Abstract 11441: Assessment of Neointimal Tissue Characterization after Bare Metal Stent Implantation: Integrated Backscatter Ultrasound Study
Purpose: Previous studies have revealed that neointimal hyperplasia after bare metal stent implantation comprised proliferated smooth muscle cells. However, some studies suggested that neointimal tissue in the late phase could cause very late stent thrombosis or late restenosis. Recently, it has been reported that lipid-rich plaque detected by integrated backscatter intravascular ultrasound (IB-IVUS) is identical to vulnerable plaque. However, neointimal tissue has not been examined extensively by IB-IVUS. The aim of the present study was to assess neointimal tissue characterization using IB-IVUS in patients with in-stent restenosis.
Methods: We prospectively performed IB-IVUS in consecutive patients requiring target lesion revascularization after bare metal stent implantation. Patients were divided into 2 groups according to follow-up time from stent implantation to the study (Group A: ≤ 12 months, Group B: > 12 months). We examined tissue characterization of neointima by 3-dimensional analyses using IB-IVUS. The exclusion criterion of this study was poor IB-IVUS imaging for assessment.
Results: Data from 50 patients were included (Group A: n = 27, Group B: n =23). Baseline clinical characteristics were similar between the two groups. Mean periods between stent implantation and this study were 7.1 ± 1.1 months for the Group A and 113.3 ± 53.0 months for the Group B (p < 0.001). The percentage of lipid and calcified volume in neointimal tissue in the Group B were significantly greater than in the Group A (25.8 ±8.9% vs. 18.2 ± 6.6%, p = 0.001, 2.2 ± 1.5% vs. 1.4 ±0.9%, p = 0.02, respectively). In contrast, the percentage of fiblous volume in the Group B was significantly lower than in the Group A (72.0 ± 8.3% vs. 80.4 ± 6.4%, p < 0.001). Follow-up time from stent implantation to IVUS examination significantly correlated with the percentage of lipid volume, calcified volume and fibrous volume in neointima (r = 0.32, p = 0.02, r = 0.37, p = 0.008 and r = -0.38, p =0.006, respectively).
Conclusions: Neointima in the late phase was associated with higher lipid and calcified volume and lower fibrous volume, suggesting the development of atheroscrelosis within bare metal stents.
- © 2012 by American Heart Association, Inc.