The Medtronic Melody® transcatheter pulmonary valve implanted at 24-mm diameter--it works

Transcatheter Pulmonary Valve in Congenital Heart Disease

Over the last 2 decades, experience with transcatheter pulmonary valve replacement (TPVR) has grown significantly and has become an effective and reliable way of treating pulmonary valve regurgitation, right ventricular outflow (RVOT) obstruction, and dysfunctional bioprosthetic valves and conduits. With the introduction of self-expanding valves and prestents, dilated native RVOT can be addressed with the transcatheter approach. In this article, the authors review the current practices, technical challenges, and outcomes of TPVR.

Transcatheter-Based Interventions for Tetralogy of Fallot Across All Age Groups

Tetralogy of Fallot (TOF) is the most common form of cyanotic congenital heart disease. Palliative procedures, either surgical or transcatheter, aim to improve oxygen saturation, affording definitive procedures at a later stage. Transcatheter interventions have been used before and after surgical palliative or definitive repair in children and adults. This review aims to provide an overview of the different catheter-based interventions for TOF across all age groups, with an emphasis on palliative interventions, such as patent arterial duct stenting, right ventricular outflow tract stenting, or balloon pulmonary valvuloplasty in infants and children and transcatheter pulmonary valve replacement in adults with repaired TOF, including the available options for a large, dilated native right ventricular outflow tract.

Catheter-based Interventions in Tetralogy of Fallot Across the Lifespan

Surgical treatment of tetralogy of Fallot (TOF) involves surgical relief of right ventricular outflow tract (RVOT) obstruction and closure of ventricular septal defect. However, some patients may require staged palliation before surgical repair. This traditionally was achieved only with surgery but recently evolved to include catheter-based techniques. RVOT dysfunction occurs inevitably after the surgical repair of TOF and, depending on the surgical approach, manifests as either progressive stenosis, regurgitation, or a combination of both. This predisposes the individual to repeated RVOT interventions with the attendant risks of multiple open-heart surgeries. The advent of transcatheter pulmonary valve replacement has reduced the operative burden, and the expansion of transcatheter pulmonary valve replacement device platforms has widened the type and size of RVOT anatomies that can be treated. This review will discuss the transcatheter therapies available throughout the lifespan of the patient with TOF.

Transcatheter Pulmonary Valve Replacement: A Review of Current Valve Technologies

Transcatheter pulmonary valve replacement was first performed by Dr Philip Bonhoeffer, who implanted a Medtronic Melody valve in a human in 2000. Over the past 2 decades, there have been many advances in transcatheter pulmonary valve technology. This includes the use of the SAPIEN transcatheter heart valve in the pulmonary position, modifications and refinements to valve implantation procedures, and development of self-expanding valves and prestents to treat large diameter native or patched right ventricular outflow tracts. This article reviews the current transcatheter pulmonary valve technologies with a focus on valve design, screening process, implant procedure, and clinical outcomes.

Transcatheter pulmonic valve implantation: Techniques, current roles, and future implications

Right ventricular outflow tract (RVOT) obstruction is present in a variety of congenital heart disease states including tetralogy of Fallot, pulmonary atresia/stenosis and other conotruncal abnormalities etc. After surgical repair, these patients develop RVOT residual abnormalities of pulmonic stenosis and/or insufficiency of their native outflow tract or right ventricle to pulmonary artery conduit. There are also sequelae of other surgeries like the Ross operation for aortic valve disease that lead to right ventricle to pulmonary artery conduit dysfunction. Surgical pulmonic valve replacement (SPVR) has been the mainstay for these patients and is considered standard of care. Transcatheter pulmonic valve implantation (TPVI) was first reported in 2000 and has made strides as a comparable alternative to SPVR, being approved in the United States in 2010. We provide a comprehensive review in this space–indications for TPVI, detailed procedural facets and up-to-date review of the literature regarding outcomes of TPVI. TPVI has been shown to have favorable medium-term outcomes free of re-interventions especially after the adoption of the practice of pre-stenting the RVOT. Procedural mortality and complications are uncommon. With more experience, recognition of risk of dreaded outcomes like coronary compression has improved. Also, conduit rupture is increasingly being managed with transcatheter tools. Questions over endocarditis risk still prevail in the TPVI population. Head-to-head comparisons to SPVR are still limited but available data suggests equivalence. We also discuss newer valve technologies that have limited data currently and may have more applicability for treatment of native dysfunctional RVOT substrates.

Procedural technique for hybrid pulmonary valve replacement in infants and small children

OBJECTIVES

Hybrid approach to pulmonary valve replacement (PVR) in the paediatric population has been reported, although data in infants and small children are limited. Several strategies are now possible. The aim of this study is to review our hybrid PVR strategy in a complex patient cohort, outlining a variety of approaches employed in our centre.

METHODS

We performed a retrospective review of infants and small children who underwent hybrid PVR between May 2017 and April 2019 in a single tertiary cardiology centre. Medical records were reviewed to ascertain demographic, clinical and outcome data.

RESULTS

Ten patients with a median (interquartile range) age of 1.5 years (1.1-1.9) and weight of 8.8 kg (8-10.6) were managed with hybrid pulmonary valve insertion. Eight patients had perventricular approach (4 sternotomy and 4 subxiphoid) and 2 patients had surgically sutured valve. Six patients underwent cardiopulmonary bypass for associated lesions. Three had insertion of the valve into conduits and 7 were deployed into native right ventricular outflow tracts. The pulmonary valve was successfully inserted in all 10 patients with no mortality. Postprocedural complications included paravalvar leak in 2 patients, suspected endocarditis in 1 patient who developed early valve regurgitation and wound infection in 1 patient.

CONCLUSIONS

Several approaches to hybrid PVR may be employed in small children with a high success rate. Follow-up studies are required to evaluate longer term durability of these approaches compared to standard surgical replacement.

The Real Need for Regenerative Medicine in the Future of Congenital Heart Disease Treatment

Bioabsorbable materials made from polymeric compounds have been used in many fields of regenerative medicine to promote tissue regeneration. These materials replace autologous tissue and, due to their growth potential, make excellent substitutes for cardiovascular applications in the treatment of congenital heart disease. However, there remains a sizable gap between their theoretical advantages and actual clinical application within pediatric cardiovascular surgery. This review will focus on four areas of regenerative medicine in which bioabsorbable materials have the potential to alleviate the burden where current treatment options have been unable to within the field of pediatric cardiovascular surgery. These four areas include tissue-engineered pulmonary valves, tissue-engineered patches, regenerative medicine options for treatment of pulmonary vein stenosis and tissue-engineered vascular grafts. We will discuss the research and development of biocompatible materials reported to date, the evaluation of materials in vitro, and the results of studies that have progressed to clinical trials.

Morphological changes and number of candidates for transcatheter pulmonary valve implantation in conduits involving heterograft and artificial material

Heterograft and artificial materials have been used for extracardiac conduit implantation to create right ventricular (RV) to pulmonary artery (PA) continuity for biventricular repair in Japan because of the limited availability of homograft valves. However, few studies have examined morphological changes and number of candidates for transcatheter pulmonary valve implantation (TPVI) in which the conduit includes more than one type of material. Overall, 88 patients who underwent biventricular repair with an external conduit were included in this evaluation. Based on catheterization data and surgical records, we estimated morphological change in the RV outflow tract for each material and the number of candidates for Melody valve implantation based on premarket approval application criteria established by the U.S. Food and Drug Administration. There were 63 candidates for TPVI (72%, 63/88). Median anteroposterior and lateral diameter of the RV outflow tract was 20.4 mm (range 9.0-41.5) and 17.8 mm (range 9.5-34.9), respectively. Bovine pericardium tended to dilate by 11.2%. Polytetrafluoroethylene (ePTFE), homograft, and Dacron polyethylene terephthalate (PET) tended to become stenotic by 11.1%, 28.0%, and 13.4%, respectively. While ePTFE (27/33, 82%) and Dacron PET (2/2, 100%) were highly suitable for TPVI, bovine pericardium (32/48, 67%) was less suitable. In Japan, many patients with hemodynamic indications for TPVI following extracardiac conduit implantation to create RV to PA continuity may also meet the morphological indications.

Endocarditis After Transcatheter Pulmonary Valve Replacement

BACKGROUND

Endocarditis has emerged as one of the most concerning adverse outcomes in patients with congenital anomalies involving the right ventricular outflow tract (RVOT) and prosthetic valves.

OBJECTIVES

The aim of this study was to evaluate rates and potential risk factors for endocarditis after transcatheter pulmonary valve replacement in the prospective Melody valve trials.

METHODS

All patients in whom a transcatheter pulmonary valve (TPV) was implanted in the RVOT as part of 3 prospective multicenter studies comprised the analytic cohort. The diagnosis of endocarditis and involvement of the TPV were determined by the implanting investigator.

RESULTS

A total of 309 patients underwent transcatheter pulmonary valve replacement (TPVR) and were discharged with a valve in place. The median follow-up duration was 5.1 years, and total observation until study exit was 1,660.3 patient-years. Endocarditis was diagnosed in 46 patients (median 3.1 years after TPVR), and a total of 35 patients were reported to have TPV-related endocarditis (34 at the initial diagnosis, 1 with a second episode). The annualized incidence rate of endocarditis was 3.1% per patient-year and of TPV-related endocarditis was 2.4% per patient-year. At 5 years post-TPVR, freedom from a diagnosis of endocarditis was 89% and freedom from TPV-related endocarditis was 92%. By multivariable analysis, age ≤12 years at implant (hazard ratio: 2.3; 95% confidence interval: 1.2 to 4.4; p = 0.011) and immediate post-implant peak gradient ≥15 mm Hg (2.7; 95% confidence interval: 1.4 to 4.9; p = 0.002) were associated with development of endocarditis and with development of TPV-related endocarditis (age ≤12 years: 2.8; 95% confidence interval: 1.3 to 5.7; p = 0.006; gradient ≥15 mm Hg: 2.6; 95% confidence interval: 1.3 to 5.2; p = 0.008).

CONCLUSIONS

Endocarditis is an important adverse outcome following TVPR in children and adults with post-operative congenital heart disease involving the RVOT. Ongoing efforts to understand, prevent, and optimize management of this complication are paramount in making the best use of TPV therapy. (Melody Transcatheter Pulmonary Valve [TPV] Study: Post Approval Study of the Original Investigational Device Exemption [IDE] Cohort; NCT00740870; Melody Transcatheter Pulmonary Valve Post-Approval Study; NCT01186692; and Melody Transcatheter Pulmonary Valve [TPV] Post-Market Surveillance Study; NCT00688571).

Pulmonary Valve Replacement for Tetralogy of Fallot

Right ventricular outflow tract (RVOT) dysfunction is common following surgical repair of tetralogy of Fallot and other forms of complex congenital heart disease. This results in pulmonary stenosis or regurgitation and may ultimately lead to RV failure and dysrhythmias. Transcatheter valve technologies are now available to treat certain patients with RVOT dysfunction. Current devices include the Medtronic Melody valve and the Edwards Lifesciences SAPIEN XT. Although these valves are approved for use in dysfunctional circumferential RVOT conduits, they are increasingly being used off label for nonconduit outflow tracts. Procedural complications include but are not limited to conduit rupture and coronary compression. Longer-term complications include stent fracture and endocarditis. Outcomes with these valves have demonstrated durable relief of stenosis and regurgitation. The Medtronic Harmony valve and the Alterra Prestent from Edwards Lifesciences are investigational devices that are intended to treat the patulous RVOT that is too large to accommodate currently available valves. This review will focus on current indications to treat RVOT dysfunction, existing transcatheter valve technologies, and investigational devices undergoing clinical trials. Hopefully, within the not-too-distant future, transcatheter pulmonary valve implantation will be feasible in the vast majority of patients with RVOT dysfunction following surgical repair of congenital heart disease.

Branch Pulmonary Artery Valve Implantation Reduces Pulmonary Regurgitation and Improves Right Ventricular Size/Function in Patients With Large Right Ventricular Outflow Tracts

OBJECTIVES

The authors sought to assess the intermediate-term effects of percutaneous placed valves in the branch pulmonary artery (PA) position.

BACKGROUND

Most patients with large right ventricular outflow tracts (RVOTs) are excluded from available percutaneous pulmonary valve options. In some of these patients, percutaneous branch PA valve implantation may be feasible. The longer-term effects of valves in the branch PA position is unknown.

METHODS

Retrospective data were collected on patients with significant pulmonary regurgitation who had a percutaneous branch PA valve attempted.

RESULTS

Percutaneous branch PA valve implantation was attempted in 34 patients (18 bilateral and 16 unilateral). One-half of the patients were in New York Heart Association (NHYA) functional class III or IV pre-implantation. There were 2 failed attempts and 6 procedural complications. At follow-up, only 1 patient had more than mild valvar regurgitation. The right ventricular end-diastolic volume index decreased from 147 (range: 103 to 478) ml/m² to 101 (range: 76 to 429) ml/m², p < 0.01 (n = 16), and the right ventricular end-systolic volume index decreased from 88.5 (range: 41 to 387) ml/m² to 55.5 (range: 40.2 to 347) ml/m², p < 0.01 (n = 13). There were 5 late deaths. At a median follow-up of 2 years, all other patients were in NYHA functional class I or II.

CONCLUSIONS

Percutaneous branch PA valve implantation results in a reduction in right ventricular volume with clinical benefit in the intermediate term. Until percutaneous valve technology for large RVOTs is refined and more widely available, branch PA valve implantation remains an option for select patients.

Transcatheter Pulmonary Valve Replacement in Congenital Heart Disease

Patients with dysfunctional right ventricular outflow tracks comprise a large portion of patients with severe congenital heart disease. Transcatheter pulmonary valve replacement in patients with dysfunctional right ventricular outflow tracks is feasible, safe, and efficacious. This article reviews current transcatheter valve replacement technology for dysfunctional right ventricular outflow tract and pulmonary valvular disease and its applications to patients with congenital heart disease. Discussed are the approach and preprocedural planning, current options, and applications of transcatheter pulmonary valve therapy. Also considered are future directions in this field as the technologies begin to develop further.

Adult Congenital Interventions in Heart Failure

Congenital heart disease (CHD) is the most common birth defect, occurring in approximately 0.8% to 1.0% of neonates. Advances in medical and surgical therapies for children with CHD have resulted in a growing population of patients reaching adulthood, with survival rates exceeding 85%. Many of these patients, especially if managed inappropriately, face the prospect of future complications including heart failure and premature death. For adults with uncorrected or previously palliated CHD, percutaneous therapies have become the primary treatment for many forms of CHD. In this article, we discuss the role of transcatheter interventions in the treatment of adults with CHD.

Percutaneous pulmonary valve implantation: what have we learned over the years?

Percutaneous pulmonary valve implantation has been widely accepted as an alternative to surgery in selected patients with right ventricular outflow tract (RVOT) dysfunction. This totally new field of our specialty pushed centres to rethink overall strategies on how to treat RVOT dysfunction. In this review, we will focus on challenges related to patient selection, and discuss innovative procedural techniques developed over the years to enlarge the number of candidates for the technique.

Landmark lecture on interventional cardiology: interventional cardiac catheterisation for CHD: the past, present, and the future

CHD affects millions of patients worldwide. Interventional therapies for CHD goes back to the mid-1960s when Bill Rashkind performed balloon atrial septostomy on a cyanotic baby with transposition of the great vessels. This was followed by development of balloon catheters to perform balloon valvuloplasties and angioplasties in the early to late 1980s. Although King and Mills performed the first transcatheter closure of secundum atrial septal defect in the mid-1970s, this procedure was better realised in the mid-1990s. More intracardiac defect closures were performed in the late 1990s and early 2000. This brings us to the current era of percutaneous valve implantation as developed by Bonhoeffer. In this paper, we will discuss the past, present, and future of interventional cardiac catheterisation for CHD patients.

Pulmonic Valve Disease: Review of Pathology and Current Treatment Options

PURPOSE OF REVIEW

Our review is intended to provide readers with an overview of disease processes involving the pulmonic valve, highlighting recent outcome studies and guideline-based recommendations; with focus on the two most common interventions for treating pulmonic valve disease, balloon pulmonary valvuloplasty and pulmonic valve replacement.

RECENT FINDINGS

The main long-term sequelae of balloon pulmonary valvuloplasty, the gold standard treatment for pulmonic stenosis, remain pulmonic regurgitation and valvular restenosis. The balloon:annulus ratio is a major contributor to both, with high ratios resulting in greater degrees of regurgitation, and small ratios increasing risk for restenosis. Recent studies suggest that a ratio of approximately 1.2 may provide the most optimal results. Pulmonic valve replacement is currently the procedure of choice for patients with severe pulmonic regurgitation and hemodynamic sequelae or symptoms, yet it remains uncertain how it impacts long-term survival. Transcatheter pulmonic valve replacement is a rapidly evolving field and recent outcome studies suggest short and mid-term results at least equivalent to surgery. The Melody valve® was FDA approved for failing pulmonary surgical conduits in 2010 and for failing bioprosthetic surgical pulmonic valves in 2017 and has been extensively studied, whereas the Sapien XT valve®, offering larger diameters, was approved for failing pulmonary conduits in 2016 and has been less extensively studied. Patients with pulmonic valve disease deserve lifelong surveillance for complications. Transcatheter pulmonic valve replacement is a novel and attractive therapeutic option, but is currently only FDA approved for patients with failing pulmonary conduits or dysfunctional surgical bioprosthetic valves. New advances will undoubtedly increase the utilization of this rapidly expanding technology.

Patient outcomes after transcatheter and surgical pulmonary valve replacement for pulmonary regurgitation in patients with repaired tetralogy of Fallot: A quasi-meta-analysis

BACKGROUND

Individuals with repaired tetralogy of Fallot develop pulmonary regurgitation that may cause symptoms (dyspnea, chest pain, palpitations, fatigue, presyncope, and syncope), impair functional capacity, and may affect health-related quality of life. Surgical pulmonary valve replacement is the gold standard of treatment although transcatheter pulmonary valve replacement is becoming more common. Patients want to know whether less invasive options are as good.

AIMS

This analysis aimed to examine the differences in surgical versus transcatheter pulmonary valve replacement effects in terms of physiological/biological variables, symptoms, functional status and health-related quality of life.

METHODS

This quasi-meta-analysis included 85 surgical and 47 transcatheter pulmonary valve replacement studies published between 1995-2016.

RESULTS

In terms of physiological/biological variables, both surgical and transcatheter pulmonary valve replacement improved pulmonary regurgitation and systolic and diastolic right ventricular volume indices but not heart function. In the left heart, only surgical pulmonary valve replacement improved heart function. Only transcatheter pulmonary valve replacement improved left ventricular end-diastolic indices and neither improved endsystolic indices. Only surgery has been demonstrated to decrease QRS duration but there is little evidence of arrhythmia reduction. Symptom change is poorly documented. Functional class improves but exercise capacity generally does not. Some aspects of health-related quality of life improve with surgery and in one small transcatheter pulmonary valve replacement study.

CONCLUSION

Transcatheter and surgical pulmonary valve replacement compare favorably for heart remodeling. Exercise capacity does not change with either technique. Health-related quality of life improves after surgical pulmonary valve replacement. There are numerous gaps in documentation of changes in arrhythmias and symptoms.

Hybrid Surgery Options for Complex Clinical Scenarios in Adult Patients with Congenital Heart Disease: Three Case Reports

The strategy for the management of adult patients with congenital heart disease (CHD) often represents a challenge for cardiac surgeons and cardiologists due to complex anatomy, wide range of clinical presentations, and a high-risk profile. However, hybrid approach may represent an attractive solution. We report three cases of adult patients previously operated for CHD and recently treated with a hybrid approach in our institution. Case 1: a 76-year-old woman with permanent atrial fibrillation, lung disease, chronic kidney disease, microcytic anemia, and type II diabetes mellitus, previously operated for atrial septal defect closure and pulmonary valvotomy, presented with severe pulmonary regurgitation and advanced right ventricular failure. In order to minimize the surgical risk, a hybrid approach was used: an extensive right ventricular outflow tract (RVOT) plication was followed by implantation of an Edwards Sapien XT prosthesis in the RVOT through the right ventricular apex, without cardiopulmonary bypass. Case 2: a 64-year-old man with previous atrial septum excision and pericardial baffle for partial anomalous pulmonary venous drainage with intact interatrial septum, presented with worsening dyspnea, right ventricular failure, and pulmonary hypertension caused by baffle stenosis. His comorbidities included coronary artery disease, atrial flutter, and previous left pneumonectomy. After performing a redo longitudinal median sternotomy, a 20-mm stent was implanted in the baffle with access through the superior vena cava. Case 3: a 50-year-old man, with previous atrioventricular septal defect repair, followed by mitral valve replacement with a mechanical prosthesis, subsequently developed a paravalvular leak (PVL) with severe mitral regurgitation and severe left ventricular dysfunction. He underwent a transapical PVL device closure with two Amplatzer Vascular Plugs. In our opinion, hybrid surgery is a promising therapeutic modality that increases the available treatment options for this patient population. A multidisciplinary and patient-tailored approach is crucial in these complex clinical scenarios.

Dysfunctional pulmonary artery conduit and co-existing large pseudoaneurysm: well-suited for a percutaneous approach with the Melody valve?

Pseudoaneurysm formation is a rare but potentially life-threatening complication after surgical repair of congenital heart disease. We present a boy with truncus arteriosus communis 14 years after homograft placement in pulmonary position. On follow-up, he presented progressive chronic homograft degeneration. Moreover, a large pseudoaneurysm in the right ventricular outflow tract was surprisingly depicted. We opted for a two-stage interventional approach.

Therapeutic Utilities of Pediatric Cardiac Catheterization

In an era when less invasive techniques are favored, therapeutic cardiac catheterization constantly evolves and widens its spectrum of usage in the pediatric population. The advent of sophisticated devices and well-designed equipment has made the management of many congenital cardiac lesions more efficient and safer, while providing more comfort to the patient. Nowadays, a large variety of heart diseases are managed with transcatheter techniques, such as patent foramen ovale, atrial and ventricular septal defects, valve stenosis, patent ductus arteriosus, aortic coarctation, pulmonary artery and vein stenosis and arteriovenous malformations. Moreover, hybrid procedures and catheter ablation have opened new paths in the treatment of complex cardiac lesions and arrhythmias, respectively. In this article, the main therapeutic utilities of cardiac catheterization in children are discussed.

Transcatheter Tricuspid Valve-in-Valve Implantation for the Treatment of Dysfunctional Surgical Bioprosthetic Valves

Background—

Off-label use of transcatheter aortic and pulmonary valve prostheses for tricuspid valve-in-valve implantation (TVIV) within dysfunctional surgical tricuspid valve (TV) bioprostheses has been described in small reports.

Methods and Results—

An international, multicenter registry was developed to collect data on TVIV cases. Patient-related factors, procedural details and outcomes, and follow-up data were analyzed. Valve-in-ring or heterotopic TV implantation procedures were not included. Data were collected on 156 patients with bioprosthetic TV dysfunction who underwent catheterization with planned TVIV. The median age was 40 years, and 71% of patients were in New York Heart Association class III or IV. Among 152 patients in whom TVIV was attempted with a Melody (n=94) or Sapien (n=58) valve, implantation was successful in 150, with few serious complications. After TVIV, both the TV inflow gradient and tricuspid regurgitation grade improved significantly. During follow-up (median, 13.3 months), 22 patients died, 5 within 30 days; all 22 patients were in New York Heart Association class III or IV, and 9 were hospitalized before TVIV. There were 10 TV reinterventions, and 3 other patients had significant recurrent TV dysfunction. At follow-up, 77% of patients were in New York Heart Association class I or II ( P <0.001 versus before TVIV). Outcomes did not differ according to surgical valve size or TVIV valve type.

Conclusions—

TVIV with commercially available transcatheter prostheses is technically and clinically successful in patients of various ages across a wide range of valve size. Although preimplantation clinical status was associated with outcome, many patients in New York Heart Association class III or IV at baseline improved. TVIV should be considered a viable option for treatment of failing TV bioprostheses.

The Utility of Intracardiac Echocardiography Following Melody™ Transcatheter Pulmonary Valve Implantation

The aim of this study was to determine the utility of intracardiac echocardiography (ICE) in assessing Melody™ transcatheter pulmonary valve (TPV) function immediately following valve implantation. ICE is used increasingly in percutaneous cardiac interventions. At our center, ICE is routinely utilized to evaluate valve function following Melody TPV implantation, but the utility of this practice remains unclear. A retrospective review of all Melody valves placed in the right ventricular outflow tract from April 2010 to September 2013 was performed. The clinical utility of ICE was described, along with the relationship between ICE data and traditional hemodynamic/angiographic data. ICE was performed in 54 cases and provided excellent Melody TPV visualization with no complications. ICE did not change clinical management but did provide supplemental information in two cases. In one case, angiography showed severe catheter-related Melody insufficiency. Subsequent ICE confirmed no insufficiency and prevented the need for additional angiography. In the second case, ICE allowed characterization of the mechanism of a residual gradient. ICE did not detect any clinically significant paravalvar leaks or valvar insufficiency not seen by angiography. The peak catheterization gradient was more closely approximated by the mean ICE gradient (median difference -7.4 % between measurements) than by the peak ICE gradient (median difference 58.3 %; p < 0.0001). ICE provides excellent and safe visualization following Melody TPV implantation but did not provide new clinical information impacting management in this series. Selective use of ICE in cases with more than expected valve insufficiency or larger than expected residual gradients may streamline use while maintaining optimal clinical outcomes.

Recent Development in Pulmonary Valve Replacement after Tetralogy of Fallot Repair: The Emergence of Hybrid Approaches

An increasing number of patients with tetralogy of Fallot require repeat surgical intervention for pulmonary valve replacement secondary to pulmonary regurgitation. Catheter-based interventions have emerged as an attractive alternative to surgery in this patient population but it is limited by patient size or the anatomy of the right ventricular outflow tract. Hybrid approaches involving both cardiac interventionists and surgeons are being developed to overcome these limitations. The purpose of this review is to highlight the recent advances in the hybrid field of pulmonary valve replacement, summarizing the advantages and disadvantages of the “traditional” surgical and the new catheter-based techniques and discuss the direction future research should take to determine the optimal management for individual patients.

Percutaneous pulmonary valve placement

Patients with congenital heart disease and pulmonary valve disease need multiple procedures over their lifetimes to replace their pulmonary valves. Chronic pulmonary stenosis, regurgitation, or both have untoward effects on ventricular function and on the clinical status of these patients. To date, all right ventricle-pulmonary artery conduits have had relatively short lifespans. Percutaneous pulmonary valve implantation, although relatively new, will probably reduce the number of operative procedures that these patients will have to undergo over a lifetime. Refinement and further development of this procedure holds promise for the extension of this technology to other patient populations.

Percutaneous pulmonary and tricuspid valve implantations: An update

The field of percutaneous valvular interventions is one of the most exciting and rapidly developing within interventional cardiology. Percutaneous procedures focusing on aortic and mitral valve replacement or interventional treatment as well as techniques of percutaneous pulmonary valve implantation have already reached worldwide clinical acceptance and routine interventional procedure status. Although techniques of percutaneous pulmonary valve implantation have been described just a decade ago, two stent-mounted complementary devices were successfully introduced and more than 3000 of these procedures have been performed worldwide. In contrast, percutaneous treatment of tricuspid valve dysfunction is still evolving on a much earlier level and has so far not reached routine interventional procedure status. Taking into account that an “interdisciplinary challenging”, heterogeneous population of patients previously treated by corrective, semi-corrective or palliative surgical procedures is growing inexorably, there is a rapidly increasing need of treatment options besides redo-surgery. Therefore, the review intends to reflect on clinical expansion of percutaneous pulmonary and tricuspid valve procedures, to update on current devices, to discuss indications and patient selection criteria, to report on clinical results and finally to consider future directions.

The use of intracardiac echocardiography during percutaneous pulmonary valve replacement

High-quality live imaging assessment of cardiac valves and cardiac anatomy is crucial for the success of catheter-based procedures. We present our experience using Intracardiac echocardiography (ICE) during transcatheter Percutaneous Pulmonary Valve replacement (tPVR).This is a retrospective study that included 35 patients who underwent tPVR between April 2008 and June 2012. Thirty-one of these patients had the procedure performed under continuous ICE guidance. Pre-procedure transthoracic echocardiography (TTE) was obtained in all patients. ICE was performed at baseline, during the procedure, and at the conclusion of the procedure. Comparisons between the pre-procedure TTE and baseline ICE data and between post-procedure ICE data and the following day TTE were performed. Total of 35 patients had tPVR during the above-mentioned time period. Twenty-one patients received the Edwards Sapien valve and 14 patients had the Melody valve. Thirty-one patients had the procedure performed under continuous ICE guidance. The mean Pre-TTE peak gradient (PG) and Pre-ICE-PG were 45.5 ± 20 vs 33 ± 13 mmHg (p < 0.001) and the mean Pre-TTE mean gradient (MG) and Pre-ICE-MG were 27.7 ± 13 vs 21 ± 18 mmHg (p < 0.001). The mean Post-TTE- PG and Post-ICE-PG were 24.3 ± 11 vs 15.3 ± 7 mmHg (p < 0.001) and the mean of the Post-TTE-MG and Post-ICE-MG were 14.2 ± 7 vs 8.4 ± 4 mmHg (p < 0.001). There was a good correlation between peak ICE and TTE gradient at baseline and after valve placement. For the degree of pulmonary regurgitation, there was no significant difference between TTE and ICE. ICE is an important modality to guide tPVR in patients with dysfunctional homograft valve between the right ventricle and pulmonary artery and should be used to assess valve function before, during and immediately after the procedure.

Transcatheter pulmonary valve insertion, expanded use (beyond large conduits from the right ventricle to pulmonary artery), and future directions

Transcatheter pulmonary valve insertion is the most important advance in congenital interventional cardiology since atrial septal defect devices became commonly available 15 years ago. It has changed the way we look at a number of diverse diagnoses and changes how we plan, diagnose, operate, and follow-up patients. It has changed how we counsel families expecting a child that may benefit from it. Expanded use of the Melody® valve, outside its United States Food and Drug Administration approved indications, has helped numerous additional patients. The use of transcatheter pulmonary valve insertion in selected patients following surgical Gore-tex® bileaflet in valve right ventricular outflow tract reconstruction and those with a history of prior small homograft conduits will be discussed.

The future of transcatheter pulmonary valvulation

Percutaneous pulmonary valve implantation now has a key role in the setting of dysfunctional right ventricle-to-pulmonary artery conduits or failing bioprosthetic pulmonary valves. However, despite the excellent results obtained with the two devices available currently (the Melody(®) valve [Medtronic Inc., Minneapolis, MN, USA] and the Edwards SAPIEN(®) valve [Edwards Lifesciences, Irvine, CA, USA]), many patients eligible for pulmonary valve replacement remain unsuitable for percutaneous pulmonary valve implantation, mainly because of large native outflow tracts. Accordingly, one of the major challenges for the future is to expand percutaneous pulmonary valve implantation to a broader population of patients. Moving forward, there is important ongoing research that is intended to improve patient outcomes, expand percutaneous pulmonary valve implantation therapy and continue to reduce the number of open-heart surgeries in this population. In this review, we underline the limitations and issues associated with the devices available currently, and we focus on the development of new strategies (such as hybrid approaches or magnetic resonance-guided procedures), new devices (such as right ventricular outflow tract reducers or the novel Native Outflow Tract valved stent from Medtronic) and new technologies (such as tissue-engineered valves), which may help to take up these challenges and represent the future of transcatheter valve implantation.

Will catheter interventions replace surgery for valve abnormalities?

PURPOSE OF REVIEW

Catheter-based valve technologies have evolved rapidly over the last decade. Transcatheter aortic valve replacement (TAVR) has become a routine procedure in high-risk adult patients with calcific aortic stenosis. In patients with congenital heart disease (CHD), transcatheter pulmonary valve replacement represents a transformative technology for right ventricular outflow tract dysfunction with the potential to expand to other indications. This review aims to summarize the current state-of-the-art for transcatheter valve replacement (TVR) in CHD; the expanding indications for TVR; and the technological obstacles to optimizing TVR.

RECENT FINDINGS

Multiple case series have demonstrated that TVR with the Melody transcatheter pulmonary valve in properly selected patients is safe, effective, and durable in short-term follow-up. The Sapien transcatheter heart valve represents an alternative device with similar safety and efficacy in limited studies. Innovative use of current valves has demonstrated the flexibility of TVR, while highlighting the need for devices to address the broad range of postoperative anatomies either with a single device or with strategies to prepare the outflow tract for subsequent device deployment.

SUMMARY

The potential of TVR has not been fully realized, but holds promise in treatment of CHD.