Thrombogenicity of polyethylene oxide-bonded Dacron sewing ring in a mechanical heart valve.
OBJECTIVE
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.
Department of Veterinary Biosciences, University of Illinois at Champaign-Urbana 61802, USA.
M K
MK
Dewanjee
D R
DR
Gross
P
P
Zhai
S
S
Lanzo
H
H
Shim
K
K
Park
D J
DJ
Schaeffer
A R
AR
Twardock
D000818:Animals; D003328:Coronary Thrombosis / Q000517:prevention & control*; D004195:Disease Models, Animal; D006350:Heart Valve Prosthesis / Q000009:adverse effects*; D008943:Mitral Valve; D015539:Platelet Activation; D011092:Polyethylene Glycols; D011474:Prosthesis Design; D013552:Swine
D011092:Polyethylene Glycols