Simulation-guided design of leaflet height in bicuspidization of the aortic valve

Bicuspidization repair is typically applied to severe congenital aortic valve lesions. Increasingly, this repair is recognized as an effective and durable surgical approach. The consequences of postoperative leaflet geometry in this repair are relatively unstudied, especially compared with current understanding of optimal geometry for a trileaflet valve. In this work, a computational approach was systematically applied to study the effect of changes in leaflet geometric height in symmetric bicuspidization repair.

Eight model valves with 4 geometric heights spanning a range of typically observed values were constructed at 2 free-edge lengths. Heights varied when loaded in diastole from approximately one-half the annular diameter to just below the annular diameter. Fluid-structure interaction simulations were performed to study the coupled dynamics of the valve and blood. Models were evaluated for stenosis, regurgitation, hemodynamics, mechanics, and diastolic gross morphology.

Cases with loaded geometric height 0.64 to 0.79 times the annular diameter showed the overall best performance, with a coaptation reserve of 4 to 7 mm. Cases with geometric height approximately one-half the annular diameter showed severe regurgitation. Cases with geometric height 0.86 to 0.95 times the annular diameter showed less "crisp" coaptation alignment and the appearance of excessive leaflet material.

The intermediate range of geometric height appeared best, with insufficient height causing regurgitation. More geometric height was not always clearly better, as excessively tall leaflets showed less alignment in the coaptation regions.