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AJNR - American Journal of Neuroradiology

Published ahead of print on January 25, 2008
doi: 10.3174/ajnr.A0917

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American Journal of Neuroradiology 29:786-791, April 2008
© 2008 American Society of Neuroradiology

INTERVENTIONAL

Monitoring of Clopidogrel-Related Platelet Inhibition: Correlation of Nonresponse with Clinical Outcome in Supra-Aortic Stenting

S. Müller-Schunk^a, J. Linn^a, N. Peters^b, M. Spannagl^c, M. Deisenberg^d, H. Brückmann^a and T.E. Mayer^a

^a Department of Neuroradiology, Ludwig Maximilians University, Munich, Germany
^b Department of Neurology, Ludwig Maximilians University, Munich, Germany
^c Department of Hemostaseology, Ludwig Maximilians University, Munich, Germany
^d Department of Anesthesiology, Ludwig Maximilians University, Munich, Germany

Please address correspondence to Stefanie Müller-Schunk, Department of Neuroradiology, Klinikum Grosshadern, Ludwig Maximilians University Munich, Marchioninistr 15, 81377 Muenchen, Germany; e-mail: smueller{at}med.uni-muenchen.de

BACKGROUND AND PURPOSE: Clopidogrel and aspirin are antiplatelet medications used in patients intended for endovascular stent placement. Although various studies have investigated individual responsiveness to clopidogrel in patients undergoing coronary interventions, there are no studies regarding patients undergoing stent placement of supra-aortic arteries supplying the brain. We analyzed platelet function in a near-patient setting to determine the effects of antiplatelet treatment in neurologic patients and correlated the results with clinical outcome after stent placement.

MATERIALS AND METHODS: The platelet function of 50 consecutive patients scheduled for neurointerventional stent placement procedures was assessed by using point-of-care testing. All of the patients had symptomatic arteriosclerotic lesions. Clopidogrel effects were tested by impedance aggregometry. Fifty healthy blood donors without clopidogrel medication served as the control group.

RESULTS: Reference values for responders and nonresponders were established from the results of the healthy control group. Fourteen (28%) of 50 neurologic patients were stratified as clopidogrel nonresponders. Adverse events were registered in 5 (10%) of 50 patients, 1 of them with a permanent neurologic deficit (1 of 50 [2%]). All 5 of the patients with adverse events were nonresponders. There was a statistically significant correlation between adverse events and clopidogrel nonresponse (Fisher exact test, P = .001).

CONCLUSION: A significant rate of clopidogrel nonresponders could be identified in the treated patients. Our data strongly suggest a correlation of insufficient clopidogrel-related platelet inhibition with an increased risk of thromboembolic events in supra-aortic stent placement.