BACKGROUND: Successful management of chronic total occlusion (CTO)by percutaneous coronary intervention (PCI) is known to be associated with better clinical outcomes than failed PCI. However, whether angiographic and clinical outcomes following PCI for long CTO lesions differ from those following PCI for short CTO lesions in the drug eluting stent (DES) era remains unknown. We therefore investigated whether CTO lesion length can significantly influence6-month angiographic and 2-year clinical outcomes following successful CTO PCI. METHODS AND RESULTS: A total of 235 consecutive patients who underwent successful CTO intervention were allocated into either the long or short CTO group according to CTO lesion length. Six-month angiographic and 2-year clinical outcomes were then compared between the 2groups. We found that baseline clinical characteristics were generally similar between the 2 groups. Exceptions were prior PCI, which was more frequent in the long CTO group, and bifurcation lesions, which were more frequent in the short CTO group. Apart from intimal dissection, which was more frequent in the long than short CTO group, in-hospital complications were also similarly frequent between the 2groups. Furthermore, both groups had similar angiographic outcomes at 6 months and clinical outcomes at 2 years. However, the incidence of repeat PCI(predominantly target vessel revascularization),was higher in the long than short CTO group, with our multivariate analysis identifying long CTO as an important predictor of repeat PCI (odds ratio, 4.26;95% confidence interval, 1.53-11.9; p = 0.006). CONCLUSION: The safety profile, 6-month angiographic, and 2-year clinical outcomes of CTO PCI were similar between patients with long and short CTO. However, there was a higher incidence of repeat PCI in long CTO patients despite successful PCI with DESs.