Spectrum of acute dissection of the ascending aorta: a transesophageal echocardiographic study.

Transesophageal echocardiography is an accurate tool for the immediate diagnosis of acute aortic dissection. In addition to establishing the diagnosis of dissection, transesophageal echocardiography provides determination of its extent and detection of complications. The purpose of this study was to delineate the full spectrum of abnormalities present in acute dissection of the ascending aorta as assessed by transesophageal echocardiography. Forty consecutive patients with acute ascending aortic dissection were evaluated. Specific attention was paid to complications of aortic valve insufficiency, pericardial effusion, and left ventricular wall motion abnormalities. The aortic arch and the descending aorta were also evaluated for involvement. Quantitative data included measurement of the aorta at the anulus, sinuses, and tubular portion, as well as the proximal and distal descending aortas. An intimal flap was identified in all patients. This was a simple linear tear in 22 patients (55%) and circumferential in eight (20%). A complex tear was noted in 10 patients (25%). The majority of patients (n = 30; 75%) had extension of the dissection into the descending thoracic aorta. At least one communication between the true and false lumens ("entrance point") was identified in 31 patients (78%). Pericardial effusions were noted in 19 patients (48%), only two of whom had a moderate-size effusion. Moderate or severe aortic insufficiency was seen in 18 patients (45%) and regional wall motion abnormalities in six patients. We conclude that acute dissection of the ascending aorta results in a complex or convoluted flap rather than a simple linear tear in many patients. The complication of clinically significant pericardial effusion was rare. Aortic insufficiency is common and can be attributed to multiple mechanisms.