The aim of this observational study is to compare the prognostic outcomes of various PCI strategies in elderly patients with complex coronary calcified lesions. The patients will be classified into two groups and assigned different PCI strategies, either stenting or stenting combined with pharmacologic balloon implantation. The investigators will assess the one-year prognosis for major adverse cardiovascular events in these patients.

Inclusion Criteria:

1. Age ≥ 60 years;
2. Meet the indications for coronary intervention;
3. IVUS examination suggests severe calcified lesions (calcification angle >270°) or OCT examination suggests severe calcified lesions (calcification angle >180° and/or length >5mm and/or thickness >0.5mm);
4. The diameter of the target lesion vessel is greater than 2.75mm;
5. The total length of the lesion is more than 60mm and/or the number of lesions to be treated is ≥3 and/or the number of vessels to be treated is ≥2.

Exclusion Criteria:

1. inability to provide written informed consent;
2. inability to administer antiplatelet agents and anticoagulant therapy;
3. the subject is participating in other unfinished clinical trials;
4. life expectancy <1 year;
5. non-in situ vascular lesions;
6. patients with haemodynamic instability;
7. Previous stroke within 6 months.
8. left main stem lesions.

Elderly patients with calcified coronary artery disease