De-escalation of Prasugrel Results in Higher Percentage of Patients within Optimal Range of Platelet Reactivity: Analysis from the HOST-REDUCE-POLYTECH-ACS Trial

Tailoring oral antiplatelet therapy in acute coronary syndromes: from guidelines to clinical practice

The assessment of bleeding and ischemic risk is a crucial step in establishing appropriate composition and duration of dual antiplatelet therapy (DAPT) in patients with acute coronary syndrome (ACS) treated with percutaneous coronary angioplasty. Evidence from recent randomized clinical trials led to some paradigm shifts in current guidelines recommendations. Options alternative to the standard 12-month DAPT duration include shorter periods of DAPT followed by single antiplatelet treatment with either aspirin or P2Y12 monotherapy, guided or unguided de-escalation DAPT, prolonged DAPT beyond the 12-month treatment period. Although DAPT composition and duration should be selected for each ACS patient on an individual basis weighing clinical and procedural variables, data from latest trials and meta-analyses may permit suggesting the most appropriate DAPT strategy according to the ischemic and bleeding risk assessed using validated tools and scores.

Differences in Optimal Platelet Reactivity after Potent P2Y12 Inhibitor Treatment in Acute Coronary Syndrome Patients Undergoing Percutaneous Coronary Intervention

Background: East Asian patients receiving treatment with the potent P2Y12 inhibitors prasugrel or ticagrelor experience more potent platelet inhibition than with clopidogrel. Methods: This study investigated differences in OPR rates with reduced doses of prasugrel (n = 38) or ticagrelor (n = 40) for maintenance therapy in 118 Korean ACS patients who had undergone PCI, in comparison to conventional-dose clopidogrel (n = 40). We assessed drug responses at one- and three-months post-PCI with VerifyNow and multiple electrode aggregometry assays. Results: At the one-month period, patients receiving standard-dose prasugrel or ticagrelor had lower platelet reactivity as determined by the three assays than those receiving the conventional dose of clopidogrel (VN: p = 0.000; MEA: p = 0.000; LTA: p = 0.000). At the 3-month point, platelet reactivity was lower in those receiving reduced-dose prasugrel or ticagrelor than the clopidogrel-treated patients (VN: p = 0.000; MEA: p = 0.012; LTA: p = 0.002). Prasugrel resulted in significantly lower platelet inhibition than ticagrelor as determined by VN and LTA (VN: p = 0.000; LTA: p = 0.003). At three months, there was a significant overall difference in OPR among the three groups when measured by VN (p < 0.001), but not when measured by MEA (p = 0.596). OPR in the reduced-dose prasugrel group was not significantly different to the clopidogrel group at three months (VN: p = 0.180; MEA: p = 0.711). OPR in the reduced-dose ticagrelor group was similar to clopidogrel as determined by MEA at three months, but was different when assessed by VN (VN: p = 0.000; MEA: p = 0.540). Compared to standard-dose, the reduced-dose prasugrel OPR rate was significantly increased (VN: p = 0.008; MEA: p = 0.020). Conclusions: OPR values for reduced-dose prasugrel and conventional-dose clopidogrel at three months were similar but higher than for reduced-dose ticagrelor as determined by VN, but no differences were noted by MEA. The MEA assay might have less sensitivity and consistency than the VN assay. Further studies are needed to explore this discrepancy.