Platelet Inhibition in the Acute Phase of STEMI

Completed

• Conditions: Acute Myocardial Infarction; Antiplatelet Therapy; ST-segment Elevation Myocardial Infarction (STEMI)

• Registration Number: NCT01144819
• Lead Sponsor: University of Aarhus

Brief Summary

Background:

Dual antithrombotic treatment with aspirin and clopidogrel is recommended in patients with ST elevation myocardial infarction (STEMI) undergoing primary percutaneous coronary intervention (PCI). The European Society of Cardiology (ESC) Guidelines recommend a bolus dose of aspirin of 250-500 mg and a 600 mg bolus dose of clopidogrel as soon as STEMI is suspected. Studies have shown that more newly produced platelets are present in the acute phase of STEMI, and it is likely that these immature platelets are haemostatically more active and might be of importance in thrombus formation.

The enhanced platelet reactivity may reduce the effect of aspirin and clopidogrel in the acute phase of STEMI compared to measurements made in the same patients 3 months after primary PCI.

Aim:

This study aims to compare platelet response to aspirin and clopidogrel in the acute phase of STEMI with the platelet response in the same patients 3 months after STEMI .

Design:

This study is an observational follow-up study.

Materials and methods:

46 patients with STEMI referred to primary PCI at Aarhus University Hospital, Skejby will be included in the study. A total of 3 blood samples are obtained in the acute phase of STEMI: Prior to primary PCI (Blood sample 1), at 4 hours (Blood sample 2) and at 12 hours (Blood sample 3) after administration of loading dose aspirin and clopidogrel. When patients are in a stable phase 3 month later, a final blood sample is taken (Blood sample 4). The blood is analyzed 30 minutes after withdrawal of blood by the platelet aggregation test Multiplate® aggregometry (agonists: Collagen, arachidonic acid and adenosinediphosphate) and VerifyNow® arachidonic acid and P2Y12 aggregometry. Platelet count, volume and the immature platelet fraction (IPF) will be measured using Sysmex® flowcytometry.

Detailed Description

Not available

Study Timeline

• Study Start: 2009-10
• Study First Submitted: 2010-03-26
• Study First Submitted QC: 2010-06-15
• Study First Posted: 2010-06-16
• Primary Completion: 2010-07
• Study Completion: 2010-08
• Status Verified: 2013-09
• Last Update Submitted: 2013-09-06
• Last Update Posted: 2013-09-09

Recruitment & Eligibility

• Status: COMPLETED
• Sex: All
• Target Recruitment: 46

Inclusion Criteria

• Above 18 years of age
• Patients with ST-segment elevation myocardial infarction (STEMI) referred to primary PCI at University Hospital of Aarhus, Skejby.

Exclusion Criteria

• Treatment with NSAID, ticlopidine and dipyramidole.
• Treatment with anticoagulants (Vitamin K antagonists)
• Patients diagnosed with platelet disease or haemophilia.
• Patients unable to give written, informed consent to participation in this project.

Study & Design

• Study Type: OBSERVATIONAL
• Study Design: Not specified

Primary Outcome Measures

Name	Time	Method
Difference between aggregation induced by agonist arachidonic acid (1,0 mM) measured by Multiplate® Aggregometry (Unit=AUC).	Approximately 2-3 months	Outcome is the difference between aggregation measurements. In this case between: Blood sample 3: 12 hours after administration of LD aspirin and clopidogrel.; Blood sample 4: 2-3 months after primary PCI.
Difference between aggregation induced by agonist adenosine diphosphate (6,4 µM) measured by Multiplate® Aggregometry (Unit=AUC).	Approximately 2-3 months	Outcome is the difference between aggregation measurements. In this case between: Blood sample 3: 12 hours after administration of LD aspirin and clopidogrel.; Blood sample 4: 2-3 months after primary PCI.
Difference between aggregation induced by agonist adenosine diphosphate (20 µM) measured by Multiplate® Aggregometry (Unit=AUC).	Approximately 2-3 months	Outcome is the difference between aggregation measurements. In this case between: Blood sample 3: 12 hours after administration of LD aspirin and clopidogrel.; Blood sample 4: 2-3 months after primary PCI.
Difference between aggregation measured by VerifyNow® Aggregometry using the P2Y12-kit (Unit = PRU).	Approximately 2-3 months	Outcome is the difference between aggregation measurements. In this case between: Blood sample 3: 12 hours after administration of LD aspirin and clopidogrel.; Blood sample 4: 2-3 months after primary PCI.
Difference between aggregation induced by agonist collagen (1 μg/ml) measured by Multiplate® Aggregometry (Unit=AUC).	Approximately 2-3 months	Outcome is the difference between aggregation measurements. In this case between: Blood sample 3: 12 hours after administration of LD aspirin and clopidogrel.; Blood sample 4: 2-3 months after primary PCI.
Difference between aggregation measured by VerifyNow® Aggregometry using the ASPI-kit (Unit = ARU).	Approximately 2-3 months	Outcome is the difference between aggregation measurements. In this case between: Blood sample 3: 12 hours after administration of LD aspirin and clopidogrel.; Blood sample 4: 2-3 months after primary PCI.

Secondary Outcome Measures

Name	Time	Method
Difference in immature platelet fraction measured by Sysmex® flowcytometry.	Approximately 2-3 months	Outcome is the difference between measurements. In this case between: Blood sample 3: 12 hours after administration of LD aspirin and clopidogrel.; Blood sample 4: 2-3 months after primary PCI.
Difference in serum P-selectin	Approximately 2-3 months	Outcome is the difference between measurements. In this case between: Blood sample 1: Obtained immediately before primary PCI in the catherization laboratory. The blood sample is obtained from the femoral artery catheter.; Blood sample 4: 2-3 months after administration of LD aspirin and clopidogrel.
Difference in serum trombopoietin	Approximately 2-3 months	Outcome is the difference between measurements. In this case between: Blood sample 1: Obtained immediately before primary PCI in the catherization laboratory. The blood sample is obtained from the femoral artery catheter.; Blood sample 4: 2-3 months after administration of LD aspirin and clopidogrel.
Difference in serum thromboxane B2	Approximately 2-3 months	Outcome is the difference between measurements. In this case between: Blood sample 1: Obtained immediately before primary PCI in the catherization laboratory. The blood sample is obtained from the femoral artery catheter.; Blood sample 4: 2-3 months after administration of LD aspirin and clopidogrel.

Trial Locations

Locations (1)

Aarhus University Hospital, Skejby; 🇩🇰 Aarhus N, Central Denmark Region, Denmark