Last modified February 8, 1997

Bioprosthetic heart valve prostheses and vascular grafts incorporate animal or human tissues which are chemically/physically processed to reduce immunological recognition, sterilize the tissue, and increase biostability. Unfortunately, these processes also alter the physical properties of the materials. A particular problem is increased bending stiffness associated with lost mechanisms for shear deformation -- a problem which can result in early fatigue failures and calcification. An industrial need exists for a workable device which can rapidly measure changes in bending stiffness in materials which are inherently *very* pliable: i.e. of low stiffness. The immediate application is to a novel coronary artery bypass graft for humans under development by Corvita Canada. Work will be undertaken in Dr. Lee's Tissue Mechanics Laboratory at Dalhousie.


Two tests to determine the bending rigidity of pliable tissue are being developed. One testing apparatus will measure the stiffness of a "hoop" or ring of material cut from an artery bypass graft. The second test measures the bending stiffness of a longitudinal "strip" cut from artery bypass graft material.



Hoop Tester

Strip Tester

Send comments and/or questions to

Back to Design Projects 1996-1997