Influence of structural geometry on the severity of bicuspid aortic stenosis

Kathryn E. Richards, Dimitri Deserranno, Erwan Donal, Neil L. Greenberg, James D. Thomas, Mario J. Garcia

Research output: Contribution to journalArticle

38 Citations (Scopus)

Abstract

Doppler-derived gradients may overestimate total pressure loss in degenerative and prosthetic aortic valve stenosis (AS) due to unaccounted pressure recovery distal to the orifice. However, in congenitally bicuspid valves, jet eccentricity may result in a higher anatomic-to-effective orifice contraction ratio, resulting in an increased pressure loss at the valve and a reduced pressure recovery distal to the orifice leading to greater functional severity. The objective of our study was to determine the impact of local geometry on the total versus Doppler-derived pressure loss and therefore the assessed severity of the stenosis in bicuspid valves. On the basis of clinically obtained measurements, two- and three-dimensional computer simulations were created with various local geometries by altering the diameters of the left ventricular outflow tract (LVOT; 1.8-3.0 cm), orifice diameter (OD; 0.8-1.6 cm), and aortic root diameter (AR; 3.0-5.4 cm). Jet eccentricity was altered in the models from 0 to 25°. Simulations were performed under steady-flow conditions. Axisymmetric simulations indicate that the overall differences in pressure recovery were minor for variations in LVOT diameter (<3%). However, both OD and AR had a significant impact on pressure recovery (6-20%), with greatest recovery being the larger OD and the smaller recovery being the AR. In addition, three-dimensional data illustrate a greater pressure loss for eccentric jets with the same orifice area, thus increasing functional severity. In conclusion, jet eccentricity results in greater pressure loss in bicuspid valve AS due to reduced effective orifice area. Functional severity may also be enhanced by larger aortic roots, commonly occurring in these patients, leading to reduced pressure recovery. Thus, for the same anatomic orifice area, functional severity is greater in bicuspid than in degenerative tricuspid AS.

Original languageEnglish (US)
JournalAmerican Journal of Physiology - Heart and Circulatory Physiology
Volume287
Issue number3 56-3
DOIs
StatePublished - Sep 2004
Externally publishedYes

Fingerprint

Bicuspid
Aortic Valve Stenosis
Pressure
Mitral Valve
Tricuspid Valve Stenosis
Computer Simulation
Pathologic Constriction

Keywords

  • Congenital heart disease
  • Doppler
  • Echocardiography

ASJC Scopus subject areas

  • Physiology

Cite this

Influence of structural geometry on the severity of bicuspid aortic stenosis. / Richards, Kathryn E.; Deserranno, Dimitri; Donal, Erwan; Greenberg, Neil L.; Thomas, James D.; Garcia, Mario J.

In: American Journal of Physiology - Heart and Circulatory Physiology, Vol. 287, No. 3 56-3, 09.2004.

Research output: Contribution to journalArticle

Richards, Kathryn E. ; Deserranno, Dimitri ; Donal, Erwan ; Greenberg, Neil L. ; Thomas, James D. ; Garcia, Mario J. / Influence of structural geometry on the severity of bicuspid aortic stenosis. In: American Journal of Physiology - Heart and Circulatory Physiology. 2004 ; Vol. 287, No. 3 56-3.
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abstract = "Doppler-derived gradients may overestimate total pressure loss in degenerative and prosthetic aortic valve stenosis (AS) due to unaccounted pressure recovery distal to the orifice. However, in congenitally bicuspid valves, jet eccentricity may result in a higher anatomic-to-effective orifice contraction ratio, resulting in an increased pressure loss at the valve and a reduced pressure recovery distal to the orifice leading to greater functional severity. The objective of our study was to determine the impact of local geometry on the total versus Doppler-derived pressure loss and therefore the assessed severity of the stenosis in bicuspid valves. On the basis of clinically obtained measurements, two- and three-dimensional computer simulations were created with various local geometries by altering the diameters of the left ventricular outflow tract (LVOT; 1.8-3.0 cm), orifice diameter (OD; 0.8-1.6 cm), and aortic root diameter (AR; 3.0-5.4 cm). Jet eccentricity was altered in the models from 0 to 25°. Simulations were performed under steady-flow conditions. Axisymmetric simulations indicate that the overall differences in pressure recovery were minor for variations in LVOT diameter (<3{\%}). However, both OD and AR had a significant impact on pressure recovery (6-20{\%}), with greatest recovery being the larger OD and the smaller recovery being the AR. In addition, three-dimensional data illustrate a greater pressure loss for eccentric jets with the same orifice area, thus increasing functional severity. In conclusion, jet eccentricity results in greater pressure loss in bicuspid valve AS due to reduced effective orifice area. Functional severity may also be enhanced by larger aortic roots, commonly occurring in these patients, leading to reduced pressure recovery. Thus, for the same anatomic orifice area, functional severity is greater in bicuspid than in degenerative tricuspid AS.",
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