The utility of platelet inhibition testing in patients undergoing Pipeline embolization of intracranial aneurysms

The utility of using the VerifyNow P2Y12 platelet inhibition assay in patients undergoing Pipeline embolization of intracranial aneurysms remains controversial. As we have routinely employed the assay for patients undergoing flow diversion, we elected to explore the relationship between P2Y12 hyporesponse as indicated by a P2Y12 Reaction Units (PRU) value >200 and treatment outcomes, including intraprocedural platelet aggregation and ischemic complications.

All successful intracranial aneurysm Pipeline treatments performed at our institution from November 2011 to May 2019 were included. The rate of P2Y12 hyporesponse and treatment outcomes were evaluated. Multivariable logistic regression was utilized to determine independent predictors of treatment outcomes.

333 qualifying treatments were performed in 297 patients. Clopidogrel hyporesponse was initially noted in 24%, falling to 17% by day-of-procedure by dose titration. A glycoprotein (GP) IIb/IIIa inhibitor was administered prophylactically in 3% of cases for persistent, profound hyporesponse. 27 (8.1%) patients developed acute platelet aggregation; only 6 demonstrated day-of-procedure P2Y12 hyporesponse. Day-of-procedure hyporesponse was not associated with intraprocedural platelet aggregation or ischemic complications. Greater Pipeline embolization device (PED) diameter was associated with a reduced odds of platelet aggregation (OR 0.38, 95% CI 0.17 to 0.85; p=0.019). Antiplatelet non-compliance (OR 25.20, 95% CI 3.86 to 164.61; p=0.001) and treatment of posterior circulation aneurysms (OR 5.23, 95% CI 1.22 to 22.33; p=0.026) were the only independent predictors of ischemic complications.

P2Y12 hyporesponse was not associated with acute platelet aggregation or ischemic complications in our patients undergoing Pipeline embolization of intracranial aneurysms, possibly due to aggressive management of the hyporesponse using clopidogrel dose titration and/or GP IIb/IIIa inhibitor administration.