Table 2. Echocardiographic methods of estimating mean pulmonary artery pressure.
| Measurement | View (modality) | Formula | Abnormal value | Description |
|---|---|---|---|---|
| Peak TR velocity | A4C | RVsP = PASP = 4(peak TR velocity)2 + RAP | RVsP > 37 mmHg | Whether the Doppler angle aligns with the CW is important. |
| PSAX | mPAP = (0.61 × PASP) + 2 mmHg | mPAP > 25 mmHg | The highest point of the TR envelope should be measured. | |
| RV inflow (CW) | ||||
| RVOTAT | PSAX (PW) | mPAP = 90 − (0.62 × RVOTAT) | RVOTAT < 130 ms | Obtained at end expiration. |
| Sample volume is placed just proximal to the pulmonary cusp on the RV side. | ||||
| Opening snap is included. | ||||
| Closing snap is not included. | ||||
| Important to measure from beginning to end of flow but not the slope. | ||||
| Correction for HR is required for HR > 110 bpm or HR < 70 bpm. | ||||
| Peak PR Doppler signal | PSAX (PW) | mPAP = 4(peak PR velocity)2 + RAP | Peak PR > 2.2 m/s | Useful when TR is not observed. |
| mPAP > 25 mmHg | May be unreliable in constrictive or restrictive physiology. | |||
| PR end velocity | PSAX (PW) | mPAP = 2/3 × PADP + 1/3 × PASP | End PR velocity is measured in multiple cycles and averaged. | |
| PADP = 4 × (PR end velocity)2 + RAP | May be underestimated in severe PH. | |||
| May be unreliable in constrictive or restrictive physiology. | ||||
| TR TVI | A4C | mPAP = TR pressure gradient (TR TVI) + RAP | TR measurement is not possible in all patients. | |
| PSAX | Values derived from the method are closely related with the mPAP of RHC patients. | |||
| RV inflow (CW) |
A4C: apical 4-chamber view, CW: continuous-wave, HR: heart rate, mPAP: mean pulmonary artery pressure, PADP: pulmonary artery diastolic pressure, PASP: pulmonary artery systolic pressure, PH: pulmonary hypertension, PR: pulmonary regurgitation, PSAX: parasternal short axis view, PW: pulse-wave, RAP: right atrial pressure, RHC: right heart catheterization, RV: right ventricle, RVOT: right ventricular outflow tract, RVOTAT: right ventricular outflow tract acceleration time, RVsP: right ventricular systolic pressure, TR: tricuspid regurgitation, TVI: time velocity interval.