How can you estimate the pulmonary artery mean pressure by Doppler echo?

How can you estimate the pulmonary artery mean pressure by Doppler echo?

Pulmonary artery mean pressure by echo: The early diastolic pulmonary regurgitation (PR) gradient (peak PR gradient) will give an estimate of mean pulmonary artery pressure.

Masuyama T and associates evaluated pulmonary regurgitation flow in 21 patients with pulmonary hypertension and 24 patients without pulmonary hypertension by continuous wave Doppler echocardiography and compared with catheter measurements [1]. The gradient from pulmonary artery to right ventricle in diastole was calculated using the simplified Bernoulli equation (P = 4V²). The peak gradient of pulmonary regurgitation determined by Doppler echocardiography correlated well with mean pulmonary artery pressure. End diastolic gradient correlated with pulmonary artery end diastolic pressure measured invasively.

Abbas AE et al also used simultaneous Doppler and invasive study to validate the role of Doppler derived peak pulmonary regurgitation gradient as a reliable non-invasive measure of mean pulmonary artery pressure [2].

End diastolic gradient of PR will give an estimate of pulmonary artery end diastolic pressure (diastolic pressure) as mentioned above. Ideally the right ventricular end diastolic pressure has to be added to the end diastolic PR gradient to get the pulmonary artery diastolic pressure.

Tricuspid regurgitation jet gradient gives an estimate of right ventricular systolic pressure. Calculation is using simplified Bernoulli equation, from the measured tricuspid regurgitation jet velocity. The right atrial pressure added to the peak TR gradient gives the right ventricular systolic pressure, which will be equal to the pulmonary artery systolic pressure in the absence of right ventricular outflow tract obstruction.

Mean pulmonary artery pressure can also be calculated from end diastolic pressure and systolic pressure as follows:

mPAP = 2/3rd of PADP + 1/3rd of PASP [3].

Intravenous agitated saline contrast can improve the signals of pulmonary regurgitation and tricuspid regurgitation [3].

The gold standard for assessment of pulmonary hypertension is still right heart catheterization [4]. But the invasive nature makes repetitive assessment difficult.

References

1. Masuyama T, Kodama K, Kitabatake A, Sato H, Nanto S, Inoue M. Continuous-wave Doppler echocardiographic detection of pulmonary regurgitation and its application to noninvasive estimation of pulmonary artery pressure. Circulation. 1986 Sep;74(3):484-92.
2. Abbas AE, Fortuin FD, Schiller NB, Appleton CP, Moreno CA, Lester SJ. Echocardiographic determination of mean pulmonary artery pressure. Am J Cardiol. 2003 Dec 1;92(11):1373-6.
3. Parasuraman S, Walker S, Loudon BL, Gollop ND, Wilson AM, Lowery C, Frenneaux MP. Assessment of pulmonary artery pressure by echocardiography-A comprehensive review. Int J Cardiol Heart Vasc. 2016 Jul 4;12:45-51.
4. Nazzareno Galiè, Marc Humbert, Jean-Luc Vachiery, Simon Gibbs, Irene Lang, Adam Torbicki, Gérald Simonneau, Andrew Peacock, Anton Vonk Noordegraaf, Maurice Beghetti, Ardeschir Ghofrani, Miguel Angel Gomez Sanchez, Georg Hansmann, Walter Klepetko, Patrizio Lancellotti, Marco Matucci, Theresa McDonagh, Luc A Pierard, Pedro T Trindade, Maurizio Zompatori, Marius Hoeper, ESC Scientific Document Group. 2015 ESC/ERS Guidelines for the Diagnosis and Treatment of Pulmonary Hypertension: The Joint Task Force for the Diagnosis and Treatment of Pulmonary Hypertension of the European Society of Cardiology (ESC) and the European Respiratory Society (ERS): Endorsed By: Association for European Paediatric and Congenital Cardiology (AEPC), International Society for Heart and Lung Transplantation (ISHLT). Eur Heart J. 2016 Jan 1;37(1):67-119.