Biaxial Mechanical Properties of Venous Valve Leaflet Tissues

Chronic venous insufficiency (CVI) is widely accepted as the seventh most common chronic debilitating disease and has a huge impact on human health all over the world. In the United States, 10% to 35% of adults are affected by CVI [1]. Venous valve incompetence is a major cause of this disease. When the venous valves become incompetent, blood reflux can occur, which results in blood pooling in the lower extremities and therefore causes CVI. Tissue engineered prosthetic venous valve is a potential effective treatment of the incompetent valves and the mechanical properties and biochemical components of native venous valve tissues are critical inputs to the proper design of functional prosthetic valves. To date, only uniaxial tensile studies have been reported on venous valve leaflet tissue mechanical properties [2]. However, it was inadequate to describe the complex mechanical behaviors of venous valve leaflets, whose native mechanical loading state is intrinsically multi-axial. In our study, we conducted equibiaxial tensile tests and collagen assay on bovine jugular and saphenous vein valve leaflet tissues to better understand their biaxial nonlinear and anisotropic mechanical properties and quantitatively analyze their collagen concentration.