Study on the potential clinical significance of subclinical stent edge effects after drug-eluting stent implantation

The edge effect (EE) of isolated restenosis at one or both ends of a stent is not reduced by drug-eluting stent (DES). The purpose of the study was to investigate the long-term outcome of 1-year subclinical DES-EE (sDES-EE), which was defined as any reduction in the minimal lumen area (MLA) at stent edge without any evidence of clinical ischemia. A total of 252 patients were enrolled from one of our previous randomized controlled studies, who were detected by optical coherence tomography (OCT) immediately after DES implantation and 1 year later. The primary endpoint was EE-related target lesion failure (EE-TLF) at 5 years. Secondary endpoints were the changes of morphologies and composition of stent edge plaque, and each component of EE-TLF. sDES-EE at 1 year was significantly correlated with EE-TLF at 5 years by binary logistic regression analysis after propensity scoring. The most valuable cutoff value of sDES-EE at 1 year was a 25% MLA reduction at the stent edge, according to receiver operating characteristic analysis, which showed a major increase in lipid normalized total volume (0.99 +/- 0.25 mm(3) vs. -0.21 +/- 0.06 mm(3), p = 0.025) and lipid percent atheroma volume (3.92 +/- 1.34% vs. -1.22 +/- 0.78%, p = 0.029). EE-TLF at 5 years was significantly higher in the sDES-EE group than in the non-sDES-EE group (15.6% vs. 4.1%, p = 0.001). sDES-EE with MLA reduction >= 25% at the stent edge at 1 year after PCI was an independent predictor of EE-TLF at 5 years, which was mainly caused by the progression of lipid components measured by OCT.