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CompletedNCT03252249Updated Feb 18, 2026Results posted

Duration of Dual Anti-Platelet Therapy (DUAL-ACS)

A Phase 4 interventional study of 3 months dual anti-platelet therapy and 12 months dual anti-platelet therapy in Acute Coronary Syndrome and Coronary Artery Disease, sponsored by University of Edinburgh. Completed at 1 site in United Kingdom. Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2026-02-18.

Sponsored by University of Edinburgh · Phase 4, Interventional, and Treatment

Phase
Phase 4
Study type
Interventional
Enrollment
5,094
Allocation
Randomized
Ages
18 Years and older
Sex
All
01

Study summary

Despite substantial evidence supporting the use of dual anti-platelet therapy in patients with acute coronary syndrome, there remains major uncertainty regarding the optimal duration of therapy. Recent evidence suggests that shorter durations of dual anti-platelet therapy are superior because the avoidance of atherothrombotic events is counterbalanced by the greater risks of excess major bleeding with apparent increases in all-cause mortality with longer durations. We here propose an international randomised controlled trial of 18,318 patients with type 1 myocardial infarction allocated to differing durations of dual anti-platelet therapy. We will use electronic health record linkage to track duration of therapy and clinical outcomes in a real-world, real-time, efficient and highly cost-effective trial. This has the potential to define treatment duration, settle a major outstanding international controversy, and influence modern cardiology practice across the world.

02

Conditions studied

  • Acute Coronary Syndrome
  • Coronary Artery Disease
03

Who can participate

Ages eligible
18 Years and older
Sexes eligible
All
Accepts healthy volunteers
No

Inclusion criteria

  • Aged ≥18 years
  • Clinical diagnosis of Type 1 myocardial infarction within 12 weeks
  • In the opinion of the attending clinician requires dual anti-platelet therapy with aspirin and a P2Y12 receptor antagonist
  • Resident in the country of recruitment with their unique health identifier
  • The attending clinician has equipoise regarding the duration of therapy
  • Provision of informed consent

Exclusion criteria

Exclusion Criteria:

  • Clear indication for specific duration of dual anti-platelet therapy
  • Type 2 myocardial infarction
  • Contraindication to aspirin or P2Y12 receptor antagonist
  • Non-resident in the country of recruitment
  • Previous recruitment into the trial
  • Inability or unwilling to give informed consent
04

Study design

Phase
Phase 4
Primary purpose
Treatment
Allocation
Randomized
Intervention model
Parallel assignment
Masking
None (open label)
Enrollment
5,094 participants (actual)

Study arms

  • Active comparator
    3 months dual anti-platelet therapy

    3 months dual anti-platelet therapy.

    Other: 3 months dual anti-platelet therapy

  • Active comparator
    12 months dual anti-platelet therapy

    12 months dual anti-platelet therapy.

    Other: 12 months dual anti-platelet therapy

Interventions

  • Other3 months dual anti-platelet therapy

    Patients with acute coronary syndrome will be randomised to 3 months dual anti-platelet therapy.

  • Other12 months dual anti-platelet therapy

    Patients with acute coronary syndrome will be randomised to 12 months dual anti-platelet therapy.

05

What researchers measure

Primary outcomes

  1. Time-to-event: All-cause Mortality

    Restricted Mean Survival Time

    Time frame: Date of index MI to 15 months

  2. Incidence: All-cause Mortality

    Occurrence of event

    Time frame: Date of index MI to 15 months

Secondary outcomes

  1. Time-to-event: Non-cardiovascular Death (Including Fatal Bleeding) and Major Non-fatal Bleeding

    Restricted Mean Survival Time

    Time frame: Date of MI to 15 months

  2. Incidence: Non-cardiovascular Death (Including Fatal Bleeding) and Major Non-fatal Bleeding

    Occurrence of event

    Time frame: Date of MI to 15 months

  3. Time-to-event: Non-cardiovascular Death (Including Fatal Bleeding)

    Restricted Mean Survival Time

    Time frame: Date of MI to 15 months

  4. Incidence: Non-cardiovascular Death (Including Fatal Bleeding)

    Occurrence of event

    Time frame: Date of MI to 15 months

  5. Time-to-event: Major Fatal and Non-fatal Bleeding

    Restricted Mean Survival Time

    Time frame: Date of MI to 15 months

  6. Incidence: Major Fatal and Non-fatal Bleeding

    Occurrence of event

    Time frame: Date of MI to 15 months

  7. Time-to-event: Gastrointestinal Bleeding

    Restricted Mean Survival Time

    Time frame: Date of MI to 15 months

  8. Incidence: Gastrointestinal Bleeding

    Occurrence of event

    Time frame: Date of MI to 15 months

  9. Time-to-event: Cardiovascular Death and Non-fatal Myocardial Infarction

    Restricted Mean Survival Time

    Time frame: Date of MI to 15 months

  10. Incidence: Cardiovascular Death and Non-fatal Myocardial Infarction

    Occurrence of event

    Time frame: Date of MI to 15 months

  11. Time-to-event: Cardiovascular Mortality (Cardiac and Non-cardiac)

    Restricted Mean Survival Time

    Time frame: Date of MI to 15 months

  12. Incidence: Cardiovascular Mortality (Cardiac and Non-cardiac)

    Occurrence of event

    Time frame: Date of MI to 15 months

  13. Time-to-event: Myocardial Infarction (Fatal and Non-fatal)

    Restricted Mean Survival Time

    Time frame: Date of MI to 15 months

  14. Incidence: Myocardial Infarction (Fatal and Non-fatal)

    Occurrence of event

    Time frame: Date of MI to 15 months

  15. Incidence: Intracranial Haemorrhage

    Occurrence of event

    Time frame: Date of MI to 15 months

  16. Time-to-event: Coronary Revascularisation

    Restricted Mean Survival Time

    Time frame: Date of MI to 15 months

  17. Incidence: Coronary Revascularisation

    Occurrence of event

    Time frame: Date of MI to 15 months

  18. Time-to-event: Stent Thrombosis

    Restricted Mean Survival Time

    Time frame: Date of MI to 15 months

  19. Incidence: Stent Thrombosis

    Occurrence of event

    Time frame: Date of MI to 15 months

  20. Time-to-event: Thrombotic Stroke

    Restricted Mean Survival Time

    Time frame: Date of MI to 15 months

  21. Incidence: Thrombotic Stroke

    Occurrence of event

    Time frame: Date of MI to 15 months

Other outcomes

  1. Time-to-event: Iron Therapy

    Restricted Mean Survival Time

    Time frame: Date of MI to 15 months

  2. Incidence: Iron Therapy

    Occurrence of event

    Time frame: Date of MI to 15 months

  3. Time-to-event: Blood Transfusion

    Restricted Mean Survival Time

    Time frame: Date of MI to 15 months

  4. Incidence: Blood Transfusion

    Occurrence of event

    Time frame: Date of MI to 15 months

06

Results

Posted Jan 28, 2026
Limitations and caveats
The major limitation is that early trial termination meant the target sample size was not achieved, leaving an underpowered trial which was unable to address its primary endpoint. The recruitment suspension due to COVID-19, and the subsequent delays in re-opening of the study sites and lack of staff capacity significantly affected recruitment.

Participant flow

All randomised participants in database.

Participant flow — Overall Study
Milestone3 Months Dual Anti-platelet Therapy12 Months Dual Anti-platelet Therapy
Started25262526
Completed25262526
Not completed00

Outcome measures

PrimaryTime-to-event: All-cause Mortality

Restricted Mean Survival Time

Time frame:
Date of index MI to 15 months
Reported as:
Mean · days
Time-to-event: All-cause Mortality
days3 Months Dual Anti-platelet Therapy12 Months Dual Anti-platelet Therapy
Time-to-event: All-cause Mortality447.337 ± 1.0542445.196 ± 1.1741
PrimaryIncidence: All-cause Mortality

Occurrence of event

Time frame:
Date of index MI to 15 months
Reported as:
Count of participants · Participants
Incidence: All-cause Mortality
Participants3 Months Dual Anti-platelet Therapy12 Months Dual Anti-platelet Therapy
Incidence: All-cause Mortality6887
Statistical analysis
  • 3 Months Dual Anti-platelet Therapy vs 12 Months Dual Anti-platelet Therapy · Regression, Cox · p = 0.1232 · Hazard ratio (hr): 0.78 · 95% CI 0.57 to 1.073 versus 12 months (the comparator).
SecondaryTime-to-event: Non-cardiovascular Death (Including Fatal Bleeding) and Major Non-fatal Bleeding

Restricted Mean Survival Time

Time frame:
Date of MI to 15 months
Reported as:
Mean · days
Time-to-event: Non-cardiovascular Death (Including Fatal Bleeding) and Major Non-fatal Bleeding
days3 Months Dual Anti-platelet Therapy12 Months Dual Anti-platelet Therapy
Time-to-event: Non-cardiovascular Death (Including Fatal Bleeding) and Major Non-fatal Bleeding442.881 ± 1.2908440.736 ± 1.3565
SecondaryIncidence: Non-cardiovascular Death (Including Fatal Bleeding) and Major Non-fatal Bleeding

Occurrence of event

Time frame:
Date of MI to 15 months
Reported as:
Number · participants
Incidence: Non-cardiovascular Death (Including Fatal Bleeding) and Major Non-fatal Bleeding
participants3 Months Dual Anti-platelet Therapy12 Months Dual Anti-platelet Therapy
Incidence: Non-cardiovascular Death (Including Fatal Bleeding) and Major Non-fatal Bleeding104127
Statistical analysis
  • 12 Months Dual Anti-platelet Therapy · Regression, Cox · p = 0.1220 · Hazard ratio (hr): 0.82 · 95% CI 0.63 to 1.06
SecondaryTime-to-event: Non-cardiovascular Death (Including Fatal Bleeding)

Restricted Mean Survival Time

Time frame:
Date of MI to 15 months
Reported as:
Mean · days
Time-to-event: Non-cardiovascular Death (Including Fatal Bleeding)
days3 Months Dual Anti-platelet Therapy12 Months Dual Anti-platelet Therapy
Time-to-event: Non-cardiovascular Death (Including Fatal Bleeding)452.453 ± 0.5873452.593 ± 0.5285
SecondaryIncidence: Non-cardiovascular Death (Including Fatal Bleeding)

Occurrence of event

Time frame:
Date of MI to 15 months
Reported as:
Number · participants
Incidence: Non-cardiovascular Death (Including Fatal Bleeding)
participants3 Months Dual Anti-platelet Therapy12 Months Dual Anti-platelet Therapy
Incidence: Non-cardiovascular Death (Including Fatal Bleeding)2729
Statistical analysis
  • 12 Months Dual Anti-platelet Therapy · Regression, Cox · p = 0.7789 · Hazard ratio (hr): 0.93 · 95% CI 0.55 to 1.57
SecondaryTime-to-event: Major Fatal and Non-fatal Bleeding

Restricted Mean Survival Time

Time frame:
Date of MI to 15 months
Reported as:
Mean · days
Time-to-event: Major Fatal and Non-fatal Bleeding
days3 Months Dual Anti-platelet Therapy12 Months Dual Anti-platelet Therapy
Time-to-event: Major Fatal and Non-fatal Bleeding445.227 ± 1.1719442.790 ± 1.2794
SecondaryIncidence: Major Fatal and Non-fatal Bleeding

Occurrence of event

Time frame:
Date of MI to 15 months
Reported as:
Number · participants
Incidence: Major Fatal and Non-fatal Bleeding
participants3 Months Dual Anti-platelet Therapy12 Months Dual Anti-platelet Therapy
Incidence: Major Fatal and Non-fatal Bleeding80102
Statistical analysis
  • 12 Months Dual Anti-platelet Therapy · Regression, Cox · p = 0.0977 · Hazard ratio (hr): 0.78 · 95% CI 0.58 to 1.05
SecondaryTime-to-event: Gastrointestinal Bleeding

Restricted Mean Survival Time

Time frame:
Date of MI to 15 months
Reported as:
Mean · days
Time-to-event: Gastrointestinal Bleeding
days3 Months Dual Anti-platelet Therapy12 Months Dual Anti-platelet Therapy
Time-to-event: Gastrointestinal Bleeding449.967 ± 0.8887450.562 ± 0.7774
SecondaryIncidence: Gastrointestinal Bleeding

Occurrence of event

Time frame:
Date of MI to 15 months
Reported as:
Count of participants · Participants
Incidence: Gastrointestinal Bleeding
Participants3 Months Dual Anti-platelet Therapy12 Months Dual Anti-platelet Therapy
Incidence: Gastrointestinal Bleeding3638
Statistical analysis
  • 12 Months Dual Anti-platelet Therapy · Regression, Cox · p = 0.8208 · Hazard ratio (hr): 0.95 · 95% CI 0.60 to 1.50
SecondaryTime-to-event: Cardiovascular Death and Non-fatal Myocardial Infarction

Restricted Mean Survival Time

Time frame:
Date of MI to 15 months
Reported as:
Mean · days
Time-to-event: Cardiovascular Death and Non-fatal Myocardial Infarction
days3 Months Dual Anti-platelet Therapy12 Months Dual Anti-platelet Therapy
Time-to-event: Cardiovascular Death and Non-fatal Myocardial Infarction422.876 ± 2.1559424.670 ± 2.1010
SecondaryIncidence: Cardiovascular Death and Non-fatal Myocardial Infarction

Occurrence of event

Time frame:
Date of MI to 15 months
Reported as:
Count of participants · Participants
Incidence: Cardiovascular Death and Non-fatal Myocardial Infarction
Participants3 Months Dual Anti-platelet Therapy12 Months Dual Anti-platelet Therapy
Incidence: Cardiovascular Death and Non-fatal Myocardial Infarction236226
Statistical analysis
  • 12 Months Dual Anti-platelet Therapy · Regression, Cox · p = 0.6158 · Hazard ratio (hr): 1.05 · 95% CI 0.87 to 1.26
SecondaryTime-to-event: Cardiovascular Mortality (Cardiac and Non-cardiac)

Restricted Mean Survival Time

Time frame:
Date of MI to 15 months
Reported as:
Mean · days
Time-to-event: Cardiovascular Mortality (Cardiac and Non-cardiac)
days3 Months Dual Anti-platelet Therapy12 Months Dual Anti-platelet Therapy
Time-to-event: Cardiovascular Mortality (Cardiac and Non-cardiac)449.943 ± 0.8891447.897 ± 1.0372
SecondaryIncidence: Cardiovascular Mortality (Cardiac and Non-cardiac)

Occurrence of event

Time frame:
Date of MI to 15 months
Reported as:
Count of participants · Participants
Incidence: Cardiovascular Mortality (Cardiac and Non-cardiac)
Participants3 Months Dual Anti-platelet Therapy12 Months Dual Anti-platelet Therapy
Incidence: Cardiovascular Mortality (Cardiac and Non-cardiac)4056
Statistical analysis
  • 12 Months Dual Anti-platelet Therapy · Regression, Cox · p = 0.1020 · Hazard ratio (hr): 0.71 · 95% CI 0.48 to 1.07
SecondaryTime-to-event: Myocardial Infarction (Fatal and Non-fatal)

Restricted Mean Survival Time

Time frame:
Date of MI to 15 months
Reported as:
Mean · days
Time-to-event: Myocardial Infarction (Fatal and Non-fatal)
days3 Months Dual Anti-platelet Therapy12 Months Dual Anti-platelet Therapy
Time-to-event: Myocardial Infarction (Fatal and Non-fatal)424.471 ± 2.1157427.444 ± 2.0181
SecondaryIncidence: Myocardial Infarction (Fatal and Non-fatal)

Occurrence of event

Time frame:
Date of MI to 15 months
Reported as:
Count of participants · Participants
Incidence: Myocardial Infarction (Fatal and Non-fatal)
Participants3 Months Dual Anti-platelet Therapy12 Months Dual Anti-platelet Therapy
Incidence: Myocardial Infarction (Fatal and Non-fatal)221203
Statistical analysis
  • 12 Months Dual Anti-platelet Therapy · Regression, Cox · p = 0.3623 · Hazard ratio (hr): 1.09 · 95% CI 0.90 to 1.32
SecondaryIncidence: Intracranial Haemorrhage

Occurrence of event

Time frame:
Date of MI to 15 months
Reported as:
Count of participants · Participants
Incidence: Intracranial Haemorrhage
Participants3 Months Dual Anti-platelet Therapy12 Months Dual Anti-platelet Therapy
Incidence: Intracranial Haemorrhage010
SecondaryTime-to-event: Coronary Revascularisation

Restricted Mean Survival Time

Time frame:
Date of MI to 15 months
Reported as:
Mean · days
Time-to-event: Coronary Revascularisation
days3 Months Dual Anti-platelet Therapy12 Months Dual Anti-platelet Therapy
Time-to-event: Coronary Revascularisation414.488 ± 2.3733417.081 ± 2.3383
SecondaryIncidence: Coronary Revascularisation

Occurrence of event

Time frame:
Date of MI to 15 months
Reported as:
Count of participants · Participants
Incidence: Coronary Revascularisation
Participants3 Months Dual Anti-platelet Therapy12 Months Dual Anti-platelet Therapy
Incidence: Coronary Revascularisation286259
Statistical analysis
  • 12 Months Dual Anti-platelet Therapy · Regression, Cox · p = 0.2324 · Hazard ratio (hr): 1.11 · 95% CI 0.94 to 1.31
SecondaryTime-to-event: Stent Thrombosis

Restricted Mean Survival Time

Time frame:
Date of MI to 15 months
Reported as:
Mean · days
Time-to-event: Stent Thrombosis
days3 Months Dual Anti-platelet Therapy12 Months Dual Anti-platelet Therapy
Time-to-event: Stent Thrombosis450.566 ± 0.8329450.026 ± 0.9228
SecondaryIncidence: Stent Thrombosis

Occurrence of event

Time frame:
Date of MI to 15 months
Reported as:
Count of participants · Participants
Incidence: Stent Thrombosis
Participants3 Months Dual Anti-platelet Therapy12 Months Dual Anti-platelet Therapy
Incidence: Stent Thrombosis3432
Statistical analysis
  • 12 Months Dual Anti-platelet Therapy · Regression, Cox · p = 0.8104 · Hazard ratio (hr): 1.06 · 95% CI 0.66 to 1.72
SecondaryTime-to-event: Thrombotic Stroke

Restricted Mean Survival Time

Time frame:
Date of MI to 15 months
Reported as:
Mean · days
Time-to-event: Thrombotic Stroke
days3 Months Dual Anti-platelet Therapy12 Months Dual Anti-platelet Therapy
Time-to-event: Thrombotic Stroke453.711 ± 0.4353454.244 ± 0.3519
SecondaryIncidence: Thrombotic Stroke

Occurrence of event

Time frame:
Date of MI to 15 months
Reported as:
Count of participants · Participants
Incidence: Thrombotic Stroke
Participants3 Months Dual Anti-platelet Therapy12 Months Dual Anti-platelet Therapy
Incidence: Thrombotic Stroke137
Statistical analysis
  • 12 Months Dual Anti-platelet Therapy · Regression, Cox · p = 0.1875 · Hazard ratio (hr): 1.86 · 95% CI 0.74 to 4.65
Other pre-specifiedTime-to-event: Iron Therapy

Restricted Mean Survival Time

Time frame:
Date of MI to 15 months
Reported as:
Mean · days
Time-to-event: Iron Therapy
days3 Months Dual Anti-platelet Therapy12 Months Dual Anti-platelet Therapy
Time-to-event: Iron Therapy439.175 ± 1.5407439.749 ± 1.4840
Other pre-specifiedIncidence: Iron Therapy

Occurrence of event

Time frame:
Date of MI to 15 months
Reported as:
Count of participants · Participants
Incidence: Iron Therapy
Participants3 Months Dual Anti-platelet Therapy12 Months Dual Anti-platelet Therapy
Incidence: Iron Therapy116122
Statistical analysis
  • 12 Months Dual Anti-platelet Therapy · Regression, Cox · p = 0.7220 · Hazard ratio (hr): 0.96 · 95% CI 0.74 to 1.23
Other pre-specifiedTime-to-event: Blood Transfusion

Restricted Mean Survival Time

Time frame:
Date of MI to 15 months
Reported as:
Mean · days
Time-to-event: Blood Transfusion
days3 Months Dual Anti-platelet Therapy12 Months Dual Anti-platelet Therapy
Time-to-event: Blood Transfusion430.118 ± 2.1292430.346 ± 2.1049
Other pre-specifiedIncidence: Blood Transfusion

Occurrence of event

Time frame:
Date of MI to 15 months
Reported as:
Count of participants · Participants
Incidence: Blood Transfusion
Participants3 Months Dual Anti-platelet Therapy12 Months Dual Anti-platelet Therapy
Incidence: Blood Transfusion138140
Statistical analysis
  • 12 Months Dual Anti-platelet Therapy · Regression, Cox · p = 0.8851 · Hazard ratio (hr): 1.017 · 95% CI 0.804 to 1.287

Adverse events

Collected over 15 months from date of randomisation.. Non-serious events are listed at a 0% frequency threshold.

Adverse event summary by group
GroupDeathsSeriousOther
3 Months Dual Anti-platelet Therapy68/2,526 (2.7%)0/2,526 (0%)0/2,526 (0%)
12 Months Dual Anti-platelet Therapy87/2,526 (3.4%)0/2,526 (0%)0/2,526 (0%)

Baseline characteristics

Age, Continuous
Age, Continuous(years)3 Months Dual Anti-platelet Therapy12 Months Dual Anti-platelet TherapyTotal
Mean63.4 ± 10.963.4 ± 10.863.4 ± 10.8
Sex/Gender, Customized
Sex/Gender, Customized(Participants)3 Months Dual Anti-platelet Therapy12 Months Dual Anti-platelet TherapyTotal
Sex; Female, Male — Female6846851369
Sex; Female, Male — Male183818373675
Sex; Female, Male — Not available448
Race/Ethnicity, Customized
Race/Ethnicity, Customized(Participants)3 Months Dual Anti-platelet Therapy12 Months Dual Anti-platelet TherapyTotal
White285284569
Mixed123
Asian121830
Black213
Other729
Not stated or not known5054104
Missing516
Data not collected for Scotland or New Zealand216421644328
Region of Enrollment
Region of Enrollment(participants)3 Months Dual Anti-platelet Therapy12 Months Dual Anti-platelet TherapyTotal
United Kingdom226522694534
New Zealand261257518
Social Deprivation
Social Deprivation(Participants)3 Months Dual Anti-platelet Therapy12 Months Dual Anti-platelet TherapyTotal
Quintile 1 (most deprived)455393848
Quintile 2484511995
Quintile 35054991004
Quintile 4467489956
Quintile 5 (least deprived)447473920
Not recorded154145299
Missing141630
Clinical Management at Randomisation
Clinical Management at Randomisation(Participants)3 Months Dual Anti-platelet Therapy12 Months Dual Anti-platelet TherapyTotal
CABG surgery8180161
Drug eluting stent136413662730
Bare metal stent131427
Medical management169164333
Conservative6967136
ICA planned8308351665
07

Study locations

1 site
  • Edinburgh Royal Infirmary
    Edinburgh, United Kingdom
08

References and documents

Study documents

  • Study protocol · Jul 22, 2022
  • Statistical analysis plan · Jun 4, 2025
  • Informed consent form · Jul 29, 2020

Documents are hosted by the registry — open the source record to download them.

Individual participant data

Plan to share: No

09

Registry details

Key details

Study ID
NCT03252249
Lead sponsor
University of Edinburgh
Collaborators
British Heart Foundation
Responsible party
Sponsor
First posted
Aug 17, 2017
Start date
Dec 11, 2018
Primary completion
Feb 4, 2023
Completion
Feb 4, 2023
Results posted
Jan 28, 2026
Last update
Feb 18, 2026

Study contacts

David Newby
principal investigator · University of Edinburgh

Oversight

Data monitoring committee
Yes
FDA-regulated drug
No
FDA-regulated device
No
View the source record on ClinicalTrials.gov ↗

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