The purpose of this observational study is to evaluate the long-term effectiveness and safety of the OSFIT drug-eluting stent designed to facilitate procedures in coronary artery lesions. Additionally, the study aims to verify the accuracy of stent placement in the lesion of interest using Optical Coherence Tomography (OCT) among subgroups of participants.

The primary endpoint was defined as the composite of target lesion failure (TLF) at the 12-month mark, including cardiac death, target vessel myocardial infarction (MI), or target lesion revascularization.

Investigator plan to enroll a total of 1000 patients who underwent percutaneous coronary intervention (PCI) for coronary artery stenosis within 5mm of the coronary artery ostium using OSFIT drug-eluting stents, with the condition that only GenossTM drug-eluting stents are used if stenting is performed simultaneously in other lesions. These patients will be followed for up to 12 months.

In addition, a subgroup analysis will be conducted using Optical Coherence Tomography (OCT) to assess the accuracy of OSFIT stent placement immediately after the procedure. OCT catheter use will involve the investigation and follow-up of 50 patients each at Ajou University Hospital and Samsung Seoul Hospital. Statistical analysis will involve categorical variables presented as percentages and numbers, compared using the chi-square or Fisher exact test. Continuous variables will be described using means, standard deviations, or medians and interquartile ranges and compared using Student's t-test or the Wilcoxon rank-sum test. The normality of baseline variable distributions will be assessed using histograms, skewness, kurtosis, and the Kolmogorov-Smirnov one-sample test. Kaplan-Meier analysis of cumulative rates of primary and secondary evaluation variables will be performed using the log-rank test.

To identify potential associations with clinical outcomes, all variables showing potential relevance to clinical outcomes will be tested through univariate Cox regression analysis. In order to reduce bias in retrospective studies, a multivariate Cox proportional hazard model will be used to test variables that have a significant impact (p-value < 0.1) in the univariate analysis.

Subgroup analysis will include an imaging analysis of stent insertion adequacy in the group where OCT was performed.

Inclusion Criteria:

1. Age 19 and above.
2. Patients who have voluntarily decided to participate in this study and have provided written consent in accordance with the subject's agreement.
3. Patients who have undergone percutaneous coronary intervention for stenosis within 5mm of the ostium of the coronary artery using OSFITTM drug-eluting stents. (In case of simultaneous stent placement for other lesions, only GenossTM drug-eluting stents should be used.)

Exclusion Criteria:

1. Patients with contraindications to stent treatment and antiplatelet therapy or who have hypersensitivity.
2. Patients with a life expectancy of less than 1 year.
3. Pregnant or lactating women, or those wishing to become pregnant.
4. Patients with ST-elevation myocardial infarction (STEMI).

A patient with stenosis within 5mm of the coronary artery ostium who qualifies for percutaneous coronary intervention with drug-eluting stents