The effect of ticagrelor monotherapy on platelet reactivity

Conditions

Coronary artery disease and ischaemic heart disease Circulatory System

Tom Johnson, Sarah Baos, Laura Collett, James L. Hutchinson, Martin Nkau et al. (14 authors)

Journal of the American Heart Association2020-12-1126 citations

10.1161/jaha.120.016495

Platelet inhibition during ticagrelor monotherapy versus ticagrelor plus aspirin in patients with coronary artery disease (TEMPLATE study): study protocol for a randomised controlled trial

Sarah Baos, Wendy Underwood, Lucy Culliford, Barnaby C Reeves, Chris Rogers et al. (9 authors)

Trials2017-11-096 citations

10.1186/s13063-017-2277-9

Interventions

Study visit 1: All participants will give blood sample 1 for platelet testing, receive a loading dose of 180mg ticagrelor, and will be randomised to one of the interventional groups below.

Eligibility

Sex/Gender

All

Inclusion criteria

Inclusion criteria: 1. Patient is treated with dual antiplatelet therapy comprising aspirin and clopidogrel for a minimum of 4 weeks (amended from: for 12 months as of 31/03/2016) 2. The patient is scheduled to stop dual antiplatelet therapy and continue with aspirin monotherapy

Exclusion criteria

Exclusion criteria: 1. Contraindication to dual antiplatelet therapy 2. Interruption of dual antiplatelet therapy because of bleeding events or increased bleeding risk 3. Contraindications to the use of ticagrelor 4. Pregnant and or lactating women 5. Women with child bearing potential (i.e. not sterilised or not post-menopausal) who are unwilling to use contraception 6. Men with a spouse or partner with child bearing potential unless the participant has agreed to use condoms

Design outcomes

Primary

Measure	Time frame
Maximum amplitude of the light transmission aggregation response of platelet rich plasma (PRP) to 10 µM TRAP expressed as a % of the absolute difference in light transmission between PRP and platelet poor plasma. This assay measures the ability of platelets to aggregate when exposed to the aggregation promoting agent TRAP. Measured at each visit, i.e. at visit 1 (baseline visit), at visit 2 (4 weeks after the baseline visit), and at visit 3 (8 weeks after the baseline visit).	—

Measure

Time frame

Maximum amplitude of the light transmission aggregation response of platelet rich plasma (PRP) to 10 µM TRAP expressed as a % of the absolute difference in light transmission between PRP and platelet poor plasma. This assay measures the ability of platelets to aggregate when exposed to the aggregation promoting agent TRAP. Measured at each visit, i.e. at visit 1 (baseline visit), at visit 2 (4 weeks after the baseline visit), and at visit 3 (8 weeks after the baseline visit).

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Secondary

Measure	Time frame
1. Light transmission aggregation responses to collagen and to ADP, arachidonic acid and the thromboxane (TP) receptor agonist U46619. This assay measures the ability of platelets to aggregate when exposed to the aggregation promoting agents collagen, ADP, arachidonic acid and U46619. 2. Flow cytometry to quantify surface CD62P expression and PAC-1 binding before and after activation with collagen and TRAP6. This assay measures the exposure of surface activation markers. 3. Plasma concentrations of soluble CD40 ligand (sCD40L) and thromboxane B2 to assess baseline in vivo platelet activation and Thromboxane A2 (TxA2) bio-synthesis respectively. This assay measures the levels of chemicals in the blood that are released when a platelet is activated and reflects the extent of platelet activation in the circulation. Measured at each visit, i.e. at visit 1 (baseline visit), at visit 2 (4 weeks after the baseline visit), and at visit 3 (8 weeks after the baseline visit).	—

Measure

Time frame

1. Light transmission aggregation responses to collagen and to ADP, arachidonic acid and the thromboxane (TP) receptor agonist U46619. This assay measures the ability of platelets to aggregate when exposed to the aggregation promoting agents collagen, ADP, arachidonic acid and U46619. 2. Flow cytometry to quantify surface CD62P expression and PAC-1 binding before and after activation with collagen and TRAP6. This assay measures the exposure of surface activation markers. 3. Plasma concentrations of soluble CD40 ligand (sCD40L) and thromboxane B2 to assess baseline in vivo platelet activation and Thromboxane A2 (TxA2) bio-synthesis respectively. This assay measures the levels of chemicals in the blood that are released when a platelet is activated and reflects the extent of platelet activation in the circulation. Measured at each visit, i.e. at visit 1 (baseline visit), at visit 2 (4 weeks after the baseline visit), and at visit 3 (8 weeks after the baseline visit).

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Countries

United Kingdom

Outcome results

None listed