A new study, entitled “Reliability of noninvasive assessment of systolic pulmonary artery pressure by Doppler echocardiography compared to right heart catheterization: analysis in a large patient population” was published on the Journal of the American Heart Association led by first author Dr. Sebastian Greiner, M.D., and senior author Dr. Derliz Mereles, M.D., both from the University of Heidelberg, Germany.
Pulmonary artery pressure (PAP) is an important biomarker in cardiovascular disorders and correlates very well with morbidity and mortality. Noninvasive assessment by Doppler echocardiography has been recommended by current guidelines, but the accuracy of this technique has been assessed only in small studies with contradictory results. Therefore, the researchers decided to analyze the accuracy of noninvasive PAP measurements by Doppler echocardiography compared to invasive measurements, such as right heart catheterization, in a large patient population.
“Although recommended in many guidelines and used routinely, noninvasive quantification of sPAP has never been tested sufficiently in unselected large patient populations undergoing routine echocardiography examination,” said the authors.
This study enrolled 1,695 patients at a single cardiac care center that were submitted to Doppler echocardiography no more than 5 days before or after right heart catheterization — a research effort that is believed to be the largest study performed to this point for using noninvasive systolic pulmonary artery pressure (sPAP) measurement. The authors pointed out that 2,119 patients submitted to full invasive and noninvasive sPAP examinations, while 20% did not receive Doppler echocardiography measurements because of the absence of tricuspid regurgitation, a condition in which the tricuspid valve of the heart does not close well. However, more than half of these patients had a mean value for sPAP of 25 mmHg or higher on right heart catheterization, “confirming that absence of a measurable tricuspid regurgitation does not exclude [pulmonary hypertension],” said the authors.
“Contrary to former assertions, characteristics of the inferior vena cava were not the main reason for inaccuracy, but rather were due to the many pitfalls inherent to the Doppler method,” the researchers noted.
The authors highlighted that sPAP underestimation was due to “an incomplete continuous-wave Doppler spectral envelope,” while one-third of overestimations were due to “false interpretation of the spectral envelope maximal velocity boundary in the presence of vertical linear Doppler [artifacts]”. The team concluded that “Thus, optimal settings when assessing tricuspid regurgitation velocities should be taken into account.”
Finally, the researchers concluded that the Doppler echocardiography technique was more accurate but had close correlation to invasive measurements and was validated to establish the noninvasive diagnosis of pulmonary hypertension in patients with cardiac diseases.