Vascular remodeling in balloon injured rabbit iliac arteries

To characterize long-term vascular remodeling associated with neointimal formation in vivo, we established a model of balloon injury in normal chow fed rabbits. The iliac artery was injured by denudation using a 2F embolectomy catheter. Injured vessels were removed after perfusion fixation (90 mm Hg) in situ at 2, 4, 6, and 12 weeks post-injury; control vessels were obtained from 2- and 12-week age-matched, uninjured animals. Intimal growth was observed in all animals post-injury. Intimal area averaged 0.13 +/- 0.02 mm2 2 weeks post-injury and continued to increase at 4 and 6 weeks post-injury; +38% and +77% relative to the 2-week time point, respectively. Medical areas were similar among the 2-, 4-, and 6-week injury groups and the 2- and 12-week control groups. From 6 to 12 weeks post-injury, both intimal and medial areas decreased significantly (30% and 34%, respectively); while lumen area increased 53% from 4 to 12 weeks and overall vessel size (area enclosed by the external elastic lamina) remained the same. These data demonstrate that intimal and medial thinning contribute to long term maintenance of lumen area in response to neointimal formation.