title: Reconsideration of patient-prosthesis mismatch definition from the valve indexed effective orifice area.
abstract: BACKGROUND
  The objective of this study was to reassess the validity of defining patient-prosthesis mismatch (PPM) in the aortic position on the basis of an indexed effective orifice area (iEOA) less than 0.85 cm(2)/m(2).
  
  
  METHODS
  From June 1996 to March 2008, 342 patients underwent aortic valve replacement with a Carpentier-Edwards Perimount valve. From the data collected, the transvalvular pressure gradient was determined by the modified Bernoulli equation, and EOA was calculated from the standard continuity equation.
  
  
  RESULTS
  The actuarial survival rate at 10 years after surgery was 84.0% +/- 8.2%. The prevalence of PPM was 6.1% when a projected iEOA less than 0.85 cm(2)/m(2) was defined as indicating significant PPM. There was no difference between patients with moderate PPM (85.2% +/- 9.8%) and patients without PPM (81.0% +/- 8.7%; p = 0.44). The relation between mean transvalvular pressure gradient and iEOA demonstrated a gentler slope than that reported previously. Postoperative mean transvalvular pressure gradient was 17.4 +/- 5.6 mm Hg and 14.5 +/- 5.6 mm Hg in patients with an iEOA less than 0.85 and 0.85 or greater, respectively. Most patients had a postoperative mean transvalvular pressure gradient more than 10 mm Hg regardless of PPM.
  
  
  CONCLUSIONS
  Our analysis suggested that an iEOA less than 2.0 cm(2)/m(2) might be the threshold for PPM, which should not be passed to achieve a low mean transvalvular pressure gradient (less than 10 mm Hg) with the Carpentier-Edwards Perimount valve. The implications of these findings include the necessity for reassessing the hemodynamic performance of each type of prosthesis when attempting to define PPM, to avoid residual significant transvalvular pressure gradient.
authors.affiliation: Department of Cardiac Surgery, Jikei University School of Medicine, Tokyo, Japan. ysakamoto@jikei.ac.jp
authors.forename: Yoshimasa
authors.initials: Y
authors.lastname: Sakamoto
authors.forename: Michio
authors.initials: M
authors.lastname: Yoshitake
authors.forename: Hirokuni
authors.initials: H
authors.lastname: Naganuma
authors.forename: Noriyasu
authors.initials: N
authors.lastname: Kawada
authors.forename: Katsushi
authors.initials: K
authors.lastname: Kinouchi
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Hashimoto
mesh_terms: D000368:Aged; D001021:Aortic Valve / Q000033:anatomy & histology* / Q000502:physiology / Q000601:surgery*; D005260:Female; D006350:Heart Valve Prosthesis; D006801:Humans; D008297:Male; D009929:Organ Size; D018579:Patient Selection; D011474:Prosthesis Design; D012189:Retrospective Studies