Diagnostic potential of combined transthoracic echocardiography and X-ray computed tomography in suspected aortic dissection

Background: Transesophageal echocardiography (TEE) and magnetic resonance imaging (MRI) are considered optimal diagnostic methods in the setting of suspected aortic dissection. However, although less sensitive as single modalities, transthoracic echocardiography (TTE) and contrast-enhanced computed tomography (x-ray CT) are more widely available and less costly. Hypothesis: This study was undertaken to compare the diagnostic performance and reliability of the combined use of TTE and x-ray CT with TEE and/or MRI findings in the setting of suspected aortic dissection. Methods: The diagnostic power of combined TTE and xray CT was compared with both single use of TTE and x-ray CT and with TEE and/or MRI in a series of 168 consecutive patients with suspected aortic dissection (AD). Of these, 28 women and 58 men (mean age 53 +/- 16 years) underwent TTE and x-ray CT prior to TEE (n = 52) and/or MRI (n = 69). Diagnostic results of combined TTE/x-ray CT were retrospectively but independently reevaluated in blinded fashion; diagnostic findings were validated by angiography (n = 63), surgery (n = 52), or autopsy (n = 7). Results: Type A dissection was found in 29 patients (34%), type B dissection in 10(12%), whereas aortic dissection was excluded in 47 (55%). With 95%. the sensitivity of TTE and x-ray CT was significantly enhanced when used in a combined access compared with 67 and 79%, respectively, when used as single methods (95%; p < 0.05). Sensitivity and specificity (95 and 91%, respectively) of combined TTE/x-ray CT evaluation were not different from TEE and/or MRI (100 and 96%, respectively; NS). Thrombus formation, side-branch involvement, aortic regurgitation, pericardial effusion or mediastinal hematoma were also detected with similar sensitivities and specificities both by combined TTE/x-ray CT and TEE and/or MRI. Conclusion: This first controlled study comparing the combined information of TTE and x-ray CT with TEE and/or MRI revealed a similar diagnostic potential of both diagnostic strategies in the setting of suspected aortic dissection. Thus, in an environment with access to color Doppler TTE and x-ray CT only, the information from both tests should be combined to decide on diagnostic management of these patients.