Experimental evaluation of a short transitional edge protection balloon for intracoronary stent deployment

The purpose of this study was to determine if balloon injury to the adjacen t arterial wall during intracoronary stent deployment influences late in-st ent neointimal formation. Stent design and deployment techniques are consid ered important factors in determining acute and long-term success with intr acoronary stenting. Experimental and clinical studies support that the exte nt of neointimal formation and the probability for restenosis are influence d by the magnitude of arterial trauma induced with stenting. Nineteen 18-mm -long balloon-expandable stainless steel stents (MULTI-LINK Duet) were impl anted at a 1:1 stent-to-artery ratio in the coronary arteries of swine with a conventional noncompliant balloon (n = 10) or a novel noncompliant ballo on with short tapered shoulders to prevent edge dissection (n = 9), Quantit ative coronary angiography and histology were used to evaluate balloon and artery interactions and the chronic vascular responses to the stents. Ninet een stents were implanted in the coronary arteries of seven swines at an in flation pressure of 14 atm using a standard noncompliant (n = 10) or a uniq ue short transitional edge protection (n = 9) balloon. Histologic analysis at 28 days demonstrated balloon-associated barotrauma in 13 of 20 (65%) of adjacent nonstented arterial segments with the conventional balloon and onl y 3 of 18 (17%) of the adjacent nonstented arterial segments with the short transition edge protection balloon (P = 0.022). In-stent neointimal area a nd % stenosis correlated with the severity of peristent arterial injury (r = 0.43, P = 0.01). In-stent vessel injury scores were similar for stents wi th peristent injury (1.0 +/- 0.3) versus stents without peristent injury (1 .0 +/- 0.03, P = 0.73). In-stent neointimal area and % stenosis were greate r for stents with peristent injury (2.36 +/- 0.74 mm(2), 32% +/- 9%) as com pared to stents without peristent injury (1.39 +/- 0.70 mm(2), 20% +/- 10%, P = 0.01). Arterial wall injury adjacent to a stent after high-pressure de ployment contributes to late in-stent neointimal hyperplasia in this model. These experimental data suggest that further study is warranted to refine stent implantation techniques and that modifications of balloon shape or ma terial may be useful to optimize stent deployment and reduce arterial traum a. Cathet Cardiovasc. Intervent 51:112-119, 2000. (C) 2000 Wiley-Liss, Inc.