title: Use of carotid intima-media thickness to identify patients with ischemic stroke and transient ischemic attack with low yield of cardiovascular sources of embolus on transesophageal echocardiography.
abstract: OBJECTIVE
  Carotid intima-media thickness (CIMT) is associated with systemic atherosclerosis and cardioembolic conditions and predicts the risk of recurrent strokes. We sought to establish the relationship between CIMT and cardiovascular sources of embolus (CSE) on transesophageal echocardiography (TEE) and hypothesized that a noninvasive strategy of CIMT assessment and transthoracic echocardiography bubble study would identify patients with ischemic stroke or transient ischemic attack in whom TEE would provide little incremental diagnostic yield.
  
  
  METHODS
  In 180 patients with ischemic stroke or transient ischemic attack of undetermined origin referred for TEE, we prospectively performed CIMT measurement/plaque screen (Phase 1, n=96) or CIMT measurement/plaque screen and transthoracic echocardiography bubble study (Phase 2, n=84) before TEE. Phase 1 results were used to construct receiver operating characteristic curves to demonstrate the ability of CIMT to detect CSE on TEE and to identify the optimal CIMT cutoff value for prospective strategy testing (Phase 2).
  
  
  RESULTS
  In Phase 1, CIMT was found to correlate with TEE markers of aortic atherosclerosis, including complex aortic plaques, and combined CSE. The optimal CIMT cutoff for detection of CSE on TEE was 0.78 mm. In Phase 2, a positive noninvasive strategy test (CIMT >or=0.78 mm, +carotid plaque, and/or a positive transthoracic echocardiography bubble study) was present in 61%. The prevalence of CSE on TEE was significantly higher among those with a positive compared with a negative noninvasive strategy test (65% versus 9%, P<0.001), and this strategy had a sensitivity of 92% and a negative predictive value of 91% for the detection of any CSE on TEE.
  
  
  CONCLUSIONS
  In patients with stroke or transient ischemic attack of undetermined origin, a noninvasive strategy of CIMT assessment/plaque screen and transthoracic echocardiography bubble study can identify patients in whom further invasive evaluation with TEE will be of low diagnostic yield.
authors: Non-Invasive Imaging Laboratories, Section of Cardiology, Department of Medicine, University of Chicago, Chicago, IL 60637, USA. pward@medicine.bsd.uchicago.edu
authors: R Parker
authors: RP
authors: Ward
authors: Georgeanne
authors: G
authors: Lammertin
authors: Daniel E
authors: DE
authors: Virnich
authors: Tamar S
authors: TS
authors: Polonsky
authors: Roberto M
authors: RM
authors: Lang
mesh_terms: D000368:Aged; D002545:Brain Ischemia / Q000175:diagnosis / Q000000981:diagnostic imaging / Q000473:pathology; D002339:Carotid Arteries / Q000033:anatomy & histology / Q000000981:diagnostic imaging / Q000473:pathology; D017548:Echocardiography, Transesophageal; D004617:Embolism / Q000175:diagnosis / Q000000981:diagnostic imaging; D006801:Humans; D002546:Ischemic Attack, Transient / Q000175:diagnosis / Q000000981:diagnostic imaging; D008297:Male; D045423:Microbubbles; D008875:Middle Aged; D011446:Prospective Studies; D012372:ROC Curve; D012307:Risk Factors; D020521:Stroke / Q000175:diagnosis / Q000000981:diagnostic imaging