Objective: To explore the imaging characteristics and related influencing factors of in-stent neoatherosclerosis (ISNA) in patients with restenosis after drug-eluting stent(DES) implantation with optical coherence tomography(OCT). Methods: A total of 25 cases of coronary heart disease patients(DES placement time ≥8 months) with coronary artery angiography showing DES in-stent restenosis (ISR) in Zunyi medical college affiliated hospital from July 2013 to December 2015 were included in this study and patient's data were retrospectively analyzed.In these patients with ISR, OCT images were acquired before percutaneous coronary intervention. Patients were divided into the ISNA group (12 patients and 12 lesions) and non-ISNA group(13 patients and 13 lesions) according to the result of OCT. ISNA on OCT was defined as neointima formation with the presence of lipids or calcification. Results: (1) The incidence of chronic kidney disease and increased low-density lipoprotein cholesterol level in ISNA group were significant higher than that in non-ISNA group(all P<0.05). The stent implantation time in ISNA group was longer than that in the non-ISNA group(53.0(14.0, 81.0) months vs. 15.0(8.5, 32.5) months, P<0.01). In addition, clinical manifestation of acute coronary syndrome was present in 8 out of 12 patientsin ISNA group, and stable angina pectoris was found in 10 out of 13 casesin non-ISNA group(P<0.01). (2) Quantitative analysis of OCT showed that the lumen area was less in ISNA group than in non-ISNA group((3.45±1.82)mm² vs. (4.17±1.68)mm², P<0.01), and neointimal area(3.89(2.26, 5.52)mm² vs. 2.96(1.99, 4.22)mm², P<0.01), neointimal load (53.15(40.18, 67.30)% vs. 41.54(32.08, 56.91)%, P<0.01), neointimal thickness(0.98(0.63, 1.36)μm vs. 0.72(0.51, 1.03)μm, P<0.01) were higher in ISNA group than in non-ISNA group.(3)Qualitative analysis of OCT showed that the prevalence of homogeneous intima was less in the ISNA group than in the non-ISNA group ((41.42±22.56)% vs.(72.06±18.68)%, P<0.05), on the contrary, the heterogeneous intima was more common in the ISNA group ((58.57±22.56)% vs. (27.94±18.68)%, P<0.05). There was no significant difference between two groups in the peri-stentmicrovessels (9/12 vs. 5/13,P>0.05), and prevalence of intraintimalmicrovessels was higher in the ISNA group than in non-ISNA group (7/12 vs. 2/13, P<0.05). In addition, thin cap fibrous plaque(7/12 vs. 0, P<0.01), disrupted intima with visible cavity (7/12 vs. 1/13, P<0.05),andintraluminal red thrombus(7/12 vs. 1/13, P<0.05) were significantly higher in ISNA group than in non-ISNA group. Conclusions Results of OCT show that ISNA occurs frequently in patients with ISR after DES implantation. The stent implantation time, incidence of chronic kidney disease and higher low-density lipoprotein cholesterol level are associated with the formation of ISNA in these patients.