Correlation Between Doppler Echocardiography and Right Heart Catheterization Derived Pulmonary Artery Pressures: Impact of Right Atrial Pressures

Abstract

Objective: To evaluate the correlation between Doppler echocardiography (DE) and right heart catheterization (RHC) derived pulmonary artery pressures and to assess the impact of right atrial (RA) pressures on this correlation.

Study design: Cross-sectional analytical study.

Place and duration of study: Cardiology Department, Tahir Heart Institute, Chenab Nagar, from June 2013 to December 2014.

Methodology: All patients undergoing RHC were included. Relevant data were collected from hospital database. Continuous variables were expressed as the mean and SD or as the median and interquartile range where the distributions were skewed. Pearson correlation coefficient and Bland-Altman method were used to correlate DE derived right ventricular systolic pressure (RVSP) and RHC derived systolic pulmonary artery pressures (sPAP). Adjusted RVSP was calculated by replacing default value of RA pressure (10 mmHg) with RHC derived mean RA pressure. Receiver operating characteristic curve (ROC) was used to identify the best cut-off value of RVSP in predicting pulmonary hypertension.

Results: Fifty-one patients completed the study protocol. Mean age of study population was 45.22 ±15.25 years with male to female ratio of 1.47:1. Median error was 13 mmHg (7 to 20). Pearson correlation coefficient (r) between RVSP and sPAP was 0.72. Bland-Altman method of correlation showed bias of +4.43 mmHg with 95% limits of agreement ranging from -34.61 to +43.47. Using ROC curve, the best cut-off value of RVSP was greater than 52 mmHg with accuracy of 75% (sensitivity: 81%, specificity: 69%) in predicting pulmonary hypertension. Adjusted RVSP showed only little improvement in correlation (r = 0.75), adjusted error (13.65 ±13.05) and diagnostic accuracy (79%).

Conclusion: Doppler echocardiography can frequently overestimate pulmonary artery pressures. Though correctly estimated RA pressure may improve this correlation, yet its contribution is only minimal.