Planimetric assessment of anatomic valve area overestimates effective orifice area in bicuspid aortic stenosis.
BACKGROUND
Although the continuity equation remains the noninvasive standard, planimetry using transesophageal echocardiography is often used to assess valve area for patients with aortic stenosis (AS). Not uncommonly, however, anatomic valve area (AVAA) obtained by planimetry overestimates continuity-derived effective valve area (AVAE) in bicuspid AS.


METHODS
Transthoracic Doppler and transesophageal echocardiography were performed to obtain AVAE and AVAA in 31 patients with bicuspid AS (age 61 +/- 11 years) and 22 patients with degenerative tricuspid AS (age 71 +/- 13 years). Aortic root and left ventricular outflow tract dimensions and the directional angle of the stenotic jet were assessed in all patients. Using these data, a computational fluid dynamics model was constructed to test the effect of these variables in determining the relationship between AVAE and AVAA.


RESULTS
For patients with tricuspid AS, the correlation between AVAA (1.15 +/- 0.36 cm2) and AVAE (1.13 +/- 0.46 cm2) was excellent (r = 0.91, P < .001, Delta = 0.02 +/- 0.21 cm2). However, AVAA was significantly larger (1.19 +/- 0.35 cm2) than AVAE (0.89 +/- 0.29 cm2) in the bicuspid AS group (r = 0.71, P < .001, Delta = 0.29 +/- 0.25 cm2). Computer simulation demonstrated that the observed discrepancy related to jet eccentricity.


CONCLUSIONS
For a given anatomic orifice, functional severity tends to be greater in bicuspid AS than in tricuspid AS. This appears to be primarily related to greater jet eccentricity and less pressure recovery.
Donal
Erwan
E
Department of Cardiology, Cleveland Clinic Foundation, Cleveland, Ohio 44195, USA.
Novaro
Gian M
GM
Deserrano
Dimitri
D
Popovic
Zoran B
ZB
Greenberg
Neil L
NL
Richards
Kathryn E
KE
Thomas
James D
JD
Garcia
Mario J
MJ
D019412:Anatomy, Cross-Sectional; D001024:Aortic Valve Stenosis / Q000000981:diagnostic imaging*; D016477:Artifacts; D003198:Computer Simulation; D015150:Echocardiography, Doppler / Q000379:methods; D017548:Echocardiography, Transesophageal / Q000379:methods; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008297:Male; D008943:Mitral Valve / Q000000981:diagnostic imaging*; D008955:Models, Cardiovascular; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity