Abstract 16511: Time-to-controlled De-escalation Of Dual Antiplatelet Therapy Does Not Impact The Change Of Laboratory Level Of Platelet Inhibition In Primary Angioplasty

BackgroundControlled de-escalation after AMI presents a real option for personalized dual antiplatelet therapy (DAPT). The randomized PRAGUE 18 study (prasugrel vs. ticagrelor in primary PCI, N 1230) suggested that a controlled switch to clopidogrel might be safe as early as the first few days after primary PCI.PurposeThe study aimed to evaluate the effect of the elapsed time from the index event (primary PCI) to de-escalation of the P2Y12 inhibitor on the level of platelet inhibition.MethodsData from the VASP sub-study were analyzed. Efficacy of P2Y12 inhibitors was measured using a VASP assay and expressed as a platelet reactivity index (PRI, %) at different time points, including the last day on the study drug and ≥7 days after the switch to clopidogrel. The difference of platelet inhibition after therapy de-escalation (Δ PRI=median PRI before-median PRI after de-escalation) was monitored in relation to the elapsed time since the index event (≤7 days, 8-29 days, 30-89 days, and ≥90 days). The results were completed by comparing the occurrence of ischemic events.ResultsThe sub-study population consisted of 192 patients, including 27 (66.3 yr, 22 men) that underwent a controlled switch to clopidogrel. De-escalation led to a significant increase in the PRI for every defined time interval from the primary PCI. PRIs (median,5-95 Percentile) on clopidogrel≤7 days after the index event was 47.0 (12.9;79.6)%, 8-29 days 47.6 (23.1;64.3)%, 30-89 days 44.0 (20.4;68.0)%, and after ≥ 90 days it was 40.0 (30.0;77.0)%. Δ PRIs were26.1% in patients (N=6) who switched within 7 days, 25.1% in patients (N=5) who switched 8-29 days, and 29.0% in patients (N=12) who switched 30-89 days after AMI (n.s.). The 1-year occurrence of the ischemic endpoint (CV death,non-fatal MI,and stroke) was 3.6% in patients with de-escalation within 1 week of the primary PCI vs. 7.5% in patients who continued on the study medication (p=0.02). Occurrences of other ischemic EPs wereCV death 4.7% vs. 1.8% (p=0.03), reMI 3.5% vs. 0.7% (p=0.02), stroke 0.2 vs. 1.4% (p=0.04).ConclusionsThe time-to-controlled de-escalation of DAPT does not impact the scope of the change nor the level of achieved inhibition of platelet reactivity. Very early controlled de-escalation of DAPT was concluded to be safe.