A 70-Year-Old Female with Unexpected Platelet Function Testing Results

Lab Med. 2020 May 6;51(3):310-314. doi: 10.1093/labmed/lmz070.

Abstract

A 70-year-old female with a history of hypertension and left A2 segment aneurysm was scheduled for pipeline embolization device (PED) placement. Preinterventional antiplatelet prophylaxis included aspirin and ticagrelor. Unexpectedly, after 13 days of treatment, VerifyNow showed a P2Y12 reaction unit (PRU) value of 216, approximately >5 times the mean PRU of other patients on aspirin and ticagrelor. We confirmed platelet reactivity and ticagrelor resistance with light transmission aggregometry. Antiplatelet therapy was switched to prasugrel, and aspirin was continued. Eight days later, the P2Y12 reaction value (PRU) was 164. PED was placed without complications. Unlike clopidogrel, ticagrelor is a direct P2Y12 inhibitor that does not require metabolism to an active metabolite. Ticagrelor resistance is very rarely reported. To the best of our knowledge, there has been no case of ticagrelor resistance reported in the context of pre-PED placement prophylaxis.

Keywords: aneurysm; anti-platelet; coagulation; platelet; resistance; ticagrelor.

Publication types

  • Case Reports

MeSH terms

  • Aged
  • Blood Platelets / physiology*
  • Embolization, Therapeutic*
  • Equipment and Supplies
  • Female
  • Humans
  • Platelet Aggregation
  • Platelet Function Tests / methods*
  • Prasugrel Hydrochloride / therapeutic use*
  • Preoperative Exercise
  • Prospective Studies
  • Receptors, Purinergic P2Y12 / metabolism
  • Ticagrelor / therapeutic use*
  • Treatment Outcome

Substances

  • P2RY12 protein, human
  • Receptors, Purinergic P2Y12
  • Prasugrel Hydrochloride
  • Ticagrelor