Aspirin vs Clopidogrel After TAVR

June 29, 2026 updated by: Yonsei University

Aspirin Versus Clopidogrel for Leaflet Thrombosis Prevention in Patients Undergoing Transcatheter Aortic Valve Replacement: ACLO-TAVR Trial

Currently, the optimal antithrombotic therapy after transcatheter aortic valve replacement (TAVR) remains still unknown., The purpose of the study is to compare aspirin versus clopidogrel monoantiplatelet therapy for preventive effect on leaflet thrombosis in patients undergoing TAVR for severe aortic stenosis. This study is designed as a prospective, multicenter, open label, randomized controlled study. Eligible patients will be randomized to aspirin or clopidogrel monotherapy after TAVR. Patients will have dual antiplatelet therapy of aspirin 100 mg and clopidogrel 75 mg for 4 weeks after TAVR and then subsequent monoantiplatelet therapy of either aspirin 100 mg or clopidogrel 75 mg according to the randomization. Leaflet thrombosis will be assessed with cardiac computed tomography (CT) and transthoracic echocardiography at 3 months after TAVR. Patients will be clinically followed for 6 months. The primary endpoint is the Incidence of leaflet thrombosis on cardiac CT at 3 months.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Recruiting

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Detailed Description

  1. Prospective, multicenter, open label, randomized controlled study
  2. Eligible patients will be randomized to aspirin or clopidogrel monotherapy after TAVR
  3. All patients will have dual antiplatelet therapy of aspirin 100 mg and clopidogrel 75 mg for 4 weeks after TAVR and then subsequent monoantiplatelet therapy of either aspirin 100 mg or clopidogrel 75 mg.
  4. Leaflet thrombosis will be assessed with cardiac computed tomography (CT) and transthoracic echocardiography at 3 months after TAVR
  5. Clinical follow-up up to 6 months

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Estimated)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
270

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact

The name and contact information for the person who can answer enrollment questions for a clinical study. Each location where the study is being conducted may also have a specific contact, who may be better able to answer those questions.
  • Name: Young-Guk Ko, MD, PhD
  • Phone Number: 82-2-2228-8460
  • Email: ygko@yuhs.ac

Study Locations

  • South Korea
      • Seoul, South Korea
        • Recruiting
        • Yonsei University Health System, Severance Hospital
        • Contact:
          • Young-Guk Ko, MD, PhD
          • Phone Number: 82-2-2228-8460
          • Email: ygko@yuhs.ac

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

19 years and older (Adult, Older Adult)

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  1. Patients >19 years old
  2. Patients who underwent TAVR symptomatic severe AS
  3. Provision of informed consent

Exclusion Criteria:

  1. Patients requiring dual antiplatelet therapy longer than 4 weeks
  2. Any conditions requiring specific antiplatelet therapy aspirin or clopidogrel
  3. History of stroke or transient ischemic attack (TIA) within 6 months
  4. Planned major surgery
  5. Cardiogenic shock or hemodynamic instability
  6. Chronic kidney disease stage 4 or 5 (eGFR <30mL/min)
  7. Valve-in-valve TAVR procedure
  8. Hypersensitivity or contraindication to aspirin or clopidogrel
  9. Indication for anticoagulation therapy

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Active Comparator: Aspirin group
Patients receive the aspirin (100 mg/day) single antiplatelet therapy after 4 weeks of dual antiplatelet therapy of aspirin (100 mg/day) and clopidogrel (75 mg/day) after TAVR.
Drug: Aspirin single antiplatelet therapy
Patients receive the aspirin (100 mg/day) single antiplatelet therapy after 4 weeks of dual antiplatelet therapy of aspirin (100 mg/day) and clopidogrel (75 mg/day) after TAVR.
Experimental: Clopidogrel group
Patients receive the clopidogrel (75 mg/day) single antiplatelet therapy after 4 weeks of dual antiplatelet therapy of aspirin (100 mg/day) and clopidogrel (75 mg/day) after TAVR.
Drug: Clopidogrel single antiplatelet therapy
Patients receive the clopidogrel (75 mg/day) single antiplatelet therapy after 4 weeks of dual antiplatelet therapy of aspirin (100 mg/day) and clopidogrel (75 mg/day) after TAVR.

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Incidence of leaflet thrombosis
Time Frame: At 3 months after TAVR
Incidence of leaflet thrombosis on cardiac CT at 3 months after TAVR
At 3 months after TAVR

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Time Frame
Any stroke
Time Frame: 3 months and 6 months after TAVR
3 months and 6 months after TAVR
Ischemic Stroke
Time Frame: 3 months and 6 months after TAVR
3 months and 6 months after TAVR
Transient ischemic attack
Time Frame: 3 months and 6 months after TAVR
3 months and 6 months after TAVR
Thromboembolic events (composite of any stroke, myocardial infarction, systemic embolism (not involving the central nervous system), deep-vein thrombosis, or pulmonary embolism)
Time Frame: 3 months and 6 months after TAVR
3 months and 6 months after TAVR
Echocardiographic parameters (maximum and mean aortic valve pressure gradient)
Time Frame: at 3 months after TAVR
at 3 months after TAVR
Echocardiographic parameters (doppler velocity index)
Time Frame: at 3 months after TAVR
at 3 months after TAVR
Echocardiographic parameters (paravalvular regurgitation)
Time Frame: at 3 months after TAVR
at 3 months after TAVR
Echocardiographic parameters (leaflet thrombosis)
Time Frame: at 3 months after TAVR
at 3 months after TAVR
VARC-3 type 3 or 4 bleeding
Time Frame: 3 months and 6 months after TAVR
3 months and 6 months after TAVR
VARC-3 type 2 bleeding
Time Frame: 3 months and 6 months after TAVR
3 months and 6 months after TAVR

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Yonsei University

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • Principal Investigator: Young-Guk Ko, MD, PhD, Division of Cardiology, Yonsei Cardiovascular Hospital, Yonsei University College of Medicine

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
February 2, 2023

Primary Completion (Estimated)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
July 21, 2026

Study Completion (Estimated)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
July 21, 2027

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
August 8, 2022

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
August 8, 2022

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
August 9, 2022

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
June 30, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
June 29, 2026

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
June 1, 2026

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • 4-2022-0744

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

Cookie Settings

We use cookies to ensure that we give you the best experience on our website. For more details carefully read our Privacy and Cookies Policy. ...>>>You can change your preferences or withdraw your consent at any time by deleting the cookies from your website or computer as described in the policy. Please accept it and choose your preferences by ticking the corresponding boxes in the "Manage Settings" section below. Please carefully read our Terms of Service before you proceed with using any part of this website.
«Manage Settings