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

Fate of the Right Ventricular Outflow Tract Following Valve-Sparing Repair of Tetralogy of Fallot

Valve-sparing repair (VSR) of tetralogy of Fallot (TOF) tends to result in higher residual right ventricular outflow tract (RVOT) gradients. We evaluated the progression and clinical implications of RVOT gradients following VSR of TOF. Demographic, clinical, and operative data were retrospectively collected from consecutive TOF patients who underwent VSR at our institution between 01/2010 and 06/2021. RVOT gradient, pulmonary valve annulus (PVA) diameter and Boston Z-scores were recorded from serial echocardiograms. Data are presented as median and interquartile range or number and percentage. A total of 156 children (boys 92, 59%) underwent VSR at 6.5 (4.9-8.4) months of age and 6.6 kg (5.6- 7.7) weight. There was 1 (0.6%) operative mortality. The remaining 155 patients were followed for 69.4 months (4-106.2). RVOT gradient was 2.4m/s (1.7-2.9) at discharge. It transiently increased, then declined and stabilized during follow-up. PVA Z-score was -1.7 (-3.1 to 0.5) at discharge and 'grew' to -0.8 (-1.7 to 0.4) at last follow-up. Freedom from RVOT re-intervention was 97%, 94% and 91% at 1, 5 and 10-year follow-up. Among 67 (43%) patients with PVA Z-score < -2, a similar RVOT gradient pattern was observed and freedom from RVOT re-intervention was 97%, 95% and 95% at 1, 5 and 8-year follow-up. Following VSR of TOF, RVOT gradients transiently increase and then fall as PVA growth catches up, resulting in durable intermediate outcomes. Patients with PVA Z-score < -2 demonstrated a similar pattern of hemodynamics in the RVOT and excellent freedom from reintervention.

An In Vitro Circulatory Loop Model of the Pediatric Right Ventricular Outflow Tract as a Platform for Valve Evaluation

PURPOSE

Tetralogy of Fallot and other conditions affecting the right ventricular outflow tract (RVOT) are common in pediatric patients, but there is a lack of quantitative comparison among techniques for repairing or replacing the pulmonary valve. The aim of this study was to develop a robust in vitro system for quantifying flow conditions after various RVOT interventions.

METHODS

An infant-sized mock circulatory loop that includes a 3D-printed RVOT anatomical model was developed to evaluate flow conditions after different simulated surgical repairs. Physiologically correct flow and pressure were achieved with custom compliant tubing and a tunable flow restrictor. Pressure gradient, flow regurgitation, and coaptation height were measured for two monocusp leaflet designs after tuning the system with a 12 mm Hancock valved conduit.

RESULTS

Measurements were repeatable across multiple samples of two different monocusp designs, with the wider leaflet in the 50% backwall model consistently exhibiting lower pressure gradient but higher regurgitation compared to the leaflet in the 40% backwall model. Coaptation height was measured via direct visualization with endoscopic cameras, revealing a shorter area of contact for the wider leaflet (3.3-4.0 mm) compared to the narrower one (4.3 mm).

CONCLUSION

The 3D-printed RVOT anatomical model and in vitro pulmonary circulatory loop developed in this work provide a platform for planning and evaluating surgical interventions in the pediatric population. Measurements of regurgitation, pressure gradient, and coaptation provide a quantitative basis for comparison among different valve designs and positions.

Clinical Application of Individualized Pulmonary Bi-Orifice for the Reconstruction of Right Ventricular Outflow Tract in Tetralogy of Fallot

Objective: The study aims to establish a new method in the Tetralogy of Fallot (ToF) called the pulmonary valve bi-orifice method (pulmonary annular sparing with an individualized autologous pericardial patch; thus, two orifices are formed at the level of the pulmonary valve annulus) to reconstruct the right ventricular outflow tract (RVOT).

Methods: A retrospective analysis of 128 TOF patients from October 2009 to June 2018 with severe pulmonary valve dysplasia who underwent transvalvular annular patch (TAP) procedure (control group) or an individualized pulmonary valve bi-orifice procedure (observation group) were studied. The RVOT for each patient in the observation group was individually reconstructed per the patient's weight and the size of the autologous pulmonary valve using the bi-orifice method; however, increasing the cross-sectional area of the pulmonary valve annulus without destroying its integrity. The result was then compared to the control group, where TAP procedures were applied to evaluate the short to mid-term outcome(s). An in vitro simulation test was used to verify the anti-regurgitation mechanism of the new method.

Results: The in vitro simulation test indicated that the anti-regurgitation mechanism was completed by the pericardial patch and the autologous pulmonary valve movement toward each other. Thus, for clinical applications, patients in both groups were compared. The results showed no significant differences in cardiopulmonary bypass and aortic cross-clamp time, mechanical ventilation, and ICU and post-operative residence between the two groups.

During the follow-up period (3- to 12-years), 14 patients in the observation group had mild regurgitation after surgery (22.2%), while 10 patients had moderate pulmonary regurgitation (15.8%) with no right ventricular (RV) dilation. On the other hand, 22 patients (39.6%) had moderate to severe regurgitation in the control group, while left pulmonary artery stenosis occurred in one patient. In the control group, six patients (9.2%) with severe RV dilation were reoperated.

Conclusion: Individualized pulmonary valve bi-orifice procedure is a safe and excellent method for reconstructing RVOT in ToF.

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.

Pulmonary valve reconstruction by allograft replacement of underdeveloped anterior leaflet in case of late combined pulmonary restenosis after early primary repair

Introduction

The native pulmonary valve (PV) reconstruction is an attractive alternative to a replacement but is challenging due to the systematic underdevelopment of the valve structures in congenital heart diseases. The partial replacement of underdeveloped parts of the valve and saving of well-developed may have advantages versus replacing the whole valve in terms of durability and patient outgrowth of the prosthesis.

Case presentation

This report describes a case of the PV reconstruction by allograft replacement of an underdeveloped anterior leaflet in an adolescent patient who previously corrected pulmonary stenosis during the first year of her life. The normal anatomy of the right and left leaflets was revealed. The rudimental anterior leaflet determined the annular restenosis. The monocusp with the related supporting aortic wall was sewn instead of the anterior leaflet. The Z-score of the pulmonary annulus changed from minus 3, 9 before to +0.8 after the procedure. The excellent function of the PV was observed in 1-year follow-up.

Discussion

Valve deterioration over time will have a less negative impact on the function when it occurs in a limited area. The annular dilatation becomes unlikely if the annulus predominantly consists of natural tissues. The procedural effectiveness allows the transcatheter valve-in-valve therapy in case of late dysfunction. The expected feature of the procedure described is that the growth of the PV remains possible.

Conclusion

If allograft replacement of the PV is scheduled and allograft is available, the partial replacement may be superior to replacement of the whole valve in terms of durability and patient outgrowth of the prosthesis.

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A pulmonary valve (PV) repair is an attractive surgical option because an ideal replacement device is still not developed.

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A PV repair is a challenge due to the systematic underdevelopment of the valve structures in congenital heart diseases.

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The partial replacement of the PV structures may be more beneficial in terms of durability vs whole valve replacement.

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The PV leaflets at the primary operation should be saved and handled carefully. They may used for valve repair in the future.

Pulmonary Valve Reconstruction Using the Ozaki Leaflet Reconstructive Techniques

The aortic valve neocuspidization, or Ozaki procedure, has been shown to be technically reproducible and have acceptable results in the aortic position in adult and pediatric patients. We report a case in which innovative techniques were utilized to create a three-leaflet pulmonary valve using a modified aortic valve neocuspidization technique.

Surgical outcome after complete repair of tetralogy of Fallot with absent pulmonary valve: comparison between bovine jugular vein-valved conduit and monocusp-valve patch

BACKGROUND

The prognosis of tetralogy of Fallot with absent pulmonary valve (TOF/APV) without operation is poor. We evaluated the surgical outcome of TOF/APV in a single center.

METHODS

Twenty-two TOF/APV patients underwent complete surgical correction in our hospital. Right ventricular outflow tract reconstruction was performed using bovine jugular vein (BJV)-valved conduit implantation (n = 10), homograft-valved conduit implantation (n = 2), or monocusp-valve patch (n = 10). Health-related quality of life (QOL) was evaluated during follow-up.

RESULTS

The overall survival at 5 and 10 years was 86.4 ± 7.3% (confidence interval 69.4-97.2%). The survival rates were significantly different between patients with and without bronchial stenosis (40 and 100%, P = 0.0003, log-rank test). The survival of patients aged > 6 months was higher than those ≤ 6 months (100 vs. 40%, P = 0.0003, log-rank test). Patients with BJV-valved conduits had higher systolic gradients from the right ventricle to the pulmonary artery (RV-PA) compared to those with monocusp-valve patches. BJV-valved conduit implantation was a risk factor for post-operative pulmonary-valve stenosis. The QOL score for patients with BJV-valved conduits was lower than those with monocusp-valve patches (P < 0.05). No reoperation was performed during follow-up.

CONCLUSIONS

Bronchial stenosis and lower age (≤ 6 months) were the main factors influencing post-operative survival. The use of a BJV-valved conduit was a main reason for RV-PA restenosis; thus, the use of a BJV-valved conduit may increase the need for repeat intervention and decrease the post-operative quality of life.

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.

Aiming to Preserve Pulmonary Valve Function in Tetralogy of Fallot Repair: Comparing a New Approach to Traditional Management

Pulmonary valve (PV) incompetence following transannular patch (TAP) repair of tetralogy of Fallot (TOF) results in long-term morbidity and mortality. Valve-sparing repairs have recently gained recognition; however, they may be associated with residual pulmonary stenosis (PS) in patients with small PV z scores. We sought to determine whether a repair that increases the PV annulus and augments the valve leaflet with a biomaterial would result in annular growth and in longer duration of valve competence compared with TAP. Eighty patients (median age 136 days, range 4-350) who underwent surgical repair of TOF between 2010 and 2014 were included in the study. Patients were divided into three groups based on the PV intervention: balloon dilation/valvotomy (n = 29), valve-sparing transannular repair (VSTAR) (n = 19) and TAP (n = 32). Intraoperative, early postoperative and midterm follow-up echocardiographic data (median 19 months, range 1-59) were obtained. The primary outcomes were the presence and severity of pulmonary regurgitation and/or PS. Compared with TAP, VSTAR patients demonstrated significantly less severe PR with 100 % freedom of severe PR immediately post-op (vs. 0 % in TAP), 60 % at 6 months and 20 % at 20 months. There were no differences in PS between VSTAR and TAP at follow-up. A subgroup analysis of the VSTAR group was performed. PV z scores were calculated and fit to a random effects model. Patient data fit the model closely, predicting a reproducible increase in valve annulus size over time. With better short-term and comparable midterm results, VSTAR may be appropriate for TOF repair in patients with small PV that would conventionally require a TAP.

"V-PLASTY": a novel technique to reconstruct pulmonary valvular and annular stenosis in patients with right ventricular outflow tract obstruction

BACKGROUND

The goal of repair of right ventricular outflow tract obstruction with or without Tetralogy of Fallot (TOF) is to eliminate valvular and/or subvalvular obstruction. However, this operation has a high risk of late complication of pulmonary insufficiency. In this study, we aimed to present early period results of our new technique that we call "V-Plasty" developed to prevent pulmonary insufficiency after pulmonary valve reconstruction in selected patients.

METHODS

Between January 2006 and January 2010, we performed V-plasty for pulmonary valve reconstruction in 10 patients. Eight patients (5 males, 3 females) had TOF and 2 patients (1 male, 1 female) had atrial septal defect concomitant with pulmonary valve stenosis. Patient selection for V-plasty reconstruction was made due to the pulmonary valve anatomy and degree of stenosis. The mean follow-up time was 55.7 ± 16.2 months (ranging from 32 to 80 months).

RESULTS

Functional capacity of the patients improved immediately after the surgery. There were no mortality and re-operation in follow-up period. Patients were followed up with echocardiography one week after the operation, at 1st, 6th, 12th months and annually. There was no pulmonary insufficiency.

CONCLUSIONS

Operative correction of the pulmonary outflow tract obstruction with or without TOF, frequently requires transannular enlargement because of the infundibular and/or annular-valvular obstruction. This conventional technique is usually a reason for late pulmonary insufficiency. In our study, we have not seen pulmonary insufficiency in early term follow-up period. Our early term results are encouraging, but long term follow-up results are needed with large case series.

Repair and follow-up of Tetralogy of Fallot with pulmonary stenosis

Tetralogy of Fallot is the most common cyanotic congenital heart defect. Advances in surgical technique and postoperative care have improved survival which is now very good. Patients now face long-term morbidities such as reduced exercise tolerance and arrthymias. Cardiologists caring for these patients are confronted with decisions regarding best care practices. This article will review the evidence available on repair and postoperative follow-up for patients with Tetralogy of Fallot with pulmonary stenosis.

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.