Biomechanics of aortic valve leaflet fusion and stiffening

摘要: OF THE THESIS Biomechanics of Aortic Valve Leaflet Fusion and Stiffening by Reshmi S. Banerjee Master Science in Bioengineering San Diego State University, 2013 Calcific Stenosis (CAS) involves narrowed aortic valve (AoV) orifice, fibrotic thickening is clinically presented with a high transvalvular gradient jet velocity. Echocardiography (EC) derived opening area (EOA) estimation used as an index for accurate assessment stenotic severity. However, there are often discrepancies between EC EOA invasive indices CAS, thus leading to incorrect CAS severity clinical decisions. There exists need alternative non-invasive quantification method analyzing the AoV dysfunction which serves predictor onset progression AoV. It generally agreed upon that influenced alterations hemodynamics, wherein it continually subjected cyclic stretches, bending, pressures, shear stresses. The objective this study measure effect leaflet fusion stiffening on geometric (GOA), hemodynamics (pressure flow) mechanical strain response using cardiac simulator. Seven bioprosthetic porcine AoVs were tested under controlled matched conditions. was simulated suturing edges together along one (F1) or two commissures (F2) fibrosis applying thin layer cyanoacrylate adhesive face leaflets (F1S, F2S). simulator mock circulatory loop has preprogrammed settings contractility (Off, Low, Medium) at heart rate 72 bpm. Pressure flow measured several points system single CCD camera mounted records images opens closes biomechanical changes. Images analyzed obtain GOA values during cycle. mean decreases due commissural stiffening. Statistical analysis confirmed level support (P < 0.01) most significant contributors reductions, indicators stenosis. Fibrotic alongwith contributes reduced distensibility seen response; turn believed lead increase internal stress. Additional studies required confirm finding.