Accuracy of noninvasively determined pulmonary artery systolic pressure

The noninvasive estimation of pulmonary artery systolic pressure (PASP) has become a standard component of the echocardiographic examination. Our aim was to evaluate the accuracy of this modality in a large series of unselected studies obtained in clinical practice. All right heart catheterizations during a 4-year period were reviewed. Studies with echocardiographic findings available within 48 hours were evaluated for PASP agreement. In an effort to mirror clinical practice, the right heart catheterization findings were used as the reference standard and the PASP values were taken directly from the respective clinical reports. Overall, 792 right heart catheterization-echocardiogram pairs were identified. Echocardiographic PASP could not be estimated in 174 of these studies (22.0%). The correlation between modalities was moderate, but agreement was poor (bias 9.0%, 95% limits of agreement -53.2% to 71.2%, r = 0.52, p <0.001). Misclassification of clinical PASP categories occurred more often than not (54.4%). Multivariate analysis using multiple potential sources of error could only account for 3.2% of the total variation in the discrepancy between the study modalities (p = 0.003). In conclusion, noninvasively estimated PASP had limited agreement with the invasively determined PASP, and misclassification of PASP clinical categories occurred frequently. Given the widespread use of echocardiographically determined PASP, these data are in need of replication in a large prospective study.