ARTERIAL REMODELING AFTER EXPERIMENTAL PERCUTANEOUS INJURY IS HIGHLY DEPENDENT ON ADVENTITIAL INJURY AND HISTOPATHOLOGY

Background: The extent and nature of unfavorable geometric remodeling, especially related to the adventitia, has not been studied previously . The purpose of this study was to examine two methods of experimental arterial injury, characterize the extent of remodeling, and determine if remodeling is injury-specific. Methods: Two methods for producing coronary stenoses in pigs were used: heat injury using thermal balloon angioplasty (resulting in adventitial fibrosis), and copper stent imp lantation (resulting in intense inflammation). Histomorphometric param eters included changes in neointimal thickness (delta neointima) from uninjured to injured sections, and differences in area circumscribed b y the internal and external elastic laminas (delta internal elastic la mina area and delta external elastic lamina area, respectively). Remod eling was calculated for each lesion as the enlargement of the externa l elastic lamina area or internal elastic lamina area for incremental neointimal thickening, expressed as the slopes delta external elastic lamina area/delta neointima and delta internal elastic lamina area/del ta neointima. Results: Remodeling indices for the heat lesions were ne gative (delta internal elastic lamina area/delta neointima=-0.15, delt a external elastic lamina area/delta neointima=-0.64) and indicated li ttle remodeling in contrast to copper stent injury (delta internal ela stic lamina area/delta neointima=0.95, delta external elastic lamina a rea/delta neointima=1.20). Conclusions: Remodeling in fibrotic compare d to inflammatory lesions differs markedly, and may explain increased restenosis rates observed in thermal balloon angioplasty in patients. This formulation may be useful to study remodeling and restenosis foll owing other interventional technologies. Copyright (C) 1997 Elsevier S cience Ireland Ltd.