Bulging Sinuses Research Articles

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.

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.

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

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. 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. 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. 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.

Use of an expanded polytetrafluoroethylene valved patch with a sinus in right ventricular outflow tract reconstruction†.

The objective of this study was to evaluate our late outcomes using expanded polytetrafluoroethylene (ePTFE) valved patches with bulging sinuses and a fan-shaped valve for right ventricular outflow tract (RVOT) reconstruction. Six hundred and ninety patients underwent RVOT reconstruction using fan-shaped ePTFE valves and ePTFE valved patches with a bulging sinus. The patients' median age and weight were 1.3 years [range 4 days-64.2 years, interquartile range (IQR) 0.9-2.3 years] and 8.7 (range 2.8-83.1, IQR 7.4-10.5) kg, respectively. The patches were monocuspid in 634 patients, bicuspid in 49 patients and tricuspid in 7 patients. Preoperative and postoperative data were collected retrospectively from the patients' medical records. The longest follow-up period was 17.5 (7.6 ± 3.9) years. There were no deaths related to the ePTFE patch. Pulmonary insufficiency was less than mild in 77.3%, and the peak RVOT gradient was <36 mmHg in 92.3% at the latest follow-up. Redo of RVOT reconstruction was performed in 40 patients, in no cases because of patch infection. Overall freedom from reoperation at 5, 10 and 15 years was 96.5%, 93.1% and 87.9%, respectively; by patient age, the rates at 5, 10 and 15 years for those younger than 1 year were 93.2%, 91.0% and 88.9%, respectively, while for those 1 year or older, they were 97.9%, 94.0% and 88.3%, respectively. Satisfactory long-term outcomes were achieved with ePTFE patches with a bulging sinus and a fan-shaped valve. This ePTFE valved patch could be the optimal choice for RVOT reconstruction.

Modification of expanded polytetrafluoroethylene valved conduit using the thin-type leaflets

ObjectivesThe expanded polytetrafluoroethylene conduit with fan-shaped leaflets and bulging sinuses for right ventricular outflow tract reconstruction was modified with a newly developed thin-type expanded polytetrafluoroethylene leaflet. The purpose of this study was to evaluate the clinical outcomes and hemodynamic performance of the modified conduit. MethodsFrom January 2010 to December 2013, 149 patients underwent definitive right ventricular outflow tract reconstruction using the expanded polytetrafluoroethylene conduit; the 55 patients receiving a conventional conduit (group N) were compared with the 94 patients receiving a modified conduit (group T). ResultsThere were no conduit-related deaths, operative deaths, or reimplantations for conduit failure. The overall survival and freedom from reintervention for conduit-related reasons at 3 years were 98.2% versus 95.6% (P = .438) and 94.7% versus 97.9% (P = .954) for groups N and T, respectively. The mean peak pressure gradients were 22.6 ± 15.6 mm Hg versus 18.2 ± 11.5 mm Hg (P = .161), and in the subanalysis within small-sized conduits, they were 30.2 ± 16.5 mm Hg versus 20.4 ± 10.7 mm Hg (P = .034). Regarding conduit insufficiency, the modified conduit showed a significantly worse grade of insufficiency (P = .014) only in the subanalysis within large-sized conduits. ConclusionsAlthough the clinical outcomes did not differ within midterm observation, the thin-type expanded polytetrafluoroethylene leaflet was considered to be suitable for the small-sized conduits, but not for large-sized conduits, based on the comparison of the hemodynamic performance. Long-term follow-up is necessary to address the appropriate sheet type for middle-sized conduits and to estimate the durability of the thin-type leaflet.

Long-term outcomes of expanded polytetrafluoroethylene conduits with bulging sinuses and a fan-shaped valve in right ventricular outflow tract reconstruction

ObjectiveVarious types of conduits are available for right ventricular outflow tract (RVOT) reconstruction. We have developed an expanded polytetrafluoroethylene (ePTFE) conduit with bulging sinuses and a fan-shaped ePTFE valve. This study summarized the results of a multicenter study evaluating the valved ePTFE conduit. MethodsThe valve functions of 902 patients (median age, 3.9 years; median weight, 12.6 kg) who underwent RVOT reconstruction using valved ePTFE conduits (9 different sizes, 8-24 mm in diameter) at 65 hospitals between 2001 and 2015 were retrospectively investigated. Median follow-up time was 5.5 years. The valve functions were assessed using echocardiography, cardiac catheterization, and magnetic resonance angiography. ResultsThere were no deaths related to the ePTFE conduit. The peak RVOT gradient was 16.5 ± 13.1 mm Hg, and pulmonary insufficiency graded better than mild was 95.9% at the latest follow-up. Conduit replacement was performed in 55 patients, and in only 3 patients because of conduit infection. Freedom from intervention at 5 years and 10 years was 92.3% and 76.1%, respectively, with small conduits (8-16 mm in diameter) and 99.6% and 95.1%, respectively, with large conduits (18-24 mm in diameter). ConclusionsThe long-term outcomes of the ePTFE conduit with a fan-shaped valve and bulging sinuses appear clinically satisfactory. We believe that the longevity of small-sized conduits can yield sufficient time to exchange them to larger-sized conduits without any loss of their valve functions. Regarding longevity and resistance to infections, this ePTFE valved conduit can be one of the best ways to reconstruct the RVOT.

右室流出路再建に用いる ePTFE 弁の膨らみが弁の開閉に与える影響

右室流出路再建に用いる ePTFE 弁の膨らみが弁の開閉に与える影響

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

One of the critical factors limiting conduitlongevity in right ventricular outflow tract (RVOT) reconstruction with homografts and xenografts isthe small size of the conduit. The aim of our study wasto assess the outcome of using smaller-sized expanded polytetrafluoroethylene (ePTFE) conduits with a fan-shaped valve and bulging sinuses for RVOT reconstruction. This retrospective review examined 303 patients who underwent RVOT reconstruction with ePTFE conduits at 63 Japanese hospitals between 2003 and 2014. Inclusion criteria were a conduit size less than or equal to 16 mm and the use of operative treatment as the primary correction for underlying heart disease. Patients undergoing palliative procedures were excluded. Median follow-up was 1.7 years. Freedom from conduit replacement and freedom from conduit reintervention were 90.1% ± 4.8% and 77.2% ± 5.6%, respectively. The most common indication for conduit reintervention was pulmonary artery (PA) bifurcation stenosis (82%). Modeling z-scores as a dichotomous variable revealed that freedom from conduit reintervention for PA bifurcation stenosis was significantly decreased for conduits with a z-score greater than or equal to 1.4 compared with z-scores less than 1.4 (p= 0.036). There were 30 patients (9.9%) who experienced at least moderate conduit stenosis and 21 patients (6.9%) with at least moderate conduit insufficiency. Univariate Cox regression analysis showed that conduit size was a significant factor for conduit stenosis (p= 0.006). Excellent midterm outcomes were achieved with ePTFE valved conduits, even when using smaller sizes. Conduit z-scores around 1.4 were optimal for RVOT reconstruction in younger patients.

Right Ventricular Outflow Reconstruction Using a Polytetrafluoroethylene Conduit With Bulging Sinuses and Tricuspid Fan-shaped Polytetrafluoroethylene Valve

We developed an expanded polytetrafluoroethylene (ePTFE) valved conduit for use in right ventricular outflow tract reconstruction, a procedure used in various congenital heart diseases with decreased pulmonary blood flow, particularly Tetralogy of Fallot. The valve was designed with a fan-shaped configuration and consisted of a 0.1-mm-thick ePTFE membrane. To improve valve mobility, bulging sinuses were constructed in the conduit. The follow-up duration was 4.9 ± 3.4 years (maximum, 14.2 years), and the reoperation-free rates were 98.8% at 5 years and 93.8% at 10 years with large-caliber conduits (16-24 mm) and 89.9% at 5 years and 68.6% at 10 years with small-caliber conduits (6-16 mm), results superior to those seen with previous commercially available conduits and homograft. The incidence of infection caused by the ePTFE conduit was very low, at 0.3%. An ePTFE conduit with bulging sinuses and a fan-shaped valve made of an ePTFE membrane is useful for right ventricular outflow tract reconstruction.

1A15 右室流出路再建に用いるePTFE弁の膨らみおよび弁葉形状が流れ場に与える影響 : 実寸法モデルによる弁開口面積の解析

1A15 右室流出路再建に用いるePTFE弁の膨らみおよび弁葉形状が流れ場に与える影響 : 実寸法モデルによる弁開口面積の解析

Hemodynamic examination for shape optimization of ePTFE valved conduit with bulging sinuses

Hemodynamic examination for shape optimization of ePTFE valved conduit with bulging sinuses

Valved Polytetrafluoroethylene Conduits for Right Ventricular Outflow Tract Reconstruction

The purposes of this study were to review our early outcomes using valved expanded polytetrafluoroethylene (ePTFE) conduits, with or without bulging sinus structure, for right ventricular outflow tract reconstruction and to examine the mechanical properties of the ePTFE material after bulging sinuses were created. A retrospective review was performed of all patients who received the valved ePTFE conduit between 2008 and 2014 at a single institution. The surface morphologies and the mechanical strengths of the ePTFE conduit with bulging sinuses examined by scanning electron microscopy and unidirectional pull test were compared with those of the original ePTFE material. There were 120 operations with the valved ePTFE conduit (60 with bulging sinuses). The patients median age and weight were 6.9 years and 23.7 kg. The conduits were a median size of 22 mm. At 5 years, freedom from conduit reoperation was 92.7% (95% confidence interval, 82.7% to 97.0%), and freedom from severe conduit insufficiency or more than a 50 mm Hg gradient was 74.8% (95% confidence interval, 60.8% to 84.4%). No significant differences in the surface morphologies were observed by the scanning electron microscopy or in the maximum tolerated loads obtained by the pull test between the original ePTFE material and the ePTFE with bulging sinuses (121 and 122 N in longitudinal direction and 115 and 121 N in circumferential direction; p = 0.88 and p = 0.68). The valved ePTFE conduits demonstrated excellent early clinical outcomes. The mechanical property examinations showed no obvious difference after bulging sinuses were created on the ePTFE material.

2F43 右室流出路再建に用いるePTFE弁の膨らみおよび弁葉形状が流れ場に与える影響 : PIV法による流れ場の解析(GS8:生体流れ)

2F43 右室流出路再建に用いるePTFE弁の膨らみおよび弁葉形状が流れ場に与える影響 : PIV法による流れ場の解析(GS8:生体流れ)

Current status of right ventricular outflow tract reconstruction: complete translation of a review article originally published in Kyobu Geka 2014;67:65-77.

Right ventricular outflow tract (RVOT) reconstruction is becoming more prevalent as the number of adult patients who require repeated surgery long after definitive repair of congenital heart defects during childhood has increased. Early primary repair and annulus-preserving surgery have been the two current strategies of RVOT reconstruction from the viewpoint of timing and indications for surgical intervention; however, the long-term outcomes of both procedures remain unknown. Although various materials have been used for pulmonary valve replacement during RVOT reconstruction, deficient durability due primarily to immunological rejection frequently arises, particularly when implanted into young patients. A multicenter study in Japan showed that the clinical outcomes of expanded polytetrafluoroethylene (ePTFE) valved patches/conduits that we developed and manufactured comprised an excellent alternative material for RVOT reconstruction. Such enhanced outcomes might have partly been attributable to the biocompatibility and low antigenicity of ePTFE, and also to the fluid dynamic properties arising from the structural characteristics of a bulging sinus and a fan-shaped valve. However, numerous issues concerning RVOT reconstruction, such as indications for and the timing of definitive repair, as well as the choice of materials for pulmonary valve replacement, must be resolved to achieve better patient prognoses and quality of life. This review describes recent surgical strategies and outstanding issues associated with RVOT reconstruction.

右室流出路再建 ―Fan─shaped ePTFE valveとbulging sinus付きePTFE conduitの有用性―

右室流出路再建 ―Fan─shaped ePTFE valveとbulging sinus付きePTFE conduitの有用性―

Engineering analysis of the effects of bulging sinuses in a newly designed pediatric pulmonary heart valve on hemodynamic function

The purpose of this study was to examine the hemodynamic characteristics of expanded polytetrafluoroethylene (ePTFE) pulmonary valves with bulging sinuses quantitatively in a pediatric pulmonary mechanical circulatory system designed by us, in order to propose the optimal design for clinical applications. In this study, we developed a pediatric pulmonary mock circulation system, which consisted of a pneumatic right ventricular model, a pulmonary heart valve chamber, and a pulmonary elastic compliance tubing with resistive units. The hemodynamic characteristics of four different types of ePTFE valves and a monoleaflet mechanical heart valve were examined. Relationships between the leaflet movements and fluid characteristics were evaluated based on engineering analyses using echocardiography and a high-speed video camera under the pediatric circulatory conditions of the mock system. We successfully performed hemodynamic simulations in our pediatric pulmonary circulatory system that could be useful for quantitatively evaluating the pediatric heart valves. In the simulation study, the ePTFE valve with bulging sinuses exhibited a large eddy in the vicinity of the leaflets, whereas the straight tubing exhibited turbulent flow. The Reynolds number obtained in the valve with bulging sinuses was calculated to be 1667, which was smaller than that in the straight tubing (R (e) = 2454).The hemodynamic characteristics of ePTFE pediatric pulmonary heart valves were examined in our mock circulatory system. The presence of the bulging sinuses in the pulmonary heart valve decreased the hydrodynamic energy loss and increased the systolic opening area. Based on an in vitro experiment, we were able to propose an optimal selection of pulmonary valve design parameters that could yield a more sophisticated pediatric ePTFE valve shape.

Expanded polytetrafluoroethylene conduits and patches with bulging sinuses and fan-shaped valves in right ventricular outflow tract reconstruction: Multicenter study in Japan

There is no optimal substitute for right ventricular outflow tract (RVOT) reconstruction in congenital heart defects. Expanded polytetrafluoroethylene (ePTFE) valved conduits and patches may be a good alternative to homografts and bovine jugular veins. We have developed a fan-shaped ePTFE valve and an ePTFE valved conduit and patch with bulging sinuses with the aim of enhancing the long-term valve function. Bulging sinuses were constructed on ePTFE conduits and patches as described previously (J Thorac Cardiovasc Surg. 2007;134:327-32). Between February 2001 and January 2011, 794 patients (aged 14 days to 56.8 years old; median, 2.0 years old) had ePTFE valves implanted for RVOT reconstruction at 52 Japanese institutes. Conduits with a fan-shaped ePTFE valve were implanted in 325 patients and a patch with a fan-shaped ePTFE valve was implanted in 469 patients. Valve function was assessed by a series of echocardiograms postoperatively. The mean follow-up was 3.6 years (1.1 months to 10.0 years). Freedom from reoperation at 10 years was 95.4% in patients with conduits and 92.3% in those with patches. Pulmonary insufficiency was mild or nonexistent in 95.0% of patients with conduits and 79.6% of patients with patches. The pressure gradient between the right ventricle and the pulmonary artery was 14.0 ± 13.2 mm Hg in patients with conduits and 11.6 ± 11.6 mm Hg in patients with patches. Fan-shaped ePTFE valved conduits and patches with bulging sinuses have a high freedom from reoperation and prevent pulmonary insufficiency. They represent a promising material for RVOT reconstruction.

Expanded polytetrafluoroethylene-valved conduit with bulging sinuses for right ventricular outflow tract reconstruction in adults

Generally, right ventricular outflow tract reconstruction in adults is performed using homografts or xenograft. However, sufficient graft material is difficult to obtain and has the problems of calcification and structure destruction. We, therefore, evaluated using expanded polytetrafluoroethylene- (ePTFE)-valved conduits with bulging sinuses for right ventricular outflow tract reconstruction in adults. Between February 2006 and April 2008, a total of five patients (three men, two women), ages 25-51 years old (mean +/- SD, 40 +/- 11 years)] underwent right ventricular outflow tract (RVOT) reconstruction in our institution. In three patients, RVOT reconstruction was performed with the Ross procedure; and in all cases, tricuspid ePTFE (valved conduits with bulging sinuses were used. The diameter of the conduit was determined according to the RVOT size. Valve function was followed up using echocardiography after surgery and during the early/mid-term periods of recovery (13 months to 3.0 years). No morbidity occurred, and no patient required further surgery during the follow-up period. During these follow-up periods, pulmonary observation revealed that no patients had stenosis; regurgitation was mild in one patient and trivial in four patients. In regard to the tricuspid valve, regurgitation was trivial in four patients and mild in one patient. Although long-term follow-up is required to confirm the durability of the ePTFE-valved conduit with bulging sinuses, the present results indicate a satisfactory result in patients who undergo RVOT reconstruction, even in adult cases.

Expanded polytetrafluoroethylene valved conduit and patch with bulging sinuses in right ventricular outflow tract reconstruction

No specific prosthetic material is currently recognized as being the most suitable for right ventricular outflow tract reconstruction for congenital heart defects. Prosthetic valves are subject to wear and stress because they do not create vortex flow, which helps natural valves to close. We designed a fan-shaped expanded polytetrafluoroethylene valved conduit and patch with bulging sinuses that create vortex flow, making them more reliable over the long term. Bulging sinuses were formed on a sheet of expanded polytetrafluoroethylene using a specially designed mold. Fan-shaped expanded polytetrafluoroethylene sheets (0.1 mm thick) were anastomosed to the edge of the bulging sinuses as valve leaflets, creating monocuspid, bicuspid, or tricuspid valves. These valves were implanted in 157 patients undergoing right ventricular outflow tract reconstruction (age 16 days to 45.4 years, median 2.0 years), in 48 patients as a conduit, and in 109 patients as a patch. Valve function was followed up by echocardiography for 5.6 to 63.7 months (mean 20.8 months). There was no mortality or morbidity, and no patients required reoperation during follow-up. No patients had stenosis, and regurgitation was less than mild in all patients with conduits and moderate in 15 patients (13.8%) with patches, but moderate regurgitation did not further develop during follow-up. Valve motion was fully maintained in all patients. The expanded polytetrafluoroethylene valved conduits and patches with bulging sinuses showed excellent early-to-midterm results. The valved conduits and patches seem to be promising alternatives to homografts in right ventricular outflow tract reconstruction. Their function will be followed up further.