[Unexplained pulmonary edema: demonstration of obstruction to pulmonary venous return by transesophageal echocardiography. Apropos of 4 cases].

The usual causes of pulmonary edema are left ventricular dysfunction, mitral valve disease or left atrial myxoma. Obstruction to pulmonary venous drainage is a rare and unrecognised diagnosis which should be considered when the usual investigations are unproductive. The authors report four cases in which transesophageal echocardiography showed pulmonary edema to be due to compression of one or more pulmonary veins by a mediastinal mass (2 cases), by the false lumen of dissection of the aorta (1 case) and postoperative stenosis of the pulmonary veins (1 case). These cases underline the diagnostic value of this technique which rapidly provides diagnostic information with privileged visualisation of the pulmonary veins and abnormalities of acceleration of blood velocities in the Doppler mode due to obstruction.