Biomechanical-Structural Correlation of Chordae tendineae in Animal Models: A Pilot Study.

Justyn Gach,Agnieszka Noszczyk-Nowak,Agnieszka Mackiewicz,Izabela Janus,Tomasz Klekiel

doi:10.3390/ani11061678

Abstract

Simple SummaryThe Chordae tendineae are part of the atrioventricular apparatus. They are mainly responsible for the mechanical functions of heart valves. Degenerative mitral valve disease is the most common heart disease in dogs and is responsible for about 75% of cases of heart failure. One of the complications of this disease is Chordae tendineae rupture. It is clinically relevant to better understand the biomechanical and structural properties of CT in order to begin further studies about biomarkers suggesting an episode of CT rupture. Such an episode leads to acute pulmonary oedema and worsens the clinical status of the patient. Information about the biomechanical and structural properties of healthy CT and CT affected by the degenerative process are essential in understanding how CT behave in an in vivo environment.The mitral valve apparatus is a complex structure consisting of the mitral ring, valve leaflets, papillary muscles and Chordae tendineae (CT). The latter are mainly responsible for the mechanical functions of the valve. Our study included investigations of the biomechanical and structural properties of CT collected from canine and porcine hearts, as there are no studies about these properties of canine CT. We performed a static uniaxial tensile test on CT samples and a histopathological analysis in order to examine their microstructure. The results were analyzed to clarify whether the changes in mechanical persistence of Chordae tendineae are combined with the alterations in their structure. This study offers clinical insight for future research, allowing for an understanding of the process of Chordae tendineae rupture that happens during degenerative mitral valve disease—the most common heart disease in dogs.

Highlights

The left atrioventricular apparatus is located between the left atrium and the left ventricle and consists of the following: mitral ring, anterior and posterior cusps, Chordae tendineae, and papillary muscles [1]
Chordae tendineae (CT) are divided into three groups: first-order CT, which connect the leaflets and the papillary muscles, second-order CT located between the midventricular surface of both cusps and the papillary muscles, and third-order CT, which extend between the parietal leaflet and the ventricular wall [2,3]
The stretch diagrams showed micro-creeping, characteristic of soft tissues, which should be explained in more detail, together with the determination of the exact mathematical model of the tissue endurance of Chordae tendineae

Summary

Introduction

The left atrioventricular apparatus is located between the left atrium and the left ventricle and consists of the following: mitral ring, anterior and posterior cusps, Chordae tendineae, and papillary muscles [1]. Chordae tendineae (CT) are columnar structures found only in mitral and tricuspid valves. The CT modulate the transmission of strain from the papillary muscles to the valve leaflets, as evidenced by the heterogeneity of the mechanical properties and structure of the chordal areas of adhesion on the leaflet [4]. In normal CT, the orientation of collagen fibres is complex throughout the area of the insert. This enables the three-dimensional transmission of strain through the CT [5]

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