Assessing Pulmonary Arterial Hypertension using 2D Echocardiography

Understanding RVSP and SPAP Measurements

The American College of Chest Physicians recommends that right ventricular systolic pressure (RVSP) is considered equal to systolic pulmonary artery pressure (sPAP) in the absence of pulmonic valve stenosis or right ventricular outflow tract obstruction, with a strong correlation between RVSP estimated from tricuspid regurgitation velocity and invasive hemodynamic measurements from right heart catheterization, in patients with pulmonary arterial hypertension (PAH) 1, 2
RVSP is calculated using the modified Bernoulli equation: RVSP = 4v² + RAP, where v is the tricuspid regurgitation (TR) jet velocity in meters per second, and RAP is the estimated right atrial pressure, in patients with PAH, with correlation coefficients ranging from 0.83 to 0.95 1, 2
Multiple studies have shown statistically significant correlations (r = 0.83 to 0.95) between RVSP estimated from TR velocity and invasive hemodynamic measurements from right heart catheterization, in patients with PAH, with a sensitivity of Doppler echocardiography for detecting PAH using RVSP ranging from 0.79 to 1.0, and specificity ranging from 0.6 to 0.98 1, 2, 3, 4

Nine studies incorporating 500 patients with various forms of PAH demonstrated strong correlations between RVSP estimated by echocardiography and invasive measurements, with correlation coefficients ranging from 0.57 to 0.95, and an area under the curve of 0.97 for classifying pulmonary hypertension, according to the American College of Chest Physicians 1
The sensitivity of Doppler echocardiography for detecting PAH using RVSP ranges from 0.79 to 1.0, with specificity ranging from 0.6 to 0.98, in patients with PAH, as recommended by the American College of Chest Physicians 3, 4
In pediatric patients, the TR Doppler signal can be enhanced by the use of agitated saline to improve measurement accuracy when the TR jet is inadequate, with a strong correlation between RVSP estimated from TR velocity and invasive hemodynamic measurements from right heart catheterization, according to the American Heart Association 5

TR jets are analyzable in 39% to 86% of patients, highlighting the importance of obtaining adequate imaging, with a strong correlation between RVSP estimated from TR velocity and invasive hemodynamic measurements from right heart catheterization, in patients with PAH, as recommended by the American College of Chest Physicians 1, 2
The Doppler beam should be aligned parallel to the TR jet, and multiple transducer positions should be used to record the highest velocity to reduce underestimation, in patients with PAH, according to the American College of Chest Physicians 5

Echocardiography may underestimate sPAP by a mean of 11 mm Hg, with underestimation of 20 mm Hg in up to 31% of patients, in patients with PAH, as reported by the American College of Chest Physicians 3
The discordance between estimated and true pulmonary artery pressure is greatest when sPAP exceeds 100 mm Hg, in patients with PAH, with a strong correlation between RVSP estimated from TR velocity and invasive hemodynamic measurements from right heart catheterization, according to the American College of Chest Physicians 3, 4
In cases of severe tricuspid regurgitation, TRV may be significantly underestimated and cannot be used to exclude PH, in patients with PAH, as recommended by the European Respiratory Society 6

When TR and pulmonic valve regurgitation jets are not present or quantifiable, right ventricular outflow patterns and time intervals can be used, in patients with PAH, with a strong correlation between RVSP estimated from TR velocity and invasive hemodynamic measurements from right heart catheterization, according to the American College of Chest Physicians 1, 3
Parameters include pre-ejection period, acceleration and deceleration times, relaxation, and contraction times, in patients with PAH, with correlation coefficients ranging from 0.57 to 0.95, as recommended by the American College of Chest Physicians 2, 3

Real-time 3D echocardiography evaluates RV volumes and ejection fraction more accurately than conventional 2D echocardiography, in patients with PAH, with a strong correlation between RVSP estimated from TR velocity and invasive hemodynamic measurements from right heart catheterization, according to the American College of Radiology 7
Pressure gradient-volume diagrams derived from 3D echocardiography data can reliably estimate RV stroke work in patients with PH, in patients with PAH, with a strong correlation between RVSP estimated from TR velocity and invasive hemodynamic measurements from right heart catheterization, as recommended by the American College of Radiology 7