title: Prosthesis-patient mismatch after aortic valve replacement predominantly affects patients with preexisting left ventricular dysfunction: effect on survival, freedom from heart failure, and left ventricular mass regression.
abstract: OBJECTIVE
  The effect of prosthesis-patient mismatch on clinical outcome and left ventricular mass regression after aortic valve replacement remains controversial. Data on whether the clinical effect of prosthesis-patient mismatch depends on left ventricular function at the time of aortic valve replacement are lacking. This study examined the long-term clinical and echocardiographic effects of prosthesis-patient mismatch in patients with and without left ventricular systolic dysfunction at the time of aortic valve replacement.
  
  
  METHODS
  Preoperative and serial postoperative echocardiograms were performed in 805 adults who underwent aortic valve replacement between 1990 and 2003 and who were subsequently followed up in a dedicated valve clinic (follow-up, mean +/- SD, 5.5 +/- 3.5 years; maximum, 14.2 years). Preoperative left ventricular function was defined as normal (ejection fraction > or =50%) in 548 patients and impaired (ejection fraction <50%) in 257 patients.
  
  
  RESULTS
  Patients with impaired preoperative left ventricular function and prosthesis-patient mismatch (indexed effective orifice area < or =0.85 cm2/m2) had a decreased overall late survival (hazard ratio, 2.8; P = .03), decreased freedom from heart failure symptoms or heart failure death (odds ratio of 5.1 at 3 years after aortic valve replacement; P = .009), and diminished left ventricular mass regression compared with patients with impaired preoperative left ventricular function and no prosthesis-patient mismatch. These effects of prosthesis-patient mismatch were not observed in patients with normal preoperative left ventricular function.
  
  
  CONCLUSIONS
  Prosthesis-patient mismatch at an indexed effective orifice area of 0.85 cm2/m2 or less after aortic valve replacement primarily affects patients with impaired preoperative left ventricular function and results in decreased survival, lower freedom from heart failure, and incomplete left ventricular mass regression. Patients with impaired left ventricular function represent a critical population in whom prosthesis-patient mismatch should be avoided at the time of aortic valve replacement.
authors: Division of Cardiac Surgery, University of Ottawa, Ottawa, Ontario, Canada. mruel@ottawaheart.ca
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