What question did this study set out to answer?

To evaluate the durability of aspirin's antiplatelet efficacy over time by measuring ex vivo platelet aggregation at repeated intervals in patients taking aspirin to prevent recurrent ischemic stroke.

December 1, 1994Stroke

Development of aspirin resistance in persons with previous ischemic stroke.

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Why the study?

Does the antiplatelet effect of aspirin change over time in patients with previous ischemic stroke?

Population

306 patients with previous ischemic stroke taking aspirin for recurrent ischemic stroke prevention.

Design

Cohort

Follow-up

Over 33 months

Authors

CHCathy M. HelgasonCross-Cutting Cardiology KBKristian BolinUniversity of Gothenburg JHJulie HoffRush University

Discussion

Member takes

Implication

Aspirin response may fluctuate over time in stroke patients; leaves open whether serial testing or dose adjustment improves outcomes.

Key Points

To evaluate the durability of aspirin's antiplatelet efficacy over time by measuring ex vivo platelet aggregation at repeated intervals in patients taking aspirin to prevent recurrent ischemic stroke.
Followed 306 patients with a history of ischemic stroke receiving aspirin doses from 325 to 1300 mg/day over 33 months.
Assessed platelet aggregation after 2 weeks of therapy and longitudinally at approximately 6-month intervals, escalating doses in 325 mg/day increments when inhibition was incomplete.
Among 119 retested patients with initial complete inhibition, 39 (32.7%) converted to partial inhibition on repeat testing without any change in aspirin dosage.
Of 52 patients with initial partial inhibition who were retested, 35 achieved complete inhibition via dosage escalation or response fluctuation, though 8 of those 35 (22.8%) later reverted to partial inhibition.
Overall, 8.2% of retested patients demonstrated resistance to 1300 mg/day of aspirin, including 15.4% (8 of 52) with initial partial inhibition and 5.0% (6 of 119) with initial complete inhibition.

Structured PICO

Does the antiplatelet effect of aspirin change over time in patients with previous ischemic stroke?

Population

306 patients with previous ischemic stroke taking aspirin for recurrent ischemic stroke prevention.

Intervention

Aspirin (ASA) at increasing doses from 325 to 1300 mg/d.

Outcome

Ex vivo effect of aspirin on platelet aggregation (complete vs partial inhibition) measured at 2 weeks and approximately 6-month intervals.surrogate

The antiplatelet effect of a fixed dose of aspirin is not constant over time, with a significant proportion of patients developing partial or complete resistance during long-term therapy.

Cite This Study

Helgason et al. (1994) studied this question.

synapsesocial.com/papers/6a7094fc35aa2c282ce1e6f5 https://doi.org/10.1161/01.str.25.12.2331

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Development of aspirin resistance in persons with previous ischemic stroke.

Discussion

Member takes

Implication

Key Points

Structured PICO

Cite This Study

Development of aspirin resistance in persons with previous ischemic stroke.

Discussion

Member takes

Implication

Key Points

Structured PICO

Cite This Study

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