DIAGNOSIS OF ASCENDING AORTIC DISSECTION BY TRANSESOPHAGEAL ECHOCARDIOGRAPHY - UTILITY OF M-MODE IN RECOGNIZING ARTIFACTS

Objectives. This study sought to assess the reliability of biplanar tr ansesophageal echocardiography in the diagnosis of ascending aortic di ssection and to test the utility of M-mode information in the differen tial diagnosis of ascending aortic ultrasound artifacts and intimal fl ap images. Background. Transesophageal echocardiography is a useful te chnique in the diagnosis of aortic dissection. However, ultrasound art ifacts in the ascending aorta are an important limitation. Methods. Tr ansesophageal echocardiography was performed in 132 consecutive patien ts with clinically suspected aortic dissection. Two-dimensional and M- mode echocardiography and color Doppler were used to diagnose intimal Bap and artifact images. Diagnoses were validated either anatomically or with reference techniques. Results. The sensitivity and specificity of transesophageal echocardiography in the diagnosis of ascending aor tic dissection were 96.8% and 100%, respectively. Ninety-three artifac ts were ob served in 56 (55%) of 101 patients without ascending aortic dissection. Two-dimensional echocardiography easily identified 74 art ifacts (80%). Color Doppler showed no ascending flow abnormalities in 71% of artifact images. M-mode echocardiography showed three location and mobility artifact patterns related to the posterior wall of the ao rta or the right pulmonary artery. In contrast, intimal flap movement showed no relation to the aortic wall movement in 25 cases (83%). Blin d analysis of transesophageal echocardiographic study tapes underlined the utility of M-mode in the differential diagnosis. Ranges of sensit ivity, specificity and positive predictive value (established by inclu ding doubtful results as either positive or negative) improved from 87 .1-93.5% to 93.5- to 96.8%, from 85.1-94.1% to 99-100% and from 65.9-8 1.8% to 96.8-100%, respectively, with the inclusion of M-mode data. Co nclusions. Biplanar transesophageal echocardiography permits reliable diagnosis of ascending aortic dissection. Ultrasound artifacts are com mon, but assessment of the location and mobility of intraluminal image s by M-mode echocardiography definitely improves diagnostic accuracy.