To date, drug-eluting stents (DES) have become the standard of care in daily practice for the treatment of ischemic heart disease, by overcoming the risk of in-stent restenosis, a major issue raised in the bare-mare stents era. The application of potent anti-proliferative drugs and polymer structures that ensures sustained released of the drugs markedly reduced the neointimal hyperplasia, leading to much improved clinical outcomes compared with bare-metal stents. However, although first-generation sirolimus-eluting stents and paclitaxel-eluting stents significantly reduced the risk of in-stent restenosis and target-vessel revascularization, an augmented risk for very late stent thrombosis and fatal clinical events emerged as a new issue to be solved. Second- and newer- generation DESs adopted innovative stent platforms, novel stent materials, anti-proliferative drugs, and biocompatible polymers (including both durable and bioresorbable). Nowadays, numerous types of DESs (over 20 types) are available in clinical practice as well as bare-metal stents. However, little is known about the clinical outcome according to type of DESs in real-word practice. Given that many of recent randomized clinical trials (RCTs) demonstrate the 'non-inferiority' of brand-new DESs over older DESs in limited period time (usually for 1-year) in a selected patients eligible for RCTs, the real-world clinical outcomes according to type of DES implanted are still unveiled. Although, the question about the differential impact of generation of DES, type of biocompatible polymers (bioresorbable versus durable), thickness of stent struts and type of eluted anti-proliferative drugs are very important in clinical aspect of view, but there is little study conducted on all patients who are actually confronted in daily clinical practice.

Korea operates national insurance system that covers most of the Koreans (97.1%) that are strictly monitored by National Health Insurance Service (NHIS). Of note, the claims database of NHIS of Korea contains all information including the demographic characters of patietns, diagnosis codes (ICD-9 and ICD-10), type of procedures or surgeries and the medical devices utilized, death certificates that contains type of death, and the drugs prescribe in outpatient clinic and hospitals in a individual pill level, that enables monitoring for the drug compliance. This unique feature of NHIS database allows the investigators to gain access to the dose and duration of cardio-protective medications including anti-platelet agents, lipid-lowering agents, anti-hypertensive agents, glucose-lowering agents, nitrate donors, vasodilators, and others. Given the benefits of NHIS database of Korea, we would like to establish a whole-population registry, named as COreaN NationwidE Claims daTa on Drug-Eluting Stent Registry (CONNECT DES Registry). A comprehensive analysis of this data is expected to shed new light on the impact of type of DESs and drug use in real-world practice that could be fully revealed through RCTs.

According to stringent policy of NHIS database to protect personal information, information regarding type of DES including the thickness of strut, eluted drugs, type of polymer, generation of the DES will be provided after sufficient encryption. Likewise, all information regarding drug prescription, including the total number of pills prescribed during the period, patients' compliance and dosage of drugs will be provided after sufficient encryption. After decrypting the information provided to establish a database suitable for analysis, all eligible patients will be divided into two or more groups according to the type of DES or drug use pattern after DES implantation, which include:

1. 1st-generation vs. 2nd-generation DES
2. Durable polymer vs. bioresorbable polymer 2nd-generaion DES
3. Ultra-thin strut vs. Conventional strut vs. Thick-strut DES
4. According to the type of eluted drugs
5. DAPT duration after DES implantation
6. Type of anti-platelet therapy after cessation of DAPT
7. Intensity of statin therapy after DES implantation
8. According to use of nitrate donor or vasodilator after DES implantation
9. Use of anti-hypertensive agents after DES implantation
10. Use of glucose-lowering agents in diabetic subset of patients

Inclusion Criteria:

• Patients who were over 20 years old at the implantation of DES and treated with DES between 1-January-2005 and 31-December-2016

Exclusion Criteria:

• Patients who died within 1 week after DES implantation

Approximately 350,000 patients with DES implantation between 2005 and 2016 would be incorporated in the analyses from National Health Insurance Service (NHIS) database

Impossible to share the data due to goverment policy