Dilation of tricuspid valve annulus immediately after rupture of chordae tendineae in ex-vivo porcine hearts

Khoiy, Keyvan Amini; Asgarian, Kourosh T.; Loth, Francis; Amini, Rouzbeh

doi:10.1371/journal.pone.0206744

Cited by 15 publications

(5 citation statements)

References 41 publications

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“…Chordae rupture affects the overall atrioventricular heart valve behaviors and can be a primary cause of valve regurgitation [3][4][5]. Khoiy et al (2018) used an in vitro valve apparatus to observe changes in the tricuspid valve closure after induced chordae rupture, and found that ruptured chordae caused up to an 8.8% dilation of the annulus and consequent regurgitation [6]. In another in vitro study for the mitral valve, it was found that a significantly lower ventricular pressure was required to cause leaflet prolapse caused by chordae rupture [7].…”

Section: Introductionmentioning

confidence: 99%

Mechanics and Microstructure of the Atrioventricular Heart Valve Chordae Tendineae: A Review

Ross

Zheng

et al. 2020

Bioengineering

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The atrioventricular heart valves (AHVs) are responsible for directing unidirectional blood flow through the heart by properly opening and closing the valve leaflets, which are supported in their function by the chordae tendineae and the papillary muscles. Specifically, the chordae tendineae are critical to distributing forces during systolic closure from the leaflets to the papillary muscles, preventing leaflet prolapse and consequent regurgitation. Current therapies for chordae failure have issues of disease recurrence or suboptimal treatment outcomes. To improve those therapies, researchers have sought to better understand the mechanics and microstructure of the chordae tendineae of the AHVs. The intricate structures of the chordae tendineae have become of increasing interest in recent literature, and there are several key findings that have not been comprehensively summarized in one review. Therefore, in this review paper, we will provide a summary of the current state of biomechanical and microstructural characterizations of the chordae tendineae, and also discuss perspectives for future studies that will aid in a better understanding of the tissue mechanics–microstructure linking of the AHVs’ chordae tendineae, and thereby improve the therapeutics for heart valve diseases caused by chordae failures.

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Section: Introductionmentioning

confidence: 99%

Mechanics and Microstructure of the Atrioventricular Heart Valve Chordae Tendineae: A Review

Ross

Zheng

et al. 2020

Bioengineering

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“…To test novel therapies for FTR, an ex vivo model of FTR is needed. Unfortunately, the currently available ex vivo models of the tricuspid valve are costly, difficult to replicate, or have not been formally validated [3][4][5][6][7][8]. Our laboratory has previously been successful in developing an ex vivo model of secondary mitral regurgitation (SMR) using isolated porcine hearts [9].…”

Section: Introductionmentioning

confidence: 99%

“…Our laboratory has previously been successful in developing an ex vivo model of secondary mitral regurgitation (SMR) using isolated porcine hearts [9]. Given the comparable tricuspid anatomy between humans and swine [5][6][7][8]10] we hypothesized that porcine hearts could similarly be used to develop a static ex vivo model of FTR.…”

Section: Introductionmentioning

confidence: 99%

Development and validation of an ex vivo porcine model of functional tricuspid regurgitation

Rando,

Quinn,

Larson

et al. 2024

JCTR

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Background and Aim: Ex vivo models of functional tricuspid regurgitation (FTR) are needed for pre-clinical testing of novel surgical and interventional repair strategies, but current options are costly or have not been formally validated. The objective of this research was to create and validate an ex vivo model to test novel repair methods for FTR. Methods: In explanted porcine hearts, the right atrium was excised to visualize the tricuspid valve. The pulmonary artery and aorta were clamped and cannulated, the coronary arteries ligated, and the right and left ventricles statically pressurized with air to 30 mmHg and 120 mmHg, respectively. FTR was induced by increasing right ventricular pressure to 80 mmHg for 3 h, which resulted in progressive tricuspid annular enlargement, right ventricular dilation, papillary muscle displacement, and central tricuspid malcoaptation. A structured light scanner was used to image the 3D topography of the tricuspid valve in both the native and FTR state, and images were exported into scan-to-computer-aided design software, which allowed for high-resolution 3D computational reconstruction. Relevant geometric measurements were sampled including annular circumference and area, major and minor axis diameter, and tenting height, angle, and area. Geometric measurements from the ex vivo model were compared to clinical transthoracic echocardiographic (TTE) measurements using two-sample t-tests. Results: A total of 12 porcine hearts were included in the study. Annular measurements of the native valve were comparable to published TTE data, except for the minor axis diameter, which was shorter in the ex vivo model (2.5 vs. 3.1 cm, P = 0.007). Induction of FTR in the ex vivo model resulted in annular enlargement (FTR vs. native: circumference 13.7 vs.11.8 cm, P = 0.012; area 14 vs. 11 cm2, P = 0.011). Ex vivo leaflet measurements in both the native and FTR model differed from published TTE data, but demonstrated comparable directional changes between the native and regurgitant states, including increased tenting height, area, and volume. Conclusion: The ex vivo pneumatically-pressurized porcine model closely recapitulates the geometry of both the native and regurgitant tricuspid valve complex in humans and holds promise for testing novel FTR repair strategies. Relevance for Patients: Currently available interventions for the tricuspid valve have a risk of permanent conduction abnormalities and are insufficient in addressing tricuspid disease for a subset of patients. This ex vivo model provides a platform for testing of novel interventions that address the deficiencies of current tricuspid therapies.

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“…In one particular in-vitro study conducted on heart valves, the assumption of no potential difference between DI water and PBS as it pertains to the mechanical responses of the tissues was adopted [12]. Notwithstanding the importance of the findings of these studies, isotonic solutions have been generally used in similar ex-vivo valvular studies to prevent changes in the mechanical responses of heart valves [14,15,16,17]. Since no previous experiments have been conducted to specifically show the effects of hypotonicity on the mechanical response of cardiac valves, we performed experiments on porcine tricuspid valve (TV) anterior leaflets in order to guide future research in heart valve biomechanics.…”

Section: Introductionmentioning

confidence: 99%

“…The TV, which is located on the pulmonary side of the heart, is composed of three leaflets: anterior, posterior and septal leaflets. The study of the biomechanics of this valve, albeit nascent in comparison to the study of mitral valve biomechanics, has seen an emergence in interest [16,18,19,20,21,22,23,24,25,26]. The TV is characterized by having a larger orifice than the mitral valve as well as having thinner leaflets [27].…”

Section: Introductionmentioning

confidence: 99%

Mechanical Response Changes in Porcine Tricuspid Valve Anterior Leaflet Under Osmotic-Induced Swelling

2019

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Since many soft tissues function in an isotonic in-vivo environment, it is expected that physiological osmolarity will be maintained when conducting experiments on these tissues ex-vivo. In this study, we aimed to examine how not adhering to such a practice may alter the mechanical response of the tricuspid valve (TV) anterior leaflet. Tissue specimens were immersed in deionized (DI) water prior to quantification of the stress–strain responses using an in-plane biaxial mechanical testing device. Following a two-hour immersion in DI water, the tissue thickness increased an average of 107.3% in the DI water group compared to only 6.8% in the control group, in which the tissue samples were submerged in an isotonic phosphate buffered saline solution for the same period of time. Tissue strains evaluated at 85 kPa revealed a significant reduction in the radial direction, from 34.8% to 20%, following immersion in DI water. However, no significant change was observed in the control group. Our study demonstrated the impact of a hypo-osmotic environment on the mechanical response of TV anterior leaflet. The imbalance in ions leads to water absorption in the valvular tissue that can alter its mechanical response. As such, in ex-vivo experiments for which the native mechanical response of the valves is important, using an isotonic buffer solution is essential.

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Dilation of tricuspid valve annulus immediately after rupture of chordae tendineae in ex-vivo porcine hearts

Cited by 15 publications

References 41 publications

Mechanics and Microstructure of the Atrioventricular Heart Valve Chordae Tendineae: A Review

Mechanics and Microstructure of the Atrioventricular Heart Valve Chordae Tendineae: A Review

Development and validation of an ex vivo porcine model of functional tricuspid regurgitation

Mechanical Response Changes in Porcine Tricuspid Valve Anterior Leaflet Under Osmotic-Induced Swelling

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