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

Outcomes of Bovine Jugular Vein Versus Porcine Valved Conduits for Right Ventricle to Pulmonary Artery Connection

Homografts conduits has been the gold standard for right ventricle to pulmonary artery (RV-PA) conduit. Several different types of xenograft valved conduits have been used as an alternative to homografts, due to their limited availability. In this single center, retrospective study, we analyzed the outcomes of patients with bovine jugular vein conduit (Contegra) and porcine valved conduit (Biointegral) in terms of survival and reintervention rate. Between 2012 and 2023, 44 children underwent surgical repair with RV-PA conduits using Contegra (n = 20) or Biointegral (n = 24). Patients with truncus arteriosus and patients who underwent unifocalization and Ross procedures were excluded. The operations in which other RV-PA conduits such as homografts, Gore-Tex grafts with PTFE handmade valved were used, were also excluded from the study. The median age of the patients was 19 (3-60) months and 84% of the patients (n = 37) had a history of previous intervention. Hospital mortality was 4.5% (n = 2). The median length of stay in intensive care unit and hospital was 5 (2-63) and 19 (2-145) days, respectively. 36 of the patients (82%) were followed for a median of 68 (4.8-143.7) months. There was one late death in Contegra group and five late deaths in Biointegral group. Survival analysis revealed that 1, 5, and 10-year survival rates were 100%, 90%, and 90% in Contegra group and 81%, 76.2%, and 33.9% (p = 0.047) in Biointegral group, respectively. During follow-up period, 11 patients (30.5%) needed reintervention (n = 3 in Contegra; n = 8 in Biointegral group). Freedom from reintervention rates were 100%, 94.1%, and 47.1% at 1, 5, and 10 years in Contegra group and 100% and 63.3% at 1 and 5 years in Biointegral group, respectively (p = 0.024). In this study, the outcomes of Contegra conduits were statistically significantly better than Biointegral conduits. Contegra is still the most valuable alternative to homografts. We believe that the choice of conduit in the first surgery is an important decision that directly affects survival and re-intervention rates.

Long-Term Outcomes With Expanded Polytetrafluoroethylene Valved Conduits in Pediatric Patients

Background

The expanded polytetrafluoroethylene (ePTFE) valved conduit (VC) has been reported for pulmonary valve replacement (PVR). The purpose of this study was to review long-term outcomes of our trileaflet ePTFE VC.

Methods

This multicenter study was performed with institutional review board approval from each institution. Our VC is fashioned from commercially available ePTFE tube grafts (for the conduit) and 0.1-mm-thick ePTFE membrane (for the trileaflet material). The patients were followed up in our clinic. Valve function was assessed by echocardiography in the operating room and at follow-up clinic visits after implantation.

Results

Fifty-five patients received ePTFE VC between 2012 and 2023 (16-28 mm in diameter). Patients' age at the time of implantation ranged from 6 months to 20 years (median, 7.5 years). Clinical follow-up ranged from 4 days to 10.1 years (average, 3.6 years). There were no hospital deaths. There were 2 non-valve-related late deaths. There have been no cases of endocarditis. Two patients required balloon dilation for the distal pulmonary artery stenosis, and 1 patient required residual ventricular septal defect closure. Five patients have received transcatheter PVR (TPVR) because of increased pressure gradient across the VC. Freedom from TPVR at 10 years was 90%. No valves required explantation or surgical replacement.

Conclusions

Compared with historical data for other PVR options, our ePTFE VC shows excellent long-term performance and, when required, provides an easily accessible "landing zone" for TPVR. Our technique is easily learned, is reproducible, and can be a valuable option for surgeons performing PVR in pediatric patients.

Pediatric RVOT reconstruction with ePTFE trileaflet valved conduits: a dual-center Chinese study

Objective

This study aims to assess the early to mid-term clinical efficacy of expanded polytetrafluoroethylene (ePTFE) trileaflet valved conduits in pediatric right ventricular outflow tract reconstruction for congenital heart disease.

Methods

We conducted a retrospective analysis of pediatric patients who underwent right ventricular outflow tract (RVOT) reconstruction using ePTFE trileaflet valved conduits at two cardiac centers in China, between January 2017 and June 2023. The main assessment criterion was the functionality of the prosthetic pulmonary valve conduit.

Results

A total of 162 pediatric patients were included, with follow-up periods ranging from 0.1 to 5 years post-discharge, and a median follow-up duration of 1 year (interquartile range: 1, 2). Three patients (1.9%) required re-operation due to conduit obstruction. During follow-up, pulmonary valve flow velocities were recorded as <3 m/s in 134 patients (82.7%), between 3 and 4 m/s in 24 patients (14.8%), and >4 m/s in 4 patient (2.5%). Mild pulmonary valve regurgitation was noted in 148 patients (91.4%), and moderate pulmonary valve regurgitation was noted in 14 patients (8.6%), with no instances of more than moderate pulmonary valve regurgitation.

Conclusion

The ePTFE trileaflet valved conduit, known for its accessibility and simplicity in manufacturing, demonstrates favorable early to mid-term clinical outcomes in pediatric RVOT reconstruction.

Ex vivo evaluation of 3 different right ventricular outflow tract substitutes

OBJECTIVES

The Ross procedure represents an excellent treatment option in younger patients with aortic stenosis but is limited by poor availability of homografts. In this study, we investigated the hydrodynamic performance of 3 different types of right ventricular outflow tract replacement with pericardium or synthetic material.

METHODS

Three different types of valved conduits were constructed using pericardium and/or synthetic material (Group PEPE: pericardial cusps and pericardial conduit, Group PEPR: pericardial cusps and Dacron conduit, Group PRPR: expanded polytetrafluoroethylene cusps and Dacron conduit). The conduits were designed according to the Ozaki method. Their hydrodynamic performance (effective orifice area, mean pressure gradient and leakage volume) were evaluated in a mock circulation loop at different hydrodynamic conditions.

RESULTS

Hydrodynamic assessment showed significantly larger effective orifice area of PEPE and PEPR compared to PRPR under all conditions and there were no significant differences between PEPE and PEPR [for condition 2: PEPE 2.43 (2.35-2.54) cm2, PEPR: 2.42 (2.4-2.5) cm2, PRPR: 2.08 (1.97-2.21) cm2, adjusted pairwise comparisons: PEPE versus PEPR: P = 0.80, PEPE versus PRPR: P  < 0.001, PEPR versus PRPR: P  < 0.001]. Mean pressure gradient was significantly lower for PEPE and PEPR compared with PRPR, whereas no significant differences were seen between PEPE and PEPR. Leakage volume was significantly lower for PEPE and PEPR compared with PRPR under all conditions while leakage was similar between PEPE and PEPR.

CONCLUSIONS

Pulmonary graft reconstruction with pericardium cusps showed superior hydrodynamic performance compared with polytetrafluoroethylene cusps. Our results suggest that it could be considered as an alternative substitute for right ventricular outflow tract replacement during the Ross procedure.

Pulmonary Homograft vs Handmade Polytetrafluoroethylene-Valved Conduits After the Ross Procedure

BACKGROUND

This study aimed to longitudinally compare expanded polytetrafluoroethylene (ePTFE)-valved conduits vs pulmonary homograft (PH) conduits after right ventricular outflow tract reconstruction in the Ross procedure.

METHODS

Patients undergoing a Ross procedure from June 2004 to December 2021 were identified. Echocardiographic data, catheter-based interventions, or conduit replacements, as well as time to first reintervention or replacement, were comparatively assessed between handmade ePTFE-valved conduits and PH conduits.

RESULTS

A total of 90 patients were identified. The median age and weight were 13.8 years (interquartile range [IQR], 8.08-17.80 years) and 48.3 kg (IQR, 26.8-68.7 kg), respectively. There were 66% (n = 60) ePTFE-valved conduits and 33% (n = 30) PHs. The median size was 22 mm (IQR, 18-24 mm) for ePTFE-valved conduits and 25 mm (IQR, 23-26 mm) for PH conduits (P < .001). Conduit type had no differential effect in the gradient evolution or the odds of presenting with severe regurgitation in the last follow-up echocardiogram. Of the 26 first reinterventions, 81% were catheter-based interventions, without statistically significant differences between the groups (69% PH vs 83% ePTFE). The overall surgical conduit replacement rate was 15% (n = 14), and it was higher in the homograft group (30% vs 8%; P = .008). However, conduit type was not associated with an increased hazard for reintervention or reoperation after adjusting for covariates.

CONCLUSIONS

Right ventricular outflow tract reconstruction using handmade ePTFE-valved conduits after a Ross procedure provides encouraging midterm results, without a differential effect in hemodynamic performance or valve function compared with PH conduits. These results are reassuring about the use of handmade valved conduits in pediatric and young adult patients. Longer follow-up of tricuspid conduits will complement valve competency assessment.

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.

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.

Outcomes of Transcatheter Pulmonary Valve Replacement and Surgical Pulmonary Valve Replacement: A Cohort Analysis

Background

Transcatheter pulmonary valve replacement (TPVR) has become an alternative to surgical pulmonary valve placement (SPVR) for patients after tetralogy of Fallot repair. This study compared the outcomes of TPVR with those of SPVR.

Methods

We reviewed data from patients who underwent pulmonary valve replacement with a median of 2 years of follow-up.

Results

Between 2010 and 2021, 215 patients underwent pulmonary valve replacement (72 TPVR and 143 SPVR). The median size of the right ventricular end-diastolic volume index in the TPVR group was 165 mL/m2 (IQR, 136-190) and 184 mL/m2 (IQR, 163-230) in the SPVR group (P = .001). The median value of the maximum landing zone at the right ventricular outflow tract (RVOT) in patients with native RVOT was 26 mm (IQR, 24-28) in the 43 patients in the TPVR group and 31 mm (IQR, 28-34) in the 101 patients in the SPVR group (P < .001). The median size of the pulmonary valve implant for the native RVOT in the TPVR group was 29.0 mm (IQR, 26.0-29.0) and 24.0 mm (IQR, 24.0-24.0) in the SPVR group (P < .001). There were no deaths in the TPVR group and 8 deaths in the SPVR group (P = .041). Major complications and the length of hospitalization were lower in the TPVR group (P = .001). After 2 years, the mean decrease in QRS duration was 5 milliseconds (IQR, 1-14) in the TPVR group and 1 millisecond (IQR, -4 to 10) in the SPVR group (P = .006).

Conclusions

TPVR allows for larger implants, resulting in lower mortality, shorter hospital stays, and fewer major cardiac events. SPVR may be preferable in patients with larger (>30 mm) native RVOT and in those who require concomitant surgical procedures.

In Vitro Modelling for Bulging Sinus Effects of an Expanded Polytetrafluoroethylene Valved Conduit Based on High-Speed 3D Leaflet Evaluation

The study aimed to develop a pulmonary circulatory system capable of high-speed 3D reconstruction of valve leaflets to elucidate the local hemodynamic characteristics in the valved conduits with bulging sinuses. Then a simultaneous measurement system for leaflet structure and pressure and flow characteristics was designed to obtain valve leaflet dynamic behaviour with different conduit structures. An image preprocessing method was established to obtain the three leaflets behaviour simultaneously for one sequence with two leaflets images from each pair of three high-speed cameras. Firstly, the multi-digital image correlation analyses were performed, and then the valve leaflet structure was measured under the static condition with fixed opening angles in the water-filled visualization chamber and the pulsatile flow tests simulating paediatric pulmonary flow conditions in the different types of conduit structures; with or without bulging sinuses. The results showed the maximum 3D reconstruction error to be around 0.06 mm. In the steady flow test, the evaluation of opening angles under the different flow rates conditions was achieved. In the pulsatile flow test, each leaflet's opening and closing behaviours were successfully reconstructed simultaneously at the high-frequency recording rate of 960fps. Therefore, the system developed in this study confirms the design evaluation method of an ePTFE valved conduit behaviour with leaflet structures interacting with local fluid dynamics in the vicinity of valves. Clinical Relevance- The system reveals the bulging sinus effects on ePTFE valve leaflet motion by the 3D reconstruction using multi-camera high-speed sequential imaging in vitro.

Ross Procedure in the era of Handmade-Valved Conduits for Right Ventricular Outflow Tract Reconstruction in Children: Short-Term Surgical Outcomes

Objective

Ross procedure is considered as the “gold standard” for aortic valve replacement, but the conduits used for right ventricular outflow tract (RVOT) reconstruction, such as homografts and bovine jugular vein (BJV) conduits, are of limited availability in China. Handmade expanded polytetrafluoroethylene-valved conduits (HVCs) have been used recently as the alternative for RVOT reconstruction, but their specific experience in Ross procedure is limited in the literature.

Methods

This was a retrospective review of 27 children who underwent Ross procedure in our center from January 2018 to January 2022.

Results

Mean age at surgery was 8.0 ± 3.8 years. During the study period, BJV conduits were used for RVOT reconstruction in 6 patients (22%), and HVCs were used in 21 patients (78%). Median conduit size was 20 mm (range, 16–24 mm), and mean conduit Z-score was +0.8 ± 0.9. Median time for cardiopulmonary bypass was 158 min (range, 109–275 min), and mean time for aortic crossclamping was 110 ± 21 min. There was no early mortality. During a median follow-up time of 1.4 years (range, 0.1–3.7 years), 3 patients (11%) with BJV conduits had peak conduit velocity of &gt; 3.5 m/s; 3 patients (11%) with HVCs developed moderate conduit insufficiency; no patients had more than moderate conduit insufficiency. Three patients with BJV conduits had 5 reinterventions, and all received conduit replacement with HVCs.

Conclusion

HVC is an appealing alternative to BJV conduit for RVOT construction for children undergoing Ross procedure, with favorable short-term outcomes.

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.

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.