Transcatheter Pulmonary Valve Replacement for Right Ventricular Outflow Tract Conduit Dysfunction After the Ross Procedure

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.

Valved Conduits for Right Ventricular Outflow Tract Reconstruction: A Review of Current Technologies and Future Directions

The need for right ventricular outflow tract reconstruction is common and growing in congenital heart surgery given expanding indications for the repair of congenital as well as acquired heart disease. Various valved conduit options currently exist including homografts, xenograft pulmonary valved conduits (Contegra™), and porcine valved conduits. The major limitation for all conduits is implant durability, which requires reoperation. Currently, cryopreserved homografts are often used given their superiority shown in long-term data. Significant limitations remain in the cost and availability of the graft, particularly for smaller sizes. Contegra conduits are available in a variety of sizes. Nonetheless, the data regarding long-term durability are less robust and studies comparing durability with homografts have been conflicting. Additionally, there is concern for increased rates of late endocarditis in this conduit. Porcine valved conduits offer a reliable option but are limited by structural valve degeneration associated with all types of bioprosthetic heart valve replacements. New developments in the field of tissue engineering have produced promising bio-restorative valved conduits that may overcome many of the limitations of previous conduit technologies. These remain in the early stages of clinical testing. This review summarizes the clinical data surrounding the conduits used most commonly in clinical practice today and explores emerging technologies that may bring us closer to developing the ideal conduit.

Long-term Outcomes of the Ross Procedure for Young Patients with Aortic Valve Disease

To define current role of the Ross operation in young patients, the outcome in those followed longer than 20 years were assessed. Between 1994 and 2020, 81 consecutive patients, 70 of 11 male and/or female, mean age 27 years underwent Ross procedure, accruing 20 years of follow-up or longer. Sixty-four had bicuspid valve (79%) and 54 (67%) aortic insufficiency, while 15 (19%) had undergone prior operations. Surgery consisted in root replacement in 53 patients, cylinder inclusion in 20 and sub-coronary graft in 8. There were 7 late deaths in 80 hospital survivors (median follow-up 21 years, IQR 20-23), with 88% ± 5% survival at 25 years. Thirty-four patients required left, 6 left and/or right and 1 right heart valve reoperation, on average 13 years after Ross procedure. Reoperation was valve-sparing in 18 (45%) patients and valve and/or root replacement in 22. Ten (24%) reoperated patients required a second reoperation 18 years after Ross procedure. Freedom from autograft reoperation was 46% ± 6%, while from autograft valve replacement was 60% ± 7%, thanks to autograft valve-sparing. Freedom from isolated right valve reoperation was 98% ± 4%. No mortality was associated with any of the 51 reoperations. Root technique was associated with reoperation (P = 0.024). Age at follow-up was 50 years (IQR 36-60), with 70 (96%) patients in NYHA class I and 6 (55%) women carrying out pregnancies. Young patients undergoing the Ross procedure enjoy unprecedented survival well into the third decade of follow-up, even when faced with reoperation. At 25 years risk of autograft reoperation is consistent, while negligible for homograft. Technical improvements at operation and valve-sparing at reoperation may prolong autograft valve durability.

Supporting the Ross procedure: preserving root physiology while mitigating autograft dilatation

PURPOSE OF REVIEW

The purpose of this article is to describe the optimized approach to nonrepairable aortic valve disease in young adults with a Ross procedure, while preserving the dynamic physiology of the aortic root.

RECENT FINDINGS

As the techniques for supporting pulmonary autografts continue to be refined, and the applicability of the Ross procedure continues to expand, an assessment of the various techniques based on aortic root physiology is warranted. Semi-resorbable scaffolds show promise in ovine models for improving the Ross procedure. Recent long-term outcomes for the Dacron inclusion technique in comparison to more physiologic methods of support emphasize the importance of balancing the prevention of early dilatation with the preservation of root haemodynamics. As this review will synthesize, the dynamic physiology of the root may be preserved even in patients at a higher risk of autograft dilatation.

SUMMARY

The favourable long-term outcomes of the Ross procedure can be partly attributed to the ability of the autograft to restore dynamism to the neoaortic root. Patient-specific modifications that respect root physiology can tailor the Ross procedure to address each patient's risk factors for early dilatation and late failure. As such, the Ross procedure should be recognized as an increasingly favourable solution for a wide spectrum of nonpreservable aortic valve disease in young adults.

Updates on the Latest Surgical Approach of the Aortic Stenosis

Over the last twenty years, we marked significant progresses in the field of tissue engineering and the development of new aortic valve structural and delivery systems. These continuous iterations on the field, have completely changed the surgical indications and approaches for AVR. Nowadays, therapeutic decisions are endorsed by international guidelines; however, new technical advances need a new integrated approach. The clinical scenarios issued from the interaction between the Guidelines and the newest approaches and technologies are regularly on debate by the Heart Team. We will present some of our most encountered situations and the pattern of our therapeutic decisions. To easily navigate through Guidelines and clinical scenarios, we reported in this review a simplified and easy to use Clinical decision-making algorithm that may be a valuable tool in our daily practice.

Long-term Clinical and Echocardiographic Outcomes in Young and Middle-aged Adults Undergoing the Ross Procedure

Importance

There is no ideal valve substitute for young adults requiring aortic valve replacement. Multicenter data supporting use of the Ross procedure with respect to long-term postoperative valve-related mortality and reintervention, as well as function of the autograft and pulmonary homograft, are needed.

Objective

To determine the long-term clinical and echocardiographic outcomes in young and middle-aged patients undergoing the Ross procedure.

Design, Setting, and Participants

A retrospective multicenter international cohort study with a median follow-up period of 9.2 years was conducted in 5 experienced centers regularly performing the Ross procedure. Consecutive patients aged 18 to 65 years were included by each center between 1991 and 2018.

Main Outcomes and Measures

Survival and autograft-related and homograft-related reintervention. Serial echocardiographic measurements of valve function were analyzed using mixed-effects modeling.

Results

During the study period, 1431 patients (74.3% men; n = 1063) were operated on at a median age of 48.5 years (mean [SD], 47.7 [9.5]; range, 18.1-65; interquartile range, 42.7-54.0). Implantation techniques were root inclusion in 355 (24.9%), root replacement in 485 (34.0%), and subcoronary implantation in 587 (41.1%). Right ventricular outflow tract reconstruction was performed with homografts in 98.6% (n = 1189) and bioprostheses in 1.4% (n = 17). Ten patients (0.7%) died before discharge. Median follow-up was 9.2 years (13 015 total patient-years). Survival after 10 and 15 years was 95.1% (95% CI, 93.8%-96.5%) and 88.5% (95% CI, 85.9%-91.1%), respectively. Freedom from autograft and homograft reintervention after 15 years was 92.0% and 97.2%, respectively. Late events were autograft endocarditis in 14 patients (0.11% per patient-year), homograft endocarditis in 11 patients (0.08% per patient-year), and stroke in 37 patients (0.3% per patient-year).

Conclusions and Relevance

Given its excellent short-term and long-term outcome in young and middle-aged adults in this study, the Ross procedure should be considered in young and middle-aged adults who require aortic valve replacement. Patients should be referred to an experienced center with a program dedicated to the Ross procedure.

The Choice of Pulmonary Autograft in Aortic Valve Surgery: A State-of-the-Art Primer

The Ross procedure has long been seen as an optimal operation for a select few. The detractors of it highlight the issue of an additional harvesting of the pulmonary artery, subjecting the native PA to systemic pressures and the need for reintervention as reasons to avoid it. However, the PA is a living tissue and capable of adapting and remodeling to growth. We therefore review the current evidence available to discuss the indications, contraindications, harvesting techniques, and modifications in a state-of-the-art narrative review of the PA as an aortic conduit. Due to the lack of substantial well-designed randomized controlled trials (RCTs), we also highlight the areas of need to reiterate the importance of the Ross procedure as part of the surgical armamentarium.

Technical Modifications that Might Improve Long-Term Outcome of the Ross Procedure in Children

BACKGROUND

Failure of the pulmonary autograft (PVA) following the Ross procedure (RP) has discouraged its widespread use and led to modifications or alternatives to the procedure. We sought to analyze whether certain technical modifications could improve results of the RP in children.

METHODS

Sixty-nine patients (median age 12 years, range 0.25 to 17.9) underwent the RP between 01/1996 and 12/2018. Concomitant Konno procedure was performed on 20/69 (29%). Prior interventions included balloon valvuloplasty in 30/69 (44%), and/or surgical valvuloplasty in 39/69 (57%). Technical modifications included utilizing the native aortic root for external annuloplasty, implanting the autograft using uniplanar horizontal sutures through the aortic wall, normalizing the sinotubular junction and wrapping the native root remnant around the PVA.

RESULTS

Operative mortality was 1/69 (1.5%), with no late death. No patient had neoaortic valvar stenosis and 7/68 (10%) had mild regurgitation on discharge echocardiogram. At latest follow-up (median 9.4 years, range 0.4 - 21.3) there was no significant change in the latest follow up Z scores of annulus, sinus or sinotubular junction diameters when compared to those at discharge. Three patients (4.4%) required late autograft replacement, two PVA repair, and two resection of pseudoaneurysm. Actuarial freedom from PVA replacement was 87% at 20 yrs. Freedom from right ventricular outflow tract catheter reintervention or reoperation was 83% and 80% respectively.

CONCLUSIONS

Technical modifications of the RP used in this cohort might successfully prolong the life of the PVA without compromising its growth, an important advantage in pediatric patients.

Prevention and management of endocarditis after transcatheter pulmonary valve replacement: current status and future prospects

Introduction: Transcatheter pulmonary valve replacement (TPVR) has become an important tool in the management of congenital heart disease with abnormalities of the right ventricular outflow tract. Endocarditis is one of the most serious adverse long-term outcomes and among the leading causes of death in patients with congenital heart disease and after (TPVR).Areas covered: This review discusses the current state knowledge about the risk factors for and outcomes of endocarditis after transcatheter pulmonary valve replacement in patients with congenital and acquired heart disease. It also addresses practical measures for mitigating endocarditis risk, as well as diagnosing and managing endocarditis when it does occur.Expert opinion: With increasing understanding of the risk factors for and management and outcomes of endocarditis in patients who have undergone TPVR, we continue to learn how to utilize TPVR most effectively in this complex population of patients.

Development of Tissue Engineered Heart Valves for Percutaneous Transcatheter Delivery in a Fetal Ovine Model

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A fully biodegradable fetal valve was developed using a zinc-aluminum alloy stent and electrospun PCL leaflets.

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In vitro evaluation of the valve was performed with accelerated degradation, mechanical, and flow loop testing, and the valve showed trivial stenosis and trivial regurgitation.

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A large animal model was used for percutaneous delivery of the valve to the fetal pulmonary annulus.

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Following implantation, the valve had no stenosis or regurgitation by echocardiography, and the fetal sheep matured and was delivered at term with the tissue-engineered valve.

This multidisciplinary work shows the feasibility of replacing the fetal pulmonary valve with a percutaneous, transcatheter, fully biodegradable tissue-engineered heart valve (TEHV), which was studied in vitro through accelerated degradation, mechanical, and hemodynamic testing and in vivo by implantation into a fetal lamb. The TEHV exhibited only trivial stenosis and regurgitation in vitro and no stenosis in vivo by echocardiogram. Following implantation, the fetus matured and was delivered at term. Replacing a stenotic fetal valve with a functional TEHV has the potential to interrupt the development of single-ventricle heart disease by restoring proper flow through the heart.

Ross Procedure vs Mechanical Aortic Valve Replacement in Adults: A Systematic Review and Meta-analysis

Importance

The ideal aortic valve substitute in young and middle-aged adults remains unknown.

Objective

To compare long-term outcomes between the Ross procedure and mechanical aortic valve replacement in adults.

Data Sources

The Ovid versions of MEDLINE and EMBASE classic (January 1, 1967, to April 26, 2018; search performed on April 27, 2018) were screened for relevant studies using the following text word search in the title or abstract: ("Ross" OR "autograft") AND ("aortic" OR "mechanical").

Study Selection

All randomized clinical trials and observational studies comparing the Ross procedure to the use of mechanical prostheses in adults undergoing aortic valve replacement were included. Studies were included if they reported any of the prespecified primary or secondary outcomes. Studies were excluded if no clinical outcomes were reported or if data were published only as an abstract. Citations were screened in duplicate by 2 of the authors, and disagreements regarding inclusion were reconciled via consensus.

Data Extraction and Synthesis

This meta-analysis was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses and Meta-analysis of Observational Studies in Epidemiology guidelines. Data were independently abstracted by 3 reviewers and pooled using a random-effects model.

Main Outcomes and Measures

The prespecified primary outcome was all-cause mortality.

Results

The search identified 2919 reports, of which 18 studies (3516 patients) met inclusion criteria, including 1 randomized clinical trial and 17 observational studies, with a median average follow-up of 5.8 (interquartile range, 3.4-9.2) years. Analysis of the primary outcome showed a 46% lower all-cause mortality in patients undergoing the Ross procedure compared with mechanical aortic valve replacement (incidence rate ratio [IRR], 0.54; 95% CI, 0.35-0.82; P = .004; I2 = 28%). The Ross procedure was also associated with lower rates of stroke (IRR, 0.26; 95% CI, 0.09-0.80; P = .02; I2 = 8%) and major bleeding (IRR, 0.17; 95% CI, 0.07-0.40; P < .001; I2 = 0%) but higher rates of reintervention (IRR, 1.76; 95% CI, 1.16-2.65; P = .007; I2 = 0%).

Conclusions and Relevance

Data from primarily observational studies suggest that the Ross procedure is associated with lower all-cause mortality compared with mechanical aortic valve replacement. These findings highlight the need for a large, prospective randomized clinical trial comparing long-term outcomes between these 2 interventions.

Clinical and pathophysiological aspects of bicuspid aortic valve disease

A bicuspid aortic valve is not only a common congenital heart defect but also an enigmatic condition that can cause a large spectrum of diseases, such as aortic valve stenosis and severe heart failure in newborns whereas aortic dissection in adults. On the contrary, a bicuspid aortic valve can also occur with normal function throughout life and never need treatment. Numerous genetic mechanisms are involved in the abnormal cellular functions that may cause abnormal development of the aortic valve during early foetal life. As several chromosomal disorders are also associated with a bicuspid valve, there does not appear to be an apparent common trigger to the abnormal development of the aortic valve. The clinical care of the bicuspid aortic valve patient has been changed by a significant body of evidence that has improved the understanding of the natural history of the disease, including when to best intervene with valve replacement and when to provide prophylactic aortic root surgery. Moreover, as bicuspid valve disease is also part of various syndromes, we can identify high-risk patients in whom a bicuspid valve is much more unfavourable than in the normal population. This review provides an overview of all aspects of the bicuspid aortic valve condition and gives an updated perspective on issues from pathophysiology to clinical care of bicuspid aortic valve disease and associated aortic disease in asymptomatic, symptomatic, and pregnant patients, as well as our viewpoint on population screening.

Repeat Pulmonary Valve Replacement: Similar Intermediate-Term Outcomes With Surgical and Transcatheter Procedures

OBJECTIVES

This study compares 30-day, 1-year, and 3-year echocardiographic findings and clinical outcomes of transcatheter pulmonary valve-in-valve replacement (TPVR) and repeat surgical pulmonary valve replacement (SPVR).

BACKGROUND

In patients with adult congenital heart disease and previous pulmonary valve replacement (PVR) who require redo PVR, it is unclear whether TPVR or repeat SPVR is the preferred strategy.

METHODS

We retrospectively identified 66 patients (TPVR, n = 36; SPVR, n = 30) with bioprosthetic pulmonary valves (PVs) who underwent either TPVR or repeat SPVR at Emory Healthcare from January 2007 to August 2017.

RESULTS

The TPVR cohort had fewer men and more patients with baseline New York Heart Association (NYHA) functional class III or IV. There was no difference in mortality, cardiovascular readmission, or post-procedural PV reintervention at 30 days, 1 year, or 3 years. Post-procedural echocardiographic findings showed no difference in mean PV gradients between the TPVR and SPVR groups at 30 days, 1 year, or 3 years. In the TPVR cohort, there was less right ventricular dysfunction at 30 days (2.9% vs. 46.7%; p < 0.01), despite higher baseline NYHA functional class in the SPVR cohort.

CONCLUSIONS

In patients with bioprosthetic PV dysfunction who underwent either TPVR or SPVR, there was no difference in mortality, cardiovascular readmission, or repeat PV intervention at 30 days, 1 year, or 3 years. Additionally, TPVR and SPVR had similar intermediate-term PV longevity, with no difference in PV gradients or PVR. The TPVR cohort also had less right ventricular dysfunction at 30 days despite a higher baseline NYHA functional classification. These intermediate-term results suggest that TPVR may be an attractive alternative to SPVR in patients with previous bioprosthetic surgical PVs.

Preprocedural Risk Assessment Prior to PPVI with CMR and Cardiac CT

Percutaneous pulmonary valve intervention (PPVI) is a less invasive and less costly approach to pulmonary valve replacement compared with the surgical alternative. Potential complications of PPVI include coronary compression and pulmonary arterial injury/rupture. The purpose of this study was to characterize the morphological risk factors for PPVI complication with cardiac MRI and cardiac CTA. A retrospective review of 88 PPVI procedures was performed. 44 patients had preprocedural cardiac MRIs or CTAs available for review. Multiple morphological variables on cardiac MRI and CTA were compared with known PPVI outcome and used to investigate associations of variables in determining coronary compression or right ventricular-pulmonary arterial conduit injury. The most significant risk factor for coronary artery compression was the proximity of the coronary arteries to the conduit. In all patients with coronary compression during PPVI, the coronary artery touched the conduit on the preprocedural CTA/MRI, whilst in patients without coronary compression the mean distance between the coronary artery and the conduit was 4.9 mm (range of 0.8-20 mm). Multivariable regression analysis demonstrated that exuberant conduit calcification was the most important variable for determining conduit injury. Position of the coronary artery directly contacting the conduit without any intervening fat may predict coronary artery compression during PPVI. Exuberant conduit calcification increases the risk of PPVI-associated conduit injury. Close attention to these factors is recommended prior to intervention in patients with pulmonary valve dysfunction.

Infective endocarditis following Melody valve implantation: comparison with a surgical cohort

BACKGROUND

Infective endocarditis has been reported post Melody percutaneous pulmonary valve implant; the incidence and risk factors, however, remain poorly defined. We identified four cases of endocarditis from our first 25 Melody implants. Our aim was to examine these cases in the context of postulated risk factors and directly compare endocarditis rates with local surgical valves.

METHODS

We conducted a retrospective review of patients post Melody percutaneous pulmonary valve implant in New Zealand (October, 2009-May, 2015) and also reviewed the incidence of endocarditis in New Zealand among patients who have undergone surgical pulmonary valve implants.

RESULTS

In total, 25 patients underwent Melody implantation at a median age of 18 years. At a median follow-up of 2.9 years, most were well with low valve gradient (median 27 mmHg) and only mild regurgitation. Two patients presented with life-threatening endocarditis and obstructive vegetations at 14 and 26 months post implant, respectively. Two additional patients presented with subacute endocarditis at 5.5 years post implant. From 2009 to May, 2015, 178 surgical pulmonic bioprostheses, largely Hancock valves and homografts, were used at our institution. At a median follow-up of 2.9 years, four patients (2%) had developed endocarditis in this group compared with 4/25 (16%) in the Melody group (p=0.0089). Three surgical valves have been replaced.

CONCLUSIONS

The Melody valve offers a good alternative to surgical conduit replacement in selected patients. Many patients have excellent outcomes in the medium term. Endocarditis, however, can occur and if associated with obstruction can be life threatening. The risk for endocarditis in the Melody group was higher in comparison with that in a contemporaneous surgical pulmonary implant cohort.