Coronary artery disease (CAD) is the leading cause of death and disability in Thailand. The incidence of CAD has constantly been increasing. Percutaneous coronary intervention (PCI) is the standard and mainstay of CAD treatment. In Thailand, PCI has been performed for more than 20 years. Because of the benefit of PCI in reducing mortality, morbidity and symptom, it is recommended by many clinical practice guideline as a standard treatment of CAD. Since the Ministry of Health realized the benefit of PCI and support the opening of new catheterization laboratories (cath lab) in all parts of the country, the number of cath lab and the number of PCI cases in Thailand has rapidly increasing for the last ten years. PCI registry is very important, as it provides many useful information (e.g. baseline demographic data of the patients, practice pattern, device and equipment use, outcome of treatment, complications, success rate, emergency CABG rate), as well as information regarding health care system (e.g. prevalence of referral cases, waiting time of the system, appropriateness of PCI, cost of PCI, cost-effectiveness/cost-utility which could be compared to treatment of other diseases (such as cancer, etc.). The information is essential in improving the outcomes of PCI, in preventing complications, in increasing the efficacy and safety of PCI, which may lead to more effective national resource allocation and proper reimbursement. With the reasons given, many countries have conducted their own data collection and PCI registry. The good examples include SCARR registry of Sweden, NCDR of USA and NCVD PCI registry of the National Heart Association of Malaysia. Cardiovascular Intervention Association of Thailand (CIAT) realized the importance of having our own data, therefore initiating the project “Thai PCI Registry” in order to collect the data of patients undergoing PCI in current clinical practice in our country. The project received financial support from Health System Research Institute (HSRI). The project was planned for 4 years with summary of the project as follow: The first year is the preparation year. The plan was to generate CRF, get approval from CREC and local EC/IRB, create definition brochure/operator manual, invite every cath lab all over the countries to participate, set up the online data entry system, set up and maintain database and server, establish national network for cath lab personnel, test the data entry system and arrange for workshop and training of research personnel/cath lab staff from every participated site. The second year would focus mainly on data entry. The plan was to maintain uneventful data registry, improve and evolve the online data entry system, maintenance of database, communicate within the network and perform site audit of all 39 participating hospital all over the countries. The third year is to close the recruitment of new cases, clean and check of the data obtained as well as perform data query. When the data quality is confirmed, the data lockdown of the baseline (in-hospital) data would be conducted. During this year, there will be initial data analysis, some manuscript writing and submission for publication. Furthermore, the follow data at 6 and 12 months will be gather as well as outcome verification and ascertainment. The final year we plan to perform data query of follow up data before the final and complete data lockdown as well as data analysis, manuscript writing and submission for publication. The main activity of this year will also focus on distribute all important results to the public and all stakeholders. This report is the full report of the Phase 1 of Thai PCI registry project (year 1-2) which received financial support from HSRI. The final Phase 2 of the Thai PCI registry project (year 3-4) will be conducted immediately after receiving approval and grant support from HSRI. There were 22,741 patients participating in Thai PCI registry. Approximately 70% were male with the mean age of 64 years. Two third of all patients use Universal Coverage (UC) scheme. Most common presentation was stable CAD (37.6%) and most common procedures were performed electively (61.2%). More than half of all patients were referral cases. In terms of coronary anatomy, most patients were classified as triple vessel disease (32.9%) follow by double vessel disease (28.7%) and single vessel disease (26.4%), respectively. Ten percent of all patients had left main stenosis. The main vascular access was femoral approach (12,568 cases; 54.4%). When we categorized the patients into their presentation of acute coronary syndrome and stable coronary disease, we found that 27.6% was STEMI, 29.8% was Non STEMI, 37.6% was Stable CAD, and others was 5.1%. The In-hospital mortality rate was 6.7%, 2.1%, 0.3%, and 3.3%, respectively. with overall in-hospital mortality was 2.8%. The overall success rate of PCI in this registry was 96% which was very good and comparable to data from other countries. The factors that were independently associated with procedural failure included older age, referral cases, hypertension, history of heart disease, complex lesion, long lesion, and poor TIMI flow. The incidence of procedural complications was approximately 5%. The common complications reported included coronary dissection, side branch occlusion, no reflow, coronary perforation, device dislodge, acute stent thrombosis. The factors that were independently associated with procedural complications included older age, female, health care coverage, hypertension, history of heart disease, cardiogenic shock, requirement of IABP/mechanical support, unsuccessful vascular access, long lesion, thrombotic lesion, complex lesion, bifurcation and abnormal TIMI flow. The common clinical complications included post-PCI MI (1,374 cases, 6.0%), bleeding within 72 hours (1,102 cases, 4.9%), stroke (85 cases, 0.4%) and emergency CABG (0.3%). In term of mortality, the in-hospital mortality rate was 2.8%. The independent factors associated with incidence of clinical complications included older age, female, referral cases, peripheral vascular disease, requirement of dialysis, emergency PCI, ACS, cardiogenic shock, requirement of IABP/mechanical support, left main stenosis, unsuccessful PCI, and procedural complication. In summary, the first phase (year 1-2) of Thai PCI registry was completed with great success. Many goals and objectives were achieved which included 1) establishing national network which can be a platform of nation-wide collaboration of other registry in the future, 2) creating CRF in PCI cases which can be used by any participating sites even after completion of the registry or can also be used by general public by request, 3) Training the new researchers from all area of the country, 4) obtaining crucial data which will lead to improvement of PCI outcomes, prevention of complications and improvement of health care system resulting in better care of patients with cardiovascular diseases in the future.