Detection of Clopidogrel Hyporesponsiveness Using a Point-of-Care Assay and the Impact of Additional Cilostazol Administration after Coronary Stent Implantation in Diabetic Patients

BACKGROUND/AIMS: Impaired responsiveness to clopidogrel is common in patients with type 2 diabetes mellitus (DM). The aim of this study was to evaluate the clinical application of a point-of-care assay to detect impaired responsiveness to clopidogrel after coronary stent implantation in patients with type 2 DM. METHODS: We measured P2Y12 reaction units (PRU) with the VerifyNow point-of-care assay in 544 consecutive patients undergoing dual or triple (i.e., dual plus cilostazol) anti-platelet therapy after coronary stent implantation. High platelet reactivity (HPR) was defined as a PRU value ≥ 240. RESULTS: The mean PRU values were 233.5 ± 83.2 and 190.3 ± 85.5 in patients undergoing dual or triple anti-platelet therapy, respectively (p < 0.001). Patients with DM manifested higher post treatment PRU values (238.3 ± 82.4 vs. 210.8 ± 86.8, p = 0.001) and a higher frequency of HPR (44.8% vs. 31.0%, p = 0.003) as compared to patients without DM. We also found that higher PRU values and a higher frequency of HPR were present in patients with DM who were undergoing both triple and dual anti-platelet therapy. However, the higher post-treatment PRU values observed in patients with DM decreased with triple anti-platelet therapy (219.4 ± 82.5 vs. 247.9 ± 81.1, p = 0.044). CONCLUSIONS: A point-of-care assay can detect elevated platelet reactivity and impaired responsiveness to clopidogrel in patients with type 2 DM. The addition of cilostazol to dual anti-platelet therapy may decrease post-treatment PRU values in patients with type 2 DM.