Point of care platelet function testing in routine neurointerventional care is unjustified
- Correspondence to Dr R V Chandra, Interventional Neuroradiology Unit, Department of Diagnostic Imaging, Monash Medical Centre, Melbourne 3168, Australia;
- Received 3 May 2013
- Accepted 3 May 2013
The crux of platelet function testing for neurointerventional (NI) procedures is to reduce the thromboembolic complication rate by individualizing platelet inhibition. There are few data to support this practice in routine NI care. Results of large (>2000 patients) randomized controlled multicenter trials in the cardiology literature do not show overall clinical outcome benefit to modification of antiplatelet therapy in patients who have a poor response to antiplatelet therapy compared with standard antiplatelet therapy without monitoring. Overall, the use of point of care platelet function testing in routine NI care seems unjustified.
The cardiology experience
Meta-analyses have shown an increased rate of poor outcome (stent thrombosis, myocardial infarction, and death) in patients with high persistent platelet reactivity (non-response) treated for symptomatic coronary atherothrombosis.1 However, modification of antiplatelet therapy according to point of care platelet function testing did not reduce the rate of poor outcome (stent thrombosis, myocardial infarction, and death) in the recent ARCTIC (Assessment by a Double Randomization of a Conventional Antiplatelet Strategy versus a Monitoring-guided Strategy for Drug-Eluting Stent Implantation and of Treatment Interruption versus Continuation One Year after Stenting Trial)2 and GRAVITAS (Gauging Responsiveness with a VerifyNow assay—Impact on Thrombosis And Safety)3 trials.
The ARCTIC study prospectively randomized 2440 patients across 38 centers to a monitoring strategy of platelet function assessment with VerifyNow P2Y12 assays and drug adjustment in patients with persistent platelet reactivity, or to a conventional strategy without monitoring and no drug adjustment.2 In the monitoring cohort, persistent platelet reactivity to clopidogrel (≥230 P2Y12 reaction units (PRU) or <15% reduction from baseline) or aspirin (≥550 aspirin reaction units) occurred in 35% and 8%, respectively. This led to administration of an additional load of ≥600 mg bolus of clopidogrel or 60 mg of prasugrel at least 6 h prior to percutaneous coronary intervention (PCI), use of …