|In Vivo Evaluation of Collagen Hemostats: Biocompatibility
(Department of Cardiovascular Surgery,
The Heart Institute of Japan and Department of Anesthesiology*,
Tokyo Women's Medical University, Tokyo, Japan)
|After bleeding is
controlled with hemostats during surgery, the residual material
should be resorbed without adverse effects such as inflammation,
infection or scar formation. To evaluate the biocompatibility
of hemostats, three kinds of commercially available collagen
hemostats, cotton type (Integran®), microfibrillar type (Avitene®),
and sheet type (TachoComb®), were examined. A rabbit ear
chamber (REC), a system for viewing materials in vivo,
was applied to the auricle of male Japanese white rabbits. The
REC was designed to leave a 50-µm-thick and 6.4mm-diameter
chamber, and 0.5mg of each specimen (Integran; n=8, Avitene;
n=6, TachoComb; n=6) was placed in the chamber.
Macroscopic and microscopic observations were performed every
week up to 5 weeks without anesthetizing or stressing the animal.
In the Integran group, capillaries infiltrated between the collagen
fibers, and the vasculature in the REC field was complete in
6 out of 8 animals at 5 weeks. Cotton type collagen fibers of
Integran became thinner every week without effusion. In the TachoComb
group, capillaries were directed toward the effusion at 2 weeks,
while in the Avitene group, a similar phenomenon was not observed.
The vasculature was incomplete, with either effusion or infection
at 5 weeks in the Avitene and TachoComb groups. Material was
recognized up to 4 weeks in the TachoComb group, whereas the
space occupied by material remained vacant without vasculature
in the Avitene group. Our results suggest that cotton type configuration
is excellent as a collagen hemostat, with smooth capillary infiltration,
rapid resorption of material and promotion of the healing process.
Jpn. J. Cardiovasc. Surg. 32: 17-22 (2003)