Drug-Coated Balloon (DCB) angioplasty is similar to plain old balloon angioplasty procedurally, but there is an anti-proliferative medication paclitaxel coated to the balloon. Treating ISR lesions with the DCB has the theoretical advantage of avoiding multiple stent layers and respecting the vessel anatomy. DCB has shown promising results for the treatment of ISR. Currently, DCB has a Class I indication to treat ISR recommended by European Society of Cardiology guidelines. In addition, some interventional cardiologist has also applied DCB in de novo lesions in their clinical practice.

Bleeding after PCI remains a substantial clinical problem. Bleeding post-PCI increases the risk of adverse outcomes such as death, non-fatal myocardial infarction, and prolongs hospital stay. Clinical data has suggested that major bleeding post-PCI would increase the risk of mortality 5.7-fold. The antiplatelet medications are the major cause of bleeding events post-PCI.

Current guidelines for stents recommended DAPT of aspirin plus a P2Y12 inhibitor for at least 12 months after stent implantation in patients with the acute coronary syndrome. Compared with the DES, because of the absence of metal inside the coronary artery, the use of DCB might theoretically allow shorter duration antiplatelet therapy. However, the optimal course of DAPT for the DCB treated patients remains controversial.

In 2013, the consensus from the German group suggested that for the acute coronary syndrome, DAPT should be used for 12 months. The consensus of DAPT developed by the European Society of Cardiology (ESC) in 2017 stated that "in patients treated with DCB, dedicated clinical trials investigating the optimal duration of DAPT are lacking." So far, there are no randomized data showing the optimal DAPT duration for the DCB treated patients.

In the current study, we use Aspirin + Ticagrelor for 1-month followed by Ticagrelor monotherapy for 5-month, afterward, Aspirin monotherapy for 6 months to be the antiplatelet regimen in the experimental arm, to compare with the Reference arm, which is Aspirin + Ticagrelor for 12-month in a non-inferiority statistical assumption, aiming to investigate the optimal duration of the DAPT in ACS patients after DCB treatment.

Inclusion Criteria:

1. Patients with an indication for PCI due to acute coronary syndrome
2. All target lesions can be successful treatment of PCI with drug-coated balloon (DCB)
3. Patients who are able to complete the follow-up and compliant to the prescribed medication

Exclusion Criteria:

1. Under the age of 18 or Older than 80 years old
2. Unable to give informed consent
3. Patient is a woman who is pregnant or nursing (a pregnancy test must be performed within 7 days prior to the index procedure in women of child-bearing potential according to local practice)
4. Known contraindication to medications such as Heparin, antiplatelet drugs, or contrast.
5. Currently participating in another trial and not yet at its primary endpoint
6. Planned elective surgery
7. Concurrent medical condition with a life expectancy of less than 1 years
8. Previous intracranial haemorrhage
9. Need long-term oral anticoagulant therapy
10. Cardiogenic shock
11. Previous stent implantation 6 month
12. In-stent thrombosis
13. Target lesion located in surgical conduit