Usefulness of pulmonary arterial flow discordance to identify pulmonary embolism.

The present study was undertaken to determine the sensitivity and specificity of echocardiography in the diagnosis of pulmonary embolism (PE). The study consisted of 2 stages. First, 600 patients were enrolled to measure bilateral pulmonary blood flow by echocardiography. Using multidetector row computed tomography, 200 subjects were diagnosed with pulmonary hypertension and 100 with defined PE. Another 300 subjects without cardiopulmonary distress served as controls. The time-velocity integral (TVI) and flow volume of both pulmonary arteries were obtained. The percentage differences in bilateral pulmonary arterial TVI (DeltaTVI/mean) were 12.0 +/- 9.3%, 13.8 +/- 12.1%, and 38.6 +/- 14.9% for controls, subjects with pulmonary hypertension, and subjects with PE, respectively. The percentage differences in bilateral pulmonary flow (Deltaflow/mean) were 15.1 +/- 11.7%, 17.6 +/- 14.9%, and 36.8 +/- 17.5% for controls, subjects with pulmonary hypertension, and subjects with PE, respectively. By receiver-operating characteristic curve analysis, the cut-off points for DeltaTVI/mean and Deltaflow/mean to identify PE were 25% and 26.5%, respectively. In the second part of study, the accuracy of DeltaTVI/mean and Deltaflow/mean to screen 300 patients with suspected PE was tested. Echocardiography provided high degrees of sensitivity and specificity for the diagnosis of PE. In conclusion, bilateral pulmonary arterial flow measurement is a simple and useful test to assess the possibility of PE.