Evaluation of native valve-sparing aortic root reconstruction with direct imaging--reimplantation or remodeling?

Effectiveness of intraoperative endoscopic evaluation in aortic valve repair with valve-sparing aortic root replacement: a comparison of short- and mid-term results

OBJECTIVES

Valve-sparing aortic root replacement requires expertise to predict repair results and prevent secondary aortic clamping for valve repair or replacement secondary to aortic valve insufficiency. Thus, intraoperative evaluation of the aortic valve using diastolic pressure at the aortic root may be helpful. The goal of this retrospective study was to compare the early and mid-term results of aortic valve repair with those of valve-sparing aortic root replacement using intraoperative endoscopic evaluation.

METHODS

We included 158 patients who underwent aortic valve repair with valve-sparing aortic root replacement at our hospital between December 2003 and January 2022. The patients were divided into a non-endoscopic evaluation group (group NE, n = 97; mean age 55 years) and an endoscopic evaluation group (group E, n = 61; mean age 51 years).

RESULTS

The incidence of a second aortic clamping for aortic valve insufficiency was significantly greater in group NE (17.5%) than in group E (1.6%; P = 0.002). The presence of none or trivial aortic valve insufficiency on transthoracic echocardiography at discharge in group E (87.6%) was significantly lower than in group NE (98.4%; P = 0.017). No significant difference in the cumulative incidence of recurrence of moderate AI (P = 0.47), hospitalization for heart failure (P = 0.84) and reoperation (P = 0.25) between groups NE and E.

CONCLUSIONS

Intraoperative endoscopic evaluation during aortic valve repair with valve-sparing aortic root replacement correlated with a lower incidence of second aortic clamping because of aortic valve insufficiency and effective aortic valve insufficiency control.

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 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.

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.

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.

In vitro evaluation of a new aortic valved conduit

BACKGROUND

This study examined whether the presence of a sinus of Valsalva equivalent in the KONECT RESILIA aortic valved conduit (Edwards Lifesciences, Irvine, Calif) improves valve hemodynamics, kinematics, and performance.

METHODS

A 28-mm KONECT RESILIA aortic valved conduit was used to create an in vitro flow test model, and the same aortic valved conduit model without a sinus section was used as a control. Particle image velocimetry and hydrodynamic characterization experiments were conducted in the vicinity of the valves in a validated left-heart simulator at 3 cardiac output levels. In addition, leaflet kinematics of the valves were determined through en face high-speed imaging.

RESULTS

The KONECT RESILIA aortic valved conduit model exhibited lower mean and peak transvalvular pressure gradients than the control model at all 3 cardiac outputs. In addition, its leaflets opened more fully than did those of the valved conduit without the sinuses, yielding greater effective and geometric orifice areas. It was found that the presence of the sinuses not only facilitated the development of larger and more stable vortices at the initial stages of the cardiac cycle but also helped to maintain these vortices during the late stages of the cardiac cycle, leading to smoother valve closure.

CONCLUSIONS

The KONECT RESILIA aortic valved conduit reproduces the bulged section of the aortic root corresponding to the sinuses of Valsalva. With this Valsalva-type conduit, larger orifice areas were observed, improving valve hemodynamics that may enhance performance.

Aortic Root Dynamics in Sleeve Aortic Sparing Procedure: Echocardiographic and Computational Studies

In Sleeve procedure, the leaflets-sinus unit is maintained. We hypothesized that this feature partially preserves aortic root (AR) dynamics and leaflets kinematics and limits tensions in the leaflets. We tested our hypothesis based on in vivo and computational assessment of leaflets and AR dynamics. AR and aortic leaflet kinematics was assessed by transthoracic echocardiography in 10 patients treated with the Sleeve procedure and in 10 healthy patients. Numerical calculations with the Finite Element Method were performed to support the analysis of the clinical results and provide a better understanding of the behavior of the AR treated via the Sleeve procedure. Echocardiographic evidence showed that AR expansion in the Sleeve group was partially preserved as compared to the Control group (2.9 ± 2.5% vs 7.7 ± 6.3%, P = 0.038) and of the sinotubular junction (2.9 ± 1.5% vs 7.3 ± 3.8%, P = 0.003), and significantly preserved at the Valsalva sinuses level (6.7 ± 2.6% vs 9.5 ± 4.3%) with not statistically significant differences (P = 0.11). In none of the cardiac phases, differences in aortic valve leaflets kinematics were measured between the 2 groups; computational results were rather consistent with this evidence. Computational results well matched echocardiographic evidences, allowing for their mechanistic interpretation. Near-normal opening and closing characteristics can be accomplished by a technique that preserves the shape and the dynamics of the Valsalva sinuses. Whether the substantial preservation of the AR distensibility and leaflets kinematics observed in this study will favorably affect long-term valve durability it remains to be ascertained.

Perspective: valve sparing root repair: tips and tricks

The remodeling and the reimplantation procedures were described more than 25 years ago with the aim of sparing otherwise normal aortic valves in the presence of a root aneurysm. Important achievements in this discipline have occurred over the past decade including development and refinement of valve preserving aortic root replacement techniques, development of a classification system for aortic insufficiency, and development of surgical approaches to cusp disease with varying cusp anatomy. The main advantage of the reimplantation is the resulting annular support, and the disadvantages are the unfavorable hemodynamics and relatively longer procedural time. Conversely, the main advantages of remodeling are the physiological hemodynamics and the shorter procedural time, and the disadvantage is the lack of annular support. With technical advances and modifications, however, the differences between these two procedures have narrowed. Today preference for a reimplantation procedure is based on the perception of a better reproducibility of the surgical procedure, an increased procedural safety due to the characteristic hemostatic feature of this surgical approach, the possibility of achieving favorable hemodynamics, and a much larger amount of data present in the literature on long-term results.

Should the annulus be fixed in aortic valve-sparing root replacement with remodeling?

OBJECTIVES

If the aortic root dilates after native aortic valve-sparing root reconstruction with remodeling, aortic regurgitation may recur. However, it has not been demonstrated clearly that the aortic root dilates after remodeling.

METHODS

This study enrolled 15 patients who underwent an aortic valve-sparing operation with remodeling (2002-2014) but without any ventriculo-aortic junction (VAJ) fixation. Technically, special care was taken to pass the sutures through the fibrous annulus. The diameter of the aortic root (VAJ, neosinus of Valsalva, and sinotubular junction), degree of aortic regurgitation, and effective height of the aortic valve were measured in the patients. All patients had postoperative follow-up, and the median follow-up period was 7.3 (IQR: 3.1-8.3) years.

RESULTS

The mean preoperative diameters of the VAJ, sinus of Valsalva, and sinotubular junction were 23.5 ± 2.3 (20-27) mm, 51.1 ± 7.2 (43-60) mm, and 42.4 ± 9.4 (29-58) mm, respectively. The postoperative diameters of the VAJ changed from 21.6 ± 2.6 (early) to 21.8 ± 2.9 mm (late) (p = 0.75). The diameters of the sinus of Valsalva and sinotubular junction changed from 26.5 ± 3.0 (early) to 28.5 ± 4.2 mm (late) (p = 0.0013), and 22.4 ± 3.0 (early) to 24.3 ± 3.3 mm (late) (p = 0.0003), respectively. The effective height of the aortic valve changed from 9.7 ± 1.3 (early) to 8.9 ± 2.0 mm (late) (p = 0.08). The degree of aortic regurgitation (grade: 0-4) changed from 0.3 ± 0.5 (early) to 1.2 ± 0.8 (late) (p = 01558).

CONCLUSIONS

Significant VAJ dilation and changes in aortic valve configuration after our remodeling procedure were not observed. Therefore, fixation of the annulus with remodeling may not be needed for cases without preoperative dilation of the annulus.

Long-term results of the valve reimplantation technique using a graft with sinuses

OBJECTIVE

Aortic valve reimplantation is the most commonly used technique to spare the aortic valve. Long-term results data are scarce and available only with the use of standard straight graft. We examined the long-term results of reimplantation of the aortic valve using a graft incorporating sinuses of Valsalva.

METHODS

From May 2000 to December 2014, 124 patients had an aortic valve reimplanted into a graft with sinuses of Valsalva. The mean age was 53 ± 13 years and the majority were men (87%). Marfan syndrome was present in 21 patients (17%) and 12% had a bicuspid valve. Patients were prospectively followed by means of transthoracic echocardiography. The mean follow-up was 63 ± 52 months.

RESULTS

Overall survival at 5, 10, and 13 years was 94.4% ± 2.2%, 90.5% ± 4.4%, and 81.4% ± 7.3%, respectively. Six patients required reoperation within a time frame of 6 to 96 months. None of the patients died at reoperation. Freedom from reoperation was 95.4% ± 2.3% at 5 years and 90.1% ± 4.3% at 10 and 13 years. All patients who needed reoperation had surgery during the first 5 years. Three patients had residual aortic insufficiency >2. Considering also all patients who underwent reoperation because of aortic insufficiency, freedom from moderate to severe residual aortic insufficiency was 94.1% ± 2.6% at 5 years, and 87.1% ± 4.7% at 10 and 13 years.

CONCLUSIONS

The majority of patients who had their valve reimplanted in a graft with sinuses continue to perform well after 10 years.

In vitro hydrodynamics, cusp-bending deformation, and root distensibility for different types of aortic valve–sparing operations: Remodeling, sinus prosthesis, and reimplantation

OBJECTIVE

Preserving aortic valve cusps during operations for aortic root pathology theoretically offers several advantages over alternative prosthetic valve-bearing conduits. Functional properties of different valve-sparing techniques under defined conditions are not well studied.

METHODS

Fresh porcine aortic roots were investigated in a pulsatile flow simulator, either native root or after different types of valve-sparing procedures (remodeling, sinus prosthesis, and reimplantation). Functional parameters, such as transvalvular pressure gradient, closing volume, cusp-bending deformation, and distensibility at different levels of the root were analyzed.

RESULTS

The mean pressure gradient was highest in reimplantation techniques (8.4 +/- 1.8 mm Hg) compared with sinus prostheses (7.2 +/- 0.9 mm Hg, P = .01) and remodeling techniques (6.8 +/- 1.0 mm Hg, P = .002), mirror imaging the closing volume (reimplantation, 1.5 +/- 0.4 mL; sinus prostheses, 2.3 +/- 0.7 mL [P < .001]; remodeling, 3.4 +/- 1.1 mL [P < .001]). Bending deformation indices increased significantly from remodeling (0.45 +/- 0.05) and sinus prostheses (0.58 +/- 0.06) to reimplantation techniques (0.73 +/- 0.09). Dynamic changes in area of all techniques were decreased at the sinotubular junction and the commissural and sinus levels when compared with those seen in native roots but increased at the annular level for techniques with unfixed annulus (remodeling and modified sinus prosthesis).

CONCLUSIONS

In vitro the various aortic valve-sparing operations differed characteristically in their ability to spare valve function, none of them completely meeting native valve behavior. The remodeling techniques exhibited valve dynamics closest to those of the native aortic root. The more the aortic valve is fixed with noncompliant prosthetic material, the more the native root dynamics are impaired.

Valve-Sparing Aortic Root Repair With Patch Technique

BACKGROUND

In the valve-sparing aortic root repair technique presented, each pathologic sinus is replaced with a teardrop-shaped patch. In this study, the clinical and echocardiographic results after the first 20 procedures are evaluated.

METHODS

Between September 2000 and May 2004, 20 patients underwent aortic root repair using a patch technique. Eight patients had an acute type A aortic dissection and 12 patients had an aneurysm of the ascending aorta. In 12 cases, the aortic root was reconstructed with three patches, in 1 case with two patches, and in 7 cases with one patch.

RESULTS

The postoperative echocardiography at discharge showed no aortic regurgitation in 15 cases and trivial regurgitation in 5 cases. Three patients with aortic dissection as an initial pathologic diagnosis died during a median follow-up period of 14.5 months (range, 0.5 to 32 months). At the time of follow-up, the echocardiographic findings in all 17 survivors remained unchanged from the early postoperative examinations. Median peak and mean transvalvular gradients were 8 mm Hg (range, 3.2 to 14 mm Hg) and 4 mm Hg (range, 1.7 to 6 mm Hg), respectively.

CONCLUSIONS

The technique presented allows an individualized reconstruction of the sinuses of Valsalva, a simplified sizing of the vascular graft, and the creation of a new sinotubular junction resulting in good hemodynamic conditions. The technique is especially advantageous in patients in whom replacement of all sinuses is not necessary.