Impact of new P2Y12 blockers on platelet reactivity and clinical outcomes after acute coronary syndrome: Insight from a large single center registry

We retrospectively studied the impact of the introduction of new P2Y12 inhibitors (prasugrel, ticagrelor) on platelet reactivity and clinical outcomes after Acute Coronary Syndrome (ACS) from a large single center registry. Consecutive patients admitted for ACS since 2007 and discharged on dual antiplatelet therapy were enrolled. Biological response was assessed one month after discharge by PRI VASP and ADP-induced aggregation (%ADP). Patients were classified according to PRI VASP as very low on-treatment platelet reactivity (VLTPR) (PRI VASP ≤ 10%), low on-treatment platelet reactivity (LTPR) (PRI VASP ≤ 20%) and high on-treatment platelet reactivity HTPR (PRI VASP > 50%). Ischemic and bleeding complications were reported. 1999 patients were analyzed, 605 before (July 2007–February 2010) and 1394 after introduction of new P2Y12 blockers (February 2010–August 2013). After introduction, we reported a significant lower PRI VASP values (38% ± 0.53 vs. 42% ± 0.81 p = 0.001), %ADP aggregation (52% ± 0.4 vs. 54% ± 0.6 p = 0.03) and HTPR incidence (22% versus 34% OR [95% CI]:0.65 [0.53–0.80]; p < 0.001). Conversely, incidence of VLTPR and LTPR were significantly higher after the introduction of new P2Y12 inhibitors: 6% versus 3% (OR [95% CI]: 2.0 [1.2–3.3]; p < 0.01) and 19% versus 8% (OR [95% CI]: 2.8 [2.0–3.9]; p < 0.001) respectively. Clinical follow-up confirmed biological findings with higher incidence of bleeding 10% versus 5% (OR [95% CI]: 2.1 [1.4–3.2]; p < 0.01) and lower incidence of stent thrombosis 1.3% versus 3.3% (OR [95% CI]: 0.39 [0.20–0.73]; p < 0.01) with new P2Y12 blockers. The introduction of new P2Y12 inhibitors modified both platelet reactivity and clinical outcome of ACS patients, with higher rate of hyper responders and bleedings, and lower rate of non responders and thrombotic events.