The rising number of cerebral aneurysms being treated with endovascular devices, particularly stents, has led to a sizeable increase in antiplatelet medications by neurointerventionalists in order to prevent device endotheliasation and parent artery thrombosis. A commonly used medication regimen is the combination of aspirin and clopidogrel. However, despite the routine use of dual anti-platelet therapy, these thromboembolic complications continue to occur. Additionally, haemorrhagic complications are also being reported with increasing frequency(1). A growing body of evidence suggests that variability in patient’s response to clopidogrel may...

Study Population Platelet response to clopidogrel was tested in 83 patients who presented to the Royal Brisbane & Women’s Hospital for elective stenting of their intracranial aneurysms between May 2011 and March 2016. Patients were premedicated with 75mg of clopidogrel daily for 7 days prior to their procedure. Platelet Inhibition Testing Testing was performed using the VerifyNow™ (Accumetrics, San Diego, CA, USA) point of care system (Figure 1) within 6 hours prior to the start of the patient’s procedure. From a previous multi-centre register study(9),...

Platelet Inhibition Of the participants (n=83), 26 were male and 57 were female, with an average age of 53 years (SD 1.1 years). 25% of participants were hypo-responders (n=21) while 28% (n=23) and 47% (n=39) were hyper- and normal responders respectively (See Figure 2). The mean PRU of all participants was 147 (SD 86.7). Post-Procedure (See Table 1) 18 patients did not require ongoing dual anti-platelet therapy due to procedure abortion (n=2), aneurysm treatment with surgical clipping (n=1), intra-procedural mortality (n=1), or aneurysms treated with...

The results from this study showed wide variations in clopidogrel response. Less than half of the study participants were within the target range for platelet inhibition following the standard regimen of anti-platelet therapy, possibly increasing their risk for adverse events peri- and post-procedurally. Figure 3 shows a possible complication of sub-optimal platelet inhibition, a thromboembolic event. These findings reinforce the necessity of preoperative P2Y12 inhibition monitoring in neurovascular intervention when clopidogrel is used as a premedication, particularly with research suggesting that peri-procedural PRU readings are...

Almandoz JED, Kadkhodayan Y, Crandall BM, Scholz JM, Fease JL, Tubman DE. Variability in initial response to standard clopidogrel therapy, delayed conversion to clopidogrel hyper-response, and associated thromboembolic and hemorrhagic complications in patients undergoing endovascular treatment of unruptured cerebral aneurysms. Journal of neurointerventional surgery. 2013:neurintsurg-2013-010976. Goh C, Churilov L, Mitchell P, Dowling R, Yan B. Clopidogrel hyper-response and bleeding risk in neurointerventional procedures. American Journal of Neuroradiology. 2013;34(4):721-6. Lee D, Arat A, Morsi H, Shaltoni H, Harris J, Mawad M. Dual antiplatelet therapy monitoring for...