96. Jahrestagung der Deutschen Gesellschaft für Pathologie e. V ...

Abstracts
FR-P-120
How effective are heart valve donation from old organ donors?
K . Große 1 , R . Meyer 2 , C . Wesslau 3 , D . Bösebeck 1 , G . Kirste 4 , R . Hetzer 2
1 Deutsche Stiftung Organtransplantation, Northeast Region, Berlin, 2 Deutsches
Herzzentrum Berlin, Berlin, 3 Foundation of European Tissue Banks,
Berlin, 4 Deutsche Stiftung Organtransplantation, Frankfurt am Main
Aims. There is no upper age limit for organ donation and a quarter of all
organ donors are 65 years old and older. The Northeast Region of the
Deutsche Stiftung Organtransplantation and the Cardiovascular Tissue
Bank of the Deutsches Herzzentrum Berlin examined 1.) 1999–2004
whether heart valves from organ donors over the former age limit of
65 years for heart valve donation were morphologically suitable as grafts
and 2.) 2005–2009 after raising the age limit to 70 years the clinical acceptance
of heart valve grafts from organ donors of 65 to 70 years of age.
Methods. 1.) 1999–2004 the heart valves of 100 old organ donors (female/male:
55/45, median age: 71.5) were examined in accordance with the
standards of the Bio Implant Services (BIS). To compare the valve grafts
above and below the age limit of 65 years, we used data on the aortic and
pulmonary valves of 380 organ donors below the age limit in the same
time period. 2.) 2005–2009 we harvested 49 hearts from organ donors 65
to 70 years of age for processing heart valve grafts in accordance with the
BIS-standards. One aortic and 21 pulmonary valves (25%) of these organ
donors (female/male: 11/10, median age: 67) were suitable as grafts. One
year after valve replacement we send the recipients’ physicans a form to
gather information about valve failure, success of transplantation and
current morphological and functional state of the valve graft.
Results. 1.) Half of all heart valves above and below the former age limit
would have fulfilled the morphological standards as grafts. The great
majority (85%) of old pulmonary valves fulfilled the acceptance criteria,
48% even showing good tissue quality. 2.) 2005–2009 the aortic and the
21 pulmonary valve grafts have been allocated to recipients (female/male:
6/15, median age: 32) suffering from late sequelae of congenital diseases
with defects of the either native valves or former grafts. Successful treatment
without morphological and functional alterations of the grafts
1 year after replacement was reported from the aortic and 13 pulmonary
valve grafts. Five further valve grafts were transplanted but follow-up
1 year later is unknown. One recipient of a pulmonary valve graft died
postoperatively of left ventricular failure. In 2 cases accepted valve grafts
were not transplanted because the surgeons decided intra-operatively on
another procedure.
Conclusions. The data clearly demonstrate, that heart valves grafts from
donors 65 years of age and older can safely be used with good long-term
success.
FR-P-121
Change of external surface roughness of vascular implants improves
implant tissue integration
M . Otto1 , J . Kriegsmann1 , S . Bertz2 1Supra-regional Joint Practice of Histology, Cytology and Molecular Diagnostics
Trier – Düren – Düsseldorf, Medical Health Center for Histology,
Cytology and Molecular Diagnostics, Trier, 2University of Erlangen, Institute
of Pathology, Erlangen
Aims. Today, one of the most important problems in implant medicine is
an optimal designed biointegration of implants. A controlled biointegration
of vascular implants is essential for an optimal biofunction as well as
for biosafety. The fast fixation of the vascular prosthesis reduces the risk
of infection as well as thrombosis, two major events which lead to rapid
functional loss. Implants with a silver coating, used to inhibit implant infection
were modified at the outer surface to accelerate tissue integration.
Methods. Silver coated vascular implant material based on expanded
polytetrafluorethylen (ePTFE, expanded Teflon) was modified by application
of a microwave procedure. Two different protocols of microwave
application induce remodeling of the implant surface. At the first step,
122 | Der Pathologe · Supplement 1 · 2012
the material is implanted subcutaneously in a defined sheep model. The
tissue integration of the implant was analyzed after 6 weeks by interposition
of the implants at the Arteria carotis in a sheep model. We used
8 cm long routinely used but surface modified implants with a diameter
of 6 mm. We used two implants, one with highly and one with slightly
modified surface roughness. The implants were histomorphologically
evaluated using qualitative parameters as well as semiquantitative parameters
of vascularization, inflammation, peri-implant fibrous reaction
and giant cell induction. The tissue reaction was compared to the standardized,
clinically used and FDA accredited SilverGraft prosthesis.
Results. After an implantation period of 6 weeks the thrombogenicity
of implants was not significantly changed. Formation of fibrotic neointima
as well the endothelialization of the inner implant surface was
changed. Other histological parameters – lymphocytic infiltration, granulocytic
infiltration and giant cell density – did not show any alteration
by implant surface modification. The slightly modified implants show
a stronger vascularization and mildly increased thickness of peri-implant
fibrosis. The highly modified implants show no significant change
in vascularization but a minimal increase of thickness of peri-implant
membrane.
Conclusions. The change of implant surface roughness effectively improves
the integration of new developed vascular implant devices by
boosting integration into the peri-implant connective tissue without any
change of typical parameters correlating with biosafety of the vascular
implant material. The highest biofunctionality is found in those implants
with slightly increased surface roughness.
FR-P-122
Change of inner surface of ePTFE vascular implants by immobilization
of heparin and heparan sulfate
M . Otto1 , J . Kriegsmann1 , S . Bertz2 1Supra-regional Joint Practice of Histology, Cytology and Molecular Diagnostics
Trier – Düren – Düsseldorf, Medical Health Center for Histology,
Cytology and Molecular Diagnostics, Trier, 2University of Erlangen, Institute
of Pathology, Erlangen
Aims. Today, one of the most important problems in vascular implant
medicine is thrombosis. Complete or incomplete occlusion of vascular
implants by thrombotic masses is the most unfavorable event in vascular
endoprosthesis and results in insufficient biofunctionality of the
implants. During the last decade several implant coatings were used to
reduce thrombotic events.
Methods. The inner implant surface of ePTFE vascular implants (ePTFE,
expanded Teflon) was modified by a coating of polyurethane with covalent
bounded heparin as well as heparin sulfate. To analyze the thrombogenicity
of these modified materials vascular implants were applied
in a sheep model by interposition into the A. carotis. Routinely clinically
used but surface-modified implants with a diameter of 6mm and a
length of 8 cm were applied. Morphology of the implants was analyzed
after 6 weeks of implantation by morphologic evaluation of qualitative
parameters, especially thrombotic changes at the material surface. Further
parameters were semiquantitative analysis of inflammation, periimplant
reaction and giant cell induction. The tissue reaction was compared
to the standardized, routinely used and FDA accredited ePTFE- as
well as GoreTex-prosthesis.
Results. After an implantation period of 6 weeks implants with heparin
and heparin sulfate coating show macroscopically more and stronger
thrombotic events compared to the uncoated ePTFE and GoreTex-controls.
The morphological analysis of the thrombotic material shows in
the heparin group an early thrombosis of the implants, often with luminal
fibrotic organization. On the other hand, the heparan sulfate group
shows late thrombosis without any organization effects. The rate of
morphologically demonstrable thrombotic events in the heparin group
(37.5%) and the heparin sulfate group (75%) exceed the control rate of 10%
by far. The heparin sulfate group shows a considerable reduced rate of