TRANSESOPHAGEAL ECHOCARDIOGRAPHY IN THE DIAGNOSIS OF PULMONARY-EMBOLISM WITH ACUTE COR-PULMONALE

Transoesophageal echocardiography is a method of visualising intracard iac thrombi and could therefore be useful for the diagnosis of pulmona ry embolism, but its diagnostic value is unknown. The authors carried out a prospective study with this diagnostic tool in massive pulmonary embolism. The study protocol was to perform transthoracic echocardiog raphy in patients with suspected acute pulmonary embolism and then to perform transoesophageal echocardiography when there were signs of acu te cor pulmonale. The results of both echocardiographic investigations were compared with two reference radiological techniques : the spiral CT scan and/or pulmonary angiography. Fifty-six patients underwent tr ansthoracic echocardiography. In the 34 patients with transthoracic ec hocardiographic signs of acute cor pulmonale, the positive predictive value of the investigation for pulmonary embolism was 91% and the nega tive predictive value was 54%. Twenty of these 34 patients underwent t ransoesophageal echocardiography. The sensitivity and specificity for the diagnosis of proximal embolism were 85% and 86% respectively. The limitations of the method were poor visualisation of the left pulmonar y artery in which only one thrombus was detected, compared with 6 by s piral CT scan, and the absence of visualisation of lobar arteries. Con sequently, the real sensitivity of transoesophageal echocardiography f or visualisation of all thrombi in the pulmonary arteries in acute cor pulmonale was only 55%. In acute cor pulmonale, the diagnostic value of transoesophageal echocardiography is poor because the sensitivity f or visualisation of intra-pulmonary arterial thrombi is low compared w ith other radiological techniques. However, in patients with proximal emboli in the right or main pulmonary artery, the diagnosis may be est ablished in a few minutes without the need of other more invasive tech niques. Nevertheless, normal transoesophageal echocardiography does no t rule out the presence of proximal in the left pulmonary artery or di stal emboli in the lobar arteries.