Measurement of pulmonary artery pressure and grading by echocardiography with emphasis on new guidelines
1. Estimation method:
The pulmonary artery systolic pressure (PASP) is typically estimated using the peak tricuspid regurgitation velocity (TRV) and adding an estimate of right atrial pressure[1][2]. This is done using the simplified Bernoulli equation: PASP = 4(TRV)^2 + estimated right atrial pressure.
2. Grading scale:
The severity of pulmonary hypertension based on mean pulmonary artery pressure (mPAP) is generally graded as[4]:
- Mild: 20-40 mmHg
- Moderate: 41-55 mmHg
- Severe: > 55 mmHg
3. Probability assessment:
Recent guidelines recommend assessing the probability of pulmonary hypertension rather than providing a specific pressure estimate[1][3]. The echocardiographic probability of pulmonary hypertension is categorized as:
- Low probability: TRV ≤ 2.8 m/s or not measurable, with no other echocardiographic signs of PH
- Intermediate probability: TRV ≤ 2.8 m/s with other signs of PH, or TRV 2.9-3.4 m/s without other signs
- High probability: TRV 2.9-3.4 m/s with other signs of PH, or TRV > 3.4 m/s
4. Additional echocardiographic signs:
Other echocardiographic parameters are considered when assessing the probability of pulmonary hypertension, including right ventricular size and function, pulmonary artery characteristics, and inferior vena cava and right atrium measurements[1][3].
5. Limitations:
It's important to note that numerical echocardiographic estimates of pulmonary artery pressure often are inaccurate compared to invasive measurements, with both overestimation and underestimation possible[1][2]. Right heart catheterization remains the gold standard for diagnosing pulmonary hypertension[4].
In summary, while specific pressure values can be estimated, current guidelines emphasize assessing the probability of pulmonary hypertension using a combination of tricuspid regurgitation velocity and other echocardiographic signs, rather than relying solely on pressure estimates.
Citations:
[1] https://pmc.ncbi.nlm.nih.gov/articles/PMC6055509/
[2] https://www.ccjm.org/content/83/4/256
[3] https://echo.biomedcentral.com/articles/10.1530/ERP-17-0071
[4] https://litfl.com/pulmonary-hypertension-echocardiography/
[5] https://www.sciencedirect.com/science/article/abs/pii/S2213260021000722
[6] https://www.ahajournals.org/doi/10.1161/jaha.113.000363
[7] https://www.ahajournals.org/doi/10.1161/circimaging.116.005711
