title: Impact of patient-prosthesis mismatch and aortic valve design on coronary flow reserve after aortic valve replacement.
abstract: OBJECTIVE
  This prospective-randomized study investigated the effect of aortic valve design and patient-prosthesis mismatch (PPM) on coronary flow reserve (CFR) after mechanical or biological aortic valve replacement (AVR) in patients with aortic stenosis (AS).
  
  
  BACKGROUND
  Coronary flow reserve may be an important parameter of long-term survival after AVR in patients with AS. Reduced CFR may contribute to more cardiovascular events and greater rates of mortality.
  
  
  METHODS
  A total of 48 patients undergoing AVR underwent magnetic resonance imaging for the measurement of coronary flow preoperatively, 5 days postoperatively, and at 6-month follow-up with measurement of CFR. Patients scheduled for mechanical AVR were randomized to a tilting disc or bileaflet prosthesis (n = 12 in each group). For biological AVR, patients were scheduled to receive a stented (n = 12) or stentless (n = 12) valve. Patients also underwent echocardiography with measurement of transvalvular pressure gradients and left ventricular mass regression.
  
  
  RESULTS
  Postoperatively, coronary flow increased significantly in all groups (p < 0.001). Only stentless valves demonstrated a normal CFR (3.4 +/- 0.3 vs. 2.3 +/- 0.1 for stented biological valves, 2.1 +/- 0.2 for tilting disc, and 2.2 +/- 0.3 for bileaflet mechanical valves). Patient-prosthesis mismatch with an indexed effective orifice area <0.85 cm2/m2 led to decreased rates of CFR in the tilting disc, stentless, and stented groups. Pressure gradients were 14 +/- 3 mm Hg for tilting disc, 12 +/- 4 mm Hg for bileaflet, 19 +/- 6 mm Hg for stented, and 10 +/- 4 mm Hg for stentless valves.
  
  
  CONCLUSIONS
  Normalization of CFR after AVR in patients with AS was observed only for stentless valves. Coronary flow reserve might explain the excellent long-term results for stentless valves. (Impact of Patient-Prosthesis Mismatch on Coronary Flow Reserve; http://www.clinicaltrials.gov/ct/show/NCT00310947?order=1; NCT00310947).
authors.affiliation: Department of Thoracic and Cardiovascular Surgery, Johann Wolfgang Goethe University Hospital, Frankfurt/Main, Germany. farhad@bakhtiary.de
authors.forename: Farhad
authors.initials: F
authors.lastname: Bakhtiary
authors.forename: Mirko
authors.initials: M
authors.lastname: Schiemann
authors.forename: Omer
authors.initials: O
authors.lastname: Dzemali
authors.forename: Selami
authors.initials: S
authors.lastname: Dogan
authors.forename: Volker
authors.initials: V
authors.lastname: Schächinger
authors.forename: Hans
authors.initials: H
authors.lastname: Ackermann
authors.forename: Anton
authors.initials: A
authors.lastname: Moritz
authors.forename: Peter
authors.initials: P
authors.lastname: Kleine
mesh_terms: D000368:Aged; D001021:Aortic Valve; D001024:Aortic Valve Stenosis / Q000000981:diagnostic imaging / Q000601:surgery*; D001705:Bioprosthesis; D001794:Blood Pressure; D003326:Coronary Circulation; D005260:Female; D006339:Heart Rate; D006350:Heart Valve Prosthesis; D006352:Heart Ventricles / Q000473:pathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D009929:Organ Size; D011446:Prospective Studies; D011474:Prosthesis Design; D011475:Prosthesis Failure; D017755:Prosthesis Fitting; D016896:Treatment Outcome; D014463:Ultrasonography