Noninvasive diagnosis ‘reliable’ for pulmonary hypertension diagnosis

09.29.2014

Source: Medwire News

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Doppler echocardiography has good accuracy relative to right heart catheterisation for detecting pulmonary hypertension, shows a large study.

The study involved 1695 patients at a single cardiac care centre who underwent Doppler echocardiography no more than 5 days before or after right heart catheterisation.

Researcher Sebastian Greiner (University of Heidelberg, Germany) and team say that their study is considerably larger than most previous analyses of noninvasive systolic pulmonary artery pressure (sPAP) measurement.

“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”, they write in the Journal of the American Heart Association.

The average sPAP was 45.3 mmHg when measured by Doppler echocardiography and 47.4 mmHg by right heart catheterization, with Doppler echocardiography underestimating the true value by an average 2.0 mmHg.

Greiner et al note that, of the original 2119 patients who underwent full invasive and noninvasive sPAP examinations, 20% did not have Doppler echocardiography measurements because of the absence of tricuspid regurgitation. However, more than half of these patients had an average sPAP of 25 mmHg or higher on right heart catheterisation, “confirming that absence of a measurable tricuspid regurgitation does not exclude [pulmonary hypertension].”

A Doppler echocardiography measurement of 36 mmHg was 87.0% sensitive and 79.1% specific for detecting pulmonary arterial hypertension, defined as an invasive sPAP measurement of 25 mmHg or higher. Reducing the cutoff to 31 mmHg increased the sensitivity to 94.6%, missing only 66 of 1221 cases, but reduced specificity to 58.0%, giving 199 false–positive results.

“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 note.

The main cause of sPAP underestimation was an incomplete continuous-wave Doppler spectral envelope, whereas one-third of overestimations were due to “false interpretation of the spectral envelope maximal velocity boundary in the presence of vertical linear Doppler [artefacts]”.

The team concludes: “Thus, optimal settings when assessing tricuspid regurgitation velocities should be taken into account.”

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