Clinical outcome of stent implantation in small coronary arteries using different types of coronary stents.

PURPOSE: We evaluated the results of stent placement in small coronary arteries.
SUBJECTS: The subjects were divided into 2 groups: the first contained 911 lesions treated with stenting in the coronary arteries (stent group), and the second contained 1,203 background- and patient-matched lesions treated with balloon angioplasty (POBA group). There was no significant difference in the background of patients or lesions between the groups. A "small coronary artery" was defined as a coronary artery with a reference vessel diameter < 3.0 mm.
RESULTS: There was no significant difference in incidence of acute myocardial infarction (AMI), coronary artery bypass grafting, or death between the groups. In the stent group, acute occlusion (0.8%) and subacute thrombosis (2.1%) occurred. The restenosis rate of 29.8% in the stent group was significantly lower than in the POBA group (38.2%; p < 0.01). The restenosis rate of 19.4% in stented vessels 3.0 mm diameter was significantly lower than in vessels < 3.0 mm diameter (29.8%; p < 0.01). The rate of restenosis was 22.9% for the Multi-Link stent, 24.4% for the NIR stent, 34.1% for the GFX stent, and 35.3% for the PS stent. The restenosis rate of 23.8% in stented vessels > 2.5 mm diameter and < or = 20 mm length was significantly lower than in vessels , < or = 2.5 mm diameter and > 20 mm length (32.7%; p < 0.01). Factors associated with restenosis, analyzed using a stepwise multivariate logistic regression model, included ostial lesions and post-procedural minimum lumen diameter.
CONCLUSIONS: Stent implantation in vessels < 3.0 mm diameter using a newly designed coronary stent yielded favorable clinical results, while there was a high prevalence of restenosis, leading to diffused stenotic lesions, in vessels < 2.5 mm diameter.