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Updated: Aug 9, 2026
Protocol for Relative Hydrodynamic Assessment of Tri-leaflet Polymer Valves
Published on: October 17, 2013
Thrombogenicity of polyethylene oxide-bonded Dacron sewing ring in a mechanical heart valve
M K Dewanjee1, D R Gross, P Zhai
1Department of Veterinary Biosciences, University of Illinois at Champaign-Urbana 61802, USA.
Background And Aim Of The Study:
The aim of the study was to evaluate the effect of binding hydrophilic polyethylene oxide (PEO) onto Dacron fibers in the sewing ring of a mechanical heart valve (MHV), in terms of thrombogenicity of the prosthesis.
Methods:
The study was performed in blinded fashion. Six Yorkshire-cross pigs (bodyweight 35-45 kg) were implanted with MHVs, in the mitral annulus, with the PEO-treated sewing ring. An additional five pigs implanted with identical MHVs, but with untreated sewing rings, served as controls. PEO of chain-length 10,000 Da was grafted to Dacron fibers using gamma irradiation. PEO-bonded Dacron fibers (diameter 100 microns) were used to weave the sewing ring, which was then assembled on a titanium stent (OD 25 mm). Autologous platelets were labeled with 111In-tropolone and injected intravenously (850-1250 microCi per injection) into the pigs on removal from cardiopulmonary bypass (CPB). At 20-24 h after surgery, platelet thrombi adherent to MHV components, and shed emboli trapped in the brain, lung, heart, kidneys and other organs/connective tissues were imaged using a gamma camera. The animals were killed and the amounts of thrombi adherent to MHV components and organ-trapped emboli quantified using an ionization chamber and gamma counter.
Results:
There was no statistically significant difference in the adhesion of 111In-labeled platelets to either control sewing rings (0.08 +/- 0.06% dose) or PEO-treated rings (0.19 +/- 0.21% dose). The thrombogenicity of MHV components in both animal groups was in the ascending order: Dacron ring > Teflon pledgets > polypropylene sutures > titanium housing > pyrolytic carbon. The number of platelet-emboli trapped in the organs was not significantly different between the two groups.
Conclusions:
Simple modifications may not reduce platelet thrombosis or wound-healing of the sewing ring in the acute phase, at which time several complex processes are activating and inactivating platelets and coagulant factors during CPB and implantation of MHVs.
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