Justification of 150 mg clopidogrel in patients with high on-clopidogrel platelet reactivity

Eur J Clin Invest 2012; 42 (4): 384–392 Background The GRAVITAS trial showed that 150 mg clopidogrel did not improve outcome in patients with high on‐clopidogrel platelet reactivity (HPR) screened by the VerifyNow assay. We aimed to determine the impact of 150 mg clopidogrel in stable angina patients with HPR identified with conventional aggregometry (LTA). Materials and methods Clopidogrel‐naive stable angina patients before ad hoc percutaneous coronary intervention were recruited into a randomized, double‐blind, placebo‐controlled trial (NCT00638326). Twelve to 24 h after the 600‐mg loading dose of clopidogrel, ADP5μM‐stimulated maximal (AGGmax), late platelet aggregation (AGGlate) and vasodilator‐stimulated phosphoprotein phosphorylation (VASP‐PRI) were evaluated. Patients with HPR (AGGmax ≥ 34%) were randomly allocated to 75 or 150 mg clopidogrel after 4 weeks. After control platelet function measurements at day 28, 75 mg clopidogrel was administered to all patients until 1 year. Results The study was prematurely terminated at the stage of 200 enroled patients. Administration of 150 mg clopidogrel significantly reduced platelet aggregation (AGGmax: 45·0 ± 6·8 vs. 33·8 ± 15·1, P