This study will evaluate the influence of total atherosclerotic burden assessed by 3-vessel fractional flow reserve (FFR) on the clinical outcomes of the patients with multi-vessel disease. For this purpose, the clinical data of the patients with 3-vessel intermediate coronary artery disease, whose FFR was measured at all 3-vessels due to their own clinical needs, will be analyzed.

Primary Analysis The Primary Analysis will be performed after 2-year follow-up data will be completed.

Pre-specified Subgroup Analysis

The pre-specified subgroup analysis will perform after 1-year follow-up data will be completed according to the following subjects:

• Concordant and discordant results between FFR and angiographic stenosis severity (patients and lesions with pre-PCI FFR will be analyzed.).

  • Association between total atherosclerotic burden and total ischemic burden, coronary CT angiography substudy (after 2-year follow-up will be completed).

    • Validation of total ischemic burden (sum of 3 vessel FFR) with Duke score, measured by treadmill test.

      • Comparison of clinical outcomes of deferred lesions according to pre-PCI FFR levels (Pre-PCI FFR <0.75, 0.75-0.80, and >0.80).

        • Comparison of clinical outcomes of deferred lesions according to iFR and FFR values ⑥ Prognosis of functional complete revascularization versus incomplete revascularization

Inclusion Criteria:

• Subject must be at least 18 years of age.
• Subject must have stenosis (>30% by visual estimate) in all 3-epicardial coronary arteries.
• FFR should be measured at all 3-vessels at the end of a procedure.

Exclusion Criteria:

• Depressed left ventricular systolic function (ejection fraction < 35%)
• ST-elevation myocardial infarction within 72 hours,
• Prior coronary artery bypass graft surgery
• Creatinine level >= 2.0mg/dL or dependence on dialysis
• Abnormal final myocardial flow (TIMI flow < 3)
• Planned bypass surgery
• Failed FFR measurement
• Failed intended revascularization

The patients with 3-vessel intermediate coronary artery disease (visually 30~70% stenosis in coronary angiogram) whose FFR was measured at all 3-vessels due to their own clinical needs.