Tricuspid regurgitation jet – Doppler echocardiography
Tricuspid regurgitation jet – Doppler echocardiography: Tricuspid regurgitation (TR) jet is usually imaged from the apical four chamber view, though it can sometimes be imaged from right parasternal and subcostal views. Initially colour Doppler imaging is done and the direction of the jet identified. Then the cursor is aligned along the direction of the TR jet and continuous wave Doppler signals obtained. Pulsed wave Doppler is not enough in most cases as the velocity range is above its aliasing limit, more so in hypertensive tricuspid regurgitation. Care should be taken to get best possible alignment of the jet along the Doppler cursor. Otherwise the full gradient will not be assessed and there will be underestimation of right ventricular systolic pressure (RVSP). Peak velocity of the TR jet is measured and the pressure gradient calculated using the modified Bernoulli equation (Pressure gradient = 4V2, where V equals the peak velocity of the TR jet). This gives the pressure difference between the right atrium and right ventricle .
RVSP is calculated from TR gradient by adding the presumed right atrial pressure, usually 10 mm Hg. When right atrial pressure is elevated, higher values have to be added. If the inferior vena cava is dilated and plethoric, usually 20 mm Hg will be added to TR gradient to get RVSP. TR gradient in this case was 48 mm Hg and hence the estimated RVSP was 58 mm Hg. The intensity of the TR jet indicates that it is at least moderate TR.
TR jet is the commonest method of evaluating RVSP, though it has its own limitation. Significant beat to beat variations can be seen in irregular rhythms sometimes. More often the problem is obtaining a good TR jet, which is more likely in those with lung disease where the lung overlaps the heart preventing a good echocardiographic interrogation.
- Roberts JD, Forfia PR. Diagnosis and assessment of pulmonary vascular disease by Doppler echocardiography. Pulm Circ. 2011 Apr-Jun;1(2):160-81.