High on-treatment platelet reactivity to adenosine diphosphate was a important reason to cause ischemic events in antiplatelet therapy. Using single testing to definite HPR may miss the "true HPR" or over estimate HPR, which may lead to randomized trials failed. It is not known whether combined multiple platelet function testing could assist to ensure"ture"HPR and improve clinical outcomes.

This was a single-center, randomized, prospective study. ACS patients undergoing PCI treated with clopidogrel and aspirin were included. in the 3-5th day after prescription of clopidogrel, platelet function were tested simultaneously by three methods: MPAADP by Light transmittance aggregometry（LTA）, MAADP by Thrombelastography (TEG) ,and CTP2Y by Innovance PFA-200 . According to three result（Two of three or all three results higher than cutoff value was identified as HPR, MPALTA>50%;MAADP>47mm;CTP2Y<106s）.Patients was defined as HPR(n=125) or unHPR(n=232), HPR patients were divided into HPR-Ticagrelor(HPR-T)and HPR-Clopidogrel(HPR-C) randomized. HPR-T group(n=77) patients' antiplatelet agents changed to ticagrelor, both unHPR and HPR-C groups keep unchanged(Clopidogrel). The major adverse cardiovascular events (MACE) were recorded during 1 year Follow-up.

Inclusion Criteria:

• ACS patients（UAP;USTEMI,STEMI）
• Undergoing PCI
• Oral antiplatelet therapy

Exclusion Criteria:

• Stable CAD