Short- and medium-term outcomes after transcatheter pulmonary valve placement in the expanded multicenter US melody valve trial

Percutaneous pulmonary valve implantation using Edwards SAPIEN transcatheter heart valve in different types of conduits: initial results of a single center experience

BACKGROUND

Percutaneous pulmonary valve implantation is frequently used as a less invasive method in patients with conduit dysfunction. The common valve type cannot be used in conduits with a diameter larger than 22 mm. There has been limited experience concerning the used of the SAPIEN Transcatheter Heart Valve, produced for use in conduits with a large diameter. This study presents hemodynamic and early follow-up results from a single center in Turkey concerning the use of the SAPIEN Transcatheter Heart Valve in different types of conduits and different lesions.

PATIENTS AND METHOD

Between October 2010 and July 2012, seven SAPIEN Transcatheter Heart Valve implantations were performed. There was mixed type 2 pure insufficiency with stenosis and insufficiency in five patients. Three different conduits were used, and one native pulmonary artery process was performed. Patients were followed for hemodynamic findings, functional capacities, valve competence, reshrinking, and breakage in the stent, and the results were evaluated.

RESULTS

Implantations were successfully performed in all patients. Right ventricular pressures and gradients were significantly reduced, and there was no pulmonary regurgitation in any patient. Functional capacities evidently improved in all patients except for one with pulmonary hypertension. No major complication was observed. During the mean time of follow-up (7.2 ± 4.7 months), no valve insufficiency or stent breakage was observed.

CONCLUSION

Procedural results and short-term outcomes of the SAPIEN Transcatheter Heart Valve were very promising in the patients included in the study. The SAPIEN Transcatheter Heart Valve can be a good alternative to surgical conduit replacement, particularly in patients with larger and different types of conduits.

Early echocardiographic changes after percutaneous implantation of the Edwards SAPIEN transcatheter heart valve in the pulmonary position

OBJECTIVES

To evaluate echocardiographic changes after SAPIEN valve implantation in the pulmonary position.

BACKGROUND

The feasibility of the SAPIEN transcatheter pulmonary valve (TPV) has recently been demonstrated. We evaluated changes in pulmonary valve function and the right ventricle after SAPIEN TPV placement.

METHODS

We evaluated echocardiograms at baseline, discharge, 1 and 6 months after TPV placement in 33 patients from 4 centers. Pulmonary insufficiency severity was graded 0-4. TPV peak and mean gradients were measured. Right ventricular (RV) size and function were quantified using routine measures derived from color, spectral, and tissue Doppler indices and two-dimensional echocardiography.

RESULTS

At baseline, 94% patients demonstrated pulmonary insufficiency grade 2-4. This decreased to 12% patients at 6 months (P < 0.01). TPV peak (P < 0.01) and mean gradient (P < 0.01) decreased. RV end-diastolic area indexed to body surface area (BSA) (P < 0.01), Tricuspid regurgitation (TR) gradient (P < 0.01), and the ratio of TR jet area to BSA (P < 0.01) decreased. Tricuspid inflow peak E:A, tissue Doppler imaging (TDI): septal E' and A', TDI: tricuspid A' improved between baseline and discharge, but trended back to baseline by 6-month follow-up. Tricuspid valve annulus z-score, RV area change, tricuspid annular plane systolic excursion (TAPSE), RV dP/dt, tricuspid E:E', and TDI: tricuspid annulus E' showed no change.

CONCLUSION

Improvements in pulmonary insufficiency and stenosis, RV size, and TR gradient and severity are seen after SAPIEN TPV placement. Selected indices of RV diastolic function improve immediately after TPV implantation, but return to baseline by 6 months. RV systolic function is unchanged.

Off-label use of percutaneous pulmonary valved stents in the right ventricular outflow tract: time to rewrite the label?

INTRODUCTION

Percutaneous pulmonary valve implantation is now considered feasible and safe. "Native" right ventricular outflow tract (RVOT), small diameter conduits (<16 mm) and relatively large RVOT with a dynamic outflow aneurysm are currently considered off-label uses. Extending indications creates concerns of safety, ethics, reimbursement, and liability.

AIM OF STUDY

To report the safety and feasibility of off-label application of percutaneous pulmonary valve implantation.

DESIGN

Retrospective analysis of prospectively collected data.

PATIENTS AND METHODS

Off-label indications: conduit-free RVOT or patients with an existing but undersized conduit.

RESULTS

Twenty-one Melody® valves and two Sapien® valves were successfully implanted in 23 patients (16.9 years; range 6.1-80.5 years). In 22 patients, prestenting was performed 4.8 months (range 0-69.2) before valve implantation (15 covered and 13 bare stents). Stent endothelial ingrowth was allowed for at least 2 months prior to implantation of the percutaneous valve if stent stability or sealing by the covering was presumed to be insufficient. Group 1 patients (n = 8) had a "conduit-free" RVOT after transannular/infundibular patch and after prestenting underwent percutaneous pulmonary valve implantation (PPVI), with a final RVOT diameter of 21.5 mm (range 16-26 mm). Group 2 patients consisted of two elderly patients with pulmonary valve stenosis and severe RVOT calcifications. Group 3 (n = 13) had an existing conduit (nominal 15.9 ± 3.2 mm; range 10-20 mm). The conduit was augmented from 14.7 ± 3.5 to 20 ± 1.6 mm with PPVI. The RVOT preparation and valve implantations were uneventful.

CONCLUSIONS

PPVI is safe and feasible in selected patients with an off-label indication. Creating an adequate "landing zone" by prestenting makes the procedure safe and predictable. Updating the indications for PPVI should be considered.

Transcatheter Pulmonary Valve Replacement: Current Status and Future Potentials

Although established, transcatheter pulmonary valve replacement is in its infancy compared with surgical pulmonary valve replacement. Extended clinical experience and follow-up have identified new challenges; however, careful evaluation of data through clinical trials has facilitated effective evolution of responses to these challenges. The limited patient population has resulted in less interest in new valve design, but having been the older sibling to transcatheter aortic valve replacement, transcatheter pulmonary valve replacement is likely to benefit in the future from design modifications to the more popular and commercially viable transcatheter aortic valve revolution. Improving valve longevity and applying the technology to native outflow tracts remain the short-to-medium term goals.

Melody valve implant within failed bioprosthetic valves in the pulmonary position: a multicenter experience

BACKGROUND

Transcatheter pulmonary valve implantation using the Melody valve has emerged as an important therapy for the treatment of postoperative right ventricular outflow tract dysfunction. Melody-in-bioprosthetic valves (BPV) is currently considered an off-label indication. We review the combined experience with transcatheter pulmonary valve implantation within BPVs from 8 centers in the United States and discuss technical aspects of the Melody-in-BPV procedure.

METHODS AND RESULTS

A total of 104 patients underwent Melody-in-BPV in the pulmonary position at 8 US centers from April 2007 to January 2012. Ten different types of BPVs were intervened on, with Melody valve implantation at the intended site in all patients. Following Melody valve implant, the peak right ventricle-to-pulmonary artery gradient decreased from 38.7 ± 16.3 to 10.9 ± 6.7 mm Hg (P<0.001), and the right ventricular systolic pressure fell from 71.6 ± 21.7 to 46.7 ± 15.9 mm Hg (P<0.001). There was no serious procedural morbidity, and no deaths related to the catheterization or implant. At a median follow-up of 12 months (1-46 months), no patients had more than mild regurgitation, and 4 had a mean right ventricular outflow tract gradient ≥30 mm Hg. During follow-up, there were 2 stent fractures, 3 cases of endocarditis (2 managed with surgical explant), and 2 deaths that were unrelated to the Melody valve.

CONCLUSIONS

Transcatheter pulmonary valve implantation using the Melody valve within BPVs can be accomplished with a high rate of success, low procedure-related morbidity and mortality, and excellent short-term results. The findings of this preliminary multicenter experience suggest that the Melody valve is an effective transcatheter treatment option for failed BPVs.

Cardiac catheterisation of patients with common arterial trunk and transposition of the great arteries

Cardiac catheterisation continues to play an important role in the long-term management of patients with common arterial trunk and transposition of the great arteries. Although non-invasive imaging has largely eliminated the need for diagnostic catheterisation in newborns with these congenital cardiac lesions, cardiac catheterisation is an important tool for the diagnosis of a variety of problems encountered after surgical intervention, and allows interventions to be performed when feasible. We review the indications for cardiac catheterisation and describe the specifics for various interventional procedures for these patients in this manuscript.

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.

Palliation using a self-expandable stent in a patient with obstructive right-ventricular outflow tract after total correction of tetralogy of Fallot: self-expandable stent in tetralogy of Fallot

Total correction of tetralogy of Fallot (TOF) is typically performed within the first year of life. However, subsequently, right-ventricular dysfunction often progresses by pulmonary stenosis or regurgitation. Although most patients with corrected TOF require additional surgery for right-ventricular outflow tract, intervention could be an alternative to palliative surgery and associated morbidities, especially in children. We describe a palliative application of the self-expandable stent in a patient with pulmonary stenosis after total correction of TOF who lacked a conduit between the right ventricle and pulmonary artery.

Transcatheter pulmonary valve insertion: when, how, and why

Transcatheter pulmonary valve replacement is fast becoming an accepted alternative to repeat surgical pulmonary valve replacement for selected patients and therefore a complementary strategy in the long-term management of those requiring surgical pulmonary valve replacement. With a combined surgical and percutaneous approach, late morbidity for some of these patients may be diminished. This manuscript will review the current indications for this procedure, its limitations, and its benefits.

Melody transcatheter pulmonary valve implantation. Results from the registry of the Italian Society of Pediatric Cardiology

BACKGROUND AND AIMS

Percutaneous implantation of pulmonary valve has been recently introduced in the clinical practice. Our aim was to analyze data of patients treated in Italy by using the Melody Medtronic valve.

METHODS

Prospective, observational, multi-centric survey by means of a web-based database registry of the Italian Society of Pediatric Cardiology (SICP).

RESULTS

Between October 2007 and October 2010, 63 patients were included in the registry (median age: 24 years; range 11-65 years). Forty subjects were in NYHA class I-II while 23 were in NYHA class III-IV. Patients included had a history of a median three previous surgeries (range 1-5) and a median of one previous cardiac catheterization (range 0-4). A cono-truncal disease was present in 39 patients, previous Ross operation in 9, and other diagnosis in 15. Indication to valve implantation was pure stenosis in 21 patients, pure regurgitation in 12, association of stenosis and regurgitation in 30. Implantation was performed in 61 subjects (97%). Pre-stenting was performed in 85% of cases. Median procedure time was 170 minutes (range 85-360). No significant regurgitation was recorded after procedure while the trans-pulmonary gradient reduced significantly. Early major complications occurred in seven subjects (11%). One death occurred in the early post-operative period in a severely ill subject. At a median follow-up of 30 months (range 12-48 months), three patients died due to underlying disease. Major complications occurred in six patients during follow-up (external electric cardioversion: one patient; herpes virus encephalitis: two patients; Melody valve endocarditis needing surgical explant: two patients; major fractures of the stent and need second Melody valve implantation: two patients). Freedom from valve failure at latest follow-up was 81.4% ± 9%.

CONCLUSION

Early results of the SICP registry on transcatheter Melody pulmonary valve implantation show that the procedure is safe and successful. Major concerns are related to the occurrence of stent fracture and bacterial endocarditis. Longer follow-up and larger series are needed.

Percutaneous pulmonary valve implantation

Pulmonary regurgitation (PR) is a frequent sequelae after repair of tetralogy of Fallot, pulmonary atresia, truncus arteriosus, Rastelli and Ross operation. Due to patient growth and conduit degeneration, these conduits have to be changed frequently due to regurgitation or stenosis. However, morbidity is significant in these repeated operations. To prolong conduit longevity, bare-metal stenting in the right ventricular outflow tract (RVOT) obstruction has been performed. Stenting the RVOT can reduce the right ventricular pressure and symptomatic improvement, but it causes PR with detrimental effects on the right ventricle function and risks of arrhythmia. Percutaneous pulmonary valve implantation has been shown to be a safe and effective treatment for patients with pulmonary valve insufficiency, or stenotic RVOTs.

State-of-the-art percutaneous pulmonary valve therapy

Transcatheter pulmonary valve replacement is one of the most exciting recent developments in the treatment of patients with congenital heart disease and is being used to treat both stenotic and regurgitant valves within previously placed surgical conduits. Although limited somewhat by both patients and available valve sizes, ongoing attempts are being made to extend this technology to native right ventricular outflow tracts. If achieved, this will represent a significant advancement in attempts to prevent morbidity and mortality secondary to the chronic effects of right ventricular volume loading. This review deals with the development, current status and future endeavors of this approach.

Transcatheter pulmonary valve replacement

Transcatheter pulmonary valve replacement (tPVR) has evolved into a viable alternative to surgical conduit or bioprosthetic valve replacement. This procedure has paved the way for a more advanced approach to congenital and structural interventional cardiology. Although many successes have been noted, there are still a number of challenges with this procedure, including large delivery systems, the need for a conduit or a bioprosthetic valve as a landing zone for the valve, optimal timing of the procedure to prevent right ventricular failure, arrhythmias, and possible death. Research is ongoing to broaden the use of this technology when treating patients with dilated right ventricular outflow tracts, and early experience with a self-expanding valve model has been reported. Affordability is an important factor that must be considered especially in developing nations. The aim of this review is to emphasize the advancement of tPVR, the benefits and challenges of valve implantation, the current state, and the future innovations associated with this approach.

Percutaneous pulmonary valve implantation: fixing the problems and pushing the envelope

PURPOSE OF REVIEW

A recent development within pediatric cardiology is percutaneous pulmonary valve implantation (PPVI). This has extended the life of surgical conduits and decreased the number of surgical procedures required. Early reports focused on feasibility and safety of the technique; recent literature has focused on avoidance of complications such as stent fractures and on expanding the procedure to nonconduit implantation. The purpose of this review is to summarize the recent data regarding stent fractures and alternative uses of the valve.

RECENT FINDINGS

Stent fractures following PPVI are reported in 20-28% of patients. Prestenting has recently been shown to be protective and to extend the freedom from stent fractures. The use of PPVI has also been reported in nonconduit positions such as in bioprosthetic tricuspid valves, branch pulmonary arteries, aortic and mitral positions. In addition, the valve has been implanted in higher pressure environments. The short-term success in these applications appears to be quite good.

SUMMARY

PPVI has allowed extension of the life of surgical conduits and failure of the valve is mainly related to stent fractures. Recent developments have minimized this complication. In addition, use of the valve has been extended to nontraditional locations and short-term results are favorable.

Left coronary artery occlusion after percutaneous pulmonary valve implantation

Percutaneous pulmonary valve implantation (PPVI) is an attractive option for patients with pulmonary valve insufficiency or stenotic right ventricular outflow tracts. We present the case of a 26-year-old patient in which PPVI was used to treat d-transposition of the great arteries, uncommon coronary artery anatomy, and conduit stenosis that resulted from multiple operations on the right outflow. Days after discharge to home, she experienced acute chest discomfort correlating with ischemia noted on an electrocardiogram and elevated troponin levels. Coronary angiography confirmed mechanical compression of the left anterior descending coronary artery. The valve was removed in an emergency operation and replaced with a biological conduit.

Obstruction of a percutaneous pulmonary valve by an Aspergillus mycotic thrombus mimicking massive pulmonary embolus

New technologies in the management of congenital and acquired heart disease may be associated with unfamiliar complications that may require repeated surgical intervention. A high index of suspicion for unusual problems and close collaboration between cardiologists and surgeons is essential when adopting evolving technologies. We report the case of near total obstruction of a 2.5-month-old implanted Melody percutaneous pulmonary valve (PPV) with a thrombus mimicking saddle embolus causing right heart failure and hemodynamic collapse. This obstruction necessitated emergency surgery and homograft replacement. Cultures and pathologic examination revealed fungal thrombus with Aspergillus fumigatus. Subsequently, the patient had rapid improvement, received antifungal treatment, and has shown excellent cardiac and systemic recovery up to 1 year after surgery.

Percutaneous implantation of the Edwards SAPIEN(™) pulmonic valve: initial results in the first 22 patients

BACKGROUND

Percutaneous pulmonary valve implantation (PPVI) was introduced in 2000 as an interventional procedure for the treatment of right ventricular outflow tract (RVOT) dysfunction. The new Edwards SAPIEN(™) pulmonic valve has reached CE certification at the end of 2010 thus offering an attractive alternative with extended sizes (23 and 26 mm) to the conventional Melody(®) valve (sizes 18, 20 and 22 mm).

PATIENTS

Over a 1-year period, PPVI using the Edwards SAPIEN(™) pulmonic valve was performed in 22 patients using a standardized procedure. Primary diagnosis was tetralogy of Fallot (n = 11), pulmonary atresia (n = 2), Truncus arteriosus (n = 3), TGA/PS-Rastelli (n = 1), Ross surgery (n = 2), double outlet right ventricle (n = 2) and absent pulmonary valve syndrome (n = 1). The character of the RVOT for PPVI was transannular patch (n = 4), bioprosthesis (n = 2), homograft (n = 5) and Contegra(®) conduit (n = 11). The leading hemodynamic problem consisted of a pulmonary stenosis (PS) (n = 2), pulmonary regurgitation (PR) (n = 11) and a combined PS/PR lesion (n = 9).

RESULTS

In 21/22 patients, PPVI was performed successfully (10 × 23 and 11 × 26 mm). There were 9 female and 13 male patients; the mean age was 21.7 years (range 6-83 years), the mean length was 162 cm (range 111-181 cm) and the weight 56.5 kg (range 20-91 kg). Invasive data showed a decrease of RV-systolic pressure from 61.2 mmHg (± 23.1) to 41.2 mmHg (± 8.6) and reduction of RV-PA gradient from 37.3 mmHg (± 23.2) to 6.9 mmHg (± 5.3). The PA-systolic pressure increased from 25.8 mmHg (± 8.6) to 33.9 mmHg (± 9.3) as did the PA diastolic pressure (from 6.0 mmHg (± 5.6) to 14.6 mmHg (± 4.3). There was a substantial reduction of pulmonary regurgitation from before (none/trivial n = 0, mild n = 2, mode rate n = 9, severe n = 11) to after PPVI (none/trivial n = 20, mild n = 1). During the short-term follow-up of 5.7 months there was no change in the immediate results.

CONCLUSION

PPVI using the Edwards SAPIEN(™) pulmonic valve can be performed safely in a wide range of patients with various diagnoses and underlying pathology of the RVOT and enables the restoration of an adult-size RVOT diameter. Although the immediate and short-term results seem promising, the long-term effects and safety have to be assessed in further clinical follow-up studies.

[Right ventricular outflow tract reconstruction in adolescents and adults after previous repair of congenital heart defects]

Due to successful surgical treatment of congenital heart defects in infants and children, the number of patients who reach the adolescent/adult age is continuously increasing.

AIMS

The authors sought to identify the short- and medium-term outcomes of reconstruction of right ventricular outflow tract in adolescents and adults who underwent surgical intervention for congenital heart defect in infancy or early childhood.

METHODS

Between 2001 and 2012, 48 patients (age: 15-39, mean 21 years) (30 tetralogy of Fallot, 11 pulmonary atresia + ventricular septal defect, 6 transposition of great arteries + ventricular septal defect + left ventricular outflow tract obstruction, and 1 truncus arteriosus) had repeat operation because of right ventricular dysfunction. All patients previously underwent right ventricular outflow tract procedures in early childhood.

RESULTS

In 31 patients, the small homograft, and in 9 patients the transannular-paths were replaced for "adult-size" homograft. Bioprosthetic pulmonary valve replacement was performed in pulmonary (6 patients) and homograft annuli (2 patients). In 14 patients, resection of the right ventricular outflow tract aneurism was also necessary to be performed. There was no early and mid-time (10 years) mortality. In 97.5% of patients with homograft-re-implantation, there was no need for repeat intervention for 5 years.

CONCLUSIONS

The right ventricular outflow tract restoration in adolescents and adults is an effective procedure. The reconstruction should be performed in early adolescent period to prevent right ventricular dysfunction. The authors prefer using bioprosthetic pulmonary valve replacement in patients with adult-size pulmonary or homograft annulus.

Clinical and stent-related outcomes after transcatheter or operative placement of bare-metal stents in the ventricular septum or subvalvar systemic outflow tract

BACKGROUND

Stenting of the systemic ventricular outflow tract and creation or enlargement of a ventricular septal defect using stents are potential therapeutic options in rare patients with congenital heart disease who develop significant ventricular hypertension due to outflow obstruction. These stents may be at increased risk of fracture because of exposure to cyclic compressive stresses. The objective of this study was to evaluate the safety and efficacy of this intervention and to determine the incidence of stent fracture and other adverse outcomes after placement of intraventricular or interventricular stents for this indication.

METHODS AND RESULTS

Between 1992 and 2010, 27 patients underwent bare-metal stent placement in the ventricular septum or subvalvar systemic outflow tract, using 1 of the following 3 delivery approaches: (1) percutaneous (n=18), (2) intraoperative (n=8), and (3) hybrid (n=1). The median ventricular-to-aortic systolic pressure ratio decreased from 1.7 (1.3-2.6) to 1.1 (0.9-1.8) (P<0.001). Survival free from surgical reintervention for outflow obstruction was 92% at 1 year and 66% at 3 years. Stent fracture was diagnosed in 11 patients (41%) a median of 2.6 years (0.03-7.8 years) after stent placement and was always associated with recurrent obstruction. Survival free from diagnosis of stent fracture was 84% at 1 year and 73% at 3 years. Other adverse events included complete heart block (n=2) and increased atrioventricular valve regurgitation requiring surgical intervention (n=2).

CONCLUSIONS

Transcatheter, intraoperative, or hybrid stenting of the ventricular septum or systemic outflow tract is feasible and effective in the short term. Stent fractures were common during follow-up and associated with recurrent obstruction.

Outcomes and safety of transcatheter pulmonary valve replacement in patients with large patched right ventricular outflow tracts

BACKGROUND

Although globally accepted, the indication for implantation of the Melody(®) (Medtronic Inc., Minneapolis, MN, USA) transcatheter pulmonary valve is limited to the treatment of haemodynamically dysfunctional right ventricular outflow tract (RVOT) with right ventricle to pulmonary artery (PA) obstruction. The use of the Melody valve for haemodynamically significant isolated pulmonary regurgitation has not been evaluated.

AIM

We evaluated the outcomes of Melody valve insertion in patients with a large patched RVOT.

METHODS

We analysed procedural and short-term outcomes data from 13 patients who underwent Melody valve implantation for a large RVOT with significant pulmonary regurgitation as the primary lesion. RVOT preparation was done in all patients using the Russian dolls technique and/or the PA jailing technique. Melody valve insertion was performed concomitantly in 10 patients and after 1 to 3 months in three patients.

RESULTS

All procedures were successful. The mean follow-up period was 30 ± 4 months after the procedure. There was no incidence of stent fracture, migration or embolization. Only one patient who underwent the jailing technique developed a significant paraprosthetic leak and is scheduled for redilatation of the Melody valve.

CONCLUSIONS

Careful patient selection, balloon sizing and RVOT preparation with prestenting using the Russian dolls technique and/or the PA jailing technique are required to modify the RVOT for transcatheter valve implantation. Short-term follow-up showed competent valves with no stent fracture or migration and appears promising. Wider experience with long-term outcomes may be required to standardize the procedure in such a subset of patients.

Use of a novel hybrid approach to salvage an attempted transcatheter pulmonary valve implant

Transcatheter pulmonary valve implantation in the setting of right ventricle-to-pulmonary artery conduit dysfunction is a relatively new procedure with encouraging early and midterm results. Malpositioning of the valve during implantation is a potentially serious complication. This report describes a case in which valve malpositioning was avoided by the use of a unique hybrid approach. This approach may prove to be useful for a select group of patients requiring pulmonary valve replacement.

The FDA Review Process for Cardiac Medical Devices in Children: A Review for the Clinician

Pediatric medical devices play a vital role in the treatment of children with cardiovascular disease. Most cardiac medical devices used in children today are used off-label where the risk-benefit of devices has not been well characterized. Pediatric medical devices face a variety of challenges to FDA approval related in large part to the small target population, heterogeneity of the patient population and ethical considerations of device testing in children. While relatively few cardiac devices have received FDA approval in children, the number of devices navigating the approval process successfully is growing. Most pediatric device approvals are being granted through the humanitarian device exemption (HDE) pathway, which is designed for rare diseases making it suitable for devices treating congenital heart disease. This review summarizes the FDA review process for pediatric medical devices as it continues to evolve in response to the unique challenges of understanding device performance in the pediatric population.

Melody valve-in-ring procedure for mitral valve replacement: feasibility in four annuloplasty types

BACKGROUND

The recurrence of regurgitation after surgical mitral valve (MV) repair remains a significant clinical problem. Mitral annuloplasty rings are commonly used in MV repair procedures. The purpose of this study was to demonstrate the feasibility of transvenous valve-in-ring (VIR) implantation using the Melody valve (Medtronic, Minneapolis, MN), which is a valved-stent designed for percutaneous pulmonary valve replacement, and 4 distinct types of annuloplasty ring (AR) in an ovine model.

METHODS

Ten sheep underwent surgical MV annuloplasty ring placement (n=10): CE-Physio, Edwards Lifesciences, Irvine, CA [n=5]; partial ring [n=3]; flexible ring [n=1]; and saddle ring [n=1]). All animals underwent cardiac catheterization, hemodynamic assessment, and Melody VIR implantation through a transfemoral venous, transatrial septal approach 1 week after surgery. Follow-up hemodynamic, angiographic, and echocardiographic data were recorded.

RESULTS

Melody VIR implantation was technically successful in all but 1 animal. In this animal a 26-mm partial AR proved too large for secure anchoring of the Melody valve. In the remaining 9 animals, fluoroscopy showed the Melody devices securely positioned within the annuloplasty rings. Echocardiography revealed no perivalvular leak, and angiography revealed no left ventricular outflow tract obstruction, vigorous left ventricular function, and no aortic valve insufficiency. The median procedure time was 55.5 (range, 45 to 78) minutes.

CONCLUSIONS

This study demonstrates the feasibility of a purely percutaneous approach to MV replacement in patients with preexisting annuloplasty rings, regardless of ring type. This approach may be of particular benefit to patients with failed repair of ischemic mitral regurgitation.

Percutaneous implantation of Edwards SAPIEN valve into pulmonary bioprosthesis (valve-in-valve)

We report the case of a 14-year-old boy affected by Tetralogy of Fallot and pulmonary atresia, who had already undergone multiple surgical procedures. He had later developed a steno-insufficiency of the pulmonary bioprosthesis. We performed a percutaneous pulmonary valve implantation (PPVI), which is a minimally invasive treatment, as effective as conventional valve surgery and associated with less morbidity and mortality. Up to now PPVI has been carried out in patients with chronic pulmonary vascular resistance (PVR) in the presence of a right ventricular outflow tract (RVOT) patch by prior deployment of an intravascular stent as an artificial conduit that makes subsequent valve implantation possible. The peculiarity of our procedure was that we implanted the valve directly on to the annulus of the bioprosthesis (valve-in-valve), without performing a prestenting of the prosthetic valve.

Implantation of a Melody valve in tricuspid position

A transcatheter pulmonary valve (Melody) was implanted within a stenotic biological valve prosthesis in tricuspid position, as an alternative to the fourth major cardiac surgery in a 12-year-old girl. There were no complications. The postinterventional result was very good.

Future horizons for catheter-based interventions in adult congenital and structural heart disease

In recent decades, there has been an exponential growth in both the number and range of catheter-based interventions for adult congenital and structural heart disease. In this article, we discuss the rationale for the ongoing development of minimally invasive multidisciplinary interventions; the required training elements necessary to achieve expertise in the field; the cardiac team needed to best perform these interventions; and the currently available and up and coming technologies for performing transcatheter valve therapies.

An ovine model of pulmonary insufficiency and right ventricular outflow tract dilatation

BACKGROUND AND AIM OF THE STUDY

The treatment of pulmonary insufficiency (PI) following reconstructive surgery of the right ventricular outflow tract (RVOT) in repair of the tetralogy of Fallot remains a significant challenge. The study aim was to establish an ovine model of dilated RVOT and PI, and to quantify the degree of PI and right ventricular remodeling over an eight-week period, using magnetic resonance imaging (MRI).

METHODS

Five sheep underwent baseline MRI scanning and catheterization. The weight-indexed right and left ventricular end-diastolic volume (EDV), end-systolic volume (ESV), stroke volume (SV), ejection fraction (EF) and pulmonary regurgitant fraction (RF) were measured at baseline. The animals then underwent pulmonary valvectomy and transannular patch repair of the RVOT. Repeat MRI and hemodynamic measurements were obtained after an eight-week period.

RESULTS

The indexed RVEDV increased from 49 +/- 4.0 ml/m2 at baseline to 80 +/- 10.3 ml/m2 at eight weeks after valvectomy (p = 0.01), while the indexed RVESV increased from 13 +/- 3.4 ml/m2 to 33 +/- 8.8 ml/m2 (p = 0.01). The indexed RVSV increased from 36 +/- 3.7 ml/m2 to 47 +/- 1.7 ml/m2 (p = 0.01). The RVEF at baseline was 74 +/- 6%, and this decreased to 59 +/- 5% at follow up (p = 0.02). The RF at baseline was 0 +/- 0% and was increased to 37 +/- 3% at eight weeks after valvectomy (p < 0.001). The left ventricular (LV) function was also diminished: LVEF at baseline was 67 +/- 2%, versus 49 +/- 10% at follow up (p = 0.01). Both, the RV and LV end-diastolic pressures were significantly elevated at follow up.

CONCLUSION

All five animals developed pulmonary regurgitation sufficient to cause significant RV dilatation and diminished RV and LV functions. This model may be used to investigate novel therapeutic approaches in the treatment of this difficult clinical problem.

Transesophageal Echocardiography in Tetralogy of Fallot

Transesophageal echocardiography (TEE) plays an important role in the anatomical, functional, and hemodynamic assessment of patients with congenital heart disease (CHD). This imaging approach has been applied to both children and adults with a wide range of cardiovascular malformations. Extensive clinical experience documents significant contributions, particularly in the perioperative setting. In fact, in the current medical era, many consider this technology to be an essential adjunct to surgical and anesthetic management in CHD. This review focuses on the applications of TEE in patients with tetralogy of Fallot (TOF), the most common form of cyanotic heart disease. Emphasis is given to the perioperative use of this imaging modality and benefits derived during the prebypass and postbypass periods. Limitations and pitfalls relevant to the TEE assessment in patients with this anomaly are also addressed.