title: Effects of fluid flow shear rate and surface roughness on the calcification of polymeric heart valve leaflet.
abstract: Surface defects, blood flow shear rates and mechanical stresses are contributing factors in the calcification process of polymeric devices exposed to the blood flow. A number of experiments were performed to evaluate the effect of surface defects such as roughness and cracks and flow shear rate on the calcification process of a polyurethane material used in the design of prosthetic heart valves. Results showed that polyurethane surface gets calcified and the calcification is more pronounced at the lower shear rates. Roughness and cracks both increase the calcification levels. The results also suggest very little diffusion of calcium to the subsurface indicating that calcification of a polyurethane material, is a surface phenomenon. Based on a simple peeling test, the bond strength between the calcified layer and polyurethane was found to be extremely weak, suggesting that the bonding is in the form of Van-der-Waals. A limited set of experiments with polycarbonate showed that polycarbonate is less prone to calcification compared to polyurethane (p values less than 0.05), indicating its potential application in medical devices exposed to blood flow.
authors.affiliation: Department of Mechanical and Industrial Engineering, Northeastern University, 334 Snell Engineering Center, 360 Huntington Avenue, Boston, MA 02115-5000, USA.
authors.forename: Parnian
authors.initials: P
authors.lastname: Boloori Zadeh
authors.forename: Scott C
authors.initials: SC
authors.lastname: Corbett
authors.forename: Hamid
authors.initials: H
authors.lastname: Nayeb-Hashemi
mesh_terms: D002114:Calcinosis; D006350:Heart Valve Prosthesis; D008855:Microscopy, Electron, Scanning; D011140:Polyurethanes / Q000737:chemistry*; D011474:Prosthesis Design; D013499:Surface Properties
chemical_list: D011140:Polyurethanes