Outcomes of Right Ventricular Outflow Tract Reconstruction in Children: Retrospective Comparison Between Bovine Jugular Vein and Expanded Polytetrafluoroethylene Conduits

Novel small-sized ePTFE valves for neonatal RVOT reconstruction: an in-vitro investigation

Small-sized right ventricle to pulmonary artery conduits are hindered by calcification, degeneration, or infective endocarditis and face limited availability. Valved conduits of expanded polytetrafluoroethylene leaflets offer a promising path toward enhanced longevity and performance. This in-vitro study introduces innovative expanded polytetrafluoroethylene valve designs for small-sized conduits.Three bicuspid and three tricuspid expanded polytetrafluoroethylene leaflets designed for size 12 mm were tested using an in-vitro pediatric right-heart mock-up loop and compared with our baseline leaflet design. Polyvinylchloride was used to create a transparent tube for visual access. Regurgitation rates, pressure gradients, effective orifice area under 0.5-3 L/min cardiac outputs, and 100-150beats/min heart rates are measured. Mechanical differences between expanded polytetrafluoroethylene and polyvinylchloride are investigated through biaxial strain tests. In newborn hemodynamic conditions, 0.5-1 L/min cardiac output, bileaflet valves demonstrated regurgitation rates below 20%, and two tricuspid models maintained regurgitation rates below 15% with gradients below 25 mmHg. In infant conditions, 1-3 L/min output, the regurgitation rates of trileaflet models were below 20%, with gradients consistently below 35 mmHg. The fully coapting bileaflet model showed a regurgitation rate of less than 15% and a gradient below 30 mmHg across newborn and infant conditions. A circumferential difference of less than 0.12 mm was detected between expanded polytetrafluoroethylene and polyvinylchloride. Both the fully coapting bileaflet and redundant trileaflet configurations can be integrated in the small conduits. Polyvinylchloride can be an alternative to expanded polytetrafluoroethylene tube graft in in-vitro studies, allowing visual access to assess leaflet kinematics.

A 10-mm Monocusp Expanded Polytetrafluoroethylene Valved Conduit for Right Ventricular Outflow Tract Reconstruction in Neonates and Young Infants

BackgroundCurrently, no ideal prosthesis is available for right ventricular outflow tract (RVOT) reconstruction in neonates and young infants. Therefore, we developed a 10-mm handmade monocusp expanded polytetrafluoroethylene (ePTFE) valved conduit and report our experience.MethodsA retrospective clinical review was conducted on 11 consecutive patients who underwent RVOT reconstruction with a 10-mm handmade monocusp ePTFE valved conduit since May 2018. Six patients underwent a definitive Rastelli operation, and five underwent palliative right ventricle-to-pulmonary artery conduit formation. The median age at the time of operation was 61 (range, 6-462; interquartile range [IQR]: 229) days, and the median weight was 4.0 (range, 3.0-11.6; IQR: 4.3) kg.ResultsOne patient died early due to brain hemorrhage, and one died late due to sepsis. The follow-up duration was 38.5 ± 18.9 months. The mean peak pressure gradients across the conduit were 6.5 ± 4.4 mm Hg at discharge and 22.0 ± 11.2 mm Hg at the latest follow-up echocardiography. Regarding conduit regurgitation, all conduits showed better than moderate grading at the last follow-up or before reintervention. There were seven conduit explantations and three catheter interventions for conduit-related reasons. The explantations included a definitive Rastelli operation in three patients and conduit stenosis due to somatic growth in four patients.ConclusionOur simple 10-mm handmade monocusp ePTFE valved conduit demonstrated satisfactory clinical outcomes and is be a suitable option for RVOT reconstruction in neonates and young infants.

Comparison of Bicuspid and Tricuspid Handmade Polytetrafluoroethylene Valved Conduits: Early and Mid-Term Results

Background: In this study, we present our early and mid-term results using two different types of handmade polytetrafluoroethylene (PTFE) valved conduits in patients who require right ventricular outflow reconstruction. Methods: Between March 2021 and May 2024, 72 patients (30 males and 42 females; median age: 69 (IQR: 26-123) months) who underwent implantation of a handmade bicuspid or tricuspid valve PTFE conduit for right ventricular outflow reconstruction were retrospectively analyzed. Preoperative, postoperative, and follow-up echocardiograms were also evaluated. Results: The first postoperative echocardiography revealed that 11 (36.7%) patients had mild regurgitation, and 3 (10%) patients had moderate regurgitation in the bicuspid group initially, while only 7 (16.7%) of the patients in the tricuspid group had mild regurgitation (p = 0.004). None of the patients required reintervention in the early postoperative period because of conduit dysfunction. In the mid-term follow-up, the mean follow-up duration was 22.4 ± 11 months. PTFE-valved conduit dysfunction was observed in three patients in the bicuspid group, while no dysfunction was observed in the tricuspid group (p = 0.049). Even if the median peak gradient was found to be slightly higher in the tricuspid group [15 (IQR: 0-25) vs. 0 (IQR: 0-15)] (p = 0.032), no conduit dysfunction was reported during follow-up. Kaplan-Meier analysis demonstrated that the tricuspid conduit group maintained 100% freedom from dysfunction during the 24-month follow-up period. In contrast, the bicuspid group had rates of 90%, 87%, and 83% at 6, 12, and 24 months, respectively (log-rank p = 0.016). Conclusions: The ePTFE valved conduits provide significant advantages in terms of durability, biocompatibility, cost-effectiveness, and hemodynamic performance for right ventricular outflow tract reconstruction in pediatric cardiac surgery. The findings of our study suggest that tricuspid valve design offers better potential for preventing conduit dysfunction.

Morphology Optimization of Leaflet for Surgical Reconstruction of the Aortic Valve: In Vitro Test and Simulation-Based DOE Study

This study was to evaluate the impact of leaflet trimming strategy on the hemodynamic behaviors of the aortic valve after reconstructive surgery, and give recommendations based on design of experiment (DOE) and in vitro studies. An in vitro hemodynamic test was performed on the simulated surgical model to quantify the efficacy of conventional reconstructive surgery. The very same computational model was built and verified, on which the full factorial DOE was carried out to summarize the correlations between leaflet trimming parameters and valve hemodynamic characteristics. Hemodynamic characteristics of the valve substitute were significantly associated with leaflet trimming parameters. The total regurgitant and transvalvular regurgitant of the valve substitute were reduced by 27.44% and 13.61% after optimization of the leaflet design. Synthetic use of in vitro tests and DOE study based on computational models helped improve outcomes of the reconstruction of aortic valve by reducing free edge length and increasing commissure height and leaflet height.

Current development of bovine jugular vein conduit for right ventricular outflow tract reconstruction

Right ventricular outflow tract (RVOT) reconstruction is a common surgical method to treat congenital cardiac lesions, and bovine jugular vein conduit (BJVC) has become a prevalent candidate of prosthetic material for this procedure since 1999. Although many clinical studies have shown encouraging results on BJVCs, complications such as stenosis, aneurysmal dilatation, valve insufficiency, and infective endocarditis revealed in other clinical outcomes still remain problematic. This review describes the underlying mechanisms causing respective complications, and summarizes the current technological development that may address those causative factors. Novel crosslinking agents, decellularization techniques, conduit coatings, and physical reinforcement materials have improved the performances of BJVCs. The authors expect that the breakthroughs in the clinical application of BJVC may come from new genetic research findings and advanced characterization apparatuses and bioreactors, and are optimistic that the BJVC will in the future provide sophisticated therapies for next-generation RVOT reconstruction.

Handmade tri-leaflet ePTFE conduits versus homografts for right ventricular outflow tract reconstruction

BACKGROUND

This study aimed to investigate the performance of handmade tri-leaflet expanded polytetrafluoroethylene (ePTFE) conduits in the absence of a suitable homograft.

METHODS

Patients who underwent right ventricular outflow tract reconstruction with tri-leaflet ePTFE conduits or homografts between December 2016 and August 2020 were included. The primary endpoint was the incidence of moderate or severe conduit stenosis (≥ 36 mmHg) and/or moderate or severe insufficiency. The secondary endpoint was the incidence of severe conduit stenosis (≥ 64 mmHg) and/or severe insufficiency.

RESULTS

There were 102 patients in the ePTFE group and 52 patients in the homograft group. The median age was younger [34.5 (interquartile range: 20.8-62.8) vs. 60.0 (interquartile range: 39.3-81.0) months, P = 0.001] and the median weight was lower [13.5 (10.0-19.0) vs. 17.8 (13.6-25.8) kg, P = 0.003] in the ePTFE group. The conduit size was smaller (17.9 ± 2.2 vs. 20.5 ± 3.0 mm, P < 0.001) and the conduit Z score was lower (1.48 ± 1.04 vs. 1.83 ± 1.05, P = 0.048) in the ePTFE group. There was no significant difference in the primary endpoints (log rank, P = 0.33) and secondary endpoints (log rank, P = 0.35). Multivariate analysis identified lower weight at surgery [P = 0.01; hazard ratio: 0.75; 95% confidence interval (CI) 0.59-0.94] and homograft conduit use (P = 0.04; hazard ratio: 8.43; 95% CI 1.14-62.29) to be risk factors for moderate or severe conduit insufficiency. No risk factors were found for moderate or severe conduit stenosis or conduit dysfunction on multivariate analysis.

CONCLUSION

Handmade tri-leaflet ePTFE conduits showed acceptable early and midterm outcomes in the absence of a suitable homograft, but a longer follow-up is needed.

Mid-term outcomes of Contegra implantation for the reconstruction of the right ventricular outflow tract to proximal branch pulmonary arteries: Japan multicentre study

OBJECTIVES

To reveal the mid-term outcomes of Contegra implantation for the reconstruction of the right ventricular outflow tract to proximal branch pulmonary arteries in a multicentre study.

METHODS

Between April 2013 and December 2019, 178 Contegra conduits were implanted at 5 Japanese institutes. The median age and body weight at operation were 16 months (25th-75th percentile: 8-32) and 8.3 kg (6.4-10.6). Sixteen patients were neonates (9.0%). Selected conduit sizes were 12 mm in 28 patients (15.7%), 14 mm in 67 patients (37.6%), 16 mm in 66 patients (37.1%), 18 mm in 5 patients (2.8%) and <12 mm in 12 patients (6.7%). Fifty-six grafts (31.4%) were ring supported. Proximal branch pulmonary arteries were concomitantly augmented in 85 patients (47.5%). Follow-up was completed in all patients and the median follow-up period was 3.1 years (1.3-5.1).

RESULTS

The overall, conduit explantation-free and conduit infection-free survival rates at 5 years were 91.3%, 71.0% and 83.7%, respectively. Infection (P = 0.009) and common arterial trunk (P = 0.024) were risk factors for explantation. Conduit durability was shorter in smaller one (P < 0.001). Catheter interventions (for conduit to proximal branch pulmonary artery)-free survival rates at 5 years was 52.9%; however, need for catheter interventions was not a risk factor for conduit explantation.

CONCLUSIONS

Mid-term outcomes of reconstruction of the right ventricular outflow tract to the proximal branch pulmonary arteries with Contegra were acceptable. The need for explantation over time was higher in smaller conduits. Conduit infection was a strong risk factor for conduit explantation. Frequently and repeated catheter interventions effectively extended the conduit durability.