Resistance of the internal mammary artery to restenosis: a histomorphologic study of various porcine arteries.
OBJECTIVE
Restenosis after percutaneous transluminal angioplasty (PTA) of the internal mammary artery (IMA) grafts is much less pronounced than in other arteries and venous grafts. The aim of the study was to test whether various arteries respond differently to dilatation.


METHODS
PTA of the IMA, carotid, renal and circumflex coronary (RCx) arteries was performed in 9 pigs (balloon to artery ratio of 1:1.5). After 8 weeks, angiography was repeated and vessels prepared for histological analysis. Immunohistochemical staining was done to examine proliferative activity (Ki67) and to identify the vasa vasorum of the adventitia (F VIII-RA).


RESULTS
The intima-media ratio after PTA was lowest in the IMA (0.06), followed by the carotid (0.27) and renal arteries (0.49) and the RCx (0.69). Proliferation of the intima was seen at 287 degrees of the vessel circumference in the RCx, at 286 degrees in the renal and at 166 degrees in the carotid artery. No proliferative activity was seen in the IMA. The intima-adventitia ratio was lower in the IMA than in the RCx and renal arteries (p < 0.05).


CONCLUSIONS
Intima proliferation after PTA varies between the different vessels, with best results seen in the IMA. There are differences in remodeling after PTA between muscular, muscular/elastic and elastic arteries.
Horstick
Georg
G
2nd Medical Clinic, Johannes Gutenberg University, Mainz, Germany. horstick@uni-mainz.de
Bierbach
Benjamin
B
Schlindwein
Peter
P
Abegunewardene
Nico
N
Vosseler
Markus
M
Bittinger
Fernando
F
Becker
Dietmar
D
Lauterbach
Michael
M
Lehr
Hans-Anton
HA
Kempski
Oliver
O
D000792:Angiography; D000800:Angioplasty, Balloon / Q000009:adverse effects*; D015906:Angioplasty, Balloon, Coronary / Q000009:adverse effects*; D000818:Animals; D002339:Carotid Arteries / Q000473:pathology; D016893:Carotid Stenosis / Q000209:etiology* / Q000473:pathology; D049109:Cell Proliferation; D017023:Coronary Angiography; D023903:Coronary Restenosis / Q000209:etiology* / Q000473:pathology; D003331:Coronary Vessels / Q000473:pathology; D006083:Graft Occlusion, Vascular / Q000209:etiology* / Q000473:pathology; D007150:Immunohistochemistry; D008323:Mammary Arteries / Q000473:pathology*; D008940:Mitotic Index; D023421:Models, Animal; D012077:Renal Artery / Q000473:pathology; D012078:Renal Artery Obstruction / Q000209:etiology* / Q000473:pathology; D013552:Swine; D013997:Time Factors; D016896:Treatment Outcome; D017539:Tunica Intima / Q000473:pathology; D017540:Tunica Media / Q000473:pathology