• Aneurysm
• Platelets

Antiplatelet therapy is a controversial and hotly debated topic in the neurointerventional literature. We have a long-standing interest in this topic,1 ,2 and have previously participated in a JNIS Point–Counterpoint regarding platelet function testing (PFT) in neurointervention (NI).3 ,4 In our previous JNIS discussion there was consensus that the thromboembolic event rate for NI procedures could be improved by more effective antiplatelet therapy, and that there was a lack of evidence to support the routine use of PFTs to tailor antiplatelet therapy.

In May 2015, Hwang and colleagues published a randomized controlled trial (RCT) on standard versus modified antiplatelet preparation for preventing thromboembolic events in patients with high on-treatment platelet reactivity (HTPR) undergoing coil embolization for an unruptured intracranial aneurysm in JAMA Neurology.5 This open-label RCT was designed to assess the effect of a modified antiplatelet regime compared with a standard preparation in NI patients with HTPR identified using PFTs. It enrolled 228 consecutive patients scheduled to undergo elective aneurysm coiling. Platelet function was assessed with the VerifyNow assay (Accumetrics) using aspirin and P2Y12 cartridges on the day prior to aneurysm coiling. Patients with HTPR were identified using cut-off values of ≥550 aspirin reaction units or >213 VerifyNow P2Y12 reaction units. Subsequently, patients with HTPR were randomized to either standard treatment (100 mg aspirin and 75 mg clopidogrel) or modified treatment (if HTPR to aspirin, then 300 mg aspirin and 75 mg clopidogrel; if HTPR to clopidogrel, then 100 mg aspirin, 75 mg clopidogrel and 200 mg cilostazol). No PFTs were performed after these modifications occurred. At 7 days the primary outcome of early peri-procedural thromboembolic complications were lower in the modified treatment group (n=1/63, 1.6%) compared with the standard treatment group (n=7/63, 11.1%) (crude risk difference (RD) …