| Objective To investigate remodeling characteristics of coronary lesions in patients with acute coronary syndromes(ACS) and stable angina pectoris (SAP) in vivo with intravascular ultrasound, and to explore the relationship between arterial remodeling and clinical presentation or matrix metalloproteinase(MMPs) , hyper sensitive C-reactive protein(hs-CRP) and interleukin-6(IL-6). Methods 1. Culprit lesions of 54 ACS patients and 24 SAP patients were studied by intravascular ultrasound before coronary intervention. The lesion site and the proximal reference site including the measurement of external elastic membrane (EEM) area and Lumen area were analyzed, plaque area and remodeling index(RI) were calculated and directions of arterial remodeling were determined. Positive remodeling was defined as RI >1.05 and negative remodeling as RI <0.95. The culprit lesions were analysed qualitatively. Soft, hard and high risk plaque were identified. Then their calcifications were measured and compared in each group. The blood level of MMP-2, MMP-9, hs-CRP and IL-6 were also determined in each group. 2. ACS patients were divided into two groups based on their troponin I(TnI) levels;elevated TnI group (TnI>0.15ng/ml, 30 cases) and normal TnI group (TnI ≤ 0. 15ng/ml, 24 cases). Then their IVUS characteristics of culprit lesions were compared. Results 1.The plaque area at culprit lesions in patients with ACS was significantly larger(11. 94±4.90 versus 9.17 ±3. 36mm~2; P=0. 035) and also the RI in ACS group was significantly greater than that of patients with SAP(0. 972 ± 0. 222 versus 0.796 ±0. 130; P=0. 003). The distribution of remodeling in these two groups was different .'positive remodeling was more frequent in ACS group than in SAP group(35.19% versus 7. 41%, P=0. 007), whereas negative remodeling was more frequent in SAP group(51.85% versus 88.89%, P=0. 001). There was higher incidence of high risk plaque in ACS group compared to SAP group(74.07% versus 51.85%; P=0. 046). 2. The maximal arc of calcium in ACS group was less than that in SAP group(85. 48 + 71. 52° versus 152.00+103.08°; P=0.018). 3. The level of serum MMP-2 in ACS group was higher than that of SAP group (249. 40 + 44. 90Mg/L versus 215. 38 + 38. 16Mg/L ; P=0. 008). The same applied for plasma MMP-9 (84. 36 + 9. lOHg/L versus 69.71 + 18. 70^g/L ; P=0. 005),serum hs-CRP (3. 56 + 3. 20mg/L versus 1. 56 + 1-. 29mg/L ; P=0. 002) and serum IL-6 (5. 26 + 0. 88mg/L versus 4. 04 + 0. 96mg/L, P=0. 000). 4. The RI (1. 004 + 0.245 versus 0.830 + 0.106; P=0. 002), the plaque area(ll. 93±5. 15mm2 versus 9. 11 + 3. 44mm2; P=0. 038) were significantly greater in patients with elevated Tnl group than in patients with normal Tnl group. The remodeling distribution between two groups was different. Positive remodeling was more frequent in elevated Tnl group than in normal Tnl group(53. 33% versus 12. 50%, P=0. 002), whereas negative remodeling was more frequent in normal Tnl group (33.33% versus 75. 00%, P=0. 002). Patients in elevated Tnl group had more frequent occurrence of high risk plaque (86.67% versus 62.50%, P = 0.039). Conclusions 1. Positive remodeling , larger plaque areas and higher incidence of high risk plaque are associated with ACS, whereas negative remodeling is more common in patients with SAP. This association between the extent of remodeling and clinical presentation may reflect a greater tendency that plaques with positive remodeling can cause ACS.
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