What question did this study set out to answer?

To determine the prevalence of ex vivo high on-treatment platelet reactivity (HTPR) using a novel longitudinal definition in patients with ischaemic cerebrovascular disease changing antiplatelet regimens.

September 20, 2012European Journal of NeurologyOpen Access

High on‐treatment platelet reactivity on commonly prescribed antiplatelet agents following transient ischaemic attack or ischaemic stroke: results from the Trinity Antiplatelet Responsiveness (TRAP) study

Q: What is the clinical evidence from this study?

Study design: Cohort. Population: Ischaemic cerebrovascular disease (TIA or ischaemic stroke) (n=48). Intervention: Antiplatelet therapy (aspirin or clopidogrel) vs. Baseline (prior to therapy change). Primary outcome: High on-treatment platelet reactivity (HTPR) and closure times.

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Key result

In patients with recent TIA or ischemic stroke, high on-treatment platelet reactivity was observed in 18% of patients 90 days after starting aspirin and 35% 90 days after switching to clopidogrel.

Why the study?

Does aspirin or clopidogrel monotherapy reduce platelet reactivity in patients with recent TIA or ischaemic stroke?

Population

48 patients with ischaemic cerebrovascular disease

Comparison

Aspirin monotherapy or clopidogrel monotherapy vs Baseline values before antiplatelet change

Design

Cohort

Follow-up

≥ 90 days

Authors

WTW. Oliver TobinMayo Clinic JKJ. A. KinsellaUniversity College Dublin TCTara CoughlanDélégation Paris 5

Discussion

Member takes

Implication

Persistent high on-treatment platelet reactivity after TIA or stroke should not yet change monotherapy; leaves open whether testing-guided therapy improves outcomes.

Key Points

To determine the prevalence of ex vivo high on-treatment platelet reactivity (HTPR) using a novel longitudinal definition in patients with ischaemic cerebrovascular disease changing antiplatelet regimens.
Prospective study of patients assessed ≤4 weeks after transient ischaemic attack or ischaemic stroke changing from no treatment to aspirin (N = 26) or from aspirin to clopidogrel monotherapy (N = 22).
Platelet reactivity was evaluated at baseline, 14 days, and ≥90 days using PFA-100 collagen-epinephrine (C-EPI) and collagen-ADP (C-ADP) cartridges along with whole-blood flow cytometry (CD62P, CD63, leukocyte-platelet complexes).
HTPR was defined longitudinally as failure to prolong closure times compared with pre-treatment baseline by more than twice the assay's coefficient of variation.
On aspirin, C-EPI closure times increased at 14 and 90 days (P = 0.002); HTPR was present in 24% of patients at 14 days and 18% at 90 days.
On clopidogrel, C-ADP closure times increased at 14 days (P = 0.001) but not at 90 days (P = 0.09); HTPR was present in 41% of patients at 14 days and 35% at 90 days.
Platelet activation was unaffected by aspirin (P = 0.09), while neutrophil-platelet complex reductions at 14 days on clopidogrel (P = 0.02) were not sustained at 90 days (P = 0.3); no recurrent vascular events occurred.

Study Design

Type

Cohort (n=48)

Structured PICO

Does aspirin or clopidogrel monotherapy reduce platelet reactivity in patients with recent TIA or ischaemic stroke?

Population

48 patients with recent transient ischaemic attack or ischaemic stroke undergoing a change in antiplatelet therapy, followed for 90 days.

Exposure

Aspirin monotherapy (changed from no medication, n=26) or clopidogrel monotherapy (changed from aspirin, n=22)

Comparator

Baseline values before antiplatelet change

Outcome

High on-treatment platelet reactivity (HTPR) assessed with PFA-100 at 14 days and ≥ 90 dayssurrogate

A significant proportion of patients with recent TIA or ischemic stroke exhibit high on-treatment platelet reactivity to aspirin or clopidogrel when assessed longitudinally.

Limitations

Requires larger, prospective studies to assess the clinical predictive value of the platelet function tests

Cite This Study

Tobin et al. (2012) conducted a cohort in Ischaemic cerebrovascular disease (TIA or ischaemic stroke) (n=48). Antiplatelet therapy (aspirin or clopidogrel) vs. Baseline (prior to therapy change) was evaluated on High on-treatment platelet reactivity (HTPR) and closure times. In patients with recent TIA or ischemic stroke, high on-treatment platelet reactivity was observed in 18% of patients 90 days after starting aspirin and 35% 90 days after switching to clopidogrel.

synapsesocial.com/papers/6a86f5fce8199558f7a23c7c https://doi.org/10.1111/j.1468-1331.2012.03861.x

Topics

Dual antiplatelet therapy

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Implication

Persistent high on-treatment platelet reactivity after TIA or stroke should not yet change monotherapy; leaves open whether testing-guided therapy improves outcomes.

High on‐treatment platelet reactivity on commonly prescribed antiplatelet agents following transient ischaemic attack or ischaemic stroke: results from the Trinity Antiplatelet Responsiveness (TRAP) study

Discussion

Member takes

Implication

Key Points

Study Design

Structured PICO

Limitations

Cite This Study

Topics

High on‐treatment platelet reactivity on commonly prescribed antiplatelet agents following transient ischaemic attack or ischaemic stroke: results from the Trinity Antiplatelet Responsiveness (TRAP) study

Discussion

Member takes

Implication

Key Points

Study Design

Structured PICO

Limitations

Cite This Study

Also Consider

Topics

Also Consider