Smaller-Sized Expanded Polytetrafluoroethylene Conduits With a Fan-Shaped Valve and Bulging Sinuses for Right Ventricular Outflow Tract Reconstruction

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.

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.

Pediatric pulmonary valve replacements: Clinical challenges and emerging technologies

Congenital heart diseases (CHDs) frequently impact the right ventricular outflow tract, resulting in a significant incidence of pulmonary valve replacement in the pediatric population. While contemporary pediatric pulmonary valve replacements (PPVRs) allow satisfactory patient survival, their biocompatibility and durability remain suboptimal and repeat operations are commonplace, especially for very young patients. This places enormous physical, financial, and psychological burdens on patients and their parents, highlighting an urgent clinical need for better PPVRs. An important reason for the clinical failure of PPVRs is biofouling, which instigates various adverse biological responses such as thrombosis and infection, promoting research into various antifouling chemistries that may find utility in PPVR materials. Another significant contributor is the inevitability of somatic growth in pediatric patients, causing structural discrepancies between the patient and PPVR, stimulating the development of various growth-accommodating heart valve prototypes. This review offers an interdisciplinary perspective on these challenges by exploring clinical experiences, physiological understandings, and bioengineering technologies that may contribute to device development. It thus aims to provide an insight into the design requirements of next-generation PPVRs to advance clinical outcomes and promote patient quality of life.

Trileaflet pulmonary valve reconstruction with the Ozaki technique in an adult patient of tetralogy of Fallot with absent pulmonary valve

Pulmonary valve interventions are one of the most common cardiac interventions that are being performed in patients with a wide variety of congenital heart diseases, more so in adults with congenital heart disease. Despite the introduction of various different reconstructive techniques and conduits, the ideal option still remains elusive. Lack of growth and re-operation for conduit replacement remains an Achilles heel in such conduits. So, surgeons have constantly tried to evolve surgical techniques that would obviate their use and allow age-related growth. The Ozaki procedure has proven to be technically reproducible and have excellent mid-term results in the aortic position in adults. Extending the same principle for reconstruction of the pulmonary valve can prove to be a reasonable alternative.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12055-022-01469-1.

Anatomic Position and Durability of Polytetrafluoroethylene Conduit ≥18 mm: Single-Center Experience

BACKGROUND

Conduit longevity after right ventricular outflow tract (RVOT) reconstruction is determined by the interaction of different factors. We evaluated the relationship between conduit anatomic position and long-term durability among ≥18 mm polytetrafluoroethylene (PTFE) conduits.

METHODS

A single-institution RVOT reconstructions using a PTFE conduit ≥18 mm were identified. Catheter-based interventions or the need for conduit replacement were comparatively assessed between orthotopic vs heterotopic conduit position. Time to the first reintervention, censored by death, was compared between the groups.

RESULTS

A total of 102 conduits were implanted in 99 patients, with a median age of 13.2 years (interquartile range [IQR] 8.9-17.8 years), median weight of 47 kg (IQR, 29-67 kg), and body surface area of 1.4 m² (IQR, 1-1.7 m²). Overall, 50.9% (n = 52) of conduits were placed in an orthotopic position after the Ross procedure in congenital aortic valve abnormalities (80% [n = 36]). Tetrology of Fallot in 39% (n = 18), followed by truncus arteriosus with 33% (n = 15), were the most common in the heterotopic position. Trileaflet configuration was similar (67% vs 69%; P = .32) between the groups. Survival free from reintervention was 91% (95% CI, 79-97) and 88% (95% CI, 71-95) in the orthotopic and the heterotopic group, respectively, at 5 years, without differences in the Kaplan Meier curves (log-rank >.05).

CONCLUSIONS

RVOT reconstruction with PTFE conduits ≥ 8 mm showed >90% conduit survival free from replacement in our cohort at 5 years. The anatomic position of the PTFE conduit does not seem to impact intermediate durability.

Midterm Outcomes for Polytetrafluoroethylene Valved Conduits

BACKGROUND

Various conduits for right ventricular outflow tract reconstruction have been reported, but most of them are not available in China. The study investigators developed a simple handsewn valved conduit using expanded polytetrafluoroethylene (ePTFE). This study evaluated the midterm outcomes for this conduit.

METHODS

This retrospective study included a total of 72 patients who underwent right ventricular outflow tract reconstruction with ePTFE valved conduits between January 2014 and June 2020. During follow-up, echocardiograms were performed for all patients, and magnetic resonance imaging was performed for patients with repaired tetralogy of Fallot.

RESULTS

Patients had a median age of 69 months (interquartile range, 28-127 months) and a median follow-up period of 33 months (interquartile range, 9-51 months). There was no early death, but 2 late deaths (2.78%) occurred. The median conduit size was 18 mm (interquartile range, 18-20 mm) and the z score was +1.3 (interquartile range, +0.6-+2). Peak velocity across the ePTFE valve was 2.38 m/s (95% CI, 2.11-2.63 m/s). Pulmonary valve regurgitation was none or trivial in 27 (38.5%) patients, mild in 42 (60.0%) patients, and moderate in 1 (1.4%) patient. Conduit dysfunction occurred in 5 patients: 4 had moderate conduit stenosis, and 1 had moderate regurgitation. The right ventricular end-diastolic volume index in repaired tetralogy of Fallot was significantly decreased after surgery (171 mL/m2 vs 130 mL/m2; P < .001). No reintervention or conduit replacement was needed.

CONCLUSIONS

This handsewn ePTFE valved conduit was associated with appreciable hemodynamic outcomes during the midterm follow-up period. Long-term follow-up studies are needed to corroborate these findings.

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 &lt; 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 &lt; 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.

Hand-Made Polytetrafluoroethylene Tricuspid-Valved Conduit for Surgical Reconstruction of the Right Ventricular Outflow Tract in a Child With Truncus Arteriosus

Although a new right ventricle outflow can be introduced during pulmonary artery reconstruction, it is a suboptimal option as the valved conduits that mimic the natural right ventricular outflow do not grow, and a surgical conduit replacement cannot be averted. This study reported the implementation of hand-made polytetrafluoroethylene (PTFE) tricuspid-valved conduits to rebuild the right ventricular outflow tract in toddlers with truncus arteriosus and risk factors for earlier conduit explant. Herein, we described a case report of a 9-month-old toddler diagnosed in November 2021 with truncus arteriosus type I with ventricular septal defect (VSD) and severe pulmonary arterial hypertension, who has been successfully discharged 20-days postoperative surgical reconstruction with good bi-ventricular functions. Hand-made PTFE tricuspid-valved conduits are efficient in the reconstruction process of the right ventricular outflow tract in children with truncus arteriosus. The conduits are cheap, easily available, and lack potential sensitization.

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.

Preliminary Results with a Novel expanded Polytetrafluoroethylene-based Pulmonary Valved Conduit

BACKGROUND

A novel polymeric pulmonary valved conduit, resistant to calcification and structural valve deterioration, may provide a more durable therapy option for the pediatric population by preventing loss of right ventricular function and increasing freedom from valve-related reintervention and mortality.

METHODS

This was a prospective, multicenter, single-arm study evaluating safety and performance of an investigational novel ePTFE-based valve. Patients met study inclusion/exclusion criteria, had a signed informed consent, had pre- and post-operative evaluation via transthoracic echocardiography and six-month cardiac magnetic resonance imaging (cMRI).

RESULTS

Seventeen patients were enrolled from 3 sites. Median age was 12 years (range, 6-17) with 52.9% male. BSA ranged from 0.82 to 1.57 m². There has been no mortality and 100% freedom from device related reinterventions. Baseline compared to six-month cMRI (in 11 of 16 patients with available data) suggests favorable right ventricular remodeling (RVEDV 123±37 to 94±25 mL/m²) with no significant change in ejection fraction. Through current follow-up, no patient has an RVOT gradient > 20 mmHg, (mean 11.2 ± 4.3 mmHg). No evidence of worsening valvular insufficiency was observed throughout postoperative serial TTE evaluations. No pulmonary regurgitation above baseline (≤ mild) was observed. No patient developed endocarditis. No thrombus or calcification was identified.

CONCLUSIONS

This preliminary evaluation of a novel ePTFE-based valved conduit suggests promising valve function with no thromboembolic or infectious complications, no valve related reinterventions, no valve-related adverse events or unexpected findings, improved right ventricular volumes, and encouraging hemodynamic performance through current follow-up.

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.

Expanded Polytetrafluoroethylene Conduits With Bulging Sinuses and a Fan-Shaped Valve in Right Ventricular Outflow Tract Reconstruction

We developed a handmade expanded polytetrafluoroethylene (ePTFE) pulmonary valvular conduit (PVC) with bulging sinuses and a fan-shaped ePTFE valve for right ventricular outflow tract (RVOT) reconstruction. We aimed to investigate the results of this device in this multicenter study. From 2001 to 2020, 1776 patients underwent RVOT reconstruction using ePTFE PVCs at 65 institutions in Japan. The median age and body weight were 4.1 years (range, 3 days to 67.1 years) and 13.3 (range, 1.8-91.3) kg, respectively. The median PVC size was 18 (range, 8-24) mm. The median Z-value of the ePTFE PVC was 1.1 (range, -3.8 to 5.0). The ePTFE PVC conditions were investigated by cardiac echocardiography and catheterization. The median follow-up period was 3.3 years (range, 0 day to 16.2 years). There were only 9 cases (0.5%) with PVC-related unknown deaths. Reintervention was performed in 283 patients (15.9%), and 190 patients (10.7%) required explantation. Freedom from reintervention and explantation at 5/10 years were 86.7/61.5% and 93.0/69.1%, respectively. At the latest echocardiography, PVC regurgitation grade was better than mild in 88.4% patients. The average peak RVOT gradient was 15.7 ± 15.9 mm Hg at the latest cardiac catheterization. ePTFE PVC infection was detected in only 8 patients (0.5%). Relative stenosis due to somatic growth was the most common cause of PVC explantation. The performance of ePTFE in terms of durability, valvular performance, and the resistance against infection is considerable and may replace conventional prosthetic materials. Further improvement of the ePTFE membrane is essential to prevent valvular dysfunction.

Evolution of pulmonary valve reconstruction with focused review of expanded polytetrafluoroethylene handmade valves

OBJECTIVES

Many surgeons develop unique techniques for unmet needs for right ventricular outflow reconstruction to resolve pulmonary regurgitation after corrective surgery for congenital heart diseases. Expanded polytetrafluoroethylene (ePTFE) stands out as a reliable synthetic material, and clinical results with handmade ePTFE valves have been promising. This review focuses on the historical evolution of the use of ePTFE in pulmonary valve replacement and in the techniques for pioneering the translation of the handmade ePTFE trileaflet design for the transcatheter approach.

METHODS

We searched for and reviewed publications from 1990 to 2020 in the Pubmed database. Nineteen clinical studies from 2005 to 2019 that focused on ePTFE-based valves were summarized. The evolution of the ePTFE-based valve over 3 decades and recent relevant in vitro studies were investigated.

RESULTS

The average freedom from reintervention or surgery in the recorded ePTFE-based valve population was 90.2% at 5 years, and the survival rate was 96.7% at 3 years.

CONCLUSIONS

Non-inferior clinical results of this ePTFE handmade valve were revealed compared to allograft or xenograft options for pulmonary valve replacement. Future investigations on transferring ePTFE trileaflet design to transcatheter devices should be considered.

Long-term results of large-calibre expanded polytetrafluoroethylene-valved conduits with bulging sinuses

OBJECTIVES

In Japan, homograft and bovine jugular vein are available in very limited institutions for the reconstruction of the right ventricular outflow tract, and handmade expanded polytetrafluoroethylene (ePTFE)-valved conduits have been widely used instead. This study aimed to clarify the long-term outcomes and the durability of the ePTFE-valved conduits purely by narrowing down to those with large sizes to eliminate the influence of the body growth.

METHODS

Between January 2002 and December 2015, patients who underwent right ventricular outflow tract reconstruction in 34 Japanese institutions using ePTFE-valved conduits with a diameter of ≥18 mm were included. All the valved conduits were made in the authors' institution and delivered to each participating institution.

RESULTS

Overall, 502 patients were included. Early mortality was 1.4% and not related to conduit failure. The overall survival rate was 98.2% at 5 years and 96.6% at 10 years. Freedom from conduit explantation was 99.5% at 5 years and 89.0% at 10 years. Three patients (0.13 per 100 patient-years) developed infective endocarditis of the conduit, and only 1 patient required conduit removal. Pulmonary insufficiency was mild or less in 480 (96%) patients, and conduit stenosis was mild or less in 436 (88%) patients at the latest follow-up.

CONCLUSIONS

By narrowing the analyses down to only ePTFE conduits with a large size, satisfactory long-term outcomes of these conduits with a fan-shaped valve and bulging sinuses were shown. These conduits would be among the optimal choices for right ventricular outflow tract reconstruction.

The Fate of Homograft Versus Polytetrafluoroethylene Conduits After Neonatal Truncus Arteriosus Repair

Background:

Despite significant improvement in outcomes with truncus arteriosus (TA) repair, right ventricular outflow tract (RVOT) reconstruction with a right ventricular to pulmonary artery (RV-to-PA) conduit remains a source of long-term reintervention and reoperation. This study evaluated our experience with reintervention in homograft and polytetrafluoroethylene (PTFE) RV-to-PA conduits in neonates.

Methods:

Primary TA repairs from 2004 to 2016 at a single institution were included. Stratification was based on RVOT reconstruction with PTFE or homograft conduit. Primary outcome was operative conduit replacement. Secondary outcomes included the rates and types of catheter-based conduit interventions.

Results:

Twenty-eight patients underwent primary TA repair and 89.3% (n = 25) of them had RVOT reconstruction with a homograft (28.0%, n = 7) or PTFE (72.0%, n = 18) conduit. Rates of reoperation for conduit replacement and catheter-based interventions were similar between those with PTFE and homograft conduits (85.7% vs 72.2%, P = .49 and 57.1% vs 83.3%, P = .11, respectively). Additionally, the median time to conduit replacement and catheter-based conduit interventions were comparable. In multivariable analysis, conduit size, but not conduit type, was a predictor of conduit revision (hazard ratio: 1.66, 95% confidence interval: 1.11-2.49, P = .02). At five-year and ten-year follow-up, patients with PTFE conduits had better survival than those with homograft conduits (100.0% vs 71.4%, P = .02); however, no mortalities were associated with conduit reoperations or catheter-based reinterventions.

Conclusions:

Polytetrafluoroethylene and homograft RVOT reconstruction in neonatal TA repair demonstrate similar durability as defined by reoperation and reintervention rates. The validation of the durability of PTFE conduits in neonatal TA repair requires confirmatory studies in larger cohorts.

The effect of a valved small conduit on systemic ventricle–pulmonary artery shunt in the Norwood-type palliation

OBJECTIVES

The aim of this study was to clarify the impact of valved systemic ventricle–pulmonary artery (SV–PA) shunt on outcomes after stage-1 Norwood-type palliation (NP) compared with the modified Blalock–Taussig shunt.

METHODS

Consecutive patients who underwent NP between 2003 and 2019 were enrolled. SV–PA shunts using the expanded polytetrafluoroethylene valved conduit were implanted in 18 patients (valved SV–PA group), and another 18 patients underwent modified Blalock–Taussig shunt during NP (modified Blalock–Taussig shunt group). All valved conduits were made in our institution in advance.

RESULTS

No differences in baseline characteristics were found between the groups, except for shunt size. During a median 2.9 (interquartile range 0.4–6.4, maximum 14.2) years of follow-up, 8 (22.2%) patients died across both groups. There were no statistically significant differences in early mortality (5.5% vs 11.1%, P = 0.55) and overall survival rates at 5 years (80.8% vs 71.4%, P = 0.48) in the valved SV–PA and modified Blalock–Taussig shunt groups. No statistically significant difference was observed in the frequency of interventions between the groups (31% vs 33%, P = 1.0). At the time of the bidirectional Glenn procedure, the systemic ventricular end-diastolic volume index was significantly lower (84 ± 24 vs 106 ± 31 ml/m2, P = 0.05) and the ejection fraction was significantly greater (62 ± 8% vs 55 ± 9%, P = 0.03) in the valved SV–PA group. There was no statistically significant difference in the pulmonary artery index (228 ± 85 vs 226 ± 60 mm2/m2, P = 0.92).

CONCLUSIONS

A valved SV–PA shunt using an expanded polytetrafluoroethylene valved conduit was associated with preserved ventricular function after NP and did not impair pulmonary artery growth by controlling pulmonary regurgitation.

0.1 mm ePTFE versus autologous pericardium for hand-sewn trileaflet valved conduit: a comparative study

A hand-sewn trileaflet valved conduit is reportedly better than a bovine jugular graft. However, the comparative efficacy and safety between 0.1 mm ePTFE and autologous pericardium in this surgical procedure remained undetermined. This single-center cohort study included 46 patients aged 3–146 months who received implanted simplified hand-sewn trileaflet valved conduits: 31 patients (Group A) received 0.1 mm ePTFE valved conduits and 15 patients (Group B) received autologous pericardium valved conduits. Perioperative and follow-up outcomes up to 3 years after the surgeries were evaluated. No perioperative complications or early mortality were observed in either group, while one Group A patient aged 46 months died 6 months after surgery due to residual ventricular septal defect. No patients in Group A developed severe regurgitation or stenosis in valves of the conduits, but two moderate stenosis by echocardiography, and seven patients in group B were deemed to be conduit dysfunction (two stenosis, three stenosis plus regurgitation, and the remaining two regurgitation). No conduits failure was detected in group A, while two patients in group B (one for severe stenosis and the other one for severe regurgitation). After 6, 12, and 36 months, 95.2%, 88.9%, and 88.9% of Group A patients and 92.3%, 68.4%, and 42.7% of Group B patients were free from valved conduit dysfunction. After the same follow-up periods, all Group A patients had no conduit failure and 92.3%, 80.8%, and 80.8% of Group B patients were free from valved conduit failure. Within the 3-year follow-up period, 0.1 mm ePTFE novel simplified hand-sewn trileaflet valved conduits appear to be associated with a lower incidence of graft failure than autologous pericardium valved conduits.

In Vitro Hemodynamic Evaluation of Right Ventricle-Pulmonary Artery Continuity Reconstruction Through a Trileaflet Expanded Polytetrafluoroethylene Valved Conduit

Percutaneous pulmonary valve implantation is a technique to treat narrowed pulmonary valves or leaky pulmonary valves in congenital heart disease. This technique provides a promising strategy to reduce surgical risk. In clinical cases, due to stent size restrictions, commercial valve stents are sometimes unsuitable for children or certain patients. Hence, handmade pulmonary valved conduits prove useful because a customized size can be obtained for valve replacement. We propose a meta-learning-based intelligent model to train an estimator (including two sub-estimators) to determine optimal trileaflet parameters for customized trileaflet valve reconstruction. The purpose of this study was to investigate the hemodynamic and functional consequences of the novel design by employing a mock circulation system. We recorded the diastolic valve leakage and calculated the pulmonary regurgitation, regurgitation fraction, and ejection efficiency in a pulsatile setting. The prosthetic leaflet behavior was assessed using an endoscope camera and the pressure drops through valves were measured. All the in vitro parameters indicated that the expanded polytetrafluoroethylene (ePTFE) valved conduits were not inferior to commercial mechanical or tissue valve conduits and could decrease the regurgitation volume and increase the efficiency. Compatible early clinical outcomes were also identified between ePTFE valved conduits and other valved conduits used for right ventricular outflow tract reconstruction. The ePTFE valved conduits could be implanted in relatively small patients. An in vitro experimental study provided evidence that a handmade ePTFE valved conduit could be an attractive alternative to other commercialized valved conduits used for right ventricle-pulmonary artery continuity reconstruction.

Handmade trileaflet valve design and validation for patch-valved conduit reconstruction using generalized regression machine learning model

Pulmonary valve diseases include the different degrees of aortic stenosis or congenital defects in children or adults. Valve repair or replacement surgery is commonly performed to relieve valvular dysfunction and improve the significant flow regurgitation in the aortic valve and the pulmonary valve. However, commercial valve stents and valved conduits are sometimes not available for children or patients with special conditions. The handmade trileaflet valve design has been used with different range of diameters for patch-valved conduit reconstruction. Thus, we propose a multiple regression model, as a generalized regression neural network (GRNN), to determine the optimal trileaflet parameters, including the width, length, and upper lower curved structure. Through computed tomography pulmonary angiography, while the diameter of the main pulmonary artery is determined, a leaflet template can be rapidly sketched and made. Using an experimental pulmonary circulation loop system, the efficacy of the valved conduit can be validated using the regurgitation fraction method. In contrast to commercial valve stents, experimental results indicate that the handmade trileaflet valve can also improve severe pulmonary regurgitations.

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.

An immobilized liquid interface prevents device associated bacterial infection in vivo

Virtually all biomaterials are susceptible to biofilm formation and, as a consequence, device-associated infection. The concept of an immobilized liquid surface, termed slippery liquid-infused porous surfaces (SLIPS), represents a new framework for creating a stable, dynamic, omniphobic surface that displays ultralow adhesion and limits bacterial biofilm formation. A widely used biomaterial in clinical care, expanded polytetrafluoroethylene (ePTFE), infused with various perfluorocarbon liquids generated SLIPS surfaces that exhibited a 99% reduction in S. aureus adhesion with preservation of macrophage viability, phagocytosis, and bactericidal function. Notably, SLIPS modification of ePTFE prevents device infection after S. aureus challenge in vivo, while eliciting a significantly attenuated innate immune response. SLIPS-modified implants also decrease macrophage inflammatory cytokine expression in vitro, which likely contributed to the presence of a thinner fibrous capsule in the absence of bacterial challenge. SLIPS is an easily implementable technology that provides a promising approach to substantially reduce the risk of device infection and associated patient morbidity, as well as health care costs.