Late Pulmonary Autograft Dilation: Can We Make a Good Operation Great? The Supported Ross

The Ross procedure is an excellent option for aortic valve replacement resulting in outstanding hemodynamic performance and the ability to avoid systemic anticoagulation. The long-term durability of the autograft is generally good but concerns for later aortic root dilation with ensuing neoaortic insufficiency have prompted efforts to stabilize the autograft, root, sinuses and Sino-tubular junction in order to delay or entirely avoid late reinterventions on the neoaortic root. We have employed an inclusion technique, supporting the Auto-graft in a Terumo Gelweave™ Valsalva graft. We performed a retrospective study of all 129 patients undergoing the Ross procedure from 1992 to 2019 at Children's Wisconsin. Fifty-one underwent the supported Ross (SR) and 78 underwent unsupported Ross (UR). Structured clinical data was collected and echocardiograms were reviewed. Median follow-up was 4.9 years (up to 22.6 years) for UR patients and 3.6 years (up to 11.4 years) for SR patients. In order to provide a fair comparison, we sub -analyzed patients aged 10 to 18 years who underwent the Ross procedure, 16 who underwent the UR and 18 patients who underwent the SR. Change in aortic annulus diameter (P = 0.002), aortic sinus diameter (P = 0.001) change in left ventricular function (P = 0.039) and change in aortic insufficiency (P = 0.008) were all worse in UR. The SR is simple, reproducible, and predictable. It seems to prevent change in annulus diameter, sinus diameter and to reduce late neoaortic insufficiency. Longer follow-up with a larger group of patients is required to draw definitive conclusions.

Long-term autograft dilation and durability after the Ross procedure are similar in infants, children, and adolescents with primary aortic stenosis

BACKGROUND

Autograft durability and remodeling are thought to be superior in younger pediatric patients after the Ross operation. We sought to delineate the fate of autografts across the pediatric age spectrum in patients with primary aortic stenosis (AS).

METHODS

We retrospectively reviewed patients age ≤18 years with primary AS who underwent the Ross operation between 1993 and 2020. Patients were categorized by age. The primary endpoint was autograft dimensional change, and secondary endpoints were severe neo-aortic insufficiency (AI) and autograft reintervention.

RESULTS

A total of 119 patients underwent the Ross operation, including 37 (31.1%) in group I (age <18 months), 24 (20.2%) in group II (age 18 months-8 years), and 58 (48.7%) in group III (age 8-18 years). All groups exhibited similar annular growth rates within the first 5 postoperative years, followed by a collective decrease in annulus growth rates from year 5 to year 10. Group III experienced rapid sinus dilation in the first 5 years, followed by stabilization of the sinus z-score from year 5 to year 10, whereas groups I and II demonstrated stable sinus z-scores over 10 years. There were 4 early deaths (3.4%) and 2 late deaths (1.7%) at a median follow-up of 8.1 years (range, 0.01-26.3 years). At 15 years, the incidences of severe neo-AI (0.0 ± 0.0% vs 0.0 ± 0.0% vs 3.9 ± 3.9%; P = .52) and autograft reintervention (8.4 ± 6.0% vs 0.0 ± 0.0% vs 2.4 ± 2.4%; P = .47) were similar in the 3 groups.

CONCLUSIONS

Age at the time of Ross operation for primary AS does not influence long-term autograft remodeling or durability. Other physiologic or technical factors are likely greater determinants of autograft fate.

Unicuspid Aortic Valve in Patients Undergoing the Ross Procedure

BACKGROUND

The prevalence and outcomes of the unicuspid aortic valve (UAV) in patients undergoing the Ross procedure have been strongly underreported in the current literature. We sought to evaluate this in comparison with bicuspid (BAV) and tricuspid valve (TAV) in our Ross cohort.

METHODS

This was a retrospective observational study of patients undergoing the Ross procedure at 2 dedicated centers between 2009 and 2020. Primary end points were the risks of midterm autograft reoperation and the onset of at least moderate aortic regurgitation during follow-up. The secondary end point was to compare the perioperative outcomes between the groups.

RESULTS

Included in the analysis were 286 patients, of those 39% with UAV, 52% with BAV, and 9% with TAV. UAV patients were operated on at the youngest age (P < .001) and more often for a combined hemodynamic aortic valve pathology (P = .02). They had the largest aortic root dimensions: annulus (P = .01), Valsalva sinuses (P = .11), sinotubular junction (P = .001), and ascending aorta (P < .0001). The risks of reoperation (P = .86) and the onset of aortic regurgitation (P = .75) were comparable among the groups over the follow-up of 4.1 years. There was no difference in perioperative outcomes.

CONCLUSIONS

UAV is a separate unit characterized by a distinct hemodynamic pathology and generated aortopathy. It is not associated with a higher risk of reoperation or new onset of aortic regurgitation after the Ross procedure in the midterm postoperatively. At the current state, UAV remains acceptable for the Ross procedure.

The Supported vs Unsupported Ross in Pediatric Patients: Neoaortic Root and Ventricular Function

BACKGROUND

The supported Ross is used to mitigate the neoaortic root dilation that has been described with the unsupported Ross. There is limited literature assessing the efficacy of the supported Ross in young patients. In this study, the fate of the neoaortic root was compared in the supported and unsupported Ross procedure in adolescent patients.

METHODS

A retrospective review was performed of patients who underwent the Ross procedure between 1996 and 2019. An analysis was conducted of patients aged 10 to 18 years who underwent the supported and unsupported Ross operation, without a Konno enlargement, to assess for longitudinal echocardiographic changes. Given differences in follow-up time, both regression analysis and Mann-Whitney nonparametric tests were used to correct for time from discharge to most recent follow-up.

RESULTS

The median follow-up time for supported and unsupported Ross patients without a Konno enlargement was 2.90 years (0.21-13.03 years) and 12.13 years (2.63-19.47 years), respectively. Unsupported Ross patients experienced a higher rate of change per year in the aortic annulus (P = .003 and P = .014) and aortic sinus (P = .002 and P = .002) diameters, respectively. There was no significant difference in the rate of change of end-diastolic left ventricular internal diameter (P = .703 and P = .92) and aortic insufficiency (P = .687 and P = .215) between the supported and unsupported Ross patients.

CONCLUSIONS

Progressive dilation of the neoaortic root in unsupported Ross patients is significantly mitigated with the supported Ross with excellent stability. The supported Ross is safe and effective and may play an increasing role in the management of children with aortic disease.

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.

Ross procedure for acute infective endocarditis

Surgical treatment of infective endocarditis remains a challenge, with concerns of optimal prosthesis selection and risks of recurrent infection remaining paramount. The pulmonary autograft has unique features which may make it the ideal aortic valve substitute, especially in infectious endocarditis. We describe strategic considerations and technical details in performing a Ross procedure in a young patient with acute aortic valve endocarditis.

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.

Ross procedure provides survival benefit over mechanical valve in adults: a propensity-matched nationwide analysis

OBJECTIVES

The choice of optimal surgical treatment for young and middle-aged adults with aortic valve disease remains a challenge. Mechanical aortic valve replacement (mAVR) is generally preferred despite promising recent outcomes of the Ross procedure. Our goal was to compare the strategies at a nationwide level.

METHODS

This study was a retrospective analysis of prospectively recorded data from the National Registry of Cardiac Surgery of the Czech Republic. Using propensity score matching, we compared the outcomes of patients undergoing the Ross procedure in 2 dedicated centres with all mAVRs performed in country between 2009 and 2020.

RESULTS

Throughout the study period, 296 adults underwent the Ross procedure and 5120 had an mAVR. We found and compared 291 matched pairs. There were no in-hospital deaths, and the risk of perioperative complications was similar in both groups. Over the average follow-up period of 4.1 vs 6.1 years, the Ross group had a lower all-cause mortality (0.7 vs 6.5%; P = 0.015). This result remained significant even when accounting for cardiac- and valve-related deaths only (P = 0.048). Unlike the Ross group, the mAVR group had a significantly lower relative survival compared with the age- and sex-matched general population. There was no difference in the risk of reoperation (4.5 vs 5.5%; P = 0.66).

CONCLUSIONS

The Ross procedure offers a significant midterm survival benefit over mAVR. The procedures have a comparable risk of perioperative complications. Patients after mAVR have reduced survival. Thus, the Ross procedure should be the preferred treatment option for young and middle-aged adults with aortic valve disease in dedicated centres.

Understanding Pulmonary Autograft Remodeling After the Ross Procedure: Stick to the Facts

The Ross, or pulmonary autograft, procedure presents a fascinating mechanobiological scenario. Due to the common embryological origin of the aortic and pulmonary root, the conotruncus, several authors have hypothesized that a pulmonary autograft has the innate potential to remodel into an aortic phenotype once exposed to systemic conditions. Most of our understanding of pulmonary autograft mechanobiology stems from the remodeling observed in the arterial wall, rather than the valve, simply because there have been many opportunities to study the walls of dilated autografts explanted at reoperation. While previous histological studies provided important clues on autograft adaptation, a comprehensive understanding of its determinants and underlying mechanisms is needed so that the Ross procedure can become a widely accepted aortic valve substitute in select patients. It is clear that protecting the autograft during the early adaptation phase is crucial to avoid initiating a sequence of pathological remodeling. External support in the freestanding Ross procedure should aim to prevent dilatation while simultaneously promoting remodeling, rather than preventing dilatation at the cost of vascular atrophy. To define the optimal mechanical properties and geometry for external support, the ideal conditions for autograft remodeling and the timeline of mechanical adaptation must be determined. We aimed to rigorously review pulmonary autograft remodeling after the Ross procedure. Starting from the developmental, microstructural and biomechanical differences between the pulmonary artery and aorta, we review autograft mechanobiology in relation to distinct clinical failure mechanisms while aiming to identify unmet clinical needs, gaps in current knowledge and areas for further research. By correlating clinical and experimental observations of autograft remodeling with established principles in cardiovascular mechanobiology, we aim to present an up-to-date overview of all factors involved in extracellular matrix remodeling, their interactions and potential underlying molecular mechanisms.

Ross Operation with Autologous External Autograft Stabilization - Long-term Results

BACKGROUND

We have proposed an external stabilization technique to minimize autograft dilatation after the Ross operation. The aim of this study was to analyze autograft function and root dimensions following root replacement with and without external root support.

METHODS

Between 10/1995 and 02/2021, 185 adult patients (73% male; age 38±9 years) underwent a Ross operation as full-root replacement with (n=136) or without support (n=49). Autograft function and root dimensions were determined echocardiographically. Median follow-up was 3.4[1.13-14.74] years; it was 95% complete. Survival and freedom from reoperation were calculated; changes in autograft root dimensions were analyzed using mixed-effect models.

RESULTS

Survival (95%) and freedom from autograft reoperation (94%) at 15 years were higher with than without support (p=0.003 or p=0.004). In the first five years, patients with support showed an indexed root size progression of 0.712mm/(year*m)(p=0.003) compared to 1.554mm/(year*m)(p=0.001) without. Progression rates were higher for patients without stabilization (p=0.045). After five years, progression rates were similar in both groups (0.248mm/(year*m)(p<0.001) with persistent difference between the groups.

CONCLUSIONS

The Ross procedure as full-root replacement is associated with a relevant rate of autograft dilatation and reoperation. The use of external root stabilization may reduce autograft dilatation and is associated with improved survival and durability.

The Ross procedure is an excellent operation in non-repairable aortic regurgitation: insights and techniques

The Ross procedure is the best operation to treat aortic stenosis (AS) in young and middle-aged adults. However, its role in non-repairable aortic regurgitation (AR) remains debated since many historical series have reported an increased risk of pulmonary autograft dilatation and subsequent need for reintervention in these patients. Some have attributed these findings to an unrecognized and poorly characterized inherited genetic defect that prevents adaptive remodelling of the pulmonary autograft. Herein, we review the contemporary evidence surrounding the use of the Ross procedure in young adults with AR and put forth the argument that with proper technical refinements, the Ross procedure may still be the best operation to treat these patients. We believe that by tailoring the operation to the patient's anatomy and ensuring strict postoperative blood pressure control, one can achieve excellent results with the Ross procedure, including in this challenging patient population.

Ross operation after failure of aortic valve repair

Background

Repair failure remains one of the most important complications of aortic valve reconstruction. Young patients might benefit from a Ross procedure in such a scenario, provided it can be performed safely and with adequate durability. The aim of this study was to assess the safety and clinical outcomes of a Ross operation following a failed repair.

Methods

Between 1996 and 2019, 80 patients (male, 76%; mean age, 31±13 years) underwent a Ross procedure after a median of 6.6 (1.7-15.9) years following an initial aortic valve repair. The previous valve repair was performed for unicuspid (53%), bicuspid (39%), tricuspid (7%), and quadricuspid morphology (1%). Median follow-up after the Ross operation was 2.8 (0.964-13.25) years, mean 5±5 years (92% complete).

Results

Median cardiopulmonary bypass and cross-clamp times were 144 [106-154] minutes and 98 [79-113] minutes, respectively. Thirty-two patients (40%) required a concomitant procedure, most commonly, an ascending aortic replacement (n=23). There were no peri-operative deaths, myocardial infarctions, or neurological complications. There was one late death from a non-cardiac cause. At 10 years, overall survival was 99%±1%, similar to that of an age- and gender-matched population. Nine patients required re-intervention after their Ross procedure (five on the autograft and four on the pulmonary conduit). The autograft re-interventions were valve-sparing procedures in all patients. The cumulative incidence of re-intervention on the autograft at 8 years was 5.1%±3.1%.

Conclusions

The stepwise strategy of an initial valve repair followed by Ross operation represents a safe and valid option for failed aortic valve repair. It is associated with low peri-operative morbidity. Mid-term survival is excellent, similar to that of a matched general population. The probability of re-intervention after the Ross procedure appears similar to that of a primary Ross operation, deeming it a warranted consideration in cases of failed aortic valve repair.

The Ross procedure is the optimal solution for young adults with unrepairable aortic valve disease

While aortic valve repair remains the ideal intervention to restore normal valvular function, the optimal aortic valve substitute for patients with a non-repairable aortic valve remains an ongoing subject for debate. In particular, younger patients with a non-repairable valve represent a unique challenge because of their active lifestyle and long life expectancy, which carries a higher cumulative risk of prosthesis-related complications. The Ross procedure, unlike prosthetic or homograft aortic valve replacement (AVR), provides an expected survival equivalent to that of the age and gender-matched general population. Contemporary data has shown that the Ross procedure can be performed safely in centers with expertise, and is associated with improved valvular durability, hemodynamics and quality of life.

AUTOGRAFT WRAPPING REINFORCEMENT IN ADOLESCENTS UNDERWENT ROSS OPERATION: A TAILORED COAT

BACKGROUND

The Ross operation is a good surgical option for pediatric population with aortic valve disease. However, the need for reoperation due to aortic root dilatation remains the principal limitation of this procedure. We report a small series of adolescents who underwent the Ross operation with goretex membrane reinforcement to avoid the progressive dilatation of the neo-aortic root.

METHODS

Between March 2002 and March 2010, 15 adolescent patients underwent a modified Ross procedure with the autograft wrapping with Gore® Preclude® pericardial membrane 0.1 mm. Follow-up was performed by clinical and echocardiographic controls.

RESULTS

The mean age of these patients was 15 ± 1.4 years. The mean aortic cross-clamp time was 130 ± 17 minutes. The mean cardiopulmonary bypass time was 187 ± 27 minutes. There was no hospital mortality. The mean follow-up was 15 ± 2.5 years (range 9.7-17.7 years). During the follow-up one patient required aortic valve reoperation for cusps prolapse. The mean diameters of annulus (22.8 ± 1.8 mm vs 23.3 ± 1.5 mm, p=0.12), aortic root (27.4±1.4 mm vs 28.2 ± 0.8 mm, p=0.09) and sino-tubular junction (24.3 ± 1.1 mm vs 25.1 ± 0.7 mm, p=0.11) were not statistically different between discharge and follow up.

CONCLUSIONS

The wrapping reinforcement autograft in Ross procedure with goretex membrane is simple, safe and does not require significant additional time. Our results showed good early and long-term outcomes in terms of reoperation, aortic root dilatation and aortic valve degeneration.

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.

Lights and Shadows on the Ross Procedure: Biological Solutions for Biological Problems

The Ross procedure represents a valid option for aortic valve replacement in young adults and was repeatedly shown to restore survival to that of the age- and sex-matched general population. However, its major drawback relies in the risk of pulmonary autograft (PA) dilation, negative histological remodeling and need for reoperation. Several techniques and materials to reinforce the PA have been proposed. They mainly include Dacron, personalized external aortic root support with a polyethylene terephthalate mesh system, autologous aortic tissue and bioresorbable materials. Synthetic materials, despite widely used in cardiac surgery, have significant biocompatibility issues with the PA and their interaction with this living structure translates into negative remodeling phenomena and disadvantageous biomechanical behaviors. Conversely, biomaterials with tailored degradable profiles might be able to reinforce while integrating with the PA and enhance its remodeling capabilities. The recent advancement in this field are here discussed.

A review of pulmonary autograft external support in the Ross procedure

Introduction: Although the Ross procedure offers several advantages over standard prosthetic AVR, its use remains limited. The risk of pulmonary autograft dilatation requiring reintervention remains one of the main concerns. Consequently, multiple techniques have been developed in attempt to mitigate this complication.Areas covered: This article reviews the incidence of pulmonary autograft dilatation, its risk factors and pathophysiology. The techniques of external pulmonary autograft support are discussed along with their respective advantages and limitations. Finally, future areas of research and developments are examined.Expert opinion: The risk of autograft dilatation is mainly prevalent in patients with aortic regurgitation and a dilated aortic annulus. In these selected patients, an external support may prevent dilatation of the autograft. However, any permanent support potentially restricts autograft root motion, mitigating some of the advantages associated with the Ross procedure. A bioresorbable matrix that could support the root during its initial adaptative phase could alleviate this problem. In our opinion, aggressive blood pressure control during the first postoperative year along with annular and sino-tubular junction support in selected patients provides optimal stability of autograft root dimensions while preserving root dynamics. Serial imaging and clinical follow-up are necessary to define the role of these various strategies.