A new outside stent--does it prevent vein graft intimal proliferation?
OBJECTIVE
The saphenous vein subjected to arterial pressure stretches to its elastic limits and constitutes intimal hyperplasia. Sheathing of the vein graft with pressure-resistant tubing might prolong vein graft patency.


METHODS
Twenty-one sheep received radial vein grafts or hybrid grafts composed of radial vein, collagen fibrin glue and highly flexible torlen/dacron mesh tubing transplanted into the carotid artery position. Veins were examined with the use of light and electron microscopy. Proliferating cell antigen (Ki-67) stains served as markers of proliferation.


RESULTS
The mean wall thickness of both intimal and medial layers was evaluated. The mean intimal wall thickness was 19+/-11 microm in hybrid grafts vs. 24+/-7 microm in unsheathed grafts (P<0.001); 22+/-6 vs. 26+/-10 microm (P<0.001); 23+/-8 vs. 52+/-15 microm (P<0.001); 37+/-21 vs. 90+/-31 microm (P<0.001); 57+/-31 vs. 104+/-28 microm (P<0.001); 58+/-21 vs. 133+/-32 microm (P<0.001); and 72+/-22 vs. 244+/-100 microm (P<0.001) after respectively 5 days, 9 days, 4 weeks, 6 weeks, 8 weeks, 10 weeks and 12 weeks from implantation. Electronic microscope examination of hybrid grafts revealed a smooth endothelial layer with intact nuclei and an intima composed of layers of collagen and muscle fibers. In unsheathed grafts endothelial edema and nuclear destruction were observed.


CONCLUSIONS
The external vein graft support with mesh tubing reduces intimal and medial layer thickening and cell proliferation in composite vein grafts transplanted in the arterial position.
Krejca
Michal
M
1st Cardiac Surgery Department, Silesian University of Medicine, SPSK nr 7, 40-635 Katowice, ul. Ziolowa 45-47, Poland. mkrejca@wp.pl
Skarysz
Janusz
J
Szmagala
Przemyslaw
P
Plewka
Danuta
D
Nowaczyk
Grazyna
G
Plewka
Andrzej
A
Bochenek
Andrzej
A
D000818:Animals; D001807:Blood Vessel Prosthesis; D002455:Cell Division; D001026:Coronary Artery Bypass / Q000379:methods; D006083:Graft Occlusion, Vascular / Q000517:prevention & control*; D008297:Male; D011093:Polyethylene Terephthalates; D011474:Prosthesis Design; D012756:Sheep; D015607:Stents; D017539:Tunica Intima / Q000648:ultrastructure*; D017540:Tunica Media / Q000648:ultrastructure; D014654:Vascular Patency; D014680:Veins / Q000637:transplantation*
D011093:Polyethylene Terephthalates