Assessment of tricuspid regurgitation by echocardiography

Assessment of tricuspid regurgitation by echocardiography

Tricuspid regurgitation can be assessed by pulsed wave Doppler, continuous wave Doppler and colour Doppler. Evidence for systolic flow reversal is sought in the inferior vena cava and hepatic veins, which if present, indicates at least moderate degree of tricuspid regurgitation. TR jet is imaged in all possible views which would include parasternal short axis view at the level of the aortic valve, right ventricular inflow view, apical four chamber view and subcostal view. Maximum frame rate of the system can be ensured by using the narrowest colour sector which would enclose the full TR jet.

Both the aliased color jet extending from the tricuspid valve into the right atrium in systole and the non-aliased adjacent portions with same direction of flow are used in the planimetry of TR jet area. The view in which maximum area of the jet is seen is taken for final assessment and the right atrial area is taken in the same view. If the ratio between the two is less than one is to five, it is taken as mild TR. If the ratio is between one fifth to one third, it is moderate and if it is more than one third, severe tricuspid regurgitation.

If the jet area is near one of the cut off points, an eccentric jet is considered to have the next higher grade of severity as it is known that eccentric wall hugging jets appear smaller. Tricuspid regurgitation is considered to be organic if there is thickening, doming or restricted motion of the valve leaflets on 2-dimensional real time echocardiography.

Another important measurement from the tricuspid regurgitation jet is the evaluation of right ventricular systolic pressure by the modified Bernoulli equation {4 x (peak TR velocity)²} which gives the TR gradient. Right atrial pressure (nominal: 10 mm Hg) is added to the TR gradient to get the estimated right ventricular systolic pressure (RVSP) [1].

Reference

1. Sagie A, Schwammenthal E, Palacios IF, King ME, Leavitt M, Freitas N, Weyman AE, Levine RA. Significant tricuspid regurgitation does not resolve after percutaneous balloon mitral valvotomy. J Thorac Cardiovasc Surg 1994;108:727-735.