What is the ideal P2Y12 (purinergic receptor P2Y12) level for endovascular flow-diverting stent placement in cerebral aneurysms?

From the Guidelines

The ideal P2Y12 reaction unit (PRU) level for endovascular flow-diverting stent placement in cerebral aneurysms is generally between 60-150 PRU, with many centers targeting a range of 70-130 PRU. Patients typically require dual antiplatelet therapy (DAPT) with aspirin 325mg daily and a P2Y12 inhibitor such as clopidogrel 75mg daily, started 5-7 days before the procedure 1. P2Y12 testing should be performed before the intervention to ensure adequate platelet inhibition. If a patient shows clopidogrel resistance (PRU >150), alternative P2Y12 inhibitors like ticagrelor (90mg twice daily) or prasugrel (10mg daily) may be used 1. Maintaining appropriate P2Y12 levels is crucial because insufficient platelet inhibition increases thromboembolic complication risk, while excessive inhibition raises hemorrhagic risk. After stent placement, DAPT is typically continued for 3-6 months, followed by aspirin monotherapy indefinitely 1. Regular monitoring of P2Y12 levels during the initial treatment period helps ensure optimal platelet inhibition is maintained for successful aneurysm treatment while minimizing complications. Some key considerations for the management of patients with cerebral aneurysms include:

• The use of aspirin and a P2Y12 inhibitor as part of DAPT 1
• The importance of P2Y12 testing to ensure adequate platelet inhibition 1
• The potential need for alternative P2Y12 inhibitors in patients with clopidogrel resistance 1
• The duration of DAPT and the transition to aspirin monotherapy 1

From the Research

Ideal P2Y12 Level for Endovascular Flow-Diverting Stent Placement

The ideal P2Y12 level for endovascular flow-diverting stent placement in cerebral aneurysms is a topic of ongoing research. Several studies have investigated the role of P2Y12 reactive units (PRUs) in patients undergoing stent-assisted coiling or flow diversion with ticagrelor therapy.

• A study published in 2020 2 suggested that the safe PRU range for patients receiving ticagrelor should be shifted to 0-100, which is lower than that of clopidogrel.
• Another study published in 2025 3 found that the majority of periprocedural ticagrelor PRUs were <100, and PRUs at the time point of thromboembolic complications were >120.
• A study from 2018 4 investigated the use of low-dose prasugrel in patients with resistance to clopidogrel and found that the mean PRU value decreased from 238.5 to 124.9 after prasugrel administration.
• A comparison of PRU results with thromboelastography (TEG) with platelet mapping (PM) found poor agreement between the two assays, with PRU likely overestimating clopidogrel resistance 5.
• A study published in 2019 6 found that the precision of VerifyNow P2Y12 assessment of clopidogrel response was often imprecise, with 24% of patients fluctuating between therapeutic categories when multiple P2Y12 assessments were drawn within a 24-h period.

Key Findings

• The ideal PRU range for patients receiving ticagrelor may be lower than that of clopidogrel, potentially 0-100 2, 3.
• PRU values >100 may be associated with an increased risk of thromboembolic complications 2, 3.
• The use of low-dose prasugrel may be effective in reducing PRU values in patients with resistance to clopidogrel 4.
• The agreement between PRU results and TEG-PM is poor, and PRU may overestimate clopidogrel resistance 5.
• The precision of VerifyNow P2Y12 assessment of clopidogrel response can be imprecise, and multiple assessments may be necessary to determine the optimal PRU range 6.