Abstract 3801: Aspirin Resistance Is Associated With Low Response to Clopidogrel After Percutaneous Coronary Intervention: The Clopidogrel and Aspirin Resistance Evaluation in Patients undergoing Coronary Revascularization (CARE-PCR) Registry
BACKGROUND: Wide inter-individual and intra-individual variability has been reported in response to aspirin and clopidogrel. However, data regarding the relationship among responses to both drugs are limited.
METHODS: We investigated a potential interrelation among clinical factors, serum inflammatory markers, and clopidogrel responsiveness in 159 consecutive patients undergoing coronary intervention according to aspirin responsiveness using rapid platelet function assay. Results of aspirin resistance (aspirin reaction unit, ARU) were not normally distributed (Figure⇓) and grouped in tertiles for data analysis.
RESULTS: Baseline demographics and procedural characteristics did not differ between the three tertiles of ARU, except that acute coronary syndromes were more commonly distributed in patients with highest tertiles (53% vs. 45% vs. 72%, p=0.049). There were also no differences in serum bio-markers and baseline medications among tertile groups (Table⇓). However, percent platelet inhibition by clopidogrel was significantly lower with increasing levels of ARU (38.9±25.0% vs. 27.5±21.8% vs. 22.5±23.6%, p=0.001).
CONCLUSIONS: Lower response to aspirin was significantly associated with decrease of platelet inhibitory effect of clopidogrel. Further studies regarding mechanisms for dual drug resistance and other platelet inhibitors should be investigated.