title: Early and midterm hemodynamics after aortic valve bypass (apicoaortic conduit) surgery.
abstract: BACKGROUND
  Aortic valve bypass (AVB [apicoaortic conduit]) relieves aortic stenosis (AS) by connecting the apex of the left ventricle to the descending thoracic aorta with a valved conduit. AVB is performed through a small left thoracotomy, without cardiopulmonary bypass, aortic cross-clamping, cardiac arrest, or debridement of the native aortic valve. Little is known about hemodynamics, including ventricular performance, relative conduit blood flow, and progression of native AS after AVB.
  
  
  METHODS
  Forty-seven very high risk patients underwent AVB for AS between 2003 and 2009. The mean age was 82 years. Predismissal and interval transthoracic quantitative two-dimensional and Doppler echocardiography was performed in a core laboratory.
  
  
  RESULTS
  No patient had obstruction of the native aortic valve or the conduit during follow-up. The AVB effectively relieved left ventricular outflow tract obstruction (average peak gradient across the conduit was 5.6 +/- 3.8 mm Hg). Native aortic valve stenosis did not progress after AVB (0.63 +/- 0.16 cm(2) before surgery to 0.7 +/- 0.24 cm(2) at latest follow-up more than 6 months; p = 0.16). Total stroke volume increased after AVB from 60 mL +/- 22 mL to 107 mL +/- 27 mL (p < 0.0001). Left ventricular outflow was distributed in a predictable fashion between the conduit and the native aortic valve, with 63% +/- 10% of the flow directed to the conduit. Relative conduit flow remained stable (68% +/- 8%) at latest follow-up more than 6 months (p = 0.17).
  
  
  CONCLUSIONS
  Aortic valve bypass effectively relieves the outflow tract obstruction of AS. Placement of an apical valved conduit halts the biologic progression of AS.
authors.affiliation: Division of Cardiology, University of Maryland Medical Center, Baltimore, Maryland, USA.
authors.forename: Crystal J
authors.initials: CJ
authors.lastname: Vliek
authors.forename: Elias
authors.initials: E
authors.lastname: Balaras
authors.forename: Shuying
authors.initials: S
authors.lastname: Li
authors.forename: Jolinta Y
authors.initials: JY
authors.lastname: Lin
authors.forename: Cindi A
authors.initials: CA
authors.lastname: Young
authors.forename: Christopher R
authors.initials: CR
authors.lastname: DeFilippi
authors.forename: Bartley P
authors.initials: BP
authors.lastname: Griffith
authors.forename: James S
authors.initials: JS
authors.lastname: Gammie
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001021:Aortic Valve / Q000503:physiopathology* / Q000601:surgery; D001024:Aortic Valve Stenosis / Q000503:physiopathology* / Q000601:surgery*; D005260:Female; D019918:Heart Valve Prosthesis Implantation; D006439:Hemodynamics; D006801:Humans; D008297:Male; D012189:Retrospective Studies