Mean Pulmonary Artery Pressure Estimated from Systolic and Diastolic Pulmonary Artery Pressure in Children with Congenital Heart Disease: An Invasive Study

This hemodynamic study documented the accuracy and precision of six empirical formulas relating mean (mPAP), systolic (sPAP), and diastolic (dPAP) pulmonary artery pressures in children with congenital heart disease. Fluid-filled PAPs of 61 children (age, 26 ± 40 months) were analyzed over an mPAP range of 7 to 74 mmHg. All formulas were accurate (mean bias, −2 to 1 mmHg). The three formulas relying on sPAP and dPAP were dPAP + 1/3 (sPAP – dPAP), dPAP + 0.41 (sPAP – dPAP), and sqrt of (sPAP × dPAP). They were precise (bias standard deviation [SD], 3 mmHg), with approximately 90% of patients exhibiting biases of less than 5 mmHg. The three formulas relying on sPAP alone all assumed that mPAP approached two-thirds of sPAP according to slightly different mathematical equations. They were less precise (bias SD, 5–6 mmHg), with biases greater than 7 mmHg for 10% to 16% patients. Accurate estimates of mPAP were obtained from sPAP alone, and this could be valuable for cross-checking the self-consistency of the pressure database obtained in the echo-Doppler laboratory. For cases that had reliable dPAP estimates available, empirical formulas relying on both sPAP and dPAP were more precise and thus must be preferred.