SWINE MODEL OF CORONARY RESTENOSIS - EFFECT OF A 2ND INJURY

Looking for a coronary artery restenosis model closer to human patholo gy, a protocol of balloon injury/reinjury (plaque of dilatation) in sw ine coronary artery was designed. Pig coronary arteries (n = 24) were dilated for this study: 12, group 1, once (sacrifice at 10.0 +/- 2.2 w eeks); 6, group 2, twice at 2-wk intervals (sacrifice at 5.2 +/- 0.2 w k); 6, group 3, twice at 4-wk intervals (sacrifice at 9.3 +/- 1.9 wk). A single overdilatation resulted in an eccentric neointimal hyperplas ia representing half of the wall area (group 1, 45.6 +/- 5.1%). In ani mals (groups 2 and 3) subjected to redilatation, fracture length, rati o of fracture length to internal elastic lamina (IEL) circumference, a nd neointimal hyperplasia response were similar to those observed in g roup 1. In group 3, the shape of the lesion appeared more concentric a nd the fracture of the IEL more fragmented than In group 1. Although t his model of injury/reinjury did not lead to more severe intimal hyper plasia, performing a second angioplasty at the same site did lead to a more concentric intimal response, related to multiple fractures of th e IEL. (C) 1996 Wiley-Liss, Inc.