Tricuspid annular dynamics before and after tricuspid annuloplasty- three-dimensional transesophageal echocardiography

Results after Repair of Functional Tricuspid Regurgitation with a Three-Dimensional Annuloplasty Ring

Background: Tricuspid valve (TV) repair is the recommended treatment for severe functional tricuspid regurgitation (fTR) in patients undergoing left-sided surgery. For this purpose, a wide range of annuloplasty devices differing in form and flexibility are available. This study reports the results using a three-dimensional annuloplasty ring (Medtronic, Contour 3D Ring) for TV repair and analysis of risk factors. Methods: A cohort of 468 patients who underwent TV repair (TVr) with a concomitant cardiac procedure from December 2010 to January 2017 was retrospectively analyzed. Results: At follow-up, 96.1% of patients had no/trivial or mild TR. The 30-day mortality was 4.7%; it significantly differed between electively performed operations (2.7%) and urgent/emergent operations (11.7%). Risk factors for recurrent moderate and severe TR were LVEF < 50%, TAPSE < 16 mm, and moderate mitral valve (MV) regurgitation at follow-up. Preoperatively reduced renal function lead to a higher 30-day and overall mortality. Reoperation of the TV was required in six patients (1.6%). Risk factors for TV related reoperations were preoperative TV annulus over 50 mm and an implanted permanent pacemaker. Conclusions: TVr with the Contour 3D annuloplasty ring shows low TR recurrence and reoperation rates. Risk-factor analysis for the recurrence of TR revealed the importance of left- and right-ventricular function.

Risk factors for postoperative recurrent tricuspid regurgitation after concomitant tricuspid annuloplasty during left heart surgery and the association between tricuspid annular circumference and secondary tricuspid regurgitation

Background

To identify the association between tricuspid annular circumference and secondary tricuspid regurgitation and analyze the risk factors of recurrent tricuspid regurgitation after concomitant tricuspid annuloplasty during left heart surgery.

Methods

From October 2018 to June 2019, a total of 117 patients receiving concomitant tricuspid annuloplasty within left heart surgery were enrolled. Severity of tricuspid regurgitation was classified as 4 subtypes: normal, mild, moderate and severe. Perioperative data and mid-term outcome were collected. Tricuspid annular circumference (TAC) was measured under cardiac arrest during surgery procedure by cardioplegia. Optimal TAC and TAC index (TAC/body surface area, BSA) cutoffs of significant tricuspid annulus dilatation (moderate and severe) were obtained. Univariable and multivariable logistic regression analyses were performed to identify the risk factors of postoperative recurrent tricuspid regurgitation. The follow up period is 13–19 months (mean 15.5 ± 3.2 months).

Results

There was 1 patient was excluded who died after surgery. A total of 116 patients receiving tricuspid annuloplasty were included. Optimal cutoffs of significant tricuspid annulus dilatation were recommended (TAC 11.45 cm, Sensitivity 82.89%, Specificity 73.68%, AUC 0.915; TAC index 7.09 cm/m², Sensitivity 73.68%, Specificity 85%, AUC 0.825, respectively). Based on findings of multivariable logistic regression, it has been showed that TAC index and postoperative atrial fibrillation were the independent risk factors of recurrent regurgitation after surgery. Optimal TAC index cutoff to predict recurrent tricuspid regurgitation was 7.86 cm/m²

Conclusions

The severity of secondary tricuspid regurgitation is associated with the tricuspid annular circumference. The cut-offs of significant tricuspid regurgitation (more than moderate) were TAC 11.45 cm and TAC index 7.09 cm/m², respectively. Clinically, concomitant tricuspid annuloplasty is relative safe and effective. TAC index ≥ 7.86 cm/m² and postoperative atrial fibrillation are the risk factors of recurrent significant tricuspid regurgitation after concomitant tricuspid annuloplasty during left heart surgery.

A Pilot Study on Linking Tissue Mechanics with Load-Dependent Collagen Microstructures in Porcine Tricuspid Valve Leaflets

The tricuspid valve (TV) is composed of three leaflets that coapt during systole to prevent deoxygenated blood from re-entering the right atrium. The connection between the TV leaflets’ microstructure and the tissue-level mechanical responses has yet to be fully understood in the TV biomechanics society. This pilot study sought to examine the load-dependent collagen fiber architecture of the three TV leaflets, by employing a multiscale, combined experimental approach that utilizes tissue-level biaxial mechanical characterizations, micro-level collagen fiber quantification, and histological analysis. Our results showed that the three TV leaflets displayed greater extensibility in the tissues’ radial direction than in the circumferential direction, consistently under different applied biaxial tensions. Additionally, collagen fibers reoriented towards the direction of the larger applied load, with the largest changes in the alignment of the collagen fibers under radially-dominant loading. Moreover, collagen fibers in the belly region of the TV leaflets were found to experience greater reorientations compared to the tissue region closer to the TV annulus. Furthermore, histological examinations of the TV leaflets displayed significant regional variation in constituent mass fraction, highlighting the heterogeneous collagen microstructure. The combined experimental approach presented in this work enables the connection of tissue mechanics, collagen fiber microstructure, and morphology for the TV leaflets. This experimental methodology also provides a new research platform for future developments, such as multiscale models for the TVs, and the design of bioprosthetic heart valves that could better mimic the mechanical, microstructural, and morphological characteristics of the native tricuspid valve leaflets.

Biomechanics of the Tricuspid Annulus: A Review of the Annulus' In Vivo Dynamics With Emphasis on Ovine Data

The tricuspid annulus forms the boundary between the tricuspid valve leaflets and their surrounding perivalvular tissue of the right atrioventricular junction. Its shape changes throughout the cardiac cycle in response to the forces from the contracting right heart myocardium and the blood-valve interaction. Alterations to annular shape and dynamics in disease lead to valvular dysfunctions such as tricuspid regurgitation from which millions of patients suffer. Successful treatment of such dysfunction requires an in-depth understanding of the normal shape and dynamics of the tricuspid annulus and of the changes following disease and subsequent repair. In this manuscript we review what we know about the shape and dynamics of the normal tricuspid annulus and about the effects of both disease and repair based on non-invasive imaging studies and invasive fiduciary marker-based studies. We further show, by means of ovine data, that detailed engineering analyses of the tricuspid annulus provide regionally-resolved insight into the kinematics of the annulus which would remain hidden if limiting analyses to simple geometric metrics.

Risk factors associated with perioperative morbidity and mortality following isolated tricuspid valve replacement

BACKGROUND

Reports of isolated tricuspid valve replacement (iTVR) are relatively rare. The present study aimed to evaluate independent risk factors of perioperative morbidity and mortality after iTVR.

MATERIALS AND METHODS

We retrospectively reviewed 118 consecutive patients (42 males; mean age, 49.1 ± 12.9 y) who underwent iTVR from May 2003 to April 2016 in our center. The multivariate logistic regression model was used to analyze the independent risk factors associated with perioperative morbidity and mortality following iTVR.

RESULTS

One hundred one patients (85.6%) were classified as New York Heart Association functional class III or IV preoperatively. The overall perioperative mortality was 11.8% (14/118), and a significant difference was observed between the nonreoperative group and the reoperative group (6.7% versus 18.3%, P = 0.047). The multivariate logistic regression analyses identified that preoperative New York Heart Association functional class IV (OR [odds ratio] = 15.43, 95% CI [confidence interval] = 3.46-68.83, P = 0.000) and ascites (OR = 4.88, 95% CI = 1.24-19.27, P = 0.024) were independent risk factors of perioperative deaths. The previous cardiac surgery (OR = 3.28, 95% CI = 1.41-7.62, P = 0.006) was independently associated with perioperative major adverse events.

CONCLUSIONS

The present study revealed that iTVR has relatively high mortality and morbidity rates. Timely surgery may be recommended for this high-risk cohort of patients before the development of severe heart and end-organ failure.

Engineering Analysis of Tricuspid Annular Dynamics in the Beating Ovine Heart

Functional tricuspid regurgitation is a significant source of morbidity and mortality in the US. Furthermore, treatment of functional tricuspid regurgitation is suboptimal with significant recurrence rates, which may, at least in part, be due to our limited knowledge of the relationship between valvular shape and function. Here we study the dynamics of the healthy in vivo ovine tricuspid annulus to improve our understanding of normal annular deformations throughout the cardiac cycle. To this end, we determine both clinical as well as engineering metrics of in vivo annular dynamics based on sonomicrometry crystals surgically attached to the annulus. We confirm that the tricuspid annulus undergoes large dynamic changes in area, perimeter, height, and eccentricity throughout the cardiac cycle. This deformation may be described as asymmetric in-plane motion of the annulus with minor out-of-plane motion. In addition, we employ strain and curvature to provide mechanistic insight into the origin of this deformation. Specifically, we find that strain and curvature vary considerable across the annulus with highly localized minima and maxima resulting in aforementioned configurational changes throughout the cardiac cycle. It is our hope that these data provide valuable information for clinicians and engineers alike and ultimately help us improve treatment of functional tricuspid regurgitation.

Suture Dehiscence in the Tricuspid Annulus: An Ex Vivo Analysis of Tissue Strength and Composition

BACKGROUND

Surgical repair of functional tricuspid regurgitation (FTR) is an increasingly common practice, but annuloplasty suture dehiscence remains a significant problem. Quantitative and mechanistic understanding of annular suture holding strength can support more effective techniques for tricuspid valve device anchoring.

METHODS

Suture holding strength of ovine tricuspid annuli (n = 15) was quantified ex vivo by pullout testing at 12 positions around their circumference. Collagen density in additional annuli (n = 7) was quantified at positions above each commissure and midleaflet point by two-photon autofluorescence microscopy, enabling mechanistic assessment of its role in imparting suture holding strength to the tissue.

RESULTS

Suture holding strength from pullout testing varied significantly by annular position, with a maximum of 10.0 ± 4.1 N at the septal leaflet (6 o'clock) and a minimum of 4.3 ± 1.3 N at the posterior leaflet (1 o'clock). Leaflet midpoints showed significantly higher annular tissue strength than commissures (7.2 ± 3.4 N versus 5.6 ± 2.1 N, respectively, p = 0.008). Collagen density, measured by a normalized mean pixel intensity, was significantly higher in the septal annulus than in the posterior-septal commissure, posterior annulus, and anterior-posterior commissure. Suture holding strength showed a strong linear correlation with collagen density (R² = 0.822, p = 0.013).

CONCLUSIONS

The clinical predominance of suture dehiscence at the septal annulus, despite its greater ex vivo holding strength, suggests either adverse suture placement techniques in this region or asymmetric tensile loading after implantation. This issue highlights the need to optimize implantation techniques and to carefully assess anchor security in existing and next-generation FTR corrective devices.

Tricuspid Regurgitation: 2015 Reflections and Re-evaluation

OPINION STATEMENT

The tricuspid valve is, in fact, anatomically and functionally more complex than its left-sided counterpart-the mitral valve. Patients may develop tricuspid regurgitation from a variety of mechanisms. While current guidelines provide a very basic approach to tricuspid regurgitation (TR) evaluation, more recent techniques, particularly 3D echocardiography, have provided novel insights into how we can ascertain the mechanism and severity of tricuspid regurgitation, how the tricuspid valve adapts to disease and, importantly, how we assess the effects of TR on right ventricular size and function. We anticipate that these advances will soon yield dividends that will help us decide on approaches to treatment and timing of surgery.