Effects of Clopidogrel Versus Ticagrelor on Peripheral Endothelial Function After Non-ST Elevation Acute Coronary Syndrome (NSTE-ACS): a Randomised Trial

Abstract

Background: Ticagrelor has been shown to improve peripheral endothelial function compared to clopidogrel in stable patients. We sought to investigate the effects of clopidogrel versus ticagrelor on peripheral endothelial function in NSTE-ACS patients. Methods: From Mar 2018-Jan 2019, patients hospitalised for NSTE-ACS were prospectively randomised 1:1 to clopidogrel (300mg loading then 75mg daily) or ticagrelor (180mg loading then 90mg twice-daily). Peripheral endothelial function was assessed in a subset of these patients with flow-mediated vasodilation (FMD) of the brachial artery, performed on admission prior to antiplatelet loading and again before discharge, using a pneumatic cuff and 10MHz linear ultrasound transducer. Results: 23 patients were included for analysis (9 clopidogrel, 14 ticagrelor). Median age 51(IQR 47–60.5) years, 21(91.3%) were male, 8(34.8%) had diabetes, 9(39.1%) were smokers. Median peak troponin T was 564 (245.5–876)ng/L and median GRACE score 94 (76.5–104.5). Admission median %FMD (change in post-stimulus diameter as a percentage of the baseline diameter) was similar between the 2 groups (clopidogrel 13.2% [10.1–17.6] vs ticagrelor 12.2% [10.2–15.8], p = 0.41). There was a trend towards higher median pre-discharge %FMD in the ticagrelor group (12.8% [12.2–18.0]) compared to the clopidogrel group (10.4% [9.5–11.2], p = 0.09). There was a trend towards lower pre-discharge %FMD compared to admission in the clopidogrel group (10.4% vs 13.2%, p = 0.05) but not the ticagrelor group (12.8% vs 12.2%, p = 0.43). Conclusions: Ticagrelor did not significantly improve peripheral endothelial function compared to clopidogrel in our NSTE-ACS cohort. However, there was a trend towards beneficial effects with ticagrelor. Further data including longer-term follow-up are awaited.