European Journal of Cardio-Thoracic Surgery, Vol 10, 20-25, Copyright © 1996 by European Association for Cardio-thoracic Surgery
Evaluation of cyropreserved internal thoracic artery as an alternative coronary graft: evidence for preserved functional, metabolic and structural integrity
JK Pacholewicz, MS Adkins, WJ Boris, J Gu, C Xenachis, RE Klabunde, T Jasionowski and LB McGrath
University of Chicago United CryoInstitute, Ill, USA.
The internal thoracic artery (ITA) is the conduit of choice for coronary
artery bypass grafting (CABG). This study, utilizing a canine model,
evaluates cryopreserved ITA. Sixteen ITAs were harvested and cryopreserved
according to United CryoInstitute protocol. Test conduits, 5 cm long and 4
mm mean diameter, were anastomosed to the ligated carotid artery of an
unmatched mongrel recipient, above and below the site of native artery
ligation. Graft patency was assessed by angiography at 14 days (early) and
980 days (late) postoperatively. Catheterization of the 16 vessels
identified three (18%) early and one (6%) late graft occlusion. Ninety days
postoperatively, each dog was killed and the graft harvested for
histopathological and functional evaluation. Morphologic evaluation, using
conventional staining, showed preserved cellular structure, decrease in
smooth muscle cells and distorted endothelial layer. Immunocytochemistry,
using an antibody against prostacyclin (PGI2), detected PGI2 immunoactivity
in the ITA smooth muscle cells. An in vitro assay performed on the arterial
rings confirmed preserved functional integrity of the vascular endothelium
and smooth muscle. These findings suggest that cryopreserved ITA may have
potential as a substitute graft, in devising conduit strategies for primary
or reoperative coronary bypass surgery.
