(978) Cangrelor Dose Adjustments and Impact on P2Y12 VerifyNow and Thromboelastography Maximum Amplitude

Introduction: Acute myocardial infarction is a leading cause of cardiogenic shock and may necessitate the use of temporary mechanical circulatory support (tMCS) as a bridge to recovery. Dual antiplatelet therapy is needed to ensure stent patency, however, patients on tMCS are at increased risk of bleeding. Cangrelor, an intravenous P2Y12 inhibitor with a short half-life, may be an appealing option to reduce the dose or temporarily hold if needed for acute bleeding. There are limited data describing cangrelor dose adjustments and impact on monitoring with VerifyNow P2Y12 Platelet Reactivity Units (PRU) and thromboelastography maximum amplitude (TEG MA), thus the goal of this study was to describe the impact of cangrelor dosing on those parameters.

Methods: This retrospective cohort study included patients on tMCS receiving cangrelor with either concomitant PRU or TEG MA monitoring from Jan 2016-June 2021. The primary outcome was percent change in PRU and TEG MA based on cangrelor dose adjustment. Secondary outcomes included intrapatient variability in PRU and TEG MA monitoring on the same dose and concordance between TEG MA and PRU.

Results: A total of 29 patients were included, with 107 VerifyNow and 144 TEG MA results. There were a total of 5 dose reductions with PRU and 3 with TEG MA; a 30% dose reduction led to a median 35% increase in PRU (IQR 25-225%) and a 33% dose reduction led to a 2% change in TEG MA. Conversely, there were 15 dose increases with PRU and 10 with TEG MA; a 33% dose increase yielded a median 15% reduction in PRU (IQR 3-20%) and a 22.5% dose increase led to a 3% change to TEG MA results. Overall, there was a 22% (IQR 10-39%) PRU and 9% (IQR 6-14%) TEG MA intrapatient variability while on the same dose. TEG MA and PRU were concordant 57% of the time, with all but one discordant value being subtherapeutic on TEG with a therapeutic PRU.

Conclusions: This study demonstrates a large variation in PRU response to cangrelor doses and adjustments, with minimal impact on TEG MA. Overall, labs were concordant 57% of the time and both values were therapeutic during bleeding events. Future research needs to determine the validity and application of PRU and TEG MA monitoring for cangrelor during tMCS.