Platelet Aggregation Function-Guided De-Escalation Antiplatelet Therapy in Patients With Acute Ischemic Stroke

Inclusion criteria

• 1.Age 18 years or older. 2.Diagnosis of acute non-disabling ischemic stroke or transient ischemic attack according to World Health Organization criteria, meeting one of the following definitions: acute non-disabling ischemic stroke, defined as a National Institutes of Health Stroke Scale score of 5 or lower at enrollment; or high-risk transient ischemic attack, defined as an ABCD2 score of 4 or higher.

3.Symptom onset within 48 hours. Onset time is defined as the interval from the last time the participant was known to be well to the time of combined administration of clopidogrel 300 mg and aspirin 100 mg.

4.MARADP <35% measured 5 to 20 hours after combined antiplatelet treatment with clopidogrel 300 mg and aspirin 100 mg within 48 hours of symptom onset.

5.Planned treatment with aspirin plus clopidogrel or clopidogrel monotherapy for antiplatelet therapy.

6.Written informed consent provided by the participant or a legally authorized representative.

Exclusion criteria

1.Imaging evidence of hemorrhagic stroke, hemorrhagic transformation, or another pathological brain disorder, such as vascular malformation, tumor, abscess, or another common non-ischemic brain disease such as multiple sclerosis.

2.Minor stroke or transient ischemic attack caused by angioplasty or vascular surgery.

3.Atrial fibrillation indicated by standard electrocardiography or typical physical signs of atrial fibrillation, including absolutely irregular rhythm, variable intensity of the first heart sound, or pulse deficit.

4.A clear indication for anticoagulation, including suspected cardioembolism such as atrial fibrillation, known artificial heart valve, or suspected endocarditis.

5.Intravenous thrombolysis, intra-arterial thrombolysis, mechanical thrombectomy, or any revascularization procedure performed after the index event or planned within 90 days.

6.Use of antiplatelet agents other than aspirin or clopidogrel within 7 days before enrollment, such as ticagrelor or prasugrel.

7.History of gastrointestinal bleeding, intracranial hemorrhage, recent major bleeding or blood transfusion, excluding minor hemoptysis or minor abnormal vaginal bleeding, or other bleeding disorder caused by coagulation dysfunction, such as purpura.

8.Contraindication or intolerance to clopidogrel or aspirin, including known allergy; severe hepatic insufficiency or renal insufficiency; severe heart failure; coagulation disorder or history of systemic bleeding; history of thrombocytopenia or neutropenia; or history of drug-induced hematologic disease or hepatic dysfunction.

9.Leukopenia, defined as white blood cell count <2 x 10^9/L, or thrombocytopenia, defined as platelet count <100 x 10^9/L.

10.Use of heparin or oral anticoagulants within 10 days before enrollment. 11.Severe cardiac, pulmonary, hepatic, or renal dysfunction, or severe comorbid disease such as tumor, chronic airflow disease, severe dementia, or severe heart failure.

12.Female participants of childbearing potential with a negative pregnancy test who refuse to use effective contraception, or women who are pregnant or breastfeeding.

13.Poor compliance or inability to complete study requirements.

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