Replacement of the aortic root with a pulmonary autograft in children and young adults with aortic-valve disease

Sex Differences in Aortic Stenosis: From the Pathophysiology to the Intervention, Current Challenges, and Future Perspectives

Calcific aortic stenosis (AS) is a major cause of morbidity and mortality in high-income countries. AS presents sex-specific features impacting pathophysiology, outcomes, and management strategies. In women, AS often manifests with a high valvular fibrotic burden, small valvular annuli, concentric left ventricular (LV) remodeling/hypertrophy, and, frequently, supernormal LV ejection fraction coupled with diastolic dysfunction. Paradoxical low-flow low-gradient AS epitomizes these traits, posing significant challenges post-aortic valve replacement due to limited positive remodeling and significant risk of patient-prosthesis mismatch. Conversely, men present more commonly with LV dilatation and dysfunction, indicating the phenotype of classical low-flow low-gradient AS, i.e., with decreased LV ejection fraction. However, these distinctions have not been fully incorporated into guidelines for AS management. The only treatment for AS is aortic valve replacement; women are frequently referred late, leading to increased heart damage caused by AS. Therefore, it is important to reassess surgical planning and timing to minimize irreversible cardiac damage in women. The integrity and the consideration of sex differences in the management of AS is critical. Further research, including sufficient representation of women, is needed to investigate these differences and to develop individualized, sex-specific management strategies.

Aortic Root Surgery in Adults: An Unsolved Problem

Nowadays, despite the rapid advancements in interventional cardiology, open surgery still deals with aortic root diseases, to assure the best "ad hoc" treatment. In case of middle-aged adult patients, the optimal operation still represents a matter of debate. A review of the last 10-year literature was conducted, focusing on patients below 65 to 70 years of age. Because of the small sample and the heterogeneity of the papers, no metanalysis was possible. Bentall-de Bono procedure, valve sparing, and Ross operations are the surgical options currently available. The main issues in the Bentall - de Bono operation are lifelong anticoagulation therapy and cavitation in case of mechanical prosthesis implantation and structural valve degeneration in case of biological Bentall. As transcatheter procedures are currently performed as valve in valve, biological prosthesis may be preferable, if the diameter may prevent postoperative high gradients. Conservative techniques, such as remodeling and reimplantation, preferred in the young, guarantee physiologic aortic root dynamics and impose surgical analysis of the aortic root structures to get a durable result. The Ross operation, which shows excellent performance, involves autologous pulmonary valve implantation and is performed only in experienced and high-volume centers. Due to its technical difficulty, it requires a steep learning curve and presents some limitations in specific aortic valve diseases. All three have advantages and downsides, and no ideal solution has still been reported.

Outcomes after the Ross procedure with pulmonary autograft reinforcement by reimplantation

Background

Pulmonary autograft reinforcement to prevent dilatation and subsequent neo-aortic valve regurgitation has been reported; however, data on long-term function of the neo-aortic valve after this modified Ross procedure are lacking. Our objective here was to assess long-term outcomes of the modified Ross procedure with autograft reinforcement using the reimplantation technique.

Patients

The outcomes of 61 consecutive patients managed using the Dacron-conduit reinforced Ross procedure between 2009 and 2021 were reviewed. Most patients had a unicuspid or bicuspid aortic valve (n = 52; 85%), predominant aortic valve regurgitation (n = 42; 77%), and >30 mm dilatation of the ascending aorta (n = 33; 54%). A prior aortic valve procedure was noted in 47 patients (77%) patients, including 38 (62%) with surgical repair and 9 (15%) with balloon dilatation. The pulmonary autograft was reimplanted within a Dacron conduit with a median diameter of 25.6 mm (range, 20-30 mm) using the David valve-sparing aortic root replacement technique.

Results

All patients survived. The median age at surgery was 16.8 years (range, 6-38 years). Neo-aortic valve replacement was required in 3 patients (4.9%; 95% CI, 0.34%- 12.7%) because of infective endocarditis, left ventricular false aneurysm, and leaflet perforation, respectively; the repeat procedure was done early in 2 of these patients (2 of 61; 3%). Six patients required right ventricular outflow conduit replacement, 5 by surgery and 1 percutaneously. The median duration of follow-up was 90 months (range, 10-124 months). The 5- and 10-year rates of reintervention-free survival were 84.3% (95% CI, 74%-95%) and 81.6% (95% CI, 72%-93%), respectively, and 5-year survival without aortic reintervention was 94.5% (95% CI, 88%-100%), with little change at 10 years. No patients experienced deterioration of initial neo-aortic valve function (ie, regurgitation or stenosis).

Conclusions

Autograft reinforcement using the reimplantation technique allowed expansion of Ross procedure indications to all patients requiring aortic valve replacement and prevented neo-aortic root dilatation. Failures were uncommon. Long-term follow-up data showed stable neo-aortic valve function.

Biomechanics of Pulmonary Autograft as Living Tissue: A Systematic Review

Introduction: The choice of valve substitute for aortic valve surgery is tailored to the patient with specific indications and contraindications to consider. The use of an autologous pulmonary artery (PA) with a simultaneous homograft in the pulmonary position is called a Ross procedure. It permits somatic growth and the avoidance of lifelong anticoagulation. Concerns remain on the functionality of a pulmonary autograft in the aortic position when exposed to systemic pressure. Methods: A literature review was performed incorporating the following databases: Pub Med (1996 to present), Ovid Medline (1958 to present), and Ovid Embase (1982 to present), which was run on 1 January 2022 with the following targeted words: biomechanics of pulmonary autograft, biomechanics of Ross operation, aortic valve replacement and pulmonary autograph, aortic valve replacement and Ross procedure. To address the issues with heterogeneity, studies involving the pediatric cohort were also analyzed separately. The outcomes measured were early- and late-graft failure alongside mortality. Results: a total of 8468 patients were included based on 40 studies (7796 in pediatric cohort and young adult series and 672 in pediatric series). There was considerable experience accumulated by various institutions around the world. Late rates of biomechanical failure and mortality were low and comparable to the general population. The biomechanical properties of the PA were superior to other valve substitutes. Mathematical and finite element analysis studies have shown the potential stress-shielding effects of the PA root. Conclusion: The Ross procedure has excellent durability and longevity in clinical and biomechanical studies. The use of external reinforcements such as semi-resorbable scaffolds may further extend their longevity.

The effectiveness and safety of pulmonary autograft as living tissue in Ross procedure: a systematic review

BACKGROUND

Reports on effectiveness and safety after the implant of pulmonary autograft (PA) living tissue in Ross procedure, to treat both congenital and acquired disease of the aortic valve and left ventricular outflow tract (LVOT), show variable durability results. We undertake a quantitative systematic review of evidence on outcome after the Ross procedure with the aim to improve insight into outcome and potential determinants.

METHODS

A systematic search of reports published from October 1979 to January 2021 was conducted (PubMed, Ovid Medline, Ovid Embase and Cochrane library) reporting outcomes after the Ross procedure in patients with diseased aortic valve with or without LVOT. Inclusion criteria were observational studies reporting on mortality and/or morbidity after autograft aortic valve or root replacement, completeness of follow-up >90%, and study size n≥30. Forty articles meeting the inclusion criteria were allocated to two categories: pediatric patient series and young adult patient series. Results were tabulated for a clearer presentation.

RESULTS

A total of 342 studies were evaluated of which forty studies were included in the final analysis as per the eligibility criteria. A total of 8,468 patients were included (7,796 in pediatric cohort and young adult series and 672 in pediatric series). Late mortality rates were remarkably low alongside similar age-matched mortality with the general population in young adults. There were differences in implantation techniques as regard the variability in stress and the somatic growth that recorded conflicting outcomes regarding the miniroot vs the subcoronary approach.

DISCUSSION

The adaptability of lung autograft to allow for both stress variability and somatic growth make it an ideal conduit for Ross's operation. The use of the miniroot technique over subcoronary implantation for better adaptability to withstand varying degrees of stress is perhaps more applicable to different patient subgroups.

Contemporary Ross procedure outcomes: medium- to long-term results in 214 patients

OBJECTIVE

Our goal was to present 2 decades of our experience with the Ross procedure and its sequential modifications, adopted since 2010, to improve the reoperation rate.

METHODS

We performed a single-centre, retrospective review of database information and medical notes about the implantation technique: the freestanding root. We compared era 1 (1997-2009) and era 2 (2010-2019).

RESULTS

Between 1997 and 2019, a total of 214 Ross procedures were performed (71% men, median age 24 years) [interquartile range (IQR) 15-38]. Of these, 87% had various forms of congenital-dysplastic aortic valves. The median cross-clamping and bypass times were 173 (IQR 148-202) and 202 (IQR 182-244) min. The median postoperative stay was 6 days (2-77). Thirty-day mortality was 0.5%. The median follow-up time was 8.2 years (IQR 3.9-13.2). Survival at 10 and 20 years was 97% and 95%; freedom from greater than moderate aortic regurgitation or aortic valve intervention was 91% and 80%; and 93% of the patients were in New York Heart Association functional class I. Twenty (21%) patients operated on during era 1 and 6 (9%) during era 2 underwent autograft reoperations. The median follow-up time was 14.3 (IQR 11.5-17.4) and 4.8 (IQR 2.5-7) years. Freedom from autograft reoperation was 87% and 69% at 10 and 20 years, with no significant difference between eras. Freedom from homograft reoperation was 96% and 76% at 10 and 20 years. The presence of aortic regurgitation, infective endocarditis and era 1 were predictors of autograft reoperation. Male gender and era 1 were predictors of neoaortic root dilatation.

CONCLUSIONS

The contemporary modified Ross procedure continues to deliver excellent results and should remain part of the strategy to treat children and young adults requiring aortic valve replacement.

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.

Finite Element Analysis Investigate Pulmonary Autograft Root and Leaflet Stresses to Understand Late Durability of Ross Operation

Ross operation might be a valid option for congenital and acquired left ventricular outflow tract disease in selected cases. As the pulmonary autograft is a living substitute for the aortic root that bioinspired the Ross operation, we have created an experimental animal model in which the vital capacity of the pulmonary autograft (PA) has been studied during physiological growth. The present study aims to determine any increased stresses in PA root and leaflet compared to the similar components of the native aorta. An animal model and a mathematical analysis using finite element analysis have been used for the purpose of this manuscript. The results of this study advance our understanding of the relative benefits of pulmonary autograft for the management of severe aortic valve disease. However, it launches a warning about the importance of the choice of the length of the conduits as mechanical deformation, and, therefore, potential failure, increases with the length of the segment subjected to stress. Understanding PA root and leaflet stresses is the first step toward understanding PA durability and the regions prone to dilatation, ultimately to refine the best implant technique.

Distinct Expression of Nonmuscle Myosin IIB in Pulmonary Arteries of Patients With Aortic Stenosis vs Insufficiency Undergoing a Ross Procedure

BACKGROUND

Clinical studies have revealed a greater risk of pulmonary autograft dilation after the Ross procedure in patients with preoperative aortic insufficiency (AI). The present study examined whether the morphologic, biomechanical, and cellular properties of the pulmonary artery (PA) from patients with AI were phenotypically different compared with patients diagnosed with aortic stenosis (AS).

METHODS

PA segments were harvested from patients undergoing the Ross procedure for AS (n = 16) and AI (n = 6). Preoperative aortic annulus was significantly larger (P < 0.05) in patients with AI (28.5 ± 1.8 mm) vs AS (22.8 ± 1.2 mm). Morphologic, biomechanical, and cellular phenotypes of the PA were analyzed.

RESULTS

Collagen and elastin content in the media of the PA wall were similar in patients with AS and AI. Elastic modulus and energy loss of the PA were not significantly different between the groups. In the media of the PA, expression of a panel of vascular smooth muscle cell-specific proteins were similar in patients with AS and AI. In contrast, nonmuscle myosin IIB protein levels in the PA of AS patients were significantly higher compared with AI patients, and immunofluorescence identified staining in α-smooth muscle actin-positive vascular smooth muscle cells.

CONCLUSIONS

Despite similar morphological and biomechanical properties, the disparate expression of nonmuscle myosin IIB protein distinguishes the PA of patients with AI from patients with AS. The biological role in vascular smooth muscle cells and the potential contribution of nonmuscle myosin IIB to pulmonary autograft dilation in a subset of AI patients after the Ross procedure remain to be determined.

Simulating the ideal geometrical and biomechanical parameters of the pulmonary autograft to prevent failure in the Ross operation

OBJECTIVES

Reinforcements for the pulmonary autograft (PA) in the Ross operation have been introduced to avoid the drawback of conduit expansion and failure. With the aid of an in silico simulation, the biomechanical boundaries applied to a healthy PA during the operation were studied to tailor the best implant technique to prevent reoperation.

METHODS

Follow-up echocardiograms of 66 Ross procedures were reviewed. Changes in the dimensions and geometry of reinforced and non-reinforced PAs were evaluated. Miniroot and subcoronary implantation techniques were used in this series. Mechanical stress tests were performed on 36 human pulmonary and aortic roots explanted from donor hearts. Finite element analysis was applied to obtain high-fidelity simulation under static and dynamic conditions of the biomechanical properties and applied stresses on the PA root and leaflet and the similar components of the native aorta.

RESULTS

The non-reinforced group showed increases in the percentages of the mean diameter that were significantly higher than those in the reinforced group at the level of the Valsalva sinuses (3.9%) and the annulus (12.1%). The mechanical simulation confirmed geometrical and dimensional changes detected by clinical imaging and demonstrated the non-linear biomechanical behaviour of the PA anastomosed to the aorta, a stiffer behaviour of the aortic root in relation to the PA and similar qualitative and quantitative behaviours of leaflets of the 2 tissues. The annulus was the most significant constraint to dilation and affected the distribution of stress and strain within the entire complex, with particular strain on the sutured regions. The PA was able to evenly absorb mechanical stresses but was less adaptable to circumferential stresses, potentially explaining its known dilatation tendency over time.

CONCLUSIONS

The absence of reinforcement leads to a more marked increase in the diameter of the PA. Preservation of the native geometry of the PA root is crucial; the miniroot technique with external reinforcement is the most suitable strategy in this context.

Pulmonary autograft in aortic position: is everything known?

The Ross operation provides several advantages compared to other valve substitutes to manage aortic valve disease, such as growth potential, excellent hemodynamics, freedom from oral anticoagulation and hemolysis, and better durability. However, progressive dilatation of the pulmonary autografts after Ross operation reflects the inadequate remodeling of the native pulmonary root in the systemic circulation, which results in impaired adaptability to systemic pressure and risk of reoperation after the first decade. A recently published article showed that remodeling increased wall thickness and decreased stiffness in the failed specimens after Ross operation, and the increased compliance might play a key role in determining the progressive long-term autograft root dilatation. Late dilatation can be counteracted by an external barrier which prevents failure. Therefore, an inclusion cylinder technique with a native aorta or a synthetic external support, such as Dacron, might stabilize the autograft root and improve long-term outcomes. In this article, we offer a prospective about the importance of biomechanical features in future developments of the Ross operation. Pre-clinical and clinical evaluations of the biomechanical properties of these reinforced pulmonary autografts might shed new light on the current debate about the long-term fate of the pulmonary autograft after Ross procedure.

Biomechanics drive histological wall remodeling of neoaortic root: A mathematical model to study the expression levels of ki 67, metalloprotease, and apoptosis transition

The pulmonary artery autograft (PA) is the ideal substitute for aortic valve disease in children and young adult. However, it is harnessed by the issue of long-term dilation and regurgitation, often requiring surgery. PA implanted in aortic position during the growth phase in children undergoes a process of mechanical remodeling. We previously developed a semiresorbable armored prosthesis able to mechanically sustain the neoaorta preventing dilation and to gradually integrate with the PA wall inducing a progressive arterial-like tissue positive remodeling. We also described the mechanisms of growth, remodeling and stress shielding of the reinforced PA through a mathematical model. We sought to demonstrate the biological counterpart and the potential molecular mechanisms underlying this histological and mechanical remodeling. A specific mathematical model was developed to describe mechanical behavior of the PA. Mallory trichrome red staining and immunohistochemistry for MMP-9 were performed to elucidate extracellular matrix remodeling phenomena. Apoptosis and cell proliferation were determined by TUNEL assay and immunohistochemistry for Ki67, respectively. An histological remodeling phenomenon sustained by increased level of MMP-9, augmented cell proliferation and reduced apoptosis in the reinforced PA was demonstrated. The mathematical model predicted the biomechanical behavior subtended by the histological changes of the PA in these settings. Changes in metalloproteinases (MMP-9), cell proliferation and apoptosis are the main actors in the remodeling process occurring after transposition of the PA into systemic regimens. Use of semiresorbable reinforcements might induce a positive remodeling of the PA in the context of Ross operation. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 104A: 2785-2793, 2016.

Systemic Semilunar Valve Replacement in Pediatric Patients Using a Porcine, Full-Root Bioprosthesis

BACKGROUND

Management of systemic semilunar valve disease in growing, young patients is challenging. When replacement is necessary, use of a pulmonary autograft is sometimes not possible for anatomic, pathologic, or technical reasons or due to parental or patient preference. We employed a stentless, porcine, full-root bioprosthesis in this setting and report our outcomes.

METHODS

Over 9 years (2005 to 2013), 24 patients of mean age 13.1 years (range, 3 months to 20.3 years) underwent operation for mixed stenosis and insufficiency in 16 of 24 (67%), pure insufficiency in 7 of 24 (29%), and pure stenosis in 1 of 24 (4%). Twenty patients had previous interventions of repair or replacement, valvuloplasty, or multiple operations. Survival, follow-up echocardiographic findings, and outcomes were documented. All patients were maintained on daily aspirin.

RESULTS

There were no hospital deaths and no early or late deaths over a mean follow-up for 23 patients of 46.1 months (range, 14 months to 9.2 years). One patient moved abroad and was lost to follow-up. Echocardiographic follow-up (mean 34.0 months) demonstrated that no patient developed more than mild insufficiency or moderate stenosis. In total, 20 of 24 (83%) showed no insufficiency and 11 of 24 patients (46%) showed no stenosis. Near or complete normalization of left ventricular mass and dimension was demonstrated. There were no explants and no thromboembolic or bleeding events.

CONCLUSIONS

When use of a pulmonary autograft is not an option, the porcine full-root bioprosthesis appears favorable for systemic semilunar valve replacement in the pediatric and young adult population. Of note, when prosthetic degeneration does occur, stenosis predominates rather than insufficiency. Longer term studies are warranted.

Approach to the analysis of cardiac valve prostheses as surgical pathology or autopsy specimens

Pathologists are likely to encounter substitute heart valves with increasing frequency. Informed evaluation of such valves provides valuable information that contributes to both patient care and our understanding of the pathobiology of host interactions with mechanical devices. This article summarizes the most important considerations underlying such analyses-including valve identification, common morphologic features and modes of failure, technical details of evaluation, and potential pitfalls.

Long-term results of the Ross procedure in a population-based follow-up

OBJECTIVES

The purpose of this study was to evaluate the long-term outcomes of the Ross procedure in a nationwide follow-up.

METHODS

This retrospective study involved all children treated with the Ross procedure in Finland between 1994 and 2009. The clinical records were reviewed for demographic and anatomical characteristics, Ross operation data, surgical history and status at the latest follow-up. The median follow-up time was 11.5 (range 2.4-19.2) years.

RESULTS

Fifty-one patients underwent either the Ross (n = 37) or the Ross-Konno (n = 14) procedure at a median age of 4.8 (range 0.02-16.3) years, including 13 infants (<1 year of age). The indication for the Ross procedure was aortic valve stenosis, regurgitation or both, which was observed in 29, 24 and 47% of patients, respectively. The early mortality (before hospital discharge) rate was 10% (31% in infants) and the late mortality rate 6% (15% in infants). Higher mortality was discovered in patients treated with the Ross-Konno procedure (P = 0.001). The most common cause for reintervention was pulmonary homograft stenosis. The rate of freedom from right ventricular outflow tract reintervention was 98% at 5 years, 83% at 10 years and 59% at 15 years. The rate of freedom from autograft reintervention was 98% at 5 and 10 years, and 81% at 15 years. At the latest follow-up visit, mild-to-moderate aortic root dilatation was reported in 52% of patients, and 4 patients had undergone autograft-related reinterventions. Trivial autograft valve regurgitation was commonly seen, but only 1 patient developed severe autograft regurgitation requiring mechanical valve replacement 15.9 years after the Ross operation.

CONCLUSIONS

The most common reason for reintervention after the Ross procedure in children is homograft stenosis. Aortic root dilatation and autograft valve regurgitation are relatively common but rarely lead to reinterventions before adulthood. Intraoperative complications and complex cardiac anatomy are associated with high mortality in infants undergoing the Ross-Konno procedure. In our centre, the Ross procedure has provided good long-term results in this challenging group of paediatric patients.

The Ross operation: utilization of the patient’s own pulmonary valve as a replacement device for the diseased aortic valve

Prosthetic heart valves have been outpaced by progress in cardiac surgery. Early biologic valve prostheses consisted of tissues mounted on a rigid stent, and did not require anticoagulation, but rarely survived two decades. Subsequently, durable mechanical valve prostheses dominated despite, the requisite anticoagulation. The mechanical design remains imperfect, with obstruction to flow, turbulence, hematological changes and also, occasionally audible clicks. Reports documenting superior function for cryopreserved human aortic heart valves (homografts) without these problems, albeit with limited durability, followed. The marketing of 'stentless biologic valves', mimicking these attributes was a reaction to the shortage of homografts. These imperfections explain the rediscovery of the Ross operation, in which the patient's pulmonary valve (autograft) is excised to replace the aortic valve. The autograft is living tissue, complete with attributes of a healthy heart valve, including growth and durability. The pulmonary valve, where lower pressure and oxygen saturation retards degeneration, is substituted with a pulmonary homograft. The Ross operation is exacting and leaves the patient with two potentially malfunctioning valves.

Stentless aortic valve replacement: current status and future trends

Stentless aortic xenografts were introduced into clinical practice as aortic valve substitutes over a decade ago. Stentless prosthetic valves were expected to provide enhanced durability and more physiologic hemodynamic behavior when compared with stented bioprostheses. Whilst the former expectation has not been fulfilled, partly due to concomitantly improved durability of second-generation stented bioprostheses, the latter has consistently been satisfied in early and late clinical observation. Evidence is accumulating suggesting improved long-term survival due to more timely and thorough regression of ventricular hypertrophy. In addition, stentless xenografts have shown extreme versatility when adopted in a variety of complex clinical conditions associated with aortic valve disease, including small aortic anulus, ascending aortic aneurysm, endocarditis and left ventricular dysfunction. Future research in the form of prospective, multicenter, randomized trials must address the issues of very long-term durability and survival, while simplification in valve design is required to promote wider use of stentless valves.

Clinical and economic outcomes after surgical aortic valve replacement in Medicare patients

Background:

Aortic valve replacement (AVR) is the standard of care for patients with severe, symptomatic aortic stenosis who are suitable surgical candidates, benefiting both non-high-risk and high-risk patients. The purpose of this study was to report long-term medical resource use and costs for patients following AVR and validate our assumption that high-risk patients have worse outcomes and are more costly than non-high-risk patients in this population.

Methods:

Patients with aortic stenosis who underwent AVR were identified in the 2003 Medicare 5% Standard Analytic Files and tracked over 5 years to measure clinical outcomes, medical resource use, and costs. An approximation to the logistic EuroSCORE (European System for Cardiac Operative Risk Evaluation) based on administrative data was used to assess surgical risk, with a computed logistic EuroSCORE > 20% considered high-risk.

Results:

We identified 1474 patients with aortic stenosis who underwent AVR, of whom 1222 (82.9%) were non-high-risk and 252 (17.1%) were high-risk. Among those who were non-high-risk, the mean age was 73.3 years, 464 (38.2%) were women, and the mean logistic EuroSCORE was 7%, whereas in those who were high-risk, the mean age was 77.6 years, 134 (52.8%) were women, and the mean logistic EuroSCORE was 37%. All-cause mortality was 33.2% for non-high-risk and 66.7% for high-risk patients at 5 years. Over this time period, non-high-risk patients experienced an average of 3.9 inpatient hospitalizations and total costs of $106,277 per patient versus 4.7 hospitalizations and total costs of $144,183 for high-risk patients.

Conclusion:

Among elderly patients undergoing AVR, long-term mortality and costs are substantially greater for high-risk than for non-high-risk individuals. These findings indicate that further research is needed to understand whether newer approaches to aortic valve replacement such as transcatheter AVR may be a lower cost, clinically valuable alternative.

The Ross-Konno procedure as reoperative treatment in a young adult with congenital aortic stenosis

Mechanical and biological prostheses are valid options when aortic valve replacement is necessary. The Ross procedure is also an alternative solution, especially for young patients. We describe the case of a young patient with congenital aortic stenosis and bicuspid aortic valve who presented with dyspnea on exertion. An open commissurotomy was performed, and within 8 months the patient developed recurrent symptoms of severe aortic stenosis. He underwent redo sternotomy and a Ross-Konno procedure with an uneventful recovery.

The Ross procedure: state of the art 2011

The purpose of this paper is to review the current literature and practice of the Ross concept of using the autologous pulmonary valve to replace a diseased aortic valve. The potential advantages and disadvantages of these operations will be evaluated in the context of alternative options and relative risks. The different surgical techniques of subcoronary and full root methods will be discussed and important technical aspects reviewed. Long-term outcomes will be described to the extent these are available, including recent publications describing a survival advantage for the Ross. Brief discussions will be presented regarding hemodynamics, child-bearing, endocarditis, and the use of the Ross in pediatric patients as well as biological adaptability of the living pulmonary autograft.

Reoperation after the Ross procedure: incidence, management, and survival

BACKGROUND

The risk of reoperation on the autograft and homograft is the major long-term drawback of the Ross procedure. The incidence and clinical implications of reoperations after the Ross procedure are reported.

METHODS

Between March 1992 and February 2010, 336 consecutive patients had a Ross procedure (mean follow-up, 6.2±4.9 years). Autograft implant technique was freestanding root replacement in 269 patients, subcoronary implantation in 52 patients and a modified root replacement with the autograft included in a Valsalva tube graft in 15.

RESULTS

Subsequently, 38 patients (11.3%) underwent reoperations, for autograft dilatation in 23 and a significant autograft insufficiency in 9, at 9.6±3.7 years and 2.6±3.9 years, respectively. Aortic and pulmonary infective endocarditis occurred in 3 patients. Three patients underwent a non valve-related cardiac reoperation. Three patients received a transcatheter pulmonary valve implantation after 12.2±1.7 years. At 15 years, freedoms for autograft and homograft explantation (with 95% confidence interval) were 83.3% (77.4%- to 9.2%) and 92.8% (87.6% to 97.9%), respectively. Native aortic valve regurgitation, indexed aortic annulus diameter exceeding 1.35 cm/m2 and autograft diameter were risk factors for dilated autograft reoperation (hazard ratio, 3.23 [95% confidence interval, 1.19 to 8.81], p=0.02; 3.83 [0.9 to 16.33], p=0.07 and 1.2 per mm [1.01 to 1.41], p=0.03), respectively.

CONCLUSIONS

Autograft dilatation was the leading cause of reoperation in patients who underwent root replacement. Long-term follow-up is mandatory to determine whether modifications of the operative technique could limit autograft dilatation.

Spectrum and outcome of reoperations after the Ross procedure

BACKGROUND

Proposed advantages to the Ross procedure included presumed increased freedom from reoperation and simpler reoperation for pulmonary conduit replacement if needed. It is increasingly apparent, however, that reoperations are frequent after the Ross procedure and that when required, they may be more complex than previously thought.

METHODS AND RESULTS

Between September 1991 and August 2008, 56 patients underwent reoperation at our institution after a Ross procedure performed by ourselves (n=13) or elsewhere (n=43). Median age at first reoperation at our institution was 26 years (range 1 to 69 years). The 4 most common indications for reoperation were isolated autograft (neoaortic) regurgitation in 11 cases (20), isolated pulmonary conduit regurgitation/stenosis in 9 (16), combined autograft regurgitation/dilatation in 8 (14), and combined autograft regurgitation and pulmonary conduit regurgitation/stenosis in 6 (11). A total of 144 procedures were performed in these 56 patients during first reoperation at our institution. The autograft valve required replacement in 21 cases (38) and aortic root replacement in 21 (38), with ascending aortic/arch reconstruction in 13 (23) and mitral valve surgery in 5 (9). The pulmonary valve was replaced in 33 cases (59) and the tricuspid valve was repaired/replaced in 10 (18). Early mortality was 1.8 (1 of 56 patients), and morbidity included 6 patients with respiratory failure and 3 who required postcardiotomy extracorporeal membrane oxygenation. There were 4 late deaths during the median follow-up of 8 months (range 1 to 179 months).

CONCLUSIONS

A broad spectrum of complex reoperations may be required after the Ross procedure. Patients and family members considering the procedure should be informed of the potential for associated morbidity should reoperation be necessary.

Emergency computed tomography for aortic valve vegetation mimicking disruption

A 47-year-old man presented with symptoms typical of infective endocarditis and history of streptococcal meningitis 8 months previously. Echocardiography showed a large aortic valve vegetation that was interpreted as disruption of the noncoronary cusp. This was ruled out by 64-slice cardiac computed tomography. Valve replacement was performed successfully.

Effective transcatheter valve implantation after pulmonary homograft failure: a new perspective on the Ross operation

Objective

The Ross procedure offers good autograft function and low reoperation rates for the neoaortic valve; however, the rate of conduit dysfunction in the right ventricular outflow tract remains a concern. This study assessed percutaneous pulmonary valve implantation in this setting.

Methods

We retrospectively analyzed outcomes of 12 patients (mean age 28 ± 5 years) referred for percutaneous pulmonary valve implantation to treat right ventricle–pulmonary artery conduit failure 11.1 ± 3.3 years after Ross procedure.

Results

Percutaneous pulmonary valve implantation was feasible in all 12 patients, with no procedural complications (procedure time 99 ± 16 minutes, fluoroscopy time 21 ± 6 minutes). Right ventricular outflow tract gradient during catheterization and pulmonary regurgitant fraction on magnetic resonance imaging fell after valve implantation (gradient 34 ± 6 to 14 ± 3 mm Hg, P < .01, regurgitant fraction 20% ± 6% to 2% ± 1%, P < .05). After restoration of right ventricular outflow tract function, indexed right ventricular end-diastolic volume decreased (91 ± 13 to 78 ± 12 mL · beat⁻¹ · m⁻², P < .01) and maximal cardiopulmonary exercise performance improved (peak oxygen consumption 25.4 ± 2.3 to 30.8 ± 3.0 mL · kg⁻¹ · min⁻¹, P < .01). During follow-up (18.8 ± 4.6 months), there was 1 device explantation (restenosis). The probabilities of freedom from right ventricular outflow tract reoperation were 100% at 1 year and 90% at 3 years.

Conclusions

Percutaneous pulmonary valve implantation provides an effective transcatheter treatment strategy to prolong the lifespan of right ventricle–pulmonary artery conduits after the Ross procedure, reducing the reoperation burden on patients with aortic valve disease.

Accuracy of intraoperative transesophageal echocardiography in the prediction of future neo-aortic valve function after the Ross procedure in children and young adults

OBJECTIVE

Neo-aortic insufficiency (neo-AI) has been noted following the Ross procedure. The purpose of this study was to evaluate the ability of intraoperative transesophageal echocardiography (TEE) to predict future neo-AI in pediatric patients undergoing the Ross from January 1995 to December 2003, who had an intraoperative TEE, and discharge and follow-up transthoracic (TTE) echocardiograms.

DESIGN

Retrospective case series.

PATIENTS

All patients who underwent the Ross procedure at Children's Hospital of Philadephia between January 1995 and December 2003, and had an intraoperative TEE, discharge, and follow-up (>6 months) transthoracic echocardiogram (TTE) (by July 1, 2004) were included.

OUTCOME MEASURES

Grade of neo-AI was assessed on intraoperative TEE, discharge, and follow-up TTE echocardiogram reports.

RESULTS

Follow-up was available in 99/115 (86%) survivors. Median age at Ross was 9.3 years (4 days-34 years). No patient had more than mild neo-AI on intraoperative TEE. At discharge, 2 patients (2%) had moderate neo-AI. At most recent follow-up (median 4.2 years, 8 months-9.3 years), 21 patients (21%) had moderate or greater neo-AI; 9 underwent neo-aortic reintervention. The presence of any neo-AI on intraoperative TEE had 100% sensitivity and negative predictive value for diagnosing moderate or greater neo-AI at discharge. Patients who had mild neo-AI on TEE were more likely to have moderate or greater neo-AI at most recent follow-up than those patients with no neo-AI on TEE (9% vs. 30%, P = 0.01).

CONCLUSION

Intraoperative TEE is an excellent screening tool for the presence of significant neo-AI at the time of hospital discharge. Neo-AI progresses over time after Ross procedure and is more likely to progress in those patients with neo-AI on intraoperative TEE. However, predictive validity decreases over time as neo-AI progresses.

Midterm outcomes and predictors of reintervention after the Ross procedure in infants, children, and young adults

OBJECTIVES

This study assessed the type, time course, and risk factors for right and left ventricular outflow tract reinterventions after the Ross procedure in a population of infants, children, and young adults.

METHODS

Patients who underwent the Ross procedure between January 1995 and June 2004 were included (n = 121 consecutive patients). Kaplan-Meier and hazard analyses of right and left ventricular outflow tract reinterventions were performed, and predictors of reintervention were identified through multivariate analysis.

RESULTS

The median age at the Ross procedure was 8.2 years (4 days to 34 years); 20% were aged less than 1 year. Half of the patients had isolated aortic valve disease; the other half had complex left-sided heart disease. Early mortality (<30 days) was 2.5% (n = 3). There were 2 late deaths (1.7%). Follow-up (median 6.5 years [2.5 months to 10.4 years]) was available for 96% of survivors (n = 111). Right ventricular outflow tract reintervention (n = 22 in 15 patients) was performed 2.0 years (2.0 weeks to 9.8 years) after the Ross procedure because of stenosis in 19 of 22 cases. Freedom from right ventricular outflow tract reintervention at 8 years was 81%. Smaller homograft size was the strongest predictor (P < .001) of right ventricular outflow tract reintervention. Left ventricular outflow tract reintervention (n = 15 in 15 patients) was performed 2.8 years (1.0 months to 11.6 years) after the Ross procedure because of severe neoaortic insufficiency in 10 of 15 patients. Freedom from left ventricular outflow tract reintervention at 8 years was 83%. Native pulmonary valve abnormalities (P < .01), original diagnosis of aortic insufficiency (P < .01), prior aortic valve replacement (P = .01), and prior ventricular septal defect repair (P = .04) predicted left ventricular outflow tract reintervention.

CONCLUSIONS

At midterm follow-up after the Ross procedure, interim mortality is rare. Neoaortic insufficiency and right ventricle to pulmonary artery conduit obstruction are common postoperative sequelae, requiring reintervention in one quarter of patients.

The Ross Procedure: Clinical and Echocardiographic Follow-Up in 219 Consecutive Patients

BACKGROUND

The replacement of the diseased aortic valve with a pulmonary autograft has been shown to provide excellent hemodynamic results and to be associated with low morbidity and mortality rates.

METHODS

From 1991 to 2005, 219 patients undergoing the Ross operation were identified. All patients underwent transthoracic echocardiography at discharge and were scheduled for a yearly study thereafter. The echocardiographic study consisted of a morphologic analysis of the pulmonary autograft with measurement of end-systolic diameters at three levels: annulus, sinuses of Valsalva, and origin of the ascending aorta 2 cm above the sinotubular junction. The dynamic analysis evaluated the function of the aortic autograft and the pulmonary homograft. Maximal and mean aortic and pulmonary transvalvular pressure gradients were investigated.

RESULTS

The 30-day mortality was 1.8% (n = 4). Cardiac deaths were not related to the autograft. The 10-year actuarial survival was 95.7% +/- 2.1%. Six patients (2.8%) had grade 2 autograft valve regurgitation. No grade 3 or 4 pulmonary regurgitation was identified. At their most recent follow-up, 28 patients (13.1%) had grade 1 insufficiency of the pulmonary homograft, and 10 patients (4.6%) had a peak transvalvular gradient of 17.9 +/- 10.2 mm Hg.

CONCLUSIONS

Our current experience suggests that replacement of the aortic root with a pulmonary autograft can be safely performed in infants, children, and adults and is associated with low mortality and morbidity rates. It constitutes an elegant alternative to the use of prosthetic valves in the treatment of aortic valve diseases.

What is the proper place of the ross procedure in our modern armamentarium?

Despite nearly four decades of experience, the role of pulmonary valve autotransplantation (Ross procedure) in the treatment of aortic valve disease in adults and children continues to evolve and remains controversial. As the picture of late results has unfolded, alternating waves of enthusiasm and caution have characterized its use and have led to ongoing refinements in indications and operative technique. At present, it is seen as indispensable in the treatment of aortic valve disease in infants and small children (for whom no satisfactory replacement alternative exists and for whom growth is essential), attractive for adolescents and young adults who wish to avoid anticoagulants because of childbirth and lifestyle considerations, a reasonable option for selected adults who desire biologic solutions with potentially better durability than conventional bioprostheses, and contraindicated for the elderly and those with connective tissue disorders. Young patients with bicuspid aortic valve are the most common potential recipients, but also the most controversial, because of the risk of autograft dilatation. Optimal matching of prosthesis to patient is a clinical challenge for all caretakers involved in the treatment of valvular heart disease; this review provides guidelines to identify those patients who will benefit most from the Ross procedure, and those for whom it is inadvisable.

The Ross operation: a Trojan horse?†

AIMS

The Ross operation is the operation of choice for children who require aortic valve replacement (AVR) and may also provide a good option in selected adult patients. Although the autograft does not require anticoagulation and has a superior haemodynamic profile, concern regarding autograft and allograft longevity has risen. In this light, we report the 13-year results of our prospective autograft cohort study.

METHODS AND RESULTS

Between 1988 and 2005, 146 consecutive patients underwent AVR with a pulmonary autograft at Erasmus Medical Center Rotterdam. Mean age was 22 years (SD 13; range 4 months-52 years), 66% were male. Hospital mortality was 2.7% (N = 4); during follow-up four more patients died. Thirteen-year survival was 94 +/- 2%. Over time, 22 patients required autograft reoperation for progressive neo-aortic root dilatation. In addition, eight patients required allograft reoperation. Freedom from autograft reoperation at 13 years was 69 +/- 7%. Freedom from allograft reoperation for structural failure at 13 years was 87 +/- 5%. Risk factors for autograft reoperation were previous AVR and adult patient age.

CONCLUSION

Although survival of the Rotterdam autograft cohort is excellent, over time a worrisome increase in reoperation rate is observed. Given the progressive autograft dilatation, careful follow-up of these patients is warranted in the second decade after operation.

Autografts, homografts, and xenografts: overview on stentless aortic valve surgery

Stentless valves, either human (autografts, homografts) or animal (porcine xenografts), were historically among the first substitutes to be used to replace the diseased aortic valve. Forty years after those pioneering days and 15 years after revival of such valves, stentless grafts have become a mainstay in aortic surgery. Although limitations associated with the use of autografts, homografts and xenografts remain, stentless valves have profoundly improved quality of life after aortic valve/root replacement. In addition, stentless surgery has greatly advanced the understanding of aortic root anatomy, physiology and pathology among surgeons.

Complications following the ross procedure: cardiac MRI findings

Aortic valve replacement with a pulmonary autograft (ie, Ross procedure) is a technique used in selected cases for the treatment of aortic valve disease. Aware of reports describing chronic complications after the Ross procedure such as aortic insufficiency, right ventricular outlet obstruction, aortic autograft dilatation, and pulmonary allograft stenosis, cardiac magnetic resonance imaging (MRI) was performed in individuals who had a previous Ross procedure (range 2 to 10 years earlier) to determine if these complications could be visualized by MRI. This case study presents the MRI findings of 5 patients (mean age: 42.0+/-7.8 years). In each patient, complications of the Ross procedure were observed. These results suggest that cardiac MRI has the potential to become a clinically important technique for evaluating post-Ross procedure patients.

Pulmonary homograft muscle reduction to reduce the risk of homograft stenosis in the Ross procedure

OBJECTIVE

The Ross procedure has gained increasing interest as an attractive alternative for aortic valve replacement. Despite its advantages, there is a certain risk of structural valve deterioration, especially of the pulmonary homograft as a result of shrinkage and subsequent stenosis predominantly at the muscular annulus. Theoretically, reduction of homograft muscle tissue could reduce this risk.

METHODS

From February 1996 through December 2002, a total of 238 patients (mean age 44 +/- 13.2 years) underwent the Ross procedure with the subcoronary technique with follow-up investigations before discharge and after 12 and 24 months. To estimate the importance of homograft muscle reduction within our institution-specific risk factor scale for change of transhomograft pressure gradient with time, we performed a generalized estimating equation approach, which identified homograft muscle reduction, higher body surface area in male patients, younger patient age, smaller homograft diameter, blood transfusions, and follow-up time as independent risk factors demonstrating a high beta value (-2.8638) for muscle reduction. To find out whether muscle reduction influences transhomograft pressure gradient, we compared patients with (group A, n = 39) and without (group B, n = 199) muscle reduction. The other mentioned independent risk factors were not different between groups, except for blood transfusions (group A greater than B, P < .01), indicating a negative bias for group A.

RESULTS

The maximum pressure gradient across the homograft was lower in patients with muscle reduction before discharge (4.5 +/- 2.8 mm Hg group A vs 6.2 +/- 3.8 mm Hg group B, P = .004) and after 1 (9.3 +/- 5.8 vs 13.1 +/- 8.4 mm Hg, P = .028) and 2 years (10.8 +/- 7.6 vs 13.7 +/- 7.5 mm Hg, P = .013). No significant differences were found concerning homograft insufficiency.

CONCLUSIONS

We provide some evidence that transhomograft pressure gradient can be reduced significantly within the first 2 years after operation by homograft muscle reduction. Longer term follow-up is necessary to evaluate this promising operative technique further.