Similar Impact of Clopidogrel or Ticagrelor on Carotid Atherosclerotic Plaque Inflammation

Background Platelets play an important role in inflammation. Inhibitors of the P2Y 12 receptor, which is involved in platelet activation, may have a direct effect on carotid atherosclerotic plaque inflammation. Hypothesis We compared the effects of clopidogrel and ticagrelor therapy for carotid atherosclerotic plaque inflammation using 18 F ‐fluorodeoxyglucose ( 18 FDG ) positron emission tomography ( PET ) imaging. Methods Fifty patients with acute coronary syndrome and ≥1 18 FDG uptake in the carotid artery (target‐to‐background ratio [ TBR ] ≥1.6) were randomized to either clopidogrel or ticagrelor groups. Of these, 46 completed PET examinations at baseline and at 6 months. The primary endpoint was the percent change in TBR of the index vessel at the most diseased segment ( MDS ). Results Baseline characteristics were similar between the 2 groups. At 6‐month follow‐up, low‐density lipoprotein cholesterol and C‐reactive protein significantly decreased in both groups ( P < 0.001). The TBR of the index vessel and aorta significantly decreased in both groups ( P < 0.01). The percent change in the MDS TBR of the index vessel was numerically but not significantly lower in the clopidogrel group than in the ticagrelor group (−9.5 ± 14.6% vs −13.5 ± 19.3%; P = 0.427). Likewise, the percent change in the whole‐vessel TBR of the index vessel was not different between the 2 groups ( P = 0.166). Similar findings were observed for changes in the MDS TBR ( P = 0.412) or whole‐vessel TBR of the aorta ( P = 0.363). Conclusions Carotid atherosclerotic plaque inflammation significantly decreases to a similar degree following 6 months of either clopidogrel or ticagrelor treatment.