Relationship of vascular remodeling and restenosis after interventional therapy: an experimental study on rabbit atherosclerotic iliac artery model

Objective To evaluate the relative contribution of every part of vascular w all to lumen area loss after angioplasty. Methods Angioplasty was performed on rabbits iliac atherosclerosis model. H istomorphometric results of histological cross-sectional areas from target vessels of animals killed immediately after angioplasty (acute group, n = 2 0) were compared with those of the same areas from animals killed 4 weeks a fter the procedure (chronic group, n = 23), when restenosis occurred in thi s model. If taking 30% diameter decrease as restenosis criteria, the chroni c group was further divided into two subgroups (nonrestenosis subgroup [NRS , n = 9] and restenosis subgroup [RS, n = 14]) and their histomorphometric results were also compared. Results The lumen area decreased by 0.48 mm(2) from acute group to chronic group (acute group 0.86 +/-t 0.23 mm(2) vs chronic group 0.38 +/- 0.20 mm(2 ), P < 0.001). Over the same period intimal area increased by 0.12 mm(2) an d the area circumscribed by inner elastic lamina (IEL area) decreased by 0. 36 mm(2). Intimal hyperplasia could only explain 25% of the later lumen are a loss. We further found a more significant IEL area decrease in RS subgrou p than in NRS subgroup (0.68 +/- 0.35 mm(2) vs 0.94 +/- 0.14 mm(2), P < 0.0 5), despite the same intimal area (0.39 +/- 0.16 mm(2) vs 0.41 +/- 0.31 mm( 2), P = NS). The different lumen area between RS subgroup and NRS subgroup (0.27 +/- 0.10 mm(2) vs 0.55 +/- 0.10 mm(2), P < 0.001) was predominantly c lue to the greater IEL shrinking in RS subgroup. Conclusion Our data indicate that later lumen area loss after angioplasty r esults from both intimal hyperplasia and arterial shrinking (remodeling), b ut the latter plays a much greater role.