Diagnostic accuracy of Doppler-echocardiography in unselected patients with suspected pulmonary embolism

This study investigates the diagnostic value of echocardiography in patients with suspected pulmonary embolism. Doppler-echocardiography was performed in fifty consecutive patients, predominantly presenting in the emergency ward, with clinically suspected pulmonary embolism. Patients were classified as having or not pulmonary embolism by a sequential non-invasive strategy including lung scan, D-dimer measurement and lower limb venous compression ultrasonography, pulmonary angiography being performed in case of an inconclusive non-invasive work-up. The prevalence of pulmonary embolism was 36% (18 of 50 patients). Right ventricular dilatation on 2-D echocardiography associated to a tricuspid regurgitation velocity ≥2.7 m/s, corresponding to a pulmonary systolic pressure ≥39 mmHg, were present in 12 of the 18 patients (67%) with and in two of the 32 patients (6.3%) without pulmonary embolism. They were, however, absent in five of the 18 patients (28%), in whom the definite diagnosis of pulmonary embolism was made. The combination of these both echocardiographic criteria yielded a sensitivity of 67% and a specificity of 94%, positive predictive value was 86% and negative predictive value was 83%. The diagnostic performance of these two combined echocardiographic criteria, when present, permitted to reach in patients with a high clinical pre-test probability of pulmonary embolism the post-test probability values above 90%. On the other hand, the absence of these two Doppler-echocardiographic criteria did not allow to exclude pulmonary embolism, except in presence of a low pre-test probability. The findings of our study show that Doppler-echocardiography in patients with high clinical suspicion of pulmonary embolism may represent a potentially useful screening technique for the diagnosis of the disease permitting prompt initiation of treatment. However, the method does not allow to exclude pulmonary embolism in all patients with intermediate or high clinical suspicion of the disease.