Over-expansion of second-generation drug-eluting stents, risk of restenosis, and relation to major adverse cardiac events

The relationship between stent expansion conditions and clinical outcomes is not completely understood. This prospective cohort study included patients who were successfully implanted with second-generation drug-eluting stent in 2012 and received follow-up angiography in 9-12 months. Stent over-expansion was defined as ≥ 1.05 of the stented segment over the reference artery diameter. Imaging parameters were measured, and the follow-up period was 7 years. A total of 123 patients with 161 lesions were enrolled, and 75 (46.58%) stents were found to be over-expanded. The baseline clinical and procedural data were comparable. Stent over-expansion showed a markedly increased diameter stenosis percentage (DSP) at 1-year follow-up (24.12 ± 21.10% vs. 14.65 ± 16.75%, = 0.002) and high late lumen loss (LLL) in-segment (0.54 ± 0.62 mm vs. 0.31 ± 0.55 mm, = 0.014). Furthermore, 63 patients with ≥ 1 over-expanded stented lesions were classified into the over-expansion group. Cumulative major cardiac adverse event (MACE) was higher in the over-expansion group than the norm-expansion group (17.5% vs. 8.3%, = 0.133). Target lesion revascularization/target vessel revascularization increased during the 7-year follow-up period in the over-expansion group compared with the norm-expansion group (11.1% vs. 3.3%, = 0.098). The Kaplan-Meier cumulative MACE-free survival showed a better tendency for statistical differences in the norm-expansion group than in the over-expansion group (log-rank test; = 0.083). Conclusion: Stent over-expansion is associated with a significant increase in LLL and DSP at 1-year angiographic follow-up and with the increasing trend of cumulative MACE during 7-year clinical follow-up period compared with stent norm-expansion. Stent over-expansion needs to be avoided.