Platelet function testing in atrial fibrillation patients undergoing percutaneous coronary intervention

Platelet function testing (PFT) could be a useful clinical tool to guide individualized antithrombotic treatment in patients with atrial fibrillation (AF) undergoing percutaneous coronary intervention (PCI). We aimed to investigate platelet reactivity (PR) in the context of a contemporary registry. "Real-world" data were retrieved from a nationwide, multicenter, observational study of AF patients on oral anticoagulants (OAC) undergoing PCI. Patients treated with a P2Y(12) inhibitor, namely clopidogrel or ticagrelor, as part of double or triple antithrombotic therapy, were submitted to PFT before discharge and were followed up for 12 months. Out of 101 patients included in the study, 66 were submitted to PFT while on clopidogrel and 35 while on ticagrelor; PR was 162.9 +/- 68 PRU and 46.02 +/- 46 PRU, respectively (P < 0.001). High on-treatment PR (HTPR) was observed in 15 patients under clopidogrel (22.7%); 7 of them escalated to ticagrelor. Low on-treatment PR (LTPR) was found in 9 clopidogrel and 28 ticagrelor-treated patients (13.6% vs. 80%, P < 0.001), of whom only 1 de-escalated to clopidogrel. PR did not differ by OAC regimen. PFT results had no impact on aspirin prescription at discharge, while failed to predict significant bleeding events at follow up. Ticagrelor administration led to lower PR and lower incidence of HTPR in comparison with clopidogrel. Physicians' behavior in response to knowledge of a patient's PR was variable. Further studies are required to elucidate the role of PFT as a tool to guide individualized antithrombotic treatment in this clinical scenario.