How are you using CYP2C19 genotyping for determining dual antiplatelet therapy for stroke?

In my practice, P2Y12 assays are the primary tool I rely on for guiding dual antiplatelet decisions. They are more widely available across clinical settings, whereas CYP2C19 genotyping requires infrastructure that is not always accessible outside of large academic and tertiary centers. CYP2C19 identifies inherited metabolizer status, while P2Y12 reflects what is happening in real time, and the latter is what drives my decision-making. With P2Y12, in the neurointerventional setting, I use it when placing devices, where confirming adequate platelet inhibition beforehand informs peri-procedural risk assessment for thromboembolic complications. In the medical management setting, I will still obtain it in higher-risk patients such as those with ...

We are currently using it only as part of a study ongoing in our center. We use CYP2C19 on all participants who will need DAPT. In intermediate metabolizers (since there is equipoise), we get P2Y. Given that the genotyping results take a few days to come back, to guide our time-sensitive decisions in the study participants - for example, loading a patient with Plavix who will be getting a stent the next day, we do use P2Y and other immediate care scenarios (including for non study participants) Patients who do not consent to participate in the study and have had recurrent ischemic stroke or TIA (due to atherosclerotic etiology), then we get a P2Y. Similarly, in a patient who is having too much bruising or mucosal bleeding after starting Pla...

I do not do CYO2C19 testing because it takes a long time to get the results back. I just used DAPT with aspirin and clopidogrel for 3 weeks.