Impact of the indexed effective orifice area on mid-term cardiac-related mortality after aortic valve replacement.
BACKGROUND
There has been ongoing controversy as to whether prosthesis-patient mismatch (PPM, defined as indexed effective orifice area (EOAI) <0.85 m(2)/cm(2)) influences mortality after aortic valve replacement (AVR). In most studies, PPM is anticipated by reference tables based on mean EOAs as opposed to individual assessment. These reference values may not reflect the actual in vivo EOAI and hence, the presence or absence of PPM may be based on false assumptions.


OBJECTIVE
To assess the impact of small prosthesis EOA on survival after aortic valve replacement AVR.


METHODS
645 patients had undergone an AVR between 2000 and 2007 entered the study. All patients underwent transthoracic echocardiography for determination of the actual EOAI within 6 months postoperatively. In order to predict time from surgery to death a proportional hazards model for competing risks (cardiac death vs death from other causes) was used. EOAI was entered as a continuous variable.


RESULTS
PPM occurred in 40% of the patients. After a median follow-up of 2.35 years, 92.1% of the patients were alive. The final Cox regression model showed a significantly increased risk for cardiac death among patients with a smaller EOAI (HR=0.32, p=0.022). The effect of EOAI on the 2-5 year mortality risk was demonstrated by risk plots.


CONCLUSIONS
In contrast to previous studies these EOAI values were obtained through postoperative echocardiography, substantially improving the accuracy of measurement, and the EOAI was modelled as a continuous variable. There was a significantly improved survival for larger EOAIs following AVR. Strategies to avoid PPM should become paramount during AVR.
Bleiziffer
Sabine
S
Clinic for Cardiovascular Surgery, German Heart Centre Munich, Munich, Germany. bleiziffer@dhm.mhn.de
Ali
Ayyaz
A
Hettich
Ina M
IM
Akdere
Deniz
D
Laubender
Rüdiger P
RP
Ruzicka
Daniel
D
Boehm
Johannes
J
Lange
Rüdiger
R
Eichinger
Walter
W
D000368:Aged; D001021:Aortic Valve / Q000000981:diagnostic imaging / Q000601:surgery*; D001024:Aortic Valve Stenosis / Q000000981:diagnostic imaging / Q000401:mortality / Q000601:surgery*; D049628:Body Size; D004812:Epidemiologic Methods; D005260:Female; D006350:Heart Valve Prosthesis; D019918:Heart Valve Prosthesis Implantation / Q000009:adverse effects* / Q000401:mortality; D006801:Humans; D008297:Male; D017755:Prosthesis Fitting / Q000401:mortality; D014463:Ultrasonography