The Ross procedure: total root technique

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.

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.

Wall stresses of early remodeled pulmonary autografts

OBJECTIVE

The Ross procedure is an excellent option for children or young adults who need aortic valve replacement because it can restore survival to that of the normal aged-matched population. However, autograft remodeling can lead to aneurysmal formation and reoperation, and the biomechanics of this process is unknown. This study investigated postoperative autograft remodeling after the Ross procedure by examining patient-specific autograft wall stresses.

METHODS

Patients who have undergone the Ross procedure who had intraoperative pulmonary root and aortic specimens collected were recruited. Patient-specific models (n = 16) were developed using patient-specific material property and their corresponding geometry from cine magnetic resonance imaging at 1-year follow-up. Autograft ± Dacron for aneurysm repair and ascending aortic geometries were reconstructed to develop patient-specific finite element models, which incorporated material properties and wall thickness experimentally measured from biaxial stretching. A multiplicative approach was used to account for prestress geometry from in vivo magnetic resonance imaging. Pressure loading to systemic pressure (120/80) was performed using LS-DYNA software (LSTC Inc, Livermore, Calif).

RESULTS

At systole, first principal stresses were 809 kPa (25%-75% interquartile range, 691-1219 kPa), 567 kPa (485-675 kPa), 637 kPa (555-755 kPa), and 382 kPa (334-413 kPa) at the autograft sinotubular junction, sinuses, annulus, and ascending aorta, respectively. Second principal stresses were 360 kPa (310-426 kPa), 355 kPa (320-394 kPa), 272 kPa (252-319 kPa), and 184 kPa (147-222 kPa) at the autograft sinotubular junction, sinuses, annulus, and ascending aorta, respectively. Mean autograft diameters were 29.9 ± 2.7 mm, 38.3 ± 5.3 mm, and 26.6 ± 4.0 mm at the sinotubular junction, sinuses, and annulus, respectively.

CONCLUSIONS

Peak first principal stresses were mainly located at the sinotubular junction, particularly when Dacron reinforcement was used. Patient-specific simulations lay the foundation for predicting autograft dilatation in the future after understanding biomechanical behavior during long-term follow-up.

Pulmonary Autograft Coronary-Cameral Fistula Leading to LVOT Pseudoaneurysm Post Ross Procedure

We report the case of a presumed coronary-cameral fistula arising directly below the commissures of the noncoronary cusp (NCC) and left coronary cusp (LCC) of the pulmonary autograft, leading to left ventricular outflow tract pseudoaneurysm and late tamponade post Ross procedure.

Autograft remodeling after the Ross procedure by cardiovascular magnetic resonance imaging: Aortic stenosis versus insufficiency

BACKGROUND

Studies suggest that patients undergoing the Ross procedure for aortic insufficiency are at greater risk of autograft dilatation than those with aortic stenosis. By using a tailored Ross technique to mitigate autograft dilatation in patients with aortic insufficiency, we aimed to compare the biomechanical and morphologic remodeling of the autograft at 1 year between patients with aortic insufficiency and patients with aortic stenosis.

METHODS

A total of 210 patients underwent a Ross procedure (2011-2016). Of those, 86 patients (mean age 43 ± 13 years; 32% were female) completed preoperative and postoperative cardiovascular magnetic resonance imaging. A total of 71 studies were suitable for analysis: 41 patients with aortic stenosis and 30 patients with aortic insufficiency. Nine healthy adults were used as controls. Autograft root dimensions, individual sinus volumes, and distensibility were measured using cardiovascular magnetic resonance.

RESULTS

At 1 year, there was no difference in autograft root dimensions between patients with aortic stenosis (mean annulus 25.1 ± 3.1 mm and sinus diameters 35 ± 4.1 mm) and patients with aortic insufficiency (26.6 ± 3 mm and 37.1 ± 3.5 mm; P = .12 and .06, respectively). Relative sinus of Valsalva volumes were symmetrical in the aortic stenosis (right 34.8% ± 4%, left 33.7% ± 3.5%, noncoronary 31.4% ± 3.2%) and aortic insufficiency groups (34.8% ± 3.9%, 33.8% ± 2.8%, 31.3% ± 3.7%, P = .85, .92, and .82), and similar to those of healthy adults. Aortic root distensibility was reduced in both groups compared with healthy adults (P = .003), but was similar between aortic stenosis (3.12 ± 1.58 × 10^-3 mm Hg^-1) and aortic insufficiency (3.04 ± 1.15 × 10^-3 mm Hg^-1; P = .9).

CONCLUSIONS

Using a tailored technique, there were no differences in the morphologic or biomechanical remodeling of the autograft root 1 year after the Ross procedure between patients with aortic stenosis and patients with aortic insufficiency. However, autograft roots are stiffer than native aortic roots.

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 Ross procedure: time for a hard look at current practices and a reexamination of the guidelines

The ideal aortic valve substitute for young adults requiring aortic valve replacement (AVR) remains elusive. Young and middle-aged patients have a longer anticipated life expectancy and a higher level of physical activity than their elderly counterparts. In recent years, there has been a growing focus on long-term outcomes following AVR in this specific patient population. These studies highlight the direct impact of the choice of prosthesis on long-term survival, quality of life and rates of valve-related complications in younger adults. Although conventional AVR using a biological or mechanical prosthesis significantly improve the natural history of the disease, there are many inherent limitations, which need to be addressed. Despite declining use of the Ross procedure in recent years, several long-term registry, cohort and comparative studies in the last decade, indicate a clear role for this operation in young and middle-aged adults requiring AVR. These advantages are manifest in terms of long-term survival, freedom from valve-related complications and quality of life. In this Perspective article, we discuss findings from a recently published propensity-matched analysis of long-term outcomes following mechanical AVR versus the Ross procedure, showing better cardiac- and valve-related survival in the Ross cohort, lower rates of stroke and major bleeding and equal rates of reoperation at 20 years. These data are placed in the broader context of currently available evidence regarding the Ross procedure and a broader discussion pertaining to its role in today's practice and the need to reexamine current valvular guidelines so they are more reflective of the actual evidence.

Successful Repair of a Bicuspid Pulmonary Autograft Valve Causing Early Insufficiency After a Ross Procedure

The Ross procedure is an excellent option in terms of long-term outcomes for young patients requiring aortic valve replacement. We report the case of a 49-year-old woman who presented with worsening dyspnea and episodes of presyncope in the context of a patient-prosthesis mismatch, 13 years after mechanical aortic valve replacement. She underwent a Ross procedure despite the pulmonary valve being bicuspid at intraoperative examination. Following implantation, the autograft valve showed an eccentric jet of regurgitation requiring bicuspid valve repair. To our knowledge, this is the first reported case of successful repair of a bicuspid pulmonary autograft valve.