Platelet reactivity in patients undergoing transcatheter aortic valve implantation.

Thromboembolic events, primarily stroke, might complicate transcatheter aortic-valve implantation (TAVI) procedures in 3-5 % of cases. Thus, it is common to administer aspirin and clopidogrel pharmacotherapy for 3-6 months following TAVI in order to prevent those events. The biologic response to the dual anti platelet treatment (DAPT) is heterogeneous, e.g. low response, known as high on treatment platelet reactivity (HTPR) may be associated with adverse thromboembolic events. Little is known about the prevalence of HTPR among patients undergoing TAVI. To assess the variability in response and rates of residual platelet reactivity in patients undergoing TAVI. We examined platelet reactivity in response to clopidogrel and aspirin in 40 consecutive patients (mean age 81.7 ± 6.5 years, 66.7 % women) who underwent successful TAVI using the VerifyNow P2Y12 assay and the multiple electrode aggregometry assay (Multiplate analyzer) in response to adenosine diphosphate and arachidonic acid respectively, at different time points before and following TAVI. Before TAVI, the majority of patients were on antiplatelet therapy (68.5 % aspirin, 12.5 % clopidogrel, 12.5 % DAPT). Following the procedure all patients were on DAPT or clopidogrel and warfarin. Among analyzed patients, 41 % had HTPR for clopidogrel and 12.5 % for aspirin at baseline, which did not significantly change 1-month following the procedure (p = 0.81 and p  = 0.33, respectively). In conclusion, patients undergoing TAVI for severe aortic stenosis and treated with DAPT have high rates of residual platelet reactivity during the peri-procedural period and up to 1-month thereafter. These findings may have clinical implications for the anti-platelet management of TAVI patients.