Hemodynamic and anatomical study was done on canine abdominal aortic graft utilizing homografts and Edwards-Tapp nylon vascular grafts for replacement graft and ivalon-teflon mesh and piece of Edwards-Tapp nylon vascular graft for patch. Homograft materials were obtained from canine abdominal aorta and preserved in 75 % ethyl-alcohol for six months. lvalon-teflon mesh patches were made in such a manner that is utilized in clinical cardiovascular surgery widely Approprivate size of nylon patch was cut of the Edwards-Tapp nylon vascular graft.
Grafts were sutured into infra-renal portion of the abdominal aorta through transperitoneal approach.
Arterial pressure tracings above and below the graft (common carotid artery and common femoral artery), aortography, macroscopic and microscopic observations were made after one to four months were elapsed since grafting.
When the graft is patent no remarkable arterial pressure gradient was recognizable between the arteries proximal and distal to the graft. Aortographs are essentially normal´´, but some showed very slight degree of constriction at both anastomotic sites. No. aneurysmal dilation-is -noted- in the graft except one infected nylon patch graft.
1). Microscopically graft was embedded in a dense fibrous connective tissue capsule and firmly incorporated into neighboring host´s tissue with complete endothelialization of the internal surface of this capsule.
2). Connective tissue in growth into the graft itself was remarkable in ivalon-teflon grafts.
3). Endothelialization and connective tissue formation were completed earlier in patch graft series
than in tube .graft series. (two or three months for the former and four months, for the latter). 4). No difference among the graft materials used were noted so far as completion of the endothelialization was concerned.
5). Calcification in and around the connective tissue capsule is noted in none´ of the fifteen long term homograft survivors, but was observed in one out of seventeen nylon tube grafts, and three out of twenty-five ivalon-teflon mesh grafts. One out of seventeen nylon patch grafts showed cartilagenous tissue in the connective tissue capsule.
Microscopic findings along with arterial pressure pattern and aortograms jshow that aortic replacementgraft with homograft preserved in 75 % ethyl-alcohol or nylon vascular graft and patch graft with ivalon-teflon mesh or nylon vascular graft bring satisfactory functional and anatomical results in long term survivors.
Patch graft showed earlier completion of endothelialization than replacement (,(tube) graft. This suggests that whenever there is a choice between these two graft methods, the former can be utilized more advantageously than the latter in clinical cases.
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