This study aims to investigate and compare the local inflammatory responses and plaque healing characteristics between sirolimus-coated and paclitaxel-coated coronary drug-coated balloons in patients with acute coronary syndrome.

This prospective, single-center, randomized, controlled trial aims to evaluate and compare the differential effects of sirolimus-coated versus paclitaxel-coated drug-coated balloons (DCBs) on local inflammatory responses and plaque healing characteristics in patients with acute coronary syndrome (ACS) with optical coherence tomography (OCT).

Inclusion Criteria:

Subjects must meet all of the following criteria to be enrolled:

1. Age between 18 and 80 years old, both genders eligible;
2. Coronary angiography showing non-complex lesions with acute coronary syndrome (non-ST-elevation myocardial infarction and unstable angina) deemed suitable for drug-coated balloon treatment by the investigator;
3. Visually estimated lesion length ≤28mm, visually estimated vessel diameter ≥2.5mm and ≤3.0mm;
4. Successful lesion pre-dilation (must simultaneously meet all 3 criteria: no Type C or greater dissection; TIMI flow grade 3; visually estimated residual stenosis ≤30%);
5. Able to understand the study purpose, willing to complete follow-up visits, and voluntarily provide informed consent.

Exclusion Criteria:

Subjects will be excluded if they meet any of the following criteria:

1. Total occlusion (TIMI 0 flow) lesion;
2. In-stent restenosis lesion;
3. Concurrent left main disease or severe three-vessel disease requiring coronary artery bypass grafting;
4. Target lesion with severe calcification or tortuosity that cannot be crossed by guidewire;
5. Coronary artery bypass graft stenosis;
6. Confirmed ST-elevation myocardial infarction;
7. Cardiogenic shock or requiring mechanical respiratory and circulatory support;
8. Hemodynamically unstable tachyarrhythmia or bradyarrhythmia;
9. Severe renal insufficiency or undergoing hemodialysis;
10. Known allergy or intolerance to aspirin, clopidogrel, ticagrelor, heparin, contrast media, paclitaxel, sirolimus and/or other analogues;
11. Systemic lupus erythematosus or other systemic autoimmune diseases;
12. History of stroke within 6 months prior to enrollment;
13. Scheduled elective surgery within 6 months after enrollment requiring discontinuation of anticoagulant or antiplatelet medications;
14. Currently participating in other drug or interventional medical device clinical studies;
15. Other conditions deemed unsuitable for enrollment by the investigator.