High platelet reactivity after P2Y12-inhibition in patients with atrial fibrillation and coronary stenting.

High platelet reactivity (HPR) after P2Y12-inhibition in patients undergoing coronary stenting is associated with an increased risk for thromboembolic events and coronary death. So far it is not known how HPR affects the clinical outcome of different treatment strategies in patients with atrial fibrillation (AF) undergoing coronary stenting. In this single centre, observational study the antiplatelet effect of P2Y12-inhibitors in AF patients undergoing coronary stenting was investigated using impedance aggregometry. Patients received either dual antiplatelet therapy (DAPT) or triple therapy (TT). HPR was defined as the ratio of ADP-to TRAP-induced aggregation (r-ADP-agg) ≥50 %. Thromboembolic and bleeding events were assessed within the first 30 days after stenting. Out of 910 screened patients 167 patients were available for the present analysis. HPR was found in 5 of 43 (12 %) patients treated with DAPT and in 18 of 124 (15 %) patients treated with TT. In patients receiving TT, HPR was not a risk factor for thromboembolic events compared to patients with adequate response to P2Y12-inhibitors (6 vs. 8 %, p = 0.712). There was a trend for less bleeding events in patients with HPR compared to r-ADP-agg <50 % in the TT group (0 vs. 16 %, p = 0.077). Our data suggest that HPR after P2Y12-antagonism in patients receiving TT due to AF and coronary stenting might protect from bleeding without increasing thromboembolic risk. Future studies will need to investigate if patients with AF receiving coronary stenting benefit from a reduction of antithrombotic therapy.