High versus standard clopidogrel maintenance dose after percutaneous coronary intervention and effects on platelet inhibition, endothelial function, and inflammation: Results of the ARMYDA-150 mg (antiplatelet therapy for reduction of myocardial damage during angioplasty) randomized study

Objectives: This study was done to compare effects of high versus standard clopidogrel maintenance doses on platelet inhibition, inflammation, and endothelial function in patients undergoing percutaneous coronary intervention. Background: Previous data suggested that clopidogrel has various biological actions in addition to antiplatelet effects. Methods: Fifty patients were randomly assigned 1 month after intervention (T-0) to receive standard (75 mg/day; n = 25) or high (150 mg/day; n = 25) clopidogrel maintenance dose for 30 days (until T-1); at this time-point, cross-over was performed, and the assigned clopidogrel maintenance regimen was switched and continued for a further 30 days (until T-2). Platelet reactivity (expressed as P2Y₁₂ reaction units by the point-of-care VerifyNow assay [Accumetrics, San Diego, California]), endothelial function (evaluated by flow-mediated vasodilation), and high-sensitivity C-reactive protein levels were measured at T-0, T-1, and T-2. Results: Patients in the 150-mg/day arm had higher platelet inhibition (50 ± 20% vs. 31 ± 20% in the 75-mg/day group; p < 0.0001), better flow-mediated vasodilation (16.9 ± 12.6% vs. 7.9 ± 7.5%; p = 0.0001), and lower high-sensitivity C-reactive protein levels (3.6 ± 3.0 mg/l vs. 7.0 ± 8.6 mg/l; p = 0.016). Higher clopidogrel dose was associated with decreased proportion of patients with P2Y₁₂ reaction units <240 (12% vs. 32%; p = 0.001), flow-mediated vasodilation <7% (16% vs. 58%; p = 0.0003), and high-sensitivity C-reactive protein levels >3 mg/l (46% vs. 64%; p = 0.07). Conclusions: For patients undergoing percutaneous coronary intervention, the 150-mg/day clopidogrel maintenance dose is associated with stronger platelet inhibition, improvement of endothelial function, and reduction of inflammation, compared with the currently recommended 75-mg/day regimen; those effects might have a role in the clinical benefit observed with clopidogrel and may provide the rationale for using the higher maintenance regimen in selected patients.