovine jugular vein conduits 45 (22.7%) and Matrix P Plus N 25 (12.5%). During the mean follow-up duration of 8.6 ± 5.8 years, there were 20 deaths, 35 conduit reoperations and 44 catheter reinterventions. Overall survival, reoperation-free and catheter reintervention-free survival at 20 years were 83%, 67.8% and 65.6%, respectively. Multivariable Cox analysis identified younger patient age, smaller conduit size, low patient weight and primary diagnosis of common arterial trunk as risk factors for reoperation and catheter reintervention.

CONCLUSIONS

Long-term outcomes of reconstruction of the RVOT using homografts, bovine jugular vein and Matrix P Plus N conduits were acceptable. The reoperation rate for conduit dysfunction did not differ significantly among groups. Over time, the need for conduit replacement was higher in smaller conduits and in patients with common arterial trunk diagnosis.

Long-Term Follow-Up of Right Ventricle to Pulmonary Artery Biologic Valved Conduits Used in Pediatric Congenital Heart Surgery

Valved conduit reconstruction between the right ventricle (RV) and the pulmonary circulation is often necessary in the surgical treatment of complex congenital heart defects. The aim of this study is to evaluate the long-term performance of the three types of conduits we have used and assess risk factors for conduit failure. Retrospective, single-center review of 455 consecutive pediatric patients with 625 conduits from 1990 to 2019 undergoing RV-to-pulmonary artery (PA) reconstruction with a valved conduit. The three conduit types investigated were pulmonary homograft, aorta homograft, and bovine jugular vein (BJV) graft. Overall patient survival was 91.4%, freedom from conduit replacement (FCR) was 47.4%, and freedom from reintervention (FFR) was 37.8% with a median follow-up of 8.7 years (interquartile range 4.3-13.3 years). For pulmonary homografts, 10-, 20-, and 28-year FCR was 79.6%, 68.6%, and 66.0%, respectively. For aortic homografts, 10-, 20-, and 30-year FCR was 49.8%, 31.5%, and 23.0%, respectively. For BJV grafts, 10- and 19-year FCR was 68.1% and 46.0%, respectively. When controlling for baseline variables, FCR was similar for pulmonary homografts and BJV grafts. Overall patient survival was excellent. Risk factors for conduit failure in patients operated with reconstruction of the RV-PA outflow tract included low age, low weight, small conduit size, and certain cardiac diagnoses. There was no evidence for a shorter life span of the second graft. Pulmonary homografts and BJV grafts performed similarly but the risk of endocarditis was greater in the BJV group.

Outcomes after right ventricular outflow tract reconstruction with valve substitutes: A systematic review and meta-analysis

Introduction

This study aims to provide an overview of outcomes after right ventricular outflow tract (RVOT) reconstruction using different valve substitutes in different age groups for different indications.

Methods

The literature was systematically searched for articles published between January 2000 and June 2021 reporting on clinical and/or echocardiographic outcomes after RVOT reconstruction with valve substitutes. A random-effects meta-analysis was conducted for outcomes, and time-related outcomes were visualized by pooled Kaplan–Meier curves. Subgroup analyses were performed according to etiology, implanted valve substitute and patient age.

Results

Two hundred and seventeen articles were included, comprising 37,078 patients (age: 22.86 ± 11.29 years; 31.6% female) and 240,581 patient-years of follow-up. Aortic valve disease (Ross procedure, 46.6%) and Tetralogy of Fallot (TOF, 27.0%) were the two main underlying etiologies. Homograft and xenograft accounted for 83.7 and 32.6% of the overall valve substitutes, respectively. The early mortality, late mortality, reintervention and endocarditis rates were 3.36% (2.91–3.88), 0.72%/y (95% CI: 0.62–0.82), 2.62%/y (95% CI: 2.28–3.00), and 0.38%/y (95%CI: 0.31–0.47) for all patients. The early mortality for TOF and truncus arteriosus (TA) were 1.95% (1.31–2.90) and 10.67% (7.79–14.61). Pooled late mortality and reintervention rate were 0.59%/y (0.39–0.89), 1.41%/y (0.87–2.27), and 1.20%/y (0.74–1.94), 10.15%/y (7.42–13.90) for TOF and TA, respectively. Endocarditis rate was 0.21%/y (95% CI: 0.16–0.27) for a homograft substitute and 0.80%/y (95%CI: 0.60–1.09) for a xenograft substitute. Reintervention rate for infants, children and adults was 8.80%/y (95% CI: 6.49–11.95), 4.75%/y (95% CI: 3.67–6.14), and 0.72%/y (95% CI: 0.36–1.42), respectively.

Conclusion

This study shows RVOT reconstruction with valve substitutes can be performed with acceptable mortality and morbidity rates for most patients. Reinterventions after RVOT reconstruction with valve substitutes are inevitable for most patients in their life-time, emphasizing the necessity of life-long follow-up and multidisciplinary care. Follow-up protocols should be tailored to individual patients because patients with different etiologies, ages, and implanted valve substitutes have different rates of mortality and morbidity.

Systematic review registration

[www.crd.york.ac.uk/prospero], identifier [CRD42021271622].

Decellularized bovine jugular vein and hand-sewn ePTFE valved conduit for right ventricular outflow tract reconstruction in children undergoing Ross procedure

Background

The Ross procedure is recommended as an optimal aortic valve replacement (AVR) in children and young adults due to several advantages. Nevertheless, multiple reconstructions of the right ventricular outflow tract (RVOT) with new valve conduits have caused some concern regarding the durability of the Ross AVR. Decellularized bovine jugular vein conduit (BJVC) (DP-BJVC) and hand-sewn expanded polytetrafluoroethylene valved conduits (ePTFE VC) are widely employed to reconstruct the RVOT with satisfactory long-term outcomes. However, few studies have compared the safety and efficacy between the two valve conduits. We aimed to evaluate the early outcomes and report our single center experience in the application of these conduits.

Methods

Twenty-two pediatric patients (aged < 18 years) who underwent Ross procedures with DP-BJVC and ePTFE VC in our center between 1 June, 2017 and 31 January, 2022 were enrolled. The Kaplan–Meier method was used to evaluate survival, freedom from RVOT reintervention, and freedom from RVOT graft dysfunction. Mixed-effects analysis with the Geisser–Greenhouse correction and Sidak's multiple comparisons test for post-hoc analysis was employed to compare the peak gradient across the conduit at varying follow-ups.

Results

All patients were followed up in full. The total early survival rate was 90.9%; two patients in the DP-BJVC group died. There was no significant difference in early mortality, cross-clamp time (p = 0.212), in-hospital stay (p = 0.469), and RVOT graft thrombosis or endocarditis between the two groups. There was similarly no significant difference between Kaplan–Meier freedom from RVOT graft dysfunction curve (P = 0.131). The transprosthetic gradient gradually increased over time in both groups and was significantly higher in the DP-BJVC group at follow-up (P < 0.05).

Conclusions

Both conduits show excellent early and midterm outcomes for RVOT reconstruction in the Ross procedure. We suggest that DP-BJVC is more suitable for infants, and ePTFE conduit is more suitable for older children who require larger conduits.

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.

Conduits for Right Ventricular Outflow Tract Reconstruction in Infants and Young Children

Purpose of Review: Right ventricular outflow tract (RVOT) reconstruction remains a challenge due to the lack of an ideal conduit. Data and experience are accumulating with each passing day. Therefore, it is necessary to review this topic from time to time. This is a 2021 update review focused on the history, evolution, and current situation of small-sized conduits (≤ 16 mm) for RVOT reconstruction in infants and young children.

Recent Findings: Currently, the available small-sized (≤16 mm) conduits can meet most clinical needs. Homograft is still a reliable choice for infants and young children validated by a half-century clinical experience. As an alternative material, bovine jugular vein conduit (BJVC) has at least comparable durability with that of homograft. The performance of expanded polytetrafluoroethylene (ePTFE) is amazing in RVOT position according to limited published data. The past century has witnessed much progress in the materials for RVOT reconstruction. However, lack of growth potential is the dilemma for small-sized conduits. Tissue-engineering based on cell-free scaffolds is the most promising technology to obtain the ideal conduit.

Summary: No conduit has proved to have lifelong durability in RVOT position. We are far from the ideal, but we are not in a state of emergency. In-depth clinical research as well as innovation in material science are needed to help improve the durability of the conduits used in infants and young children.

Outcomes Following Heterotopic Placement of Right Ventricle to Pulmonary Artery Conduits

BACKGROUND

We sought to evaluate the outcomes following right ventricle to pulmonary artery (RV-PA) conduit placement in pediatric patients, excluding those with a RV-PA conduit for the Ross procedure which is associated with improved conduit durability, partly related to its orthotopic position.

METHODS

Outcomes for 119 patients who underwent RV-PA conduit placement at a single institution from January 2004 to December 2016 were reviewed. Primary outcome measures were reintervention-free survival (RFS) and overall survival. Survival analyses were performed using the Kaplan-Meier method, and risk factors associated with reintervention were evaluated.

RESULTS

The median age at the time of conduit placement was 6 months (interquartile range, IQR: 1-14), and the median length of follow-up was 63 months (range: 0-156). During follow-up, 39 patients required conduit-related reintervention, while 6 patients died perioperatively with an overall survival of 90% at 10 years. Among the remaining 113 patients, the RFS at one, five, and ten years was 91% (84%-95%), 72% (60%-80%), and 33% (16%-50%), respectively. The median time to conduit replacement in the series was 43.5 months (IQR: 19.3-76.2). The use of a pulmonary homograft was associated with improved RFS (P = .03), and this was particularly pronounced in comparison with aortic homografts in neonates. Infection was the indication for replacement in only one patient.

CONCLUSIONS

The majority of the conduits placed during the neonatal period required conduit replacement before the age of five years. Endocarditis was not a common indication for replacement. In neonates and infants, we prefer pulmonary homografts for most indications.

Midterm Outcomes of Crosslinked Acellular Bovine Jugular Vein Conduit for Right Ventricular Outflow Tract Reconstruction

Objectives: Conduits for reconstructing right ventricular outflow tract (RVOT) in children with congenital heart disease have evolved for better durability over the past decades, but conduits failure remains common. We designed decellularized and photooxidatively crosslinked bovine jugular vein conduit (DP-BJVC) and now aim to evaluate the midterm results of DP-BJVC for RVOT reconstruction. Methods: Ninety patients (median age: 4.2 years) undergoing RVOT reconstruction using DP-BJVC were prospectively followed for median of 4.7 years (range: 0.2-16.1 years). Kaplan-Meier analysis was used to examine the survival, freedom from conduit explantation and catheter-based reintervention. Risk factors were analyzed with Cox regression analysis. Results: Follow-up was completed in 92% of patients. There were five (5.6%) early deaths. The 10-year survival rate was 85.2%, with palliative procedure at DP-BJVC implantation as the risk factor. The 10-year freedom from conduit explantation and reintervention were 84.4 and 67.3% respectively, with previous cardiac operation as the only risk factor for explantation. Complications during the follow-up included conduit stenosis (peak gradient ≥50 mmHg) in 12 (12.9%), severe regurgitation in 2 (2.4%), and infective endocarditis in 2 (2.4%). The annual increase in gradient was highest in the first year (P = 0.003), but not appreciably afterwards. The echo-measured annulus diameter trends to increase by an average of 0.37 mm per year. Calcification appeared mild in the failed conduits. Conclusions: DP-BJVC provides satisfactory durability and functionality for RVOT reconstruction for children, with low morbidity of stenosis and endocarditis, as well as increase in diameter mildly with age in midterm follow-ups.

Long-term course after pediatric right ventricular outflow tract reconstruction

OBJECTIVES

Valved homografts are commonly used for right ventricular outflow tract reconstruction. However, despite good early results, they lack durability. This study was designed to compare single-center results of implantation of 3 types of right ventricular outflow tract conduit, in terms of patient survival, graft failure, reoperation, and risk factors for reoperation.

METHODS

One hundred and forty-three pediatric patients who underwent right ventricular outflow tract conduit implantation between January 2006 and December 2018 were reviewed. We stratified conduits by aortic, pulmonic homograft, and Contegra; 74 aortic homografts, 61 pulmonic homografts, and 8 Contegra conduits were implanted. Median age at implantation was 3 years. The primary diagnosis was truncus arteriosus in 41.3%. We analyzed the role of sex, age, diagnosis, and graft size. Endpoints included freedom from graft failure, freedom from reoperation, and survival.

RESULTS

The survival rate was 83.2% at 10 years. Freedom from graft failure at 2, 5, and 10 years was 100%, 97.9%, and 63.4%, respectively. Freedom from reoperation was 85.8% for pulmonic homografts and 74.9% for aortic homografts at 10 years, and 100% for Contegra at 6 years. Multivariable analysis identified conduit diameter <18 mm as a risk factor for reoperation (hazard ratio: 3.16, 95% confidence interval: 1.38-7.23, p = 0.007).

CONCLUSION

Homograft valves used for right ventricular outflow tract reconstruction provided excellent long-term durability and late survival. The only factor that adversely affected graft longevity was small graft size (diameter <18 mm). Reoperation for conduit failure was not significantly different among the groups.

The Role of Novel Transcatheter Procedures in Patients With Congenital Heart Disease

The development of percutaneous structural interventions in patients with acquired heart disease is happening at an exponential rate, and some of this technology is being used to treat patients with congenital heart disease. This review describes the pathophysiology of valvular abnormalities specific to congenital heart disease and discusses the application of structural procedures in this population. Although the overall experience has been encouraging, especially in high-risk patients, this article will highlight the reasons that a cautious approach to adoption of this technology is necessary in these patients.