Does anyone utilize P2Y12 assays to determine if clopidogrel may be ineffective when used for DAPT?   

Yes, if the patient has undergone genetic testing indicating nonresponsiveness to clopidogrel, I would consider substituting ticagrelor. In most cases, DAPT is short-term, typically lasting for one month, after which aspirin monotherapy would be sufficient.

I do check the P2Y12 assay in patients experiencing stroke on clopidogrel, especially before asking neurosurgery to see for "failed best medical therapy " in ICAD.

Yes, I use P2Y12 assays in two distinct settings. Medical management: If a patient on clopidogrel mono/dual therapy has disease progression with ICAD or experiences a recurrent ischemic event, I obtain a P2Y12 assay to assess responsiveness. This helps guide the decision to switch to ticagrelor and...

Yes, especially if there are any questions about the efficacy.

Yes. I do, especially with another ischemic event in those on Plavix monotherapy (for small or large vessel disease) or DAPT (even for a short period with an event recurring due to atherosclerotic disease or small vessel disease) during that time of DAPT therapy. Also, if genetic testing is done, I ...

Agree with the answers above. I think getting the P2Y12 assay is useful if there is a question of "responsiveness" and efficacy. One thing to keep in mind, if the patient was on clopidogrel (and patient states they were compliant; can also check pharmacy records if they were refilling their medicat...