Objective Few data are available about the acut and late patency of small side branch. Our purpose was to identify angiographic and procedural predictors for acute and late side branch occlusion after coronary stent implantation. Methods We evaluated 196 side branches (41 patients with 49 lesions) with a reference diameter of <2mm; the lesions were covered by 50 stents. Angiographic follow-up was completed in all patients with 196 side branches 6 ± 3 months after stent implantation. Side branch occlusion (SBO) was defined as a Thrombolysis In Myocardial Infarction (TIMI) flow ≤1. The TIMI flow of before PCI, after stent implantation, and at follow-up were evaluated. Clinical and the following angiographic parameters were recorded: reference diameter, minimal lumen diameter, diameter stenosis, AHA/ACC lesion type, TIMI flow, lesion length, number of side branches, stent size. Side branches were also characterized by ostial and reference diameter, ostial stenosis, TIMI flow, and ostial side branch angle related to the main vessel. Results Acute SBO affected 50 side branches in 196 side branches(39.2%). By multiple logistic regression, independent predictors for acute SBO were (1) the side branch TIMI flow ≤1 at baseline (OR [odds ratio] 0.2109, 95% CI 1.126-3.950, P = .020); (2) an ostial side branch angle less than 60 degree(OR 2.809, 95% CI 1.136-7.350, P = .026); (3) AHA/ACC lesion type B2/C (OR 0.392, 95% CI 0.162-0.949, P = .038) Among the initially occluded side branches, 84.0% were spontaneously reperfused at follow-up. Late SBO involved 4.1% of the side branches. By multiple logistic regression, independent predictors for late SBO was the ostial side branch stenosis(>50%) before stenting (OR 0.565, 95% CI 0.038-0.839, P = .005)
Conclusions Acute SBO after stenting occurred in 39.2% of cases. Most acutely occluded side branches underwent late spontaneous reperfusion. The predictors for acute SBO were the side branch TIMI flow at baseline, the ostial side branch angle less than 60 degree, and AHA/ACC lesion type B2/C. The predictor for late SBO was the ostial side branch stenosis before stenting.
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