Tricuspid valve regurgitation

Tricuspid regurgitation (TR) is a valvular cardiac anomaly where there is regurgitation of flow from the right ventricle back into the right atrium through the tricuspid valve. It is considered an important predictor of both morbidity and mortality in heart failure ⁸.

Clinical presentation

Clinical features can vary dependent of the severely of regurgitation from being entirely asymptomatic in mild cases to having several classical signs such as:

• Carvello's sign
• pulsatile liver
• prominent jugular venous V waves

Pathology

Primary tricuspid regurgitation in isolation is very rare. It is more often found in association other valvular disease (more often with mitral rather than with aortic valve disease).

In a majority of patients (70-85%), the TR is considered “functional” ¹², where it is caused by dilatation of the annulus as a result of increased pulmonary and right ventricular pressures; in the remaining 15–30% , it may be organic and related to direct involvement of the tricuspid valve.

A major haemodynamic consequence of tricuspid regurgitation is an increase in the total stroke volume of the right ventricle.

Causes

Tricuspid regurgitation can result from number of causes such as:

• congenital abnormalities (e.g. Ebstein anomaly)
• dilatation of the right ventricle and/or the tricuspid annulus
  • considered one of the commonest causes
  • can occur secondary to mitral valvulopathy or pulmonary hypertension
• as a late complication following mitral valve surgery ¹¹
• direct factors affecting the valve
  • endocarditis: infective endocarditis
  • rheumatic heart disease
  • valve dysfunction due to infarction
  • valve disruption from trauma
  • carcinoid syndrome: cardiac lesions in carcinoid syndrome

Associations

• Marfan syndrome
• phentermine +/- fenfluramine use ¹⁰

Radiographic features

Ultrasound - echocardiography

This is probably the most traditional best used methods of detection and assessment. It may be best evaluated from the apical window. Left parasternal, right ventricular inlet view and short axis at the aortic valve level may be other useful positions.

In TR, systolic turbulence may be detected just behind the tricuspid valve leaflets. The flow contour profile can be very similar to that seen with mitral regurgitation.

The shape of the tricuspid annulus can alter with regurgitation. A normal annulus has a bimodal shape with distinct high points located anteroposteriorly and low points located mediolaterally. With functional tricuspid regurgitation, the annulus can become larger, more planar, and circular ⁸.

Cardiac MRI

On spin-echo MR images, features that may be visible which could suggest towards a diagnosis of TR include:

• enlargement of the right ventricle
• enlargement of the right atrium
• distension of the vena cavae and hepatic veins

Cine gradient-echo imaging can be used to evaluate tricuspid regurgitation based on the area of the signal void corresponding to the regurgitant flow jet in systole. The signal void is best demonstrated on a four-chamber view and a coronal oblique view encompassing the right atrium and the right ventricle.

The degree of tricuspid regurgitation may be calculated in terms of regurgitant volume and fraction in similar ways to mitral regurgitation - i.e. subtraction of the forward stroke volume (as measured in the pulmonary artery with phase contrast) from the total right ventricular stroke volume (obtained from SSFP images).

CT

Enlargement of the right atrium and right ventricle may also be seen on standard as well as cardiac CT.

Ancillary features

Dynamic contrast enhanced abdominal computed tomography (CT) may show intense opacification of the inferior vena cava and hepatic veins.

Treatment and prognosis

Typically treated medically with diuretics to reduce blood volume.

If the valve is replaced it is usually performed at the same time that other cardiac valves are replaced (since these patients frequently have multiple cardiac valve abnormalities). Indications and timing for sole replacement of the tricupid valve are not well established.

Complications

Complications of untreated tricupsid regurgitation:

• cirrhosis: cardiac cirrhosis

Practical points

• tricuspid regurgitation is a common (~70%) incidental finding on echocardiography and cardiac MRI; it should be considered physiological if ¹³:
  • the size of the RA and RV are normal
  • the jet extends <0.7 cm into the RA
  • hepatic vein pulsatility is normal

See also

• tricuspid regurgitation
• tricuspid stenosis​
• tricuspid atresia
• tricuspid hypoplasia