The goal of this observational study is to learn about in patients with complex coronary lesions undergoing PCI. The main question[s] it aims to answer are: the clinical efficacy and safety of an IVUS-guided approach in patients with complex coronary lesions undergoing PCI, as well as clinical outcomes up to 2 years. Participants will be treated with IVUS-guided PCI.

Inclusion Criteria:

1. The patient must be ≥18 years of age

2. Patients with an indication for PCI of at least one lesion satisfying any of the following criteria:

   1. Angiographic heavy calcification
   2. Ostial lesions
   3. True bifurcation lesions involving side-branches >2.5mm
   4. Left main lesions
   5. Chronic total occlusion
   6. In-stent restenosis
   7. Long-lesions (estimated stent length > 28mm) OR Patient with an indication for PCI for any lesion and in need for elective mechanical circulatory support assisted PCI

3. Presenting with silent ischemia, stable angina, unstable angina or non-ST-elevation acute coronary syndrome (NSTE-ACS)

4. All lesions must be suitable for treatment with 2nd generation drug eluting stents (or drug-coated balloons when indicated, e.g., in-stent restenosis, branching of bifurcation lesions)

5. The patient is willing and able to cooperate with registry procedures and follow-up until registry completion

6. Subject is able to confirm understanding of risks, benefits and treatment alternatives and he/she provides informed consent prior to any protocol-related procedure, as approved by the appropriate Ethics Committee

Exclusion Criteria:

1. ST-elevation myocardial infarction or cardiogenic shock within prior 7 days
2. Known untreated severe valvular heart disease
3. Requiring PCI in a diseased aorto-coronary bypass
4. Known contraindication or hypersensitivity to anticoagulants
5. Absolute contraindications or allergy that cannot be pre-medicated, to iodinated contrast or to antiplatelet drugs, including both aspirin and P2Y12 inhibitors
6. Non-cardiac co-morbidities with a life expectancy less than 1 year
7. Currently participating in a clinical trial that is not yet at its primary endpoint. The patient is not allowed to participate in an investigational device or drug study until the trial primary endpoint time point is achieved and may only be enrolled once in the study
8. Women who are pregnant or who are breastfeeding
9. Subject's circumstances that will not allow appropriate consenting procedures or follow-up activities (per investigator's discretion)

IVUS-guided approach in patients with complex coronary lesions undergoing PCI

Currently,All data of projects will be shared with sponsors and leading site principal investigators. Other site investigators are undecided.