COMPARISON OF IMPEDANCE WHOLE BLOOD AGGREGATION AND OPTICAL PLATELET-RICH PLASMA AGGREGATION TO MEASURE THE ANTIPLATELET EFFECT OF ASPIRIN IN HEALTHY CONTROLS AND IN PATIENTS WITH PERIPHERAL ARTERY DISEASE (PAD)

Abstract number: P-T-361

Tran¹ H.A., Anand² S.S., Ginsberg² J.S., Weitz² J.I., Johnston³ M., Eikelboom² J.W.

¹¹Clinical Haematology, Australian Centre for Blood Diseases, Melbourne, Australia ²²Medicine, McMaster University ³³Hemostasis Reference Laboratory, Henderson Research Centre, Hamilton, Canada

How-to-cite Tran HA, Anand SS, Ginsberg JS, Weitz JI, Johnston M, Eikelboom JW. COMPARISON OF IMPEDANCE WHOLE BLOOD AGGREGATION AND OPTICAL PLATELET-RICH PLASMA AGGREGATION TO MEASURE THE ANTIPLATELET EFFECT OF ASPIRIN IN HEALTHY CONTROLS AND IN PATIENTS WITH PERIPHERAL ARTERY DISEASE (PAD). J Thromb Haemost 2007; 5 Supplement 2: P-T-361

Abstract

Introduction: Clinical aspirin resistance (failure to prevent a thrombotic clinical event) probably occurs in some patients from sub-optimal inhibition of platelet function. Although contemporary studies suggest a relation between "laboratory" and clinical aspirin resistance, experts disagree about the best test to measure aspirin's anti-platelet effect. To assess the anti-platelet effect of aspirin, impedance-based whole blood aggregation (IPWBA) and optical-based platelet rich plasma aggregation (OBPRPA) were performed in healthy controls and patients with PAD.

Methods: 44 healthy controls (77% women, median age 44 years) received aspirin 81 mg/d for 3 weeks and 40 patients with PAD (18% women, median age 67 years) were taking ongoing aspirin 81 mg/day. Citrated blood was collected prior to initiation of, and after completion of 3 weeks of aspirin in controls, and during ongoing aspirin in patients. The agonist used in all aggregation studies was 0.5mM arachidonic acid (AA).

Results: Controls showed inhibition of OBPRPA (84.014.4% [baseline] to 4.112.3% [3 weeks]) and IPWBA (12.73.3W [baseline] to 0.62.8W [3 weeks]). There was no significant correlation or weak correlation between OBPRPA and IPWBA (r=0.10, p=0.53), and at 3 weeks results were consistent with the "post-therapy" controls. IPWBA showed complete inhibition of platelet aggregation in 91% of post-treatment controls and 85% of cases at 3 weeks. There was no significant correlation between IPWBA and OBPRPA at 3 weeks (r=-0.04, p=0.79).

Conclusions: OBPRPA and IPWBA are both highly responsive to the ant-platelet effects of low-dose (81 mg/day) aspirin. Further studies should be undertaken to determine whether clinically useful cut-points for these assays can be identified that identify aspirin resistance.

To cite this abstract use the following format:

Journal of Thrombosis and Haemostasis 2007; Volume 5, Supplement 2: abstract number

Session Details

Date:	01/08/2007
Time:	00:00-00:00
Session name:	XXIst ISTH Congress
Subject:
Location:	Oxford, UK
Presentation type:
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