Coronary calcified lesion is associated with a poor clinical outcome. Intravascular ultrasound (IVUS) provides anatomic information in detail about reference vessel dimensions and lesion characteristics including severity of diameter stenosis, lesion length, and morphology. Both randomized and observational studies have reported the clinical benefits of IVUS guidance for patients with chronic total occlusion (CTO), long lesions, acute coronary syndrome (ACS) with complex bifurcation lesions. Our previous ULTIMATE trial has demonstrated that IVUS-guided drug-eluting stent (DES) implantation significantly improved clinical outcome in all-comers, particularly for patients who had an IVUS-defined optimal procedure, compared with angiography guidance. However, the benefit of IVUS guidance in coronary severe calcification still remains unknown in the modern DES era.

Inclusion Criteria:

1. Silent ischemia, stable or unstable angina, non-ST-segment elevation myocardial infarction > 48 hours, or ST-segment elevation myocardial infarction > 7 days;
2. De novo coronary lesion eligible for drug-eluting stent implantation;
3. Target lesion with severe calcification;

Exclusion Criteria:

1. Age less than 18-year-old;
2. Comorbidity with a life expectancy <12 months;
3. Intolerant of antithrombotic therapy;
4. Significant anemia, thrombocytopenia, or leucopenia;
5. History of major hemorrhage (intracranial, gastrointestinal, and so on);
6. Chronic total occlusion lesion not recanalized;
7. Scheduled major surgery in the next 12 months;
8. Left ventricular ejection fraction < 25%;
9. Uremia dependent on dialysis treatment;
10. Previous drug-eluting stent implantation in target vessel;