Accuracy of Echocardiographic Estimates of Pulmonary Artery Pressures in Pulmonary Hypertension: Insights From the KARUM Hemodynamic Database

BACKGROUND. Accurate assessment of pulmonary artery (PA) pressures is integral to diagnosis, follow-up and therapy selection in pulmonary hypertension (PH). Despite wide utilization, the accuracy of echocardiography to estimate PA pressures has been debated. We aimed to evaluate echocardiographic accuracy to estimate right heart catheterization (RHC) based PA pressures in a large, dual-centre hemodynamic database. METHODS. Consecutive PH referrals that underwent comprehensive echocardiography within 3 hours of clinically indicated right heart catheterization were enrolled. Subjects with absent or severe, free-flowing tricuspid regurgitation (TR) were excluded. Accuracy was defined as mean bias between echocardiographic and invasive measurements on Bland-Altman analysis for the cohort and estimate difference within ±10mmHg of invasive measurements for individual diagnosis. RESULTS. In 419 subjects, echocardiographic PA systolic and mean pressures demonstrated minimal bias with invasive measurements (+2.4 and +1.9mmHg respectively) but displayed wide limits of agreement (-20 to +25 and -14 to +18mmHg respectively) and frequently misclassified subjects. Recommendation-based right atrial pressure (RAP) demonstrated poor precision and was falsely elevated in 32% of individual cases. Applying a fixed, median RAP to echocardiographic estimates resulted in relatively lower bias between modalities when assessing PA systolic (+1.4mmHg; 95% limits of agreement +25 to –22mmHg) and PA mean pressures (+1.4mmHg; 95% limits of agreement +19 to -16mmHg).CONCLUSIONS. Echocardiography accurately represents invasive PA pressures for population studies but may be misleading for individual diagnosis owing to modest precision and frequent misclassification. Recommendation-based estimates of RAPmean may not necessarily contribute to greater accuracy of PA pressure estimates.