Aims: To identify a correction of the modified Bernoulli formula used to estimate systolic and mean pulmonary artery pressure [sPAP and mPAP; respectively: sPAP = 4 × TRv (tricuspid regurgitation velocity)(2)+ RAP (right atrial pressure); and mPAP = 0.61sPAP + 2], applicable in the follow-up of pulmonary hypertension (PH) patients.
Methods and results: From January 1979 to December 2009, 60 patients with precapillary (class I and IV) and 'out of proportion' PH were consecutively enrolled in the PH Registry of Trieste. All patients underwent both echocardiographic and right heart catheter evaluation. We used a simple-linear-regression method in order to compare sPAP and mPAP Doppler-estimated values with the respective right-heart catheterization invasive variables. The comparison of the estimated with the traditional modified Bernoulli formula echo-Doppler data and the effective invasive values confirmed a significant association between them (for sPAP P< 0.001; for mPAP P= 0.006). Simple-linear-regression-derived formulas were sPAP = 1.07 × (4TRv(2)+ RAP) + 7.4 (1) and mPAP = 1.1 × (0.61sPAP + 2) + 2.5 (2). These regression-corrected formulas were validated in an external population of PH patients.
Conclusion: Our data suggest that formulas (1) and (2) could be more reliable with respect to the traditional modified Bernoulli equation, when estimating echocardiographically sPAP and mPAP in patients with PH confirmed by right-heart catheterization.