Mechanism of in-stent restenosis:An intravascular ultrasound observation

AIM: To investigate the in-stent restenosis process by coronary artery angiography (CAG) and intravascular ultrasound(IVUS). METHODS: The study consisted of 92 patients with 118 stents(LAD53, L32, RCA33). Follow-up CAG and IVUS were performed 6 months after stent placement. There were 39 stents with and 79 stents without in-stent restenosis by CAG. The reference areas, minimal stent cross-sectional areas(CSA), minimal stent luminal CSA, intimal hyperplasia CSA, stent lumen and intimal hyperpla volume were measured by IVUS. RESULTS: Reference areas, minimal stent CSA and stent volume had no significant differences between restenotic and nonrestenotic stents(P0.01). Restenotic stents had smaller minimal stent luminal CSA (2.3±1.1)mm~2 vs (5.4±1.8) mm~2, P0.01 than nonrestenotic stents, but had bigger intimal hyperplasia CSA and intimal hyperplasia volume than nonrestenotic stents (4.7±1.5) mm~2 vs (1.6±0.8) mm~2, (121.1±31.9) mm~3 vs (54.3±11.4) mm~3, P0.01〕. CONCLUSION: Intimal hyperplasia was important in the development of in-stent restenosis. But the vascular remodeling and the degree of stent dilation had no obvious relationship with in-stent restenosis.