Cardiology MCQ: Pulmonary hypertension by echo

Most common method of assessment of pulmonary hypertension by Doppler echocardiography is by using:

A: Forward velocity across the tricuspid valve

B: Reverse velocity across the tricuspid valve

C: Forward velocity across the pulmonary valve

D: Reverse velocity across the mitral valve

Correct answer: B: Reverse velocity across the tricuspid valve

Reverse velocity across the tricuspid valve is that due to tricuspid regurgitation. Bernoulli equation (P=4V²) gives the gradient of tricuspid regurgitation flow, which corresponds to the pressure difference between right ventricle and right atrium in systole. If a nominal right atrial pressure of 10 mm Hg is added to it, right ventricular pressure and indirectly the pulmonary artery systolic pressure are obtained, in the absence of pulmonary stenosis. If there is high right atrial pressure with elevated jugular venous pressure, 15 or 20 mm Hg may have to be added instead of 10 mm Hg. The early diastolic pulmonary regurgitation (PR) gradient (peak PR gradient) will give an estimate of mean pulmonary artery pressure. End diastolic gradient of PR will give an estimate of pulmonary artery end diastolic pressure (diastolic pressure). Ideally the right ventricular end diastolic pressure has to be added to the end diastolic PR gradient to get the pulmonary artery diastolic pressure.