Durability of hand-sewn valves in the right ventricular outlet

Expanded polytetrafluoroethylene conduits with curved and handsewn bileaflet designs for right ventricular outflow tract reconstruction

OBJECTIVE

This study reviewed the application of curved and bileaflet designs to pulmonary expanded polytetrafluoroethylene conduits with diameters of 10 to 16 mm and characterized this conduit on in vitro experiment, including particle image velocimetry.

METHODS

All patients who received this conduit between 2010 and 2022 were evaluated. Three 16-mm conduits were tested in a circulatory simulator at different cardiac outputs (1.5-3.6 L/minute) and bending angles (130°-150°).

RESULTS

Fifty consecutive patients were included. The median operative body weight was 8.4 kg (range, 2.6-12 kg); 10-, 12-, 14-, and 16-mm conduits were used in 1, 4, 6, and 39 patients, respectively. In 34 patients, the conduit was implanted in a heterotopic position. The overall survival rate was 89% at 8 years with 3 nonvalve-related deaths. There were 10 conduit replacements; 5 16-mm conduits (after 8 years) and 1 12-mm conduit (after 6 years) due to conduit stenosis, and the remaining 4 for reasons other than conduit failure. Freedom from conduit replacement was 89% and 82% at 5 and 8 years, respectively. Linear mixed-effects models with echocardiographic data implied that 16-mm conduits were durable with a peak velocity <3.5 m/second and without moderate/severe regurgitation until the patient's weight reached 25 kg. In experiments, peak transvalvular pressure gradients were 11.5 to 25.5 mm Hg, regurgitant fractions were 8.0% to 14.4%, and peak Reynolds shear stress in midsystolic phase was 29 to 318 Pa.

CONCLUSIONS

Our conduits with curved and bileaflet designs have acceptable clinical durability and proven hydrodynamic profiles, which eliminate valve regurgitation and serve as a reliable bridge to subsequent conduit replacement.

Educating Surgeons to Construct Valved Conduits: What Does It Take to Achieve Reproducible Results?

BACKGROUND

Despite the demonstrated utility of surgeon-fashioned polytetrafluoroethylene (PTFE) valved conduits, methods for educating surgeons to reproducibly construct these conduits are lacking. We present a surgeon education process and early outcomes for children receiving surgeon-fashioned PTFE valved conduits during the initial learning curve.

METHODS

The educational curriculum included 4 hours of proctored instruction/supervised valve construction, followed by 2 hours of individual practice. A surgeon with prior mastery of the technique provided templated designs, videos, and follow-up consultation. A retrospective medical record review (2017-2022) described early outcomes and valve function for patients receiving surgeon-fashioned PTFE right ventricle-to-pulmonary artery conduits.

RESULTS

Two surgeons were educated using the method described. Fifteen valved conduits were implanted in 14 patients (median patient age, 38 months; conduit size range, 10-24 mm). At discharge, no patient had more than mild stenosis or regurgitation, and 12 of 15 valves (80%) had none or trivial regurgitation. Median follow-up was 14 months (range, 1-52 months). At the last follow-up, median peak conduit gradient of the 15 valves was low (18 mm Hg), 1 (7%) had moderate stenosis, and 1 (7%) had mild-moderate regurgitation. Two conduits were replaced concomitantly during repair of associated lesions at 14 and 38 months (sizes 10 and 12 mm, respectively). There were no deaths and no infectious complications.

CONCLUSIONS

Four hours of proctored surgeon education plus deliberate practice is an effective method for teaching valved PTFE conduit construction and is associated with excellent early valve function. This study provides educational methods and initial evidence of safety for congenital surgeons wishing to learn and adopt this technique.

Short-term outcome of Polytetrafluoroethylene Membrane Valve versus Transannular Pericardial patch Reconstruction of Right Ventricular Outflow Tract in Tetralogy of Fallot: a Randomized Controlled Trial

INTRODUCTION

Reconstruction of right ventricular outflow tract during primary repair of tetralogy of Fallot often requires the placement of a transannular patch which results in pulmonary regurgitation (PR). We compared the short-term outcomes of bicuspid polytetrafluoroethylene membrane valve versus transannular pericardial patch reconstruction of the right ventricular outflow tract.

METHODS

Thirty consecutive patients undergoing primary repair of tetralogy of Fallot were randomly allocated to two groups - polytetrafluoroethylene valve (PTFEV) group (n=15) and transannular pericardial patch (TAP) group (n=15). The two groups had similar preoperative demographic characteristics. We compared the short-term clinical and echocardiographic outcomes between these groups. The transthoracic echocardiographic follow-up was performed at one week, one month and six months after surgery.

RESULTS

The PTFEV group had significantly lower central venous pressure in the immediate postoperative period compared to the TAP group (7.60±2.06 vs. 10.13±1.73, P=0.002). Extubation time was significantly shorter in the PTFEV group compared to the TAP group (12.93±7.55 hrs vs. 22.23±15.11 hrs, P=0.04). PR in the PTFEV group was absent in five patients at 24 hours post-surgery. At the study endpoint, PR was absent in six, trivial in one and mild in eight patients in the PTFEV group compared to TAP group, where all 15 patients had severe PR.

CONCLUSION

The bicuspid polytetrafluoroethylene membrane valves significantly decrease the central venous pressure in the immediate postoperative period, facilitate early extubation and, thus, prevent ventilator-related comorbidities. They achieve a high degree of pulmonary competence and do not increase the right ventricular outflow tract gradient in short-term follow-up.

Comparison of different pulmonary valve reconstruction techniques during transannular repair of tetralogy of fallot

BACKGROUND

Transannular patch, which results in pulmonary insufficiency (PI), is usually required during repair of tetralogy of fallot (TOF). In this study, we compared three types of pulmonary valve reconstruction techniques during transannular repair of TOF.

METHODS

Between February 2014 and January 2018, 50 patients with TOF underwent primary repair with transannular patch. These patients were divided into three groups. In Group 1, (n = 15), a single gluteraldehyde-treated autologous pericardial patch (standard method) was reconstructed as monocusp. In Group 2, (n = 16) Nunn's bileaflet pulmonary valve reconstruction technique was used with pericardial patch. In Group 3, (n = 19), Nunn's bileaflet technique was performed with expanded polytetrafluoroethylene membrane. The outcomes of the patients and early and midterm competency of the pulmonary valves were analyzed.

RESULTS

These techniques were significantly effective in early postoperative period. Freedom from moderate to severe PI were 73.3%; 100% and 89.4%, respectively. Mortality, duration of intensive care unit and hospital stay were similar between the groups. The mean follow-up period was 17.5 ± 13.0 (3-57) months. Freedom from moderate to severe PI decreased to 40%; 81.2% and 73.7%, respectively at the end of the follow-up period. Presence of moderate to severe PI was significantly higher in Group 1 (p = .018 between Groups 1 and 2, p = .048 between Groups 1 and 3).

CONCLUSION

All three pulmonary valve reconstruction techniques provided competent pulmonary valves. Nunn's bileaflet technique had better outcome at midterm. It has a potential to delay right ventricular dysfunction at long-term.

Short-term clinical and echocardiographic outcomes after use of polytetrafluoroethylene bicuspid pulmonary valve during the repair of tetralogy of Fallot

Background:

Application of transannular patch (TAP) during the repair of tetralogy of Fallot (TOF) leads to the development of pulmonary regurgitation (PR). This PR is known to cause right ventricular (RV) volume overload and dysfunction which in turn leads to increase in both morbidity and mortality both in immediate and long-term periods. Here, we sought to analyze the effects of polytetrafluoroethylene (PTFE) pulmonary bicuspid valve on the early outcome of patients with TOF repair where TAP is needed.

Subjects and Methods:

This is a retroprospective, observational study where PTFE bicuspid pulmonary valve was incorporated in all consecutive patients undergoing repair of TOF involving the application of TAP. Postoperative inhospital course was assessed, and patients were followed till 6 months for the status of PR and peak RV outflow tract (RVOT) gradient.

Results:

38 patients were enrolled in the study. The mean age of participants was 53.66 ± 78.67 months. Extubation in operating room was done in 31 (81.58%) patients. Duration of ventilator support was 10.48 ± 24.22 h, and duration of hospital stay was 7.95 ± 3.08 days. These data were compared with three recent studies where only TAP was applied. Extubation in operating room, mechanical ventilation time, and hospital stay were significantly improved in the present study. Out of 37 live patients, four (10.81%) patients had no PR, 28 (75%) had mild, 1 (2.7) had moderate, and 4 (10.81%) had severe PR. Average RVOT peak gradient was 18.8 ± 8.1 mmHg.

Conclusion:

Incorporation of PTFE bicuspid pulmonary valve during the repair of TOF appears to facilitate early extubation and thus reduces ventilator-associated comorbidities. Study needs further long-term follow-up to look for behavior of PTFE bicuspid valve.

Hand-sewn trileaflet valve in the right ventricular outflow tract

A 4-year-old girl with pulmonary regurgitation after complete repair of tetralogy of Fallot, underwent an alternative surgical repair for pulmonary valve replacement. Hand-sewn trileaflet valve reconstruction using expanded polytetrafluoroethylene membrane is a feasible method for pulmonary regurgitation in such a young child in whom a large-sized bioprosthetic valve cannot be implanted.

Right ventricular outflow tract obstruction: a quest for ideal management

Management of right ventricular outflow tract obstruction has undergone much change over the last century. Techniques described in the literature include anatomical repairs and the use of various patches, conduits, and innovative grafts. However, many of these approaches require reoperations or catheter-based interventions, leading to increased morbidity, mortality, and cost. The search for the ideal long-lasting conduit continues and there are new techniques on the horizon, using genetic engineering and nanotechnology. This review discusses the evolution of various techniques for repair of right ventricular outflow tract obstruction, past and current conduits, as well as ongoing research.

Pulmonary valve cusp augmentation for pulmonary regurgitation after percutaneous balloon pulmonary valvuloplasty of valvular pulmonary stenosis

Pulmonary valvular stenosis is a relatively common disorder, accounting for approximately 10% of all CHDs. Pulmonic valvular disease can get clinically detected at different ages of life. The more severe the obstruction, the earlier detected the valvular abnormality. Surgical pulmonary valvotomy has been available as a treatment since 1956. This article is about a case of pulmonary annular and valvular stenosis in a 1-year-old child, and it also explores surgical operation of this condition. Transannular patches are usually used within the 1st year of age in pulmonary annular and valvular stenosis. In recent years, anterior leaflet augmentation has been preferred for annulus enlargements. In our 1-year-old case, we expanded the annulus by the anterior leaflet expansion technique and we also augmented other leaflets by polytetrafluoroethylene patch.

Functional near-tricuspid atresia in a patient with absent pulmonary valve and an intact ventricular septum

Absent pulmonary valve with an intact ventricular septum is a rare malformation. We report a case of absent pulmonary valve and intact ventricular septum with functional near-tricuspid atresia caused by pulmonary regurgitation. Initial palliation with main pulmonary artery ligation and bilateral pulmonary artery banding was performed at 1 day of age. More antegrade flow across the tricuspid valve was recognised postoperatively, resulting in a successful right ventricular outflow tract reconstruction by a hand-sewn bileaflet polytetrafluoroethylene valve and modified Blalock-Taussig shunt at 11 days of age.

Multimodality Imaging Assessment of Prosthetic Heart Valves

Echocardiography and fluoroscopy are the main techniques for prosthetic heart valve (PHV) evaluation, but because of specific limitations they may not identify the morphological substrate or the extent of PHV pathology. Cardiac computed tomography (CT) and magnetic resonance imaging (MRI) have emerged as new potential imaging modalities for valve prostheses. We present an overview of the possibilities and pitfalls of CT and MRI for PHV assessment based on a systematic literature review of all experimental and patient studies. For this, a comprehensive systematic search was performed in PubMed and Embase on March 24, 2015, containing CT/MRI and PHV synonyms. Our final selection yielded 82 articles on surgical valves. CT allowed adequate assessment of most modern PHVs and complemented echocardiography in detecting the obstruction cause (pannus or thrombus), bioprosthesis calcifications, and endocarditis extent (valve dehiscence and pseudoaneurysms). No clear advantage over echocardiography was found for the detection of vegetations or periprosthetic regurgitation. Whereas MRI metal artifacts may preclude direct prosthesis analysis, MRI provided information on PHV-related flow patterns and velocities. MRI demonstrated abnormal asymmetrical flow patterns in PHV obstruction and allowed prosthetic regurgitation assessment. Hence, CT shows great clinical relevance as a complementary imaging tool for the diagnostic work-up of patients with suspected PHV obstruction and endocarditis. MRI shows potential for functional PHV assessment although more studies are required to provide diagnostic reference values to allow discrimination of normal from pathological conditions.

Safe surgical strategy for extracardiac conduit replacement in common arterial trunk

Repair of common arterial trunk using an extracardiac right ventricular to pulmonary arterial conduit is the preferred method in most cardiac surgical centres. Reoperation is a fact of life for survivors of common arterial trunk and related cardiac lesions who have undergone such repairs. Long-term survivors may require periodic conduit revisions, with a potentially escalating technical difficulty and risk. Herein we present an analysis of the currently available choices for extracardiac conduits, and outline what we consider to be a safe and reliable surgical strategy for conduit revision.

Perioperative care of children with tetralogy of fallot

OPINION STATEMENT

Complete surgical repair of tetralogy of Fallot (TOF) around 3 months of age is the commonly undertaken management strategy in many centers and has excellent outcomes. Intervention at an earlier age, including the newborn period, may be required for children with symptoms. Early extubation from mechanical ventilation where possible may help improve outcomes for children undergoing complete repair of TOF.

Use of a pulmonary neovalve with a transannular patch for repair of tetralogy of fallot

INTRODUCTION AND OBJECTIVES

To report on our initial experience with the implantation of a pulmonary valve using Nunn's technique in association with a transannular patch for the complete repair of the tetralogy of Fallot.

METHODS

In total, 21 patients were treated between September 2008 and February 2010. Their ages ranged from 7 months to 15 years (median 12 months) and weights from 6.8 kg to 44 kg (median 10 kg). Four patients had previously undergone palliative shunt placement; in two, it was associated with the diagnosis of a complete atrioventricular septal defect. Use of the transannular patch (treated autologous pericardium) was preceded by implantation of a 0.1-mm polytetrafluoroethylene (PTFE) monocusp valve using posterior fixation. Intraoperative transesophageal echocardiography and pressure gradient measurement were carried out, and echocardiography was repeated before discharge.

RESULTS

No deaths were recorded. One patient had a residual ventricular septal defect that required reintervention. Echocardiography showed that the maximum gradient across the PTFE valve was 25 mmHg. Regurgitation was mild in 19 cases and moderate in 2 (the first and second in the series).

CONCLUSIONS

Initial results using a transannular patch with a modified monocusp valve to repair the outflow tract in the tetralogy of Fallot were promising: there was only a slight pressure gradient and mild regurgitation. A medium-or long-term follow-up study is required to confirm these findings and to compare them with results obtained using other techniques.

Reconstruction of trileaflet pulmonary valve using autologous pericardium

Tetralogy of Fallot with atretic or absent pulmonary valve may require pulmonary valve replacement or reconstruction. We propose a technique of reconstruction of a trileaflet valve at the level of the pulmonary annulus using untreated autologous pericardium. Six cases operated upon, using this technique, had trivial pulmonary regurgitation with a median gradient of 24 mmHg (18-38) across the newly created valve. This approach can be considered in cases with limited availability of more suitable alternatives.

Pulmonary homograft monocusp reconstruction of the right ventricular outflow tract: outcomes to the intermediate term

BACKGROUND

There is limited information on longer-term outcomes of pulmonary homograft monocusp (PHM) reconstruction of the right ventricular outflow tract (RVOT).

METHODS

A retrospective review of 131 consecutive patients undergoing RVOT reconstruction with PHM was completed.

RESULTS

Median age was 7.6 months (range, 1 day to 14 years) and weight was 7.3 kg (range, 2 to 65 kg). Most patients (108 of 131; 82%) underwent repair for Tetralogy. After PHM, median duration of mechanical ventilation was 1 day (range, 0 to 89) and hospital stay was 6.5 days (range, 2 to 137). Hospital mortality was 2% (3 of 131) with 1 patient undergoing early replacement of PHM. Echocardiogram at hospital discharge demonstrated peak RVOT gradient of 16 mm Hg (range, 4 to 64 mm Hg); and pulmonary insufficiency was absent/trivial in 40%, mild in 42%, moderate in 16%, and severe in 2%. Follow-up is completed in 91% of hospital survivors at a median of 5 years (range, 1 to 12). There were 5 late deaths, with an actuarial survival of 96% +/- 3.7%, 94% +/- 4.6%, and 89% +/- 9.2% at 1 year, 5 years, and 10 years, respectively. There were 24 reinterventions, including 10 pulmonary valve replacements. Median time to valve replacement was 1.9 years (range, 0.4 to 4.6). Actuarial freedom from pulmonary valve replacement was 97% +/- 3.0%, 90% +/- 6.1%, and 85% +/- 10.3% at 1 year, 5 years, and 10 years, respectively. Echocardiogram at last follow-up demonstrated no increase in RVOT gradient compared with hospital discharge (16 mm Hg), but there was significant increase in pulmonary insufficiency (mild 27%, moderate 39%, severe 34%).

CONCLUSIONS

Pulmonary homograft monocusp reconstruction is an alternative strategy for RVOT reconstruction and provides early but gradually diminishing protection against pulmonary insufficiency without a risk of stenosis. As expected, PHM function decreases over time as the RVOT grows and the homograft tissue undergoes structural deterioration.