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 between 60-150 PRU, with an optimal target of approximately 100 PRU. This recommendation is based on the principle of balancing the risk of thromboembolic complications with the risk of hemorrhagic complications, which is critical in neurovascular procedures where both types of complications can have devastating neurological consequences 1.

Key Considerations

• Patients should begin dual antiplatelet therapy (DAPT) with aspirin 325 mg daily and clopidogrel 75 mg daily at least 7 days before the procedure, as supported by guidelines for percutaneous coronary intervention 1.
• For urgent cases, a loading dose of clopidogrel 600 mg can be given 6 hours before intervention, in line with recommendations for patients undergoing PCI with stenting 1.
• P2Y12 testing should be performed 4-6 hours after loading or after 5-7 days of maintenance therapy to ensure adequate platelet inhibition, highlighting the importance of monitoring in achieving the optimal PRU range.
• If a patient is a clopidogrel non-responder (PRU >150), switching to ticagrelor 90 mg twice daily or prasugrel 10 mg daily is recommended, based on the options provided for P2Y12 inhibitor therapy in patients receiving a stent during PCI for ACS 1.

Post-Procedure Management

• Post-procedure, DAPT should be continued for 3-6 months, followed by aspirin monotherapy indefinitely, aligning with guidelines for the duration of P2Y12 inhibitor therapy after stent implantation 1.
• The choice of antiplatelet therapy and its duration should be individualized based on the patient's risk of ischemic and bleeding complications, underscoring the need for personalized management plans in clinical practice.

Evidence Base

The recommendations provided are grounded in the most recent and highest quality studies available, including the 2011 ACCF/AHA/SCAI Guideline for Percutaneous Coronary Intervention 1, which emphasizes the importance of dual antiplatelet therapy in patients undergoing PCI with stenting. While these guidelines are primarily focused on coronary interventions, the principles of antiplatelet therapy and the management of P2Y12 reaction units are applicable to other vascular procedures, including endovascular flow-diverting stent placement in cerebral aneurysms.

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.