Transesophageal echocardiography was accurate in identifying aortic dissection
ACP J Club. 1992 Mar-April;116:53. doi:10.7326/ACPJC-1992-116-2-053
Ballal RS, Nanda NC, Gatewood R, et al. Usefulness of transesophageal echocardiography in assessment of aortic dissection. Circulation. 1991 Nov;84:1903-14.
To assess the usefulness of transesophageal echocardiography in diagnosing and characterizing aortic dissections.
Comparison of findings from transesophageal echocardiographic examinations with those from aortography, surgery, and autopsy.
A university-affiliated hospital.
34 patients had a proven aortic dissection (group 1): 18 had an acute aortic dissection (having symptoms for < 2 weeks) and 16 had a chronic aortic dissection. 26 of 27 patients in group 2 were not suspected of having an aortic dissection: 13 had aortic aneurysms and 14 had no thoracic aortic aneurysms.
Description of test and diagnostic standard
In group 1, transesophageal echocardiography was done intraoperatively in 47% of patients, in the awake state in 44% of patients, and in both settings in the remaining 9%. In group 2 the corresponding percentages were 78%, 22%, and 0%. All echocardiograms were reviewed by 2 independent observers. A diagnosis of aortic dissection was made when a consistent linear echo indicative of a dissection flap was seen within the aortic lumen. The type of dissection (DeBakey classification) was also established. In group 1 the diagnosis was confirmed by aortography and surgery in 18 patients, by aortography alone in 9, by surgery alone in 6, and by autopsy in 1 patient. In group 2 all patients had aortography. 71% of patients in group 1 and 26% in group 2 independently had computed tomography of the chest.
Agreement between the 2 observers who reviewed the echocardiograms was 100%. In group 1 transesophageal echocardiography indicated the presence of aortic dissection in 33 of 34 patients (sensitivity 97%). In group 2 echocardiography did not suggest aortic dissection in any of the 27 patients (specificity 100%). The corresponding values for computed tomography were 67% and 100%. The type of dissection was correctly classified by transesophageal echocardiography for all 29 patients where aortographic or surgical proof was available, except for the 1 patient incorrectly diagnosed as not having a dissection. Coronary artery involvement was seen with transesophageal echocardiography in 6 of 7 patients where the involvement was confirmed by surgery. The arteries were not visualized in the seventh patient.
Transesophageal echocardiography was highly accurate in confirming the presence of aortic dissection among patients with proven dissection and in not indicating the presence of dissection among patients not suspected of having this disease.
Source of funding: Not stated.
Address for article reprint: Dr. N.C. Nanda, University of Alabama at Birmingham, Heart Station SWB/S102, Birmingham, AL 35294, USA.
This study and others suggest that transesophageal echocardiography will become an important noninvasive tool for the diagnosis of patients with suspected aortic dissection and for the evaluation of chronic diseases of the aorta. In this report a selected group of patients with and without dissection was examined. As with many new technologies, initial reports such as this one indicate a high sensitivity and specificity. Whether these figures will be attenuated over time as the usefulness of this technique is examined prospectively against a gold standard among all patients suspected of dissection is not yet known. However, this study highlights the unique features of transesophageal echocardiography that will probably result in its becoming the prime noninvasive technique for detecting and evaluating aortic dissection. It is able to image the extent of aortic regurgitation, the presence or absence of coronary artery involvement, the sites of communication or thrombus in the false and true channel, and the presence of pericardial effusion.
Despite enthusiasm for this technique, we must not forget that, even in this selected group, 1 patient with an acute dissection was missed on transesophageal echocardiography. The chance for false-negative results is not only true for the noninvasive tests but even for aortography (1). This is especially true for very limited dissections, particularly occurring in the proximal ascending aorta in patients with pre-existing aortic disease such as those with the Marfan syndrome. Therefore, a single negative noninvasive test in a patient with a high index of suspicion for dissection should lead to consideration of either another noninvasive test or aortography because the methods appear to be complementary and not simply duplicative.
Kim A. Eagle, MD
Massachusetts General HospitalBoston, Massachusetts, USA
Kim A. Eagle, MD
Massachusetts General Hospital
Boston, Massachusetts, USA