Aspirin Responsiveness in Acute Brain Ischaemia: Association with Stroke Severity and Clinical Outcome

Abstract

Purpose: Platelets play a critical role in the pathogenesis of acute brain ischaemia. We studied the association between the degree of inhibition of platelet function by aspirin (ASA) and the severity and outcome of acute brain ischaemia. Methods: Platelet responsiveness to ASA was assessed in patients with acute brain ischaemia, treated with ASA since hospital admission. The degree of ASA responsiveness was assessed by optical aggregometry and categorized into patients with good response, partial response and complete unresponsiveness to ASA (good responders, partial responders and non-responders, respectively). An additional evaluation of responsiveness to ASA was performed by Impact-R (cone and platelet analyzer). Patients underwent serial clinical assessment during hospitalization, at discharge and during follow-up. Results: Among 105 patients (mean age 63 ± 12 years; 66% men), impaired ASA responsiveness at baseline as assessed by aggregometry was associated with increased stroke severity at baseline, unfavourable clinical course, and poor functional outcome during follow-up (p < 0.05 for all). Age-adjusted odds ratios in non-responders compared to good responders were 9.8 for severe stroke on admission (95% CI 2.8–34.9), 3.1 for lack of early clinical improvement (95% CI 1.1–8.8) and 8.6 for poor functional outcome during follow-up (95% CI 2.4–30.4). Less robust trends were observed with the Impact-R. Conclusions: Impaired responsiveness to ASA in acute brain ischaemia is common and is associated with worse neurological deficits at stroke onset, early clinical deterioration and poorer functional outcome. The clinical significance of these findings requires further evaluation in larger longitudinal studies.

Clinical Outcomes Using a Platelet Function-Guided Approach for Secondary Prevention in Patients With Ischemic Stroke or Transient Ischemic Attack

“…5,6 Nonresponse to aspirin in patients with ischemic stroke is associated with an increased risk of death, adverse cardiac events, and worse functional status. [7][8][9] Adverse cardiac events associated with clopidogrel nonresponse are well described, yet this association has not been well studied in patients with ischemic stroke or TIA. 10 Despite antiplatelet nonresponse signifying a risk factor for adverse events, improvement in clinical outcomes by intensifying antiplatelet therapy has not been demonstrated in patients with ischemic stroke or TIA.…”

Aspirin Resistance in Acute Ischemic Non-cardioembolic Stroke: Frequency and Clinical Study

“…Shwammenthal et al [19] had another opinion as they stated in their study that AR patients were scored lower on NIHSS on admission, however large number of their patients in their cohort study were already on aspirin therapy prior to stroke onset by a long period of time.…”

Platelet function testing in transient ischaemic attack and ischaemic stroke: A comprehensive systematic review of the literature

“…Evidence pertaining to the relationship between antiplatelet-HTPR status and functional outcome, stroke severity and mortality on antiplatelet therapy following TIA or stroke is emerging, but available data from small-medium sized studies need to be validated in larger studies [51,64,66,92,93]. Furthermore, with the exception of three studies [45,51,64], duration of clinical follow-up has been relatively short.…”

“…Schwammenthal et al performed an observational study on 105 patients within 36 hours of acute stroke; 40% were on aspirin for 41 week prior to presentation, and all were treated with 100-325 mg of aspirin daily for at least 6 hours before blood sampling [45]. 'Aspirin HTPR', assessed with 1.6 mmol/L AA-induced optical platelet aggregometry in PRP, was observed in 31% within 36 hours and in 45% of the 87 patients retested at days 4-5 after stroke onset.…”