Anatomy and function of the tricuspid
How to assess the anatomy?
The tricuspid valve was considered to be an unimportant structure until the mid-1980s when it came to prognosis. Even older publications even said that tricuspid reflux would physiologically be an escape valve to protect the right ventricle, which today is an absurd concept. With the development of more appropriate surgical techniques for the left side valves and with the improvement in survival of these individuals, a disease on the right became more important, as it could now have long-term repercussions.
In view of this, recently the so-called “valve-ventricular” complex on the right side has been better investigated with new diagnostic methods, in addition to two-dimensional echocardiography.
It is worth mentioning the complex anatomy of the tricuspid valve, composed of 3 leaflets, papillary muscles, tendinous cords and a fibrous annulus (in the shape of a cell) that is anatomically almost vertical. The anterior leaflet is the largest and the septal is the smallest, the latter being at least 10 mm further apical than the septal insertion of the anterior mitral valve leaflet.
The classic echocardiographic measurement of the tricuspid ring occurs through the apical 4-chamber window with values ranging from 25 to 39mm, according to some publications (click here). However, the perfect evaluation of the leaflets is impaired, due to their positioning and exuberant anatomical variability, different from other heart valves. Transesophageal complementation often adds little information, as different from mitral, the tricuspid is located far anterior in the chest. The use of the three-dimensional method can bring better anatomical definition, such as “tethering”, traction and ellipsoid reflux holes, more important for a percutaneous approach programming.
The role of tomography in the evaluation of the tricuspid valve is basically summarized in static measurements of its anatomy. The presence of failure of coaptation between the leaflets, as well as a possible spatial displacement of the ring are very well evaluated by tomography, but functional aspects are not enough. At this point, cardiac resonance is the method of choice to complement an initial echocardiographic assessment, bringing good accuracy in anatomical and functional measurements.
The analysis, both echocardiographic and the resonance of the systolic function of the right ventricle, presents an additional challenge, since it is very dependent on the volume load to which the ventricle is temporarily submitted and not specifically only on the intrinsic myocardial contractility. Thus, obtaining data that can predict an adequate evolution after a surgical intervention is not always possible, but it is known that the parameters currently used by echocardiography (S wave by tricuspid annulus tissue doppler, TAPSE and FAC), when preserved, indicate good prognosis.
MRI is able to assess the speed of a tricuspid reflux, as well as its contracted vena and the regurgitant volume, but an irregular rhythm or other associated valvular disorders usually hinder the proper measurement, being the responsibility of the echocardiogram, which must always analyze the same variables in together with possible hemodynamic repercussions, such as dilation of the inferior vena cava, size of the right atrium, reverse reflux in hepatic veins, etc.
1 – Dahou A, Levin D, Reisman M, Hahn RT. Anatomy and Physiology of the Tricuspid Valve. JACC Cardiovasc Imaging. 2019; 12 (3): 458‐468.
2 – Medvedofsky D, León Jiménez J, Addetia K, et al. Multi-parametric quantification of tricuspid regurgitation using cardiovascular magnetic resonance: A comparison to echocardiography. Eur J Radiol. 2017 Jan; 86: 213-220.