Biomechanical implications of the congenital bicuspid aortic valve: A finite element study of aortic root function from in vivo data

• Published in: The Journal of thoracic and cardiovascular surgery Vol. 140; no. 4; pp. 890 - 896.e2
• Main Authors: Conti, Carlo A., MD, Della Corte, Alessandro, MD, PhD, Votta, Emiliano, PhD, Del Viscovo, Luca, MD, Bancone, Ciro, MD, De Santo, Luca S., MD, Redaelli, Alberto, PhD
• Format: Journal Article
• Language: English
• Published: New York, NY Mosby, Inc 01.10.2010; Elsevier
• Subjects: Adult; Anesthesia. Intensive care medicine. Transfusions. Cell therapy and gene therapy; Aortic Valve - abnormalities; Aortic Valve - pathology; Aortic Valve - physiopathology; Biological and medical sciences; Biomechanical Phenomena; Cardiology. Vascular system; Cardiothoracic Surgery; Computer Simulation; Congenital heart diseases. Malformations of the aorta, pulmonary vessels and vena cava; Endocardial and cardiac valvular diseases; Female; Finite Element Analysis; Heart; Heart Defects, Congenital - pathology; Heart Defects, Congenital - physiopathology; Humans; Imaging, Three-Dimensional; Kinetics; Magnetic Resonance Imaging; Male; Medical sciences; Middle Aged; Models, Cardiovascular; Pneumology; Stress, Mechanical; Young Adult; tricuspid aortic valve; 35; 35.1; magnetic resonance imaging; bicuspid aortic valve; MRI; 17; BAV; TAV; 26.1.4; Congenital; Root; Cardiovascular disease; Data; Congenital disease; Biomechanics; In vivo; Cardiac valvular disease; Bicuspid aortic valve; Anesthesia; Aorta; Circulatory system; Cardiology; Finite element
• ISSN: 0022-5223; 1097-685X
• DOI: 10.1016/j.jtcvs.2010.01.016

Objective Congenital bicuspid aortic valves frequently cause aortic stenosis or regurgitation. Improved understanding of valve and root biomechanics is needed to achieve advancements in surgical repair techniques. By using imaging-derived data, finite element models were developed to quantify aortic valve and root biomechanical alterations associated with bicuspid geometry. Methods A dynamic 3-dimensional finite element model of the aortic root with a bicuspid aortic valve (type 1 right/left) was developed. The model's geometry was based on measurements from 2-dimensional magnetic resonance images acquired in 8 normotensive and otherwise healthy subjects with echocardiographically normal function of their bicuspid aortic valves. Numeric results were compared with those obtained from our previous model representing the normal root with a tricuspid aortic valve. The effects of raphe thickening on valve kinematics and stresses were also evaluated. Results During systole, the bicuspid valve opened asymmetrically compared with the normal valve, resulting in an elliptic shape of its orifice. During diastole, the conjoint cusp occluded a larger proportion of the valve orifice and leaflet bending was altered, although competence was preserved. The bicuspid model presented higher stresses compared with the tricuspid model, particularly in the central basal region of the conjoint cusp (+800%). The presence of a raphe partially reduced stress in this region but increased stress in the other cusp. Conclusions Aortic valve function is altered in clinically normally functioning bicuspid aortic valves. Bicuspid geometry per se entails abnormal leaflet stress. The stress location suggests that leaflet stress may play a role in tissue remodeling at the raphe region and in early leaflet degeneration.