The influence of tricuspid annuloplasty prostheses on ovine annular geometry and kinematics

Mid-term outcomes of tricuspid annuloplasty using the Tri-Ad Adams tricuspid annuloplasty ring

OBJECTIVES

The Tri-Ad Adams tricuspid annuloplasty ring is a recent innovative prosthesis characterized by a semi-rigid central component and fully flexible extremities. The goal of this study was to assess the short-term and mid-term results following implantation of the Tri-Ad Adams ring.

METHODS

A retrospective analysis was conducted on patients who underwent tricuspid annuloplasty using the Tri-Ad Adams ring between August 2016 and October 2021.

RESULTS

Our study enrolled a total of 248 participants. The median age was 64.0 (interquartile range: 56.0-71.5) years. The median EuroSCORE II was 4.3% (2.7-7.5%), with 37 patients (14.9%) having a history of cardiac operations. Tricuspid regurgitation of grade 2-3 was observed in 63.7% of cases, and the median tricuspid annular diameter was 3.3 (2.8-3.6) cm. Concurrent procedures included mitral valve replacement (n = 160, 64.5%), mitral valve repair (n = 75, 30.2%), aortic valve replacement (n = 72, 29.0%) and the maze procedure (n = 170, 68.5%). Immediate postoperative tricuspid regurgitation≥moderate was present in 1 patient (0.4%). Early death occurred in 14 patients (5.6%). Major complications included low cardiac output syndrome (n = 18, 0.3%), acute kidney injury (n = 14, 5.6%) and permanent pacemaker placement (n = 15, 6.0%). According to the Kaplan-Meier analysis, the 4-year rates of freedom from overall mortality and moderate-to-severe tricuspid regurgitation were 96.9% and 91.6%, respectively. There were no incidents of tricuspid valve reoperations, ring detachment or significant tricuspid stenosis (trans-tricuspid valve gradient ≥ 5 mmHg).

CONCLUSIONS

Tricuspid annuloplasty utilizing the Tri-Ad Adams ring demonstrated favourable outcomes in both the early and midterm periods. Further studies are warranted to confirm the long-term results.

Midterm comparison between different annuloplasty techniques for functional tricuspid regurgitation

BACKGROUND

Several tricuspid annuloplasty (TA) techniques are used for concomitant repair of functional tricuspid regurgitation. This study aims to compare the midterm clinical and valvular outcome between 3 annuloplasty techniques.

METHODS

TA was performed in 307 patients (age 75.9±10.4y) with a rigid ring (RA=184), a flexible band(FA=80) and a suture annuloplasty(SA=43). Study endpoints were survival and recurrence of TR > grade 2 at 5 years.

RESULTS

TA was performed concomitantly to mitral valve surgery (n=136, 44.3%), aortic valve surgery(n=18, 5.9%), CABG(n=13, 4.2%) or a combined procedure(n=140, 45.6%). The majority had TR>grade 2(78.5%) without significant differences between TA groups(p=0.878). Within a median follow-up of 3.4 y(IQR 2.2-5.0) the 5-year survival was 80.1±3.4% for RA, 83.5±4.7% for FA and 85.1±6.5% for SA(p=0.471). Independent risk factors for late mortality were renal impairment(HR 2.83, CI 1.16-6.89, p=0.022), diabetes(HR 2.10, CI 1.07-4.11, p=0.030) and severe RV dysfunction by TAPSE <10 mm(HR 11.52, CI 4.98-26.66, p<0.001). Pulmonary hypertension was nearly significant(HR 1.92, CI 0.98-3.74, p=0.057). The cumulative incidence of TR recurrence at 5 years was 15.9%, 19.4% and 21.1% for respectively RA, FA and SA(p=0.342). Severe pulmonary hypertension(HR 2.64, 95%CI 1.38-5.07, p=0.003) preoperative TR grade(HR 1.82, 95%CI 1.01-3.27, p=0.046) and residual TR>grade 2 at discharge(HR 3.38, 95%CI 1.64-6.96, p=0.001) were predictive for later TR recurrence, regardless of the annuloplasty technique.

CONCLUSIONS

This study demonstrates that advanced pathophysiological right circulatory impairment like severe pulmonary hypertension and RV dysfunction affects the midterm survival as well as TR recurrence rate more than the annuloplasty technique used for concomitant repair of functional tricuspid regurgitation.

Tricuspid leaflet kinematics after annular size reduction in ovine functional tricuspid regurgitation

OBJECTIVE

Tricuspid annular size reduction with annuloplasty rings represents the foundation of surgical repair of functional tricuspid regurgitation. However, the precise effect of annular size reduction on leaflet motion and geometry remains unknown.

METHODS

Ten sheep underwent surgical implantation of a pacemaker with an epicardial lead and were paced 200-240 beats/min to achieve biventricular dysfunction and functional tricuspid regurgitation. Subsequently, sonomicrometry crystals were implanted on the right ventricle, the tricuspid annulus, and on the belly of anterior, posterior, and septal tricuspid leaflets. Double-layer polypropylene suture was placed around the tricuspid annulus and externalized to a tourniquet. Simultaneous echocardiographic, hemodynamic, and sonomicrometry data were acquired with functional tricuspid regurgitation and during 5 consecutive annular reduction steps. Annular area, tenting height, and volume, together with each leaflet strain, radial length, and angles, were calculated from crystal coordinates.

RESULTS

Rapid pacing reduced both left ventricle and right ventricle function and induced functional tricuspid regurgitation (0-3+) in all animals (from 0 ± 0 to 2.4 ± 0.7, P = .002), whereas tricuspid annulus diameter increased from 2.6 ± 0.3 cm to 3.3 ± 0.3 cm (P = .001). Tricuspid annular size reduction 1 to 5 resulted in 16% ± 7%, 37% ± 11%, 55% ± 11%, 66% ± 10%, and 76% ± 8% tricuspid annulus area reduction, respectively, and successively decreased tricuspid regurgitation. Tricuspid annular size reduction 2 to 5 induced anterior and posterior leaflet restricted motion and lower diastolic motion velocities. Tricuspid annular size reduction 5 perturbed septal leaflet range of motion but preserved its angle velocities. Tricuspid annular size reduction 3-5 generated compressive strains in all leaflets.

CONCLUSIONS

Tricuspid annular area reduction of 55% perturbed anterior and posterior leaflet motion while maintaining normal septal leaflet movement. More extreme reduction triggered profound changes in anterior and posterior leaflet motion, suggesting that aggressive undersizing impairs leaflet kinematics.

Tricuspid Valve Annuloplasty Alters Leaflet Mechanics

Tricuspid valve regurgitation is associated with significant morbidity and mortality. Its most common treatment option, tricuspid valve annuloplasty, is not optimally effective in the long-term. Toward identifying the causes for annuloplasty's ineffectiveness, we have previously investigated the technique's impact on the tricuspid annulus and the right ventricular epicardium. In our current work, we are extending our analysis to the anterior tricuspid valve leaflet. To this end, we adopted our previous strategy of performing DeVega suture annuloplasty as an experimental methodology that allows us to externally control the degree of cinching during annuloplasty. Thus, in ten sheep we successively cinched the annulus and quantified changes to leaflet motion, dynamics, and strain in the beating heart by combining sonomicrometry with our well-established mechanical framework. We found that successive cinching of the valve enforced earlier coaptation and thus reduced leaflet range of motion. Additionally, leaflet angular velocity during opening and closing decreased. Finally, we found that leaflet strains were also reduced. Specifically, radial and areal strains decreased as a function of annular cinching. Our findings are critical as they suggest that suture annuloplasty alters the mechanics of the tricuspid valve leaflets which may disrupt their resident cells' mechanobiological equilibrium. Long-term, such disruption may stimulate tissue maladaptation which could contribute to annuloplasty's sub-optimal effectiveness. Additionally, our data suggest that the extent to which annuloplasty alters leaflet mechanics can be controlled via degree of cinching. Hence, our data may provide direct surgical guidelines.

Tricuspid Annuloplasty Rings: A Quantitative Comparison of Size, Nonplanar Shape, and Stiffness

BACKGROUND

Functional tricuspid regurgitation due to annular and ventricular dilatation is increasingly recognized as a significant source of morbidity and mortality. To repair the annulus, surgeons implant one of many annuloplasty devices that differ in size, 3-dimensional (3D) shape, and stiffness. However, there have been no quantitative comparisons between various available devices.

METHODS

Three-dimensional scanning, micro-computed tomography imaging, analytical methods, and mechanical tests were used to compare 3 Edwards Lifesciences (Irvine, CA) and 3 Medtronic (Minneapolis, MN) annuloplasty devices of all available sizes. We measured in-plane metrics of maximum diameter, perimeter, area, height, as well as elevation and curvature profiles. Furthermore, we computed bending stiffness as well as the maximum and minimum axes of the bending stiffness.

RESULTS

Most annular prostheses differed little in their in-plane geometries but varied significantly in height. In-plane properties deviated significantly from measurements of healthy human tricuspid annuli. Height of the Edwards' MC3 and Medtronic's Contour 3D resembled healthy human tricuspid valve annuli, whereas the Edwards' Physio and Classic, and Medtronic's TriAd, did not. Additionally, the elevation profiles of the MC3 and Contour 3D and curvature profiles between all devices were consistent and matched those of healthy human annuli. The tested devices also differed in their bending stiffness, both in terms of absolute values and their maximum and minimum axes.

CONCLUSIONS

Contoured devices, such as Edwards' MC3 and Medtronic's Contour 3D, most accurately resembled the healthy human tricuspid annulus but differed significantly in bending stiffness. To what extent prosthesis properties and shape affect tricuspid valve function remains to be determined.