Assessment of platelet function after discontinuation of ticagrelor.

Abstract

Patients presenting with acute coronary syndromes (ACS) are often treated by percutaneous coronary intervention (PCI) with insertion of coronary artery stents and a majority receive dual antiplatelet therapy (DAPT), usually a combination of a COX-1 inhibitor (aspirin) and a P2Y12 inhibitor (eg ticagrelor). Not seldom the question arises as to when DAPT should be discontinued prior to interventional surgery. This study was done with the primary aim of investigating thrombocyte function immediately prior to and after discontinuation of ticagrelor. In this prospective, longitudinal, observational study including 24 patients, venous blood was obtained from patients on day 0, before stopping maintenance dose of 90mg ticagrelor twice daily, and then on days 1, 3, 5, and 8, after discontinuation. Samples were analyzed using Multiplate® and VerifyNow® . Prior to urgent surgery platelet aggregation >30 aggregation units (Multiplate® ) and >208 P2Y12 reaction units (VerifyNow® ) have been shown to correlate with reduced risk of peri- and postoperative bleeding risk. On day 3 after ticagrelor discontinuation, 100% (P=.016) and 67% (P=<.001) of patients had reached these levels on Multiplate® and VerifyNow® , respectively. On day 5, the corresponding figures were 100% (P=.016) and 78% (P=<.001). Discontinuation of ticagrelor for 3days resulted in return of adequate platelet function in all patients on Multiplate® and in a majority of patients on VerifyNow® , indicating a lower bleeding risk. A bedside test for platelet function may be considered if time to anticipated surgery is less than 5days after ticagrelor discontinuation.