Abstract: Objective To evaluate the feasibility of monitoring clopidogrel resistance with flow cytometric analysis of platelet
vasodilator stimulated phosphoprotein (VASP) phosphorylation. Methods Twenty patients with coronary heart disease
(CHD) and 17 healthy volunteers were examined for platelet aggregation rate and phosphorylation of VASP (calculated as
platelet reactivity index, PRI) using traditional optical nephelometry and flow cytometry before and after concurrent therapy
of clopidogrel and aspirin. Results No significant differences were found in PRI between CHD group and healthy control
group [(89.45±5.22)% vs (86.58±4.35)%] before treatment. The PRI in CHD group was significantly lowered after treatment to
(67.66±19.77)% (P<0.05). Clopidogrel resistance was found in 6 (30%) cases in CHD group by flow cytometric analysis, which
showed a higher sensitivity than optical nephelometry (10%). Conclusion Flow cytometric analysis of VASP phosphorylation
is a more reliable test to specifically evaluate clopidogrel resistance.