Population and Study Design
Between January 1991 and December 1998, 469 patients undergoing a TEE examination for suspected AD or TDA were recruited from two tertiary referral teaching hospitals (Du-puytren University Hospital, Limoges, France, and The University of Chicago Medical Center, Chicago, IL). Patients were excluded when the diagnostic confirmation of TEE findings was not obtained by an alternative imaging modality or at surgery (n = 102), or when TEE was performed to exclude a potential complication involving a previously repaired AD or disruption (n = 16). Thus, 351 patients (248 men and 103 women; mean ± SD age, 57 ± 16 years; range, 17 to 85 years; 97 patients receiving mechanical ventilation) were studied. In all these patients, confirmation of the aortic condition was obtained using an alternative imaging technique, such as (1) CT scan or MRI (n = 193), (2) aortography (n = 70) in patients sustaining severe blunt chest trauma at high risk of aortic disruption, or (3) at the time of surgery (n = 81), or (4) necropsy (n = 7). canadian health&care mall
In order to determine the incidence of intra-aortic linear artifacts and to establish the differential diagnostic criteria that would allow differentiation between multiple-path artifacts and true aortic flaps, we retrospectively studied 230 patients (172 men and 58 women; mean age, 58 ± 16 years; range, 17 to 85 years) who underwent TEE to rule out an AD or a TDA (protocol A). Subsequently, TEE diagnostic criteria that were independently predictive of the presence of underlying linear artifacts were prospectively tested in a second cohort of 121 patients (76 men and 45 women; mean age, 56 ± 17 years; range, 17 to 81 years) referred for suspicion of an acute aortic lesion (protocol B). In all patients, TEE interpretations were compared with the results of the reference methods.
All TEE studies were performed using either a 5-MHz monoplane (n = 144) or multiplane probe (n = 207) connected to an ultrasound system (Sonos 1500, 2500, or 5500; Hewlett-Packard; Andover, MA) and recorded on videotape for off-line analysis. During the prospective study (protocol B), all procedures were performed with a multiplane TEE probe. Arterial BP, heart rate, and oximetry were monitored throughout the procedure.
The TEE study was conducted as previously described, with particular attention directed toward the examination of the ascending, horizontal, and descending segments of the thoracic aorta, using two-dimensional echocardiography in conjunction with color Doppler echocardiographic flow mapping. Image depth and sector width were set to maximize frame rate, and the velocity scale was set between 60 cm/s and 80 cm/s in order to enable detection of low intra-aortic blood flow velocities, while limiting the aliasing effect. Gain settings were carefully adjusted to avoid the presence of color clutters outside the vascular lumen. When using the multiplane probe, the 110° to 140° echocardio-graphic plane was routinely used to visualize the ascending aorta to its fullest extent, while the descending thoracic aorta was examined in both the transverse (0°) and longitudinal views (80° to 110°). In addition, the TEE examination was also focused on excluding the presence of an associated cardiac abnormality (eg, pericardial effusion, aortic regurgitation).