OPTIMized Diagnosis and Treatment System Based on AI and Multimodal Imaging Fusion for PCI (OPTIMAI-PCI) (OPTIMAI-PCI)

Inclusion Criteria:

1. Age 18 to 80 years, inclusive, at the time of informed consent.
2. Planned PCI for a target non-left-main coronary lesion meeting at least one of the following: typical myocardial ischemic symptoms with angiographic stenosis >70%; atypical symptoms with angiographic stenosis >=90%; functional measurement by FFR or QFR <0.80; or minimum lumen area below the protocol threshold for vessel diameter (<2.4 mm2 for <3.0 mm, <2.7 mm2 for 3.0-3.5 mm, or <3.6 mm2 for >3.5 mm).
3. Complex coronary lesion: a single diffuse long lesion >20 mm or tandem lesions separated by >10 mm of non-diseased vessel.
4. Participant or legally authorized representative can understand and sign written informed consent, can follow study procedures, and agrees to required contraception during the study.

Exclusion Criteria:

1. Allergy or contraindication to heparin, aspirin, P2Y12 receptor antagonists, or contrast media, except contrast allergy controllable by premedication.
2. Active pathologic bleeding or gastrointestinal or genitourinary bleeding within 3 months before PCI.
3. Bleeding tendency or known coagulation disorder, including heparin-induced thrombocytopenia.
4. Life expectancy <1 year or inability to comply with the protocol, in the investigator's judgment.
5. Bypass graft lesion, left-main or unprotected left-main coronary lesion.
6. STEMI within 24 hours of symptom onset or cardiogenic shock at admission (Killip class IV).
7. Uncontrolled severe systemic disease, including severe hepatic, renal, hematologic, or psychiatric disease; examples include ALT or AST >3 times the upper limit of normal, total bilirubin >1.5 times the upper limit of normal, albumin <35 g/L, cirrhosis or uncontrolled ascites, eGFR <30 mL/min/1.73 m2 or dialysis, platelet count <50 x 10^9/L, hemoglobin <80 g/L, hemolytic anemia, or aplastic anemia.
8. Pregnant or breastfeeding participant, or plans for pregnancy or breastfeeding during the study.
9. Target-vessel PCI within 12 months or in-stent restenosis.
10. Severe calcified lesion or major epicardial coronary ostial lesion expected to require atherectomy pretreatment.
11. IVUS catheter cannot cross the lesion.
12. Angiographic image quality inadequate for muQFR analysis, including severe overlap, insufficient projections, or poor contrast filling.

Withdrawal and Exclusion from Per-Protocol Analysis:

1. PCI not performed after randomization or key imaging missing and not recoverable; participant remains in the intention-to-treat set where applicable.
2. Withdrawal of informed consent.
3. Investigator judges continued participation may endanger the participant, such as a serious adverse event or very poor compliance.

Recruitment:

Participants will be screened among inpatients and outpatients scheduled for PCI for complex coronary lesions at participating centers. Investigators will explain the study and obtain written informed consent before enrollment.