Transoesophageal echocardiography for definitive diagnosis of haemodynamically significant pulmonary embolism.

Transesophageal echocardiographic evaluation of right and left pulmonary arteries, up to the origin of their lobar branches, was prospectively performed with a single plane probe in 32 consecutive patients (18 M, 14 F, aged 55.5 +/- 14.6, from 32 to 80 years) with clinical or echocardiographic suspicion of pulmonary embolism, who met transthoracic echocardiographic criteria of right ventricular overload. Transoesophageal echocardiography showed unequivocal (20 patients) or suspected (three patients) intraluminar thrombi in 88.5% of 26 patients with haemodynamically significant acute or chronic pulmonary embolism, confirmed with reference methods. The sensitivity of the unequivocal transoesophageal echocardiographic diagnosis was 80% for acute and 73% for chronic haemodynamically significant pulmonary embolism. No false-positive results were found (specificity 100%). Additionally, in three cases, transoesophageal echocardiography disclosed the cause of the right ventricular overload revealing a previously undiagnosed atrial septal defect or Ebstein anomaly. Direct visualization of proximal pulmonary arterial thrombi by transoesophageal echocardiography emerges as a useful new method of prompt and definite diagnosis of haemodynamically important pulmonary embolism.