[Transesophageal echocardiography in patients with systemic arterial embolism]

The percentage of ischemic strokes or peripheral arterial embolism attributed to cardiogenic embolism is about 30% and 75%, respectively. Diagnostic work-up in patients with prior arterial embolism is of prognostic importance, because embolic events are often recurrent. Cardioembolic sources with major risk of embolism are atrial fibrillation, mechanical or biological heart valve prosthesis, left ventricular or left atrial thrombi, left atrial myxomas, bacterial endocarditis, nonbacterial thrombotic endocarditis and nonischemic dilative cardiomyopathies. Cardioembolic sources with minor risk of embolism are mitral valve prolapse, isolated mitral annular calcification, patent foramen ovale, atrial septal aneurysm and calcific aortic valve stenosis. Studies have shown that two-dimensional transthoracic echocardiography yields little useful information in patients with arterial embolism. The advent of transesophageal echocardiography in the late 1980s allowed a more reliable identification of potential cardioembolic sources. The close contact of the echoprobe in the esophagus to the heart allows better resolution of intracardiac structures, particularly when cardiovascular abnormalities at the atrial level, the base of the heart and the thoracic aorta are sought. We studied 153 patients with clinically suspected arterial embolism by transthoracic and transesophageal echocardiography. Patients with extracranial carotide occlusive disease and patients older than 60 years were excluded from the study. In 88 out of 153 patients (58%) a cardioembolic mechanism could be detected by the combination of transthoracic and transesophageal echocardiography. Using the transthoracic method alone, a cardioembolic source could only be found in 55 patients (36%). Valvular heart disease and regional or global wall motion abnormalities could be visualized by both methods with similar results. However, only two out of 22 left atrial thrombi detected by transesophageal echocardiography could be documented also with the transthoracic approach. Transesophageal echocardiography was superior in the evaluation of valvular vegetations, intracardiac tumors, diseases of the thoracic aorta and abnormalities of the interatrial septum. Only left ventricular thrombi could be better evaluated by the transthoracic method, because visualization of the left ventricular apex by the transesophageal approach is problematic. In patients with systemic arterial embolism the combination of transthoracic and transesophageal echocardiography is the diagnostic method of choice to detect a cardioembolic source. Randomized studies in the future must prove, whether the echocardiographic findings can lead to better therapeutic strategies to improve the prognosis of patients with embolic disease.