A Study of Low Dose vs Standard Ticagrelor on Platelet Function After Intervention for Acute Coronary Syndrome in Senior Patients

Study Overview
=================
Brief Summary
-----------------
In this study, the investigates try to confirm our hypothesis that low dose ticagrelor(60mg) had similar anti-platelets function compared with the standard dose ticagrelor in senior （no less than 75 years old)acute coronary syndrome patients . Totally 40 senior ACS patients will be divided into 2 groups randomly one month after PCI . Group 1 will be treated with ticagrelor 90mg and aspirin 100mg after PCI for 12 months as the standard group; Group 2 will be treated with ticagrelor 60mg plus aspirin 100 mg for 11 months after one month standard DAPT treatment. The platelets function will be tested in VASP and TEG methods 2 months after PCI as the primary endpoints.The clinical events will be observed 12 months after PCI.

Official Title
-----------------
A Randomized Controlled sTudy of Low Dose vs Standard tIcaGrelor on Platelet Function After intErvention for Acute Coronary syndRome in Senior Patients

Conditions
-----------------
Senior Acute Coronary Syndrome Patients After PCI

Intervention / Treatment
-----------------
* Drug: Ticagrelor


Participation Criteria
=================
Eligibility Criteria
-----------------
Inclusion Criteria: 1.Subject must be at least 75 years of age 2 Patients should have undergone successful percutaneous coronary intervention with drug-eluting stent for acute coronary syndrome 3.Subject understand the study requirements and the treatment procedures and provided informed consent before the procedure Exclusion Criteria: Female of childbearing potential, unless a recent pregnancy test is negative, who possibly plan to become pregnant any time after enrollment into this study Active bleeding Known hypersensitivity or contraindication to study medications Female of childbearing potential, unless a recent pregnancy test is negative, who possibly plan to become pregnant any time after enrollment into this study Non-cardiac co-morbid conditions are present with life expectancy <2 year or that may result in protocol non-compliance (per site investigator's medical judgment). Subjects with Cerebral hemorrhage history Subjects with stroke history in half a year subjects with active malignant tumor subjects with whom oral anticoagulants are needed Other conditions which the investigators think not applicable to the study.

Ages Eligible for Study
-----------------
Minimum Age: 75 Years

Sexes Eligible for Study
-----------------
All

Accepts Healthy Volunteers
-----------------
No

Study Plan
=================
How is the study designed?
-----------------

Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: standard dose ticargrelor based DAPT therapy<br>treated with ticagrelor 90mg and aspirin 100mg after PCI for 12 months as the standard group | Drug: Ticagrelor<br>* 90mg ticargrelor based DAPT vs 60mg ticargrelor based DAPT<br>|
| Experimental: low dose ticargrelor based DAPT<br>treated with ticagrelor 60mg plus aspirin 100 mg for 11 months after one month standard DAPT treatment | Drug: Ticagrelor<br>* 90mg ticargrelor based DAPT vs 60mg ticargrelor based DAPT<br>|

What is the study measuring?
-----------------
Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| changes of PRI detected by VASP methods | platelet reactivity index (PRI) detected by VASP (Vasodilator Stimulated | changes of PRI from baseline (4weeks after index PCI) to 8 and 12 weeks after index PCI | 
| changes of Maximum Amplitude (MA) detected by TEG | Maximum Amplitude (MA) detected by TEG(Thromboelastography) | changes of MA from baseline (4weeks after index PCI) to 8 and 12 weeks after index PCI |