Early time course of neointima formation and vascular remodelling following percutaneous coronary intervention and vascular brachytherapy of in-stent restenotic lesions as assessed by intravascular ultrasound analysis

Abstract

In-stent restenosis (ISR) represents the major limitation of stent implantation. Treatment, although of relative technical ease, is unsatisfactory due to a high incidence of recurrent restenosis. Vascular brachytherapy (VBT) has emerged as a powerful adjunct therapeutic modality to treat ISR. Inhibition of neointima formation has been regarded as the relevant mechanism of action. Yet, positive remodelling has been suspected as another contributing factor. Since only very few precise analyses of the extent, distribution and time course of the respective mechanims exist, the goal of the present study was to describe the changes of the vessel geometry at the target lesion and at the reference site following angioplasty and VBT of ISR in 42 patients by means of quantitative coronary angiography (QCA) and intravascular ultrasound (IVUS) before and after the index procedure and at the 3 and 6 month follow-up. By QCA the acute lumen gain measured 2.2+/-0.8 mm, the late lumen loss at 3 months was 0.1+/-0.5 mm and at 6 months 0.4+/-0.7 mm. By IVUS luminal cross-sectional area increased from 1.5+/-1.2 mm(2) to 7.9+/-1.9 mm(2) (p<0.001). The intima hyperplasia cross-sectional area at 3 months was only 0.2+/-1.0 mm(2) (p=0.191), but increased to 0.7+/-0.6 mm(2) (p<0.001) at 6 months resulting in a lumen cross-sectional area of 7.1+/-1.7 mm(2). Stent dimensions did not show any significant changes over time. The external elastic membrane cross-sectional area at 3 months increased by 1.3+/-1.9 mm(2) (p<0.001), and showed a further increase by 0.7+/-2.9 mm(2) at 6 months. Positive remodelling could be demonstrated also at the reference segment. In conclusion the absolute amount of intima hyperplasia during a 6-month follow-up period after VBT of ISR is low and most pronounced between the third and sixth month. Besides this, predominantly within the first 3 months of follow-up, significant positive remodelling could be demonstrated at the target lesion and at the reference site. Both observed effects may contribute to the preservation of the vessel lumen.

Non-Coronary Vessel Exploration Under Intravascular Ultrasound: Principles and Applicability

“…The volumetric approach using 3-D border-detection techniques is currently applied in serial IVUS studies examining atherosclerotic disease progression or regression, allowing the assessment of plaque burden in an entire vessel segment through fast analysis of large image sequences. New interventional approaches also use a volumetric IVUS imaging approach to provide new mechanistic insights, such as innovative techniques aimed at the prevention and treatment of in-stent restenosis correlated with histomorphometry measurements (Mehran et al, 1998;Murata et al, 2002); approaches in understanding the effects of radiation therapy and the arterial remodeling on a stented segment (brachytherapy) (Lekston et al, 2008;Weichert et al, 2003;Zimarino et al, 2002;Zimmermann et al, 2005); or using drug-eluting stents on the neointimal hyperplasia development (Jensen et al, 2008;Min et al, 2007;Sano et al, 2006).…”

Efficacy and Safety of Absorbable Metallic Stents with Adjunct Intracoronary Beta Radiation in Porcine Coronary Arteries

“…VBT has been demonstrated as an effective treatment to reduce neointima formation and restenosis 7,8 . Besides its antiretinoic effect, VBT has been associated with positive remodeling of stented 16,17 and nonstented 18 vessels. Thus the purpose of the current study was to evaluate the impact of VBT on restenosis and positive remodeling of the vessels following AMS implantation in porcine coronaries.…”