Abstract P86: Predicting Mean Pulmonary Arterial Pressure Using Systemic Arterial Pressure (SPAP)

Background: The assessment of pulmonary pressure is elementary in the management of patients with pulmonary hypertension. Presently, pulmonary artery systolic pressure (PASP) can be reliably estimated using non-invasive means, but mean pulmonary pressure (MPAP) cannot be derived. The aim of this study was to derive a formula to non-invasively predict MPAP from PASP. Methods: Invasive hemodynamic pressures at steady state were examined in 198 consecutive patients who underwent right heart catheterization in the Mayo Clinic (Rochester, MN). Simple regression techniques were used to determine the relationship between MPAP and PASP separately for derivation and validation samples. Bland-Altman analysis was performed to examine predicted vs. observed MPAP values. Results: Over a wide range of MPAP (10 to 80 mmHg), MPAP and SPAP were strongly related (r2=0.89, n=198). The relation of MPAP to PASP in the derivation sample (n=100; MPAP=0.6133*SPAP + 1.1; r2=0.90) was validated in the test sample with an r2 value of 0.91 for predicted versus observed MPAP (p=x). The relation of predicted vs. observed MPAP values was significant across different degrees of pressure elevation, as well as different etiologies of pulmonary hypertension. Conclusion: MPAP can be accurately predicted from SPAP over a wide pressure range and among different etiologies for pulmonary hypertension. This relation may help to define MPAP non-invasively and assist in the clinical management of patients with pulmonary hypertension.