The prognostic factors after a percutaneous coronary intervention (PCI) have not been comprehensively investigated. The investigators sought to develop a risk model to predict future clinical events after PCI using contemporary coronary stents.

Percutaneous coronary intervention (PCI) is a standard treatment strategy for coronary artery disease (CAD). With the presence of myocardial ischemia, PCI reduces the risks of death, myocardial infarction (MI) and revascularization compared to medical therapy. However, the risk of future clinical events still remain high and about 10% of patients experienced further cardiovascular events after PCI. There are several factors that are associated with these poor outcomes. Known patient-related risk factors are diabetes mellitus, chronic kidney disease, left ventricular dysfunction, previous MI and presentation with the acute coronary syndrome. Procedure-related factors, such as stent underexpension, malapposition, edge dissection, the number of the used stent and total stent length, are also related to poor prognosis after PCI. Recent studies reported that fractional flow reserve (FFR) after coronary stenting, or post PCI FFR, was associated with future clinical outcomes after PCI and low post PCI FFR value was associated with procedural factors. However, all of these risk factors were identified in individual studies there have been no studies that comprehensively evaluated these risk factors. Therefore, the investigators sought to investigate the risk predictors of future clinical events in patients after PCI and develop a risk model, incorporating clinical, angiographic, and physiologic factors, to predict the clinical events after PCI using contemporary coronary stents.

The study population of this study is from the International Post PCI FFR Registry, which included 4 different registries from Korea, China, and Japan. All patients in this registry are available with clinical, angiographic and physiologic data and used 2nd generation drug-eluting stent (DES) for PCI. The COE-PERSPECTIVE registry (NCT01873560) was designed to evaluate the clinical relevance of post PCI FFR from 9 hospitals in Korea and Japan and enrolled a total of 835 patients available post PCI FFR value after angiographically successful PCI between May 2013 and December 2016. The 3V-FFR-FRIENDS registry (NCT01621438) enrolled a total of 1,136 patients (3,298 vessels) who underwent 3-vessel FFR measurements from 12 centers in Korea, Japan, and China between November 2011 and March 2014. Among them, 266 patients with 337 vessels who measure post PCI FFR values were included in this international registry. The DKCRUSH VII registry (ChiCTR-PRCH-12001976) enrolled a total of 1,476 patients from 9 hospitals (5 hospitals in China, 2 hospitals in the United States, 1 hospital in Asia and 1 hospital in European country) between May 2012 and September 2013 to evaluate the prognostic value of post PCI FFR on patients' future outcome. For this international registry, 780 patients with 794 vessels from Nanjing First Hospital in China, who were available with whole clinical, angiographic and physiologic data, were included in this registry. Last, the Institutional registry of Tsuchiura Kyodo General Hospital, Ibaraki, Japan included 347 patients (357 vessels) who underwent PCI and final post-PCI FFR measurement.

Inclusion Criteria:

• Patients who underwent PCI and post-PCI FFR measurements after angiographically successful stent implantation (residual stenosis < 20% by visual estimation)
• Patients who provided informed consent

Exclusion Criteria:

• Post-PCI TIMI flow of < 3
• Depressed left ventricular systolic function (ejection fraction < 30%)
• Culprit lesion for acute coronary syndrome
• Graft vessel
• Collateral feeder
• In-stent stenosis
• Primary myocardial or valvular heart disease
• Patients with life expectancy < 2 years.

Patients who were diagnosed as obstructive coronary artery disease and treated by 2nd generation DES and measured post PCI FFR after PCI.