What Is the Role of the Ross Procedure in Today's Armamentarium?

Novel Techniques and Technologies for Surgical Aortic Valve Replacement: A Large Retrospective Cohort Analysis

Background/Objectives: In an era of growing evidence for transaortic valve implantation (TAVI), our research topic was the evaluation of how surgical aortic valve replacements (SAVRs) are performing in terms of short- and long-term outcomes in different risk categories. Methods: This was a single centre, prospective, and observational cohort study of consecutive patients with aortic valve stenosis, undergoing isolated aortic valve replacement using a biological or mechanical prosthesis, Freestyle™ (Medtronic, Minneapolis, MN, USA) graft, homograft, or Ross procedure. The participant data were collected by review of an internal database. The primary endpoints were all-cause operative mortality (in hospital and at 30 days) and late mortality at the follow-up date. The secondary composite endpoint was the incidence of postoperative complications. Results: 1501 patients underwent SAVR; the mean age was 67 years (SD: 12.6). The in-hospital mortality was 1% (n = 16). At a median follow-up of 60 months, the survival rate was 98.7%. The main predictors for mortality were operative urgency and cardiogenic shock. The overall incidence of PPM was 2.3% (n = 34). Patients who underwent Ross procedure were younger (mean age: 20 years (SD: 1.7)), had a lower incidence of postoperative complications, and were all alive at follow-up. Conclusions: SAVR shows an excellent survival rate and a low rate of postoperative complications despite an increasing surgical risk. Recent advancements in technology, like sutureless/rapid deployment prostheses and minimally invasive techniques, are shown to have favourable effects on outcomes.

The Ross Procedure in Children and Infants: A Systematic Review With Pooled Analyses

Background

The Ross procedure is a surgical option for congenital aortic stenosis that involves replacing the diseased aortic valve with a pulmonary autograft. Little is known about outcomes in children, particularly those younger than 1 year.

Methods

A systematic review with pooled analyses was conducted according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) criteria. Inferred individual patient data were extracted from life tables. The primary end points were early (≤30 days) and late (>30 days) mortality rates following the Ross procedure in children. Secondary end points were freedom from reintervention for the right ventricular outflow tract and pulmonary autograft. These end points were assessed in the overall population of children. Sensitivity analyses were performed in subgroups younger than 1 year of age (infants) and in noninfant children.

Results

A total of 25 studies on 2737 patients met inclusion criteria. The pooled early survival rate was 96.0% (95% confidence interval [CI]: 95.1%-96.8%) overall and 86.8% (95% CI: 82.1%-90.3%) among infants. Pooled overall 10-year survival, freedom from pulmonary autograft reintervention, and freedom from right ventricular outflow tract reintervention rates were 91.1%, 90.2%, and 79.7%, respectively. Corresponding pooled rates in infants were 79.3%, 87.1%, and 51.2%. Mortality was significantly higher among infants compared with noninfant children (hazard ratio: 3.38, 95% CI: 2.44-4.68; P < 0.001). In metaregression analyses, younger age was strongly associated with poorer survival and higher reintervention rates.

Conclusions

Modest survival and autograft reoperation rates were observed following the Ross procedure in children. Surgery in infancy was strongly associated with poorer survival and higher reintervention rates.

Computational modeling reveals inflammation-driven dilatation of the pulmonary autograft in aortic position

The pulmonary autograft in the Ross procedure, where the aortic valve is replaced by the patient's own pulmonary valve, is prone to failure due to dilatation. This is likely caused by tissue degradation and maladaptation, triggered by the higher experienced mechanical loads in aortic position. In order to further grasp the causes of dilatation, this study presents a model for tissue growth and remodeling of the pulmonary autograft, using the homogenized constrained mixture theory and equations for immuno- and mechano-mediated mass turnover. The model outcomes, compared to experimental data from an animal model of the pulmonary autograft in aortic position, show that inflammation likely plays an important role in the mass turnover of the tissue constituents and therefore in the autograft dilatation over time. We show a better match and prediction of long-term outcomes assuming immuno-mediated mass turnover, and show that there is no linear correlation between the stress-state of the material and mass production. Therefore, not only mechanobiological homeostatic adaption should be taken into account in the development of growth and remodeling models for arterial tissue in similar applications, but also inflammatory processes.

The Ross Operation in Young Patients: A 15-Year Experience Focused on Right Ventricle to Pulmonary Artery Conduit Outcomes

Background

Data on long-term outcomes of the Ross operation in children and young adult patients are limited. The best pulmonary valve substitute for the right ventricular outflow tract reconstruction remains uncertain. This study aimed to assess the outcomes of right ventricular outflow tract reconstruction in the Ross operation in young patients using various pulmonary valve substitutes at a single institution. In addition, a comparison of reintervention rates between patients younger than 18 years and those older than 18 years was performed.

Methods

The study assessed all patients (N = 110) who underwent the Ross operation at the University Hospital of Bordeaux, France, between 2004 and 2020.

Results

The median follow-up time was 4.2 years, and the median age at operation was 15.9 years. There was no operative mortality and 1 late noncardiac death (0.8%). The overall survival rate at 10 years was 99.2%. The need for right ventricular outflow tract reoperation was lower with the pulmonary homograft compared with the Contegra conduit and Freestyle bioprosthesis: 94.3%, 93.8%, and 80% at 5 years, respectively, and 94.3%, 72.3%, and 34.3% at 10 years, respectively (P = 0.011). The probability of reintervention was not significantly different at 10 years among children vs adults (P = 0.22).

Conclusions

The Ross procedure in children and young adults was associated with a lower requirement for right ventricular outflow tract reoperation when pulmonary homografts were used instead of xenografts.

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.

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.

The Prospective Randomized On-X Valve Anticoagulation Clinical Trial (PROACT): Lower is better, but is it good enough?

Due to their durability, mechanical prostheses are frequently used for aortic valve replacement (AVR) in young adults. However, these valves are thrombogenic and require lifelong anticoagulation. Over the last few decades, efforts have been made towards the lowering of INR targets in an effort to reduce bleeding events without influencing the thromboembolic risk. The Prospective Randomized On-X Valve Anticoagulation Clinical Trial (PROACT) was designed to compare standard versus low anticoagulation targets in high-risk patients undergoing mechanical AVR with the ON-X prosthesis.

Imaging of the Postsurgical Thoracic Aorta: A State-of-the-Art Review

Techniques for repair of the aorta currently include open and endovascular methods, hybrid approaches, minimally-invasive techniques, and aortic branch vessel reimplantation or bypass. Collaboration among radiologists and vascular and cardiothoracic surgeons is essential. An awareness of the various surgical techniques, expected postoperative appearance, and potential complications is essential for radiologists. This review will cover the postoperative appearance of the thoracic aorta with a focus on the ascending aorta. The value of three-dimensional image evaluation will also be emphasized.

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.

Ross, Hybrid Arch, and Frozen Elephant Trunk Reconstruction for Late Complications of Bicuspid Aortic Valve and Aortopathy

Young patients with bicuspid aortic valve disease and aortopathy remain a clinical challenge, with many requiring multiple corrective operations throughout their lifetimes. Innovative surgical approaches are often required to address complex aortic pathologic conditions but leave patients at risk for reintervention, lifelong anticoagulation, and suboptimal hemodynamics. We describe an active 44-year-old female triathlete with recurrent bicuspid aortic stenosis, a small aortic root, a hypoplastic aortic arch and complex distal arch, and a descending aortic aneurysm, who underwent a single-stage reconstruction with a combined Ross procedure, hybrid arch, and frozen elephant trunk reconstruction.

Biomechanics of Failed Pulmonary Autografts Compared With Normal Pulmonary Roots

BACKGROUND

Progressive dilatation of pulmonary autografts after the Ross operation may reflect inadequate remodeling of the native pulmonary root to adapt to systemic circulation. Understanding the biomechanics of autograft root dilatation may aid designing strategies to prevent dilatation. We have previously characterized normal human pulmonary root material properties; however, the mechanical properties of failed autografts are unknown. In this study, failed autograft roots explanted during reoperation were acquired, and their material properties were determined.

METHODS

Failed pulmonary autograft specimens were obtained from patients undergoing reoperation after the Ross operation. Fresh human native pulmonary roots were obtained from the transplant donor network as controls. Biaxial stretch testing was performed to determine tissue mechanical properties. Tissue stiffness was determined at patient-specific physiologic stresses at pulmonary pressures.

RESULTS

Nonlinear stress-strain response was present in both failed autografts and normal pulmonary roots. Explanted pulmonary autografts were less stiff than were their native pulmonary root counterparts at 8 mm Hg (134 ± 42 vs 175 ± 49 kPa, respectively) (p = 0.086) and 25 mm Hg (369 ± 105 vs 919 ± 353 kPa, respectively) (p = 0.006). Autograft wall stiffness at both 8 and 25 mm Hg was not correlated with age at the Ross procedure (p = 0.898 and p = 0.813, respectively) or with time in the systemic circulation (p = 0.609 and p = 0.702, respectively).

CONCLUSIONS

Failed pulmonary autografts retained nonlinear response to mechanical loading typical of healthy human arterial tissue. Remodeling increased wall thickness but decreased wall stiffness in failed autografts. Increased compliance may explain progressive autograft root dilatation in autograft failures.

The Ross procedure: total root technique

We describe our technique for the Ross procedure using a total root technique without any foreign material for autograft support. We insist on technical principles, based on the surgical anatomy of the aortic and pulmonary root, aimed at optimizing aortic root dynamics while ensuring long-term stability of the autograft root.

Cardiac, obstetric, and fetal outcomes during pregnancy after biological or mechanical aortic valve replacement

BACKGROUND

The aim of this study was to assess pregnancy-related cardiac, maternal, and fetal outcomes in women who underwent aortic valve replacement (AVR).

METHODS

From 1978-2011, 67 women < 40 years of age underwent 74 isolated AVRs (52 mechanical prostheses and 22 bioprostheses). All patients were prospectively followed at our dedicated valve clinic. Patients with Turner syndrome, previous hysterectomy, or tubal ligation were excluded. Cardiovascular, obstetric, and fetal outcomes were gathered from medical records and telephone interviews.

RESULTS

A total of 27 pregnancies were reported in 14 patients (bioprosthetic AVR, n = 20; mechanical AVR, n = 7). In the bioprosthetic AVR group, the following adverse events occurred: hospitalizations for syncope (n = 2), prosthetic valve deterioration after pregnancy necessitating reintervention 6 months postpartum (n = 1), miscarriages (n = 9), and preterm birth (n = 1). In the mechanical AVR group, the following adverse events occurred: embolic myocardial infarctions with a decrease in systolic function (n = 2; 1 pregnancy was terminated and 1 was completed), miscarriage (n = 1), postpartum bleeding (n = 1), urgent cesarean section for placental abruption (n = 1), and preterm birth (n = 1).

CONCLUSIONS

Findings from this study suggest that pregnancies in women with mechanical AVRs are associated with a higher risk of cardiac and obstetric adverse events. Thus, from this limited cohort, it appears that pregnancies in women with bioprostheses are safer than those in patients with mechanical AVRs.