Response to balloon injury is vascular bed specific A consequence of de novo vessel structure?

Relative contributions of remodelling and neointimal hyperplasia to resteno sis after coronary angioplasty have been inferred from studies using iliofe moral arteries, despite differences in structure/function and smooth muscle cell lineage. We compared the response to balloon overstretch injury of co ronary arteries (C, n = 16) and similar sized branches of the iliac arterie s (I, n = 18) using preinjury vessel diameter (P), inflated balloon size in vivo (B) and the manufacturer predicted inflated size (M) to examine arter ial compliance, as well as resulting injury and morphology in perfusion fix ed vessels. Despite similar degrees of oversizing (M/P) in the coronary and iliac arteries (C, 1.44 +/- 0.04; I, 1.51 +/- 0.02), the compliance to ove rstretch (B - P/M - P) was significantly greater in the coronary than the i liac arteries (C, 0.71 +/- 0.05; I, 0.51 +/- 0.03) (P < 0.05) and was assoc iated with a higher injury score (C, 1.64 +/- 0.31; I, 0.39 +/- 0.18 P < 0. 05)-only 5/18 iliac vessels had rupture of the IEL compared with 13/16 in t he coronary bed. In a subgroup of animals whose vessels (C:n = 7; I:n = 8) were perfusion fixed 28 days after injury, coronary arteries had greater in timal area (C:1.03 +/- 0.42; 1:0.10 +/- 0.03 mm(2), P < 0.05) but larger lu minal area (C:1.61 +/- 0.71 I:0.76 +/- 0.51, P < 0.05) due to greater area within EEL (C:3.38 +/- 0.49;I:1.49 +/- 0.54, P < 0.05) or less inward remod elling. The injuries resulting from similar strategies of balloon overstret ch in the coronary and the iliac arteries are different and affect healing responses-iliac arteries remodel more while coronary arteries develop more intimal hyperplasia. These results indicate that caution is warranted when extrapolating results from the iliac to the coronary artery when investigat ing restenosis after angioplasty. (C) 2000 Elsevier Science Ireland Ltd. Al l rights reserved.