title: Usefulness of intraoperative epiaortic echocardiography to resolve discrepancy between transthoracic and transesophageal measurements of aortic valve gradient - a case report.
abstract: OBJECTIVE
  Intraoperative measurement of the aortic valve (AV) gradient in patients undergoing cardiac surgery is routinely performed using transesophageal echocardiography (TEE). In patients with severe aortic stenosis (AS), TEE Doppler beam alignment with the blood flow through the stenotic valve may be inaccurate, resulting in an underestimation of the AV gradient. We describe here the use of epiaortic echocardiography as an alternative to TEE for the intraoperative evaluation of AS.
  
  
  METHODS
  A patient diagnosed with severe AS (peak pressure gradient by transthoracic echocardiography: 108 mmHg) was undergoing AV replacement. In contrast, intraoperative TEE examination performed prior to bypass showed only a mild pressure gradient across the AV (peak pressure gradient: 38 mmHg). In order to resolve the conflicting information, epiaortic echocardiography was used to measure the AV gradient, confirming severe AS (peak pressure gradient: 98 mmHg). Most likely, Doppler beam alignment through the stenotic valve was more parallel to blood flow using epiaortic echocardiography, thus revealing the true pressure gradient.
  
  
  CONCLUSIONS
  Intraoperative epiaortic measurement of AV gradients can be successfully performed in patients where TEE may be inaccurate due to difficulty in aligning a Doppler beam with the transvalvular blood flow.
authors.affiliation: Department of Anesthesiology, Perioperative and Pain Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts 02115, USA.
authors.forename: Thomas
authors.initials: T
authors.lastname: Edrich
authors.forename: Stanton K
authors.initials: SK
authors.lastname: Shernan
authors.forename: Brian
authors.initials: B
authors.lastname: Smith
authors.forename: Holger K
authors.initials: HK
authors.lastname: Eltzschig
mesh_terms: D001024:Aortic Valve Stenosis / Q000000981:diagnostic imaging*; D004452:Echocardiography; D017548:Echocardiography, Transesophageal; D006801:Humans; D008875:Middle Aged; D016343:Monitoring, Intraoperative; D011312:Pressure