A porcine coronary stent model of increased neointima formation in the left anterior descending coronary artery.
BACKGROUND
Clinical trials suggest an increased frequency of restenosis after coronary intervention in left anterior descending (LAD) compared to the left circumflex or right coronary arteries. Experimental studies correlate stent-induced arterial injury and the extent of neointima formation. This study investigates whether the coronary artery affects the relationship between arterial injury and neointima hyperplasia in the porcine stent model.


METHODS
Non-lipemic farm pigs underwent stent placement in the LAD (n = 26) and the right coronary artery (RCA; n = 30). Quantitative coronary angiography (QCA) was performed before and after stent placement, and at follow-up; quantitative histomorphometry and injury score were analyzed at 30-day follow-up.


RESULTS
Initial procedure balloon/artery ratios (LAD 1.17 +/- 0.11 vs RCA 1.17 +/- 0.09, P = NS), and minimal stent lumen diameters (MLD; LAD 2.91 +/- 0.31 vs RCA: 2.93 +/- 0.28 mm, P = NS) were similar suggesting no difference in deployment technique. At follow-up there was more restenosis in the LAD (diameter stenosis: 55.0 +/- 26.4% vs 37.3 +/- 18.1%, and MLD: 1.24 +/- 0.78 mm vs. 1.71 +/- 0.57 mm, P < 0.05 for both comparisons). No differences were seen for injury score (1.09 +/- 0.51 vs 1.01 +/- 0.57; LAD vs RCA) or stent area (6.13 +/- 0.99 vs 6.55 +/- 1.42 mm2). Histomorphometry demonstrated smaller lumen area (2.15 +/- 0.94 vs 2.96 +/- 1.29 mm2) and thicker neointima (0.63 +/- 0.25 vs 0.51 +/- 0.17 mm; all P < 0.05) in the LAD. Multiple linear regression analysis identified the LAD as an independent predictive factor for increased neointima formation.


CONCLUSIONS
These observations establish an animal model that is consistent with clinical experience showing that restenosis after stenting is more common in the LAD. The findings may be useful for understanding and developing systemic and local antirestenotic strategies.
Hausleiter
J
J
Deutsches Herzzentrum München Lazarettstrasse 36 80636 München, Germany. hausleiter@dhm.mhn.de
Sebastian
M
M
Li
A N
AN
Abbey
C K
CK
Honda
H
H
Makkar
R
R
Whiting
J S
JS
Eigler
N
N
D015906:Angioplasty, Balloon, Coronary / Q000295:instrumentation*; D000818:Animals; D017023:Coronary Angiography; D023903:Coronary Restenosis / Q000000981:diagnostic imaging / Q000473:pathology*; D003331:Coronary Vessels / Q000293:injuries* / Q000473:pathology; D004195:Disease Models, Animal; D005352:Fibromuscular Dysplasia / Q000000981:diagnostic imaging / Q000473:pathology; D007091:Image Processing, Computer-Assisted; D016014:Linear Models; D015607:Stents; D013552:Swine; D017539:Tunica Intima / Q000293:injuries* / Q000473:pathology