No abstract

Background:Prasugrel has been shown to provide more potency and less variability than clopidogrel, but its potential temporal variability has not been described. Methods and Results:We conducted a prospective open-label study, evaluating platelet reactivity overtime in acute coronary syndrome (ACS) patients on aspirin and clopidogrel (n=60) or prasugrel (n=61), after a percutaneous coronary intervention (PCI). Blood samples were taken at discharge and at 3 and 6 months. Platelet function tests included VerifyNow (VN-P2Y12), and Multiplate Aggregometry (MEA). By means of VN-P2Y12, prasugrel patients displayed significantly (P<0.001) higher platelet inhibition than clopidogrel patients over time, although there were not significant differences using MEA. Prasugrel patients showed higher platelet inhibition at baseline than at 3 months (59.3±8.1 vs. 105.0±49.2; P<0.001), without significant change at 6 months (107.9±72.0; P=0.919 vs. 3 months). Clopidogrel patients showed a similar trend (160.1±65.1, 184.8±62.7 and 185.0±53.3; baseline vs. 3 months P=0.060; 3 months vs. 6 months P=0.974). High platelet reactivity (HPR) was shown in 16.3% prasugrel patients, with no patient consistently remaining in HPR over time. HPR was detected in 36.6% of the clopidogrel patients, being consistently observed in 15.0% of them. Low platelet reactivity (LPR) was detected in 60.5% prasugrel and 9.8% clopidogrel patients. Conclusions:Prasugrel patients showed less temporal variation than patients on clopidogrel in terms of HPR. In contrast, higher variability in LPR was detected in prasugrel patients for up to 6 months' follow-up.

Everolimus-eluting bioabsorbable scaffolds (BVSs) have exhibited similar long-term clinical outcomes compared to its everolimus-eluting metallic counterparts. However, reports from earlier studies have shown a signal for an increased rate of stent thrombosis. The aim of the current investigation is to describe the platelet reactivity profiles over time in patients treated with everolimus-eluting BVS in comparison to everolimus-eluting metallic stents. This is a pilot study in which patients on aspirin and clopidogrel with at least 1 everolimus-eluting BVS were included (n = 24). Patients with at least 1 everolimus-eluting metallic stent implanted were included as control group (n = 25). Blood samples were taken at time of discharge and at 3- and 6-month follow-up. Platelet function tests included VerifyNow (VN-P2Y12), multiplate aggregometry (MEA), and light transmission aggregometry (LTA). There was no difference in platelet reactivity at discharge, 3- and 6-month visits (unadjusted p = 0.733 and p = 0.582; p = 0.432 and p = 0.899 after adjusting for discharge value platelet reactivity0, respectively) using VN-P2Y12. Similar findings were observed with LTA. However, patients with BVS showed significantly higher platelet reactivity than patients with metallic stents at 3 and 6 months in the crude analysis (p = 0.003) and after adjusting for discharge value (p = 0.013) measured with ADP-MEA. There were no differences in platelet reactivity mediated by the T × A pathway between both groups. Finally, there is no statistical difference in high on-clopidogrel platelet reactivity (HPR) rate between both groups. The results of this pilot study suggest that BVS might have different platelet reactivity profiles, and warrants further investigation in dedicated clinical studies.