STUDY QUESTIONS
- What is the real prevalence of platelet "resistance" to aspirin during the acute phase
of stroke and after 3 months, and 1 year, as measured using different platelet function
tests?
- Do all methods measure similar levels of resistance, or are some methods more sensitive
than others?
- Does this resistance result in a worse clinical prognosis? Is this result independent of
other variables?
OBJECTIVES
1. Hospital Phase (Acute Stroke)
- Determination, using various methods, of the prevalence of platelet hyperreactivity
in patients treated with aspirin to treat ischemic stroke (acute phase)
- Comparison of different assessment methods and identification of the most accurate
of these
- Identification of variables that correlate with platelet hyperreactivity
2. Follow-up Phase
- Correlation between platelet hyperreactivity and important clinical outcomes at 12,
24, and 36 months
- Correlation between platelet hyperreactivity and death or dependency at hospital
discharge, at 3, 12, 24, and 36 months (Modified Rankin Scale)
- Correlation between platelet hyperreactivity and recurrent stroke of any type
- Correlation between different methods for evaluating platelet functions and
identification of the most accurate method
- Analysis of hyperreactivity over time
THE STUDY
- The study will include 200 consecutive patients seen in the emergency department of a
large, urban hospital (1500 inpatient beds) and diagnosed with stroke in the acute
phase; these patients will be treated with aspirin for an undetermined period
- The investigators will not include patients who require full anticoagulation treatment,
regardless of the cause
- Importantly, the analysis of primary and secondary outcomes will be carried out after
blinding the examiner to the results of the platelet aggregation tests
PLATELET TESTS
- Whole Blood Aggregometer, ChronoLog
- VerifyNow, Accumetrics
- PFA-100, Siemens
- Plateletworks, Helena
- Impact-R, Diamed
- Serum thromboxane B2
Phase:
Phase 4
Details
Lead Sponsor:
University of Sao Paulo
Collaborators:
Accumetrics, Inc. Chrono-Log Corporation Fundação de Amparo à Pesquisa do Estado de São Paulo Helena Laboratories Point of Care