CC Cardiol Croat Cardiologia Croatica Cardiol. Croat. 1848-543X 1848-5448 Croatian Cardiac Society CC_2013_8_9_279 10.15836/ccar.2013.279 Extended Abstract Suboptimal platelet response to clopidogrel after percutaneous coronary intervention in patients with acute coronary syndrome is not associated with total platelet count and mean platelet volume SamardzicJure1KrpanMiroslav1BrestovacMarija2SkoricBosko1CikesMaja1PetricevicMate1MilicicDavor1 University of Zagreb School of Medicine, University Hospital Centre Zagreb, Zagreb, Croatia Dr. Andrija Stampar Institute of Public Health, Zagreb, Croatia Correspondence to Jure Samardzic, Klinicki bolnicki centar Zagreb, Kispaticeva 12, HR-10000 Zagreb, Croatia; Phone: +385-1-2367-467; E-mail: jure.samardzic@gmail.com 092013 092013 8 9 279 279 Croatian Cardiac Society 2013 Croatian Cardiac Society KEYWORDS: acute coronary syndromeclopidogrelmean platelet volume

Objectives: Responsiveness to clopidogrel is characterized by large variability in platelet inhibition among patients.1 Suboptimal response to clopidogrel is known to be associated with higher risk for subsequent cardiovascular ischaemic events such as in-stent thrombosis or recurrent acute coronary syndrome (ACS)2-3. We sought to evaluate correlation of platelet count and mean platelet volume (MPV) with low clopidogrel response in patients with acute coronary syndrome undergoing percutaneous coronary intervention (PCI).

Patients and Methods: We enrolled 359 consecutive ACS patients in the study. Patients with thrombocytopenia, suboptimal PCI and those who received glycoprotein IIbIIIa antagonists during and/or after PCI were excluded (120 patients). Residual platelet activity specific to clopidogrel was measured using Multiplate® function analyzer — a point of care instrument which determines platelet function in small quantities of whole blood.

Results: Fifty-three patients (22.2%) had suboptimal response to clopidogrel. Average platelet number and MPV in patients with decreased response was 240.8x109/L (SD ± 52.40) and 9.63 fL (SD ± 1.00), respectively. Patients with normal or increased response had average platelet number of 226.6x109/L (SD ± 53.02) and average MPV 9.3 fL (SD ± 0,91). There was no statistically significant difference in total platelet number (P=0.07) nor MPV values (P=0.13) between low responders and other patients. (Figure 1)

Patient selection.

Conclusion: MPV and total platelet number are not associated with low respond to clopidogrel after successful PCI in ACS. (1-3)

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