Evaluation of restenosis in major vessels and side branches

Objectives. The indications for concurrent intervention for stenosis of a side branch during the treatment for stenosis of the main vessel were investigated using quantitative coronary angiography. Methods. The retrospective study included 451 patients treated for a stenotic main vessel incorporating a side branch, who underwent follow-up angiography within 6 months. Patients were divided into Group I with the side branch treated by coronary angioplasty, and Group II with the side branch left untreated. Quantitative coronary angiography was used to measure the minimum luminal diameter(MLD) and percentage diameter stenosis (%DS) of the main vessel and the side branch. Results. The MLD of the side branch after treatment was larger in Group I (1.4 ± 0.1 mm) than in Group II (0.7 ± 0.1 mm), and the %DS of the side branch after treatment was smaller in Group I (34 ± 3%) than in Group II (63 ± 2%). These differences decreased at follow-up to 1.1 ± 0.1 mm, 48 ± 2% in Group I; 0.9 ± 0.04 mm, 46 ± 2% in Group II, respectively. The MLD and %DS of the side branch at follow-up in Groups I and II were affected by the presence of main vessel restenosis [Restenosis (+): 0.9 ± 0.1 mm, 57 ± 4%; restenosis (-): 1.2 ± 0.1 mm(p < 0.05), 43 ± 3% (p < 0.05) in Group I; Restenosis (+): 0.9 ± 0.1 mm, 51 ± 8%; restenosis (-): 1.0 ± 0.1 mm, 44 ± 3% in Group II]. Multivariate analysis showed that %DS of the main vessel at follow-up was the only powerful predictor of restenosis of the side branch (p = 0.0249, odds ratio = 1.031, confidence interval = 1.004-1.059) in Groups I and II. Conclusions. Restenosis of the main vessel rather than the initial outcome of the side branch is the major influence on restenosis of the side branch.