In vivo testing of an intra-annular aortic valve annuloplasty ring in a chronic calf model

A modern approach to aortic valve insufficiency: Aortic root restoration via HAART 300 internal annuloplasty ring

BACKGROUND AND AIM OF THE STUDY

HAART 300 is an internal geometric annuloplasty ring. The safety and efficacy of this novel device in aortic valve (AV) repair in a single referral center are reported.

METHODS

Twenty patients with trileaflet AV insufficiency with ascending aorta and/or aortic root enlargement were included. Subannular implantation was performed to correct annular dilatation, whereas concomitant leaflet repair was performed whenever required. All but two patients also received ascending aorta replacement, whereas selective sinus replacement was performed in all but five patients.

RESULTS

Follow-up was for a maximum of 3.8 years and a mean of 2.2 years. Mean age was 54.2 years old. Moderate to severe preoperative AV insufficiency was noted in 75% of patients, whereas 70% of them had an ascending aorta over 45 mm. One patient was lost from follow-up. Overall mortality as well as major complication rates were zero. Early postoperatively, no more than mild AV regurgitation was detected, whereas only one patient appeared with moderate AV regurgitation during our 2.2-year follow-up. New York Heart Association class was also significantly lower compared to preoperative values and valve gradients remained low at last follow-up.

CONCLUSIONS

Geometric ring annuloplasty is a safe and effective valve sparing approach to deal with AV insufficiency contributing to overall root reconstruction. Short-term results are excellent rendering this easily reproducible and versatile method very attractive.

Aortic annulus and the importance of annuloplasty

Dystrophic aortic insufficiency accounts for the majority of Western cases of aortic insufficiency and can be divided into the three phenotypes of isolated aortic insufficiency, dilated aortic root, and dilated ascending aorta. Each of these phenotypes is associated with a dilated annulus and/or sinotubular junction. Recent international guidelines recommend reimplantation or remodeling with aortic annuloplasty for valve-sparing root replacement, as well as consideration of aortic valve repair in cases of aortic insufficiency. A dilated aortic annulus is a major risk factor for failure of aortic valve repair procedures, indicating the need to address the annulus at the time of aortic valve or root repair. Calibrated annuloplasty should be performed at sub- and supravalular levels in order to restore the ratio of the sinotubular junction and annulus and be adapted according to the phenotype of the root and ascending aorta. Standardization of aortic valve repair techniques with use of a calibrated annuloplasty will improve dissemination of techniques and rate of aortic valve repair. Current medical evidence shows that aortic valve repair is safe, produces better quality of life, and reduces valve-related mortality compared to prosthetic valve replacement.

Balloon Transcatheter Aortic Valve Replacement After Aortic Valve Repair With HAART 300 Device

The HAART 300 (BioStable Science and Engineering, Austin, TX) is a rigid, elliptical device introduced to facilitate aortic valve repair providing annular stabilization in the setting of aortic regurgitation. Percutaneous strategies have been described for patients with dysfunctional biological prostheses or recurrence insufficiency after mitral ring annuloplasty. This report shows the feasibility of aortic valve-in-ring transcatheter aortic valve replacement (TAVR). The sufficient ring stability to support the implanted TAVR-prosthesis and the fact that the elliptical shape of the HAART-ring did not result in a problem concerning paravalvular leakage were important for the success of this procedure.

Geometric changes in the aortic valve annulus during the cardiac cycle: impact on aortic valve repair

OBJECTIVES

The growing experience in aortic valve (AV) repair showed that annular stabilization is a crucial component to achieve stable long-term results after AV repair. Dynamic changes in the AV annulus during the cardiac cycle may have an impact on annuloplasty design.

METHODS

We retrospectively analysed full cardiac cycle multislice computed tomography data from 58 consecutive patients (mean age 75.9 ± 6.5 years, 36% men) with normally functioning tricuspid AVs (normal AV subgroup). The following computed tomography parameters were measured during systole and diastole: maximum, minimum and mean AV annulus diameter, AV annular area and AV annular perimeter. The AV annular eccentricity index was calculated (%) [(max AV annulus × 100/min AV annulus) - 100] in systole and diastole. Subsequently, multislice computed tomography data from 20 patients with severe aortic regurgitation were analysed [aortic valve regurgitation (AR) subgroup].

RESULTS

In the normal AV subgroup, there was a significant decrease in the mean AV annulus diameter from systole to diastole (i.e. 24.6 ± 2.5 mm vs 23.9 ± 2.4 mm, respectively; P < 0.001), which occurred predominantly in the short annular axis (i.e. 21.2 ± 2.4 mm in systole vs 19.9 ± 2.3 mm in diastole; P < 0.001). The mean AV annular area decreased significantly in diastole (i.e. 467.5 ± 94.5 mm2 in systole vs 444.8 ± 86.1 mm2 in diastole; P = 0.012). The annular eccentricity index increased significantly in diastole (33.0 ± 12.2% in systole vs 41.4 ± 13.5% in diastole; P < 0.001). Furthermore, we found an inverse linear correlation between the mean AV annulus diameter and the annular eccentricity index (r = -0.40, P = 0.034). The diastolic annular eccentricity index was significantly reduced in the AR subgroup (i.e. 41.4 ± 13.5% in the normal AV subgroup vs 33.7 ± 14.8% in the AR cohort; P = 0.035).

CONCLUSIONS

The normal AV annulus undergoes important geometric deformation during the cardiac cycle that is significantly reduced in diastole in the AR scenario. A novel AV annuloplasty system should ideally adapt for this marked diastolic annular eccentricity and thereby allow for dynamic aortic root changes during the cardiac cycle.

Rationale for aortic annuloplasty to standardise aortic valve repair

Available evidence shows that aortic valve repair reduces valve-related mortality and improves quality of life compared to prosthetic aortic valve replacement. One of the most important predictors of bicuspid and tricuspid aortic valve repair failure is the absence of treating a dilated aortic annulus greater than 25-28 mm. Competency of the aortic valve depends on multiple factors including the diameter of the annulus, sinotubular junction, valve cusps and commissures. Dystrophic aortic insufficiency (AI) is the commonest cause of AI in the Western world and is characterised by dilatation of the aortic annulus (≥25 mm), sinuses and/or sinotubular junction (≥30 mm). Depending on whether the sinuses of Valsalva and/or tubular ascending aorta are dilated, three phenotypes can be identified: dilated aortic root, dilated ascending aorta and isolated AI. All three phenotypes are associated with a dilated aortic annulus. Aortic annuloplasty reduces the dilated aortic annulus and improves the surface of coaptation, as in the case of mitral valve repair. In treating AI, it is also important to restore the physiological sinotubular junction/annulus ratio, which can be carried out with remodeling root repair + subvalvular annuloplasty (for dilated aortic root), tubular ascending aorta replacement + subvalvular annuloplasty (for dilated ascending aorta) and double sub- and supra-valvular annuloplasty (for isolated AI). Aortic annuloplasty is now considered an essential component of aortic valve repair and valve-sparing root surgery.

Leaflet reconstructive techniques for aortic valve repair

BACKGROUND

Refining leaflet reconstruction has become a primary issue in aortic valve repair. This descriptive analysis reviews leaflet pathology, repair techniques, and early results in a prospective regulatory trial of aortic valve repair.

METHODS

Sixty-five patients underwent valve repair for predominant moderate to severe aortic insufficiency (AI). The mean age was 63 ± 13 years, and 69% of the patients were male. Ascending aortic/root replacement was required in 62%. As a first step, ring annuloplasty was performed, and then leaflet repair included leaflet plication for prolapse, nodular unfolding, double pericardial patching of commissural defects or holes, complete pericardial leaflet replacement, leaflet extension, and Gore-Tex reinforcement. Leaflet techniques and causes of adverse outcomes were evaluated.

RESULTS

The follow-up time was 2-years maximal and 0.9 years mean, with a survival of 97%. Eighty percent of patients required repair of leaflet defects: leaflet prolapse (52/65-80%), ruptured commissures (6/65-9%), leaflet holes (4/65-6%), and nodular retraction (6/65-9%). The average preoperative AI grade of 2.9 ± 0.8 fell to 0.7 ± 0.7 (p < 0.0001). Three patients (4.6%) required interval valve replacement because of (1) suture untying, (2) iatrogenic leaflet tear, or (3) diphtheroid endocarditis. Five other patients experienced grade 2 or grade 3 AI: probable suture untying in 1 patient, ineffective leaflet extensions in 2 patients, and unsuccessful Gore-Tex reinforcements in 2 patients. Two patients with single pericardial leaflet replacements and all those with double pericardial reconstructions did well.

CONCLUSIONS

Leaflet defects are common in patients with moderate to severe AI. Leaflet plication, nodular unfolding, and double pericardial patching performed well. Gore-Tex and leaflet extension seemed less satisfactory. Standardization and experience with leaflet reconstruction will be important for optimizing the outcomes of aortic valve repair.

Design Characteristics of a Three-Dimensional Geometric Aortic Valve Annuloplasty Ring

Objective

A full geometric annuloplasty ring could facilitate aortic valve repair. The purpose of this report was to document the design of such a ring using mathematical analyses of normal human aortic valve computed tomographic angiograms.

Methods

One-millimeter axial slices of high-resolution computed tomographic angiograms from 11 normal aortic roots were used to generate high-density x, y, and z coordinates of valve structures in Mathematica. Three-dimensional least squares regression analyses of leaflet-sinus coordinates were used to assess geometry of aortic valve and root structures.

Results

Normal valve geometry could be represented as three leaflet-sinus general ellipsoids nested within an elliptical aortic root. Minor-major diameter ratio of the valve base was 0.60 ± 0.07, and elliptical geometry extended vertically up the commissures. By contrast, leaflet-sinus horizontal circumferences were fairly circular (diameter ratios, 0.82–0.87), and the left coronary/noncoronary commissural post was located at the posterior base minor diameter-circumference junction, with the center of the right coronary leaflet opposite. Post location on the circumference was symmetrical, with a deviation of only ±2% to ±3% from 33.3% symmetry. Commissural posts flared outward by 5 to 10 degrees, and leaflet areas were statistically equivalent ( P > 0.10). From end diastole to midsystole, the aortic root became less elliptical (diameter ratio increased by 0.15), but root area expanded minimally (less than +5%). A one-piece rigid annuloplasty ring was designed with 2:3 base ellipticality, three 10-degree outwardly flaring symmetrical posts, and post height = base circumference/2π.

Conclusions

A three-dimensional aortic annuloplasty ring was designed that could prove useful for enhancing applicability and stability of aortic valve repair.