• Aneurysm
• arteriovenous malformation
• brain
• spine
• stroke
• artery
• angiography
• angioplasty
• atherosclerosis
• fistula
• stenosis
• stent
• subarachnoid
• thrombectomy

Two recent papers have evaluated the safety and efficacy of prasugrel in suspected clopidogrel non-responders in the neurointerventional population.1 ,2 In both papers the platelet response to clopidogrel was assessed preprocedurally and prasugrel was administered to patients meeting the criteria for inadequate platelet inhibition. The first found a statistical trend towards increased hemorrhagic complications with prasugrel while the second reported similar complication rates between prasugrel and clopidogrel. We commend the authors for these valuable contributions to the literature, highlighting the delicate balance between thrombosis and hemorrhage that must be maintained in the care of neurointerventional patients.

We wish to advance the following comments.

Since the FDA warning in March 2010 about the diminished effectiveness of clopidogrel in patients unable to fully convert the drug into its active form, there has been growing interest in the topic of clopidogrel response and routine point-of-care patient testing. There is good data to suggest that the variability in clopidogrel response has important clinical sequelae, with increased rates of cardiovascular morbidity and mortality in poor responders.3 ,4 However, no standard method exists to measure the platelet effects of clopidogrel, which leads to significant intra- and inter-individual variability in this continuous parameter.5 Such variability makes dichotomisation into clopidogrel responders and non-responders especially problematic.

Both studies use the VerifyNow technology (Accumetrics Inc, San Diego, California, USA) which uses an …