There is no definite conclusive work about the benefit of OCT-guided PCI, which should be determined in complex PCI, assuming better stent optimization by OCT. In the study, we will explore the clinical implication of OCT-guided PCI of complex lesions.

Eligible patients will be randomly assigned to either OCT-guided PCI arm and angiography-guided PCI with routine high pressure NC ballooning arm in 1:1 ratio. Within OCT-guided PCI arm, the use of OCT will be also assigned to full OCT-guidance arm and postprocedural OCT only arm. and comparison of stent implantation with and without preprocedural OCT will be evaluated by postprocedural OCT (OCT-defined stent optimization will be assessed). In angiography-guided PCI arm, PCI for complex lesion will be performed without guidance of intravascular imaging, and routine use of high pressure postdilation with NC balloon will be also recommended. Primary endpoint will be evaluated during 12 months after PCI.

Inclusion criteria

• Age 19-85 years

• Patients with ischemic heart diseases (including stable angina, unstable angina and acute myocardial infarction) presented with typical chest pain or objective evidences of myocardial ischemia (positive invasive or non-invasive studies, electrocardiogram (ECG) consistent with ischemia, or elevated cardiac enzymes)

• Complex coronary stenotic lesions (>50% based on visual estimate) considered for coronary revascularization with DES

• Definition of complex lesions (at least one):

  • Acute myocardial infarction
  • Chronic total occlusion
  • Long lesion: expected stent length ≥28mm based on angiographic estimation
  • Calcified lesion
  • Bifurcation (including all techniques, one- or two-stent)
  • Unprotected left main disease
  • Small vessel diseases with reference vessel diameter less than 2.5 mm
  • Intracoronary thrombus visible on the angiography
  • Stent thrombosis
  • In-stent restenosis
  • Bypass graft lesion

• Patients who provide signed informed consent

Exclusion criteria

• Severe hepatic dysfunction (≥3 times normal reference values)
• Significant renal dysfunction (Serum creatinine >2.0 mg/dL)
• Platelet count <100,000 cells/mm3 or >700,000 cells/mm3, a white blood cell count of <3,000 cells/mm3, hemoglobin <8.0 g/dL, or other known bleeding diathesis
• Hemodynamically unstable during procedures or cardiogenic shock
• Pregnant women or women who might be pregnant
• Life expectancy; less than 1 year
• Inability to understand or read the informed content