Monitoring the Antiplatelet Therapy Efficacy in Patients with Acute Ischemic Stroke

Stroke is one of the leading causes of morbidity and mortality in populations of developed countries. Ischemic strokes account for 85 - 90% of all strokes, with the majority of strokes of non-cardioembolic pathogenesis. Platelet aggregation plays a key role in arterial thrombus formation. Therefore, effective antiplatelet therapy plays a key role in secondary prevention. Acetylsalicylic acid (ASA) is the main drug of choice, and clopidogrel therapy is another recommended treatment option. Monitoring of the efficacy of antiplatelet therapy has been intensively studied in patients with coronary artery disease in the context of coronary stent implantation. It is not yet part of the routine procedure in patients with stroke [1-3].

This study investigated the efficacy of antiplatelet therapy with ASA and clopidogrel using optical and impedance aggregometry in 42 consecutive patients with acute ischemic stroke. Patients were treated with throm-bolysis at baseline and platelet function was examined 24 hours after administration, focusing on the occurrence of platelet hyperaggregability and assessing the efficacy of any chronically administered antiplatelet therapy. Subsequently, patients were administered a loading dose of ASA or clopidogrel followed by a check of its efficacy 24 hours after administration. In the following days, the maintenance dose of the drug was continued and regular laboratory monitoring of treatment efficacy was performed every 24 hours.

In patients with atherothrombotic stroke indicated for antiplatelet therapy, monitoring of residual platelet activity allowed for detection of potentially atrisk patients. These were 35% (9% borderline ineffective) of patients taking ASA and 55% (18% borderline ineffective) of patients treated with clopidogrel. The dose was adjusted, increased the administered treatment and no recurrence of stroke was observed in this study group at 1-year follow-up.

Personalized antiplatelet therapy based on platelet function tests appears to be a useful method to reduce the risk of recurrent vascular events.