To evaluate the relationship between the CYP2C19 genotype and the antiplatelet effect of clopidogrel therapy and to predict the risk of mid-term ischemic events after endovascular treatment of arteriosclerosis obliterans (ASO).

From January 2011 to July 2012, a total of seventy-four consecutive patients with ASO (TASCⅡA-C) in the superficial femoral artery (SFA) were included in a prospectively maintained database. Patients received a recommended dosage of 75 mg clopidogrel and 100 mg aspirin daily for at least 5 days prior to CYP2C19 single nucleotide polymorphisms TaqMan analysis and the thromboelastography assay of clopidogrel response, before endovascular procedure. Patients were divided into two groups according to CYP 2C19 genotypes. During the follow up, stent patency was assessed at 1-, 3-, 6-, and 12-month postoperatively.

Fifty enrolled patients (67.6%) in the study were completely investigated in follow-up analysis. The mean duration of follow-up was (9.8 ± 2.1) months (range 1-30 months). CYP2C19 loss-of-function (LOF) allele group had a diminished pharmacodynamics response to clopidogrel (P = 0.022). One LOF carriers or two LOF had an increased incidence of ischemic events (P = 0.008, 0.002, respectively). Cumulative primary patency rate at 12 months was 56.0%, with significant differences between the two groups (73.1% vs 34.6%, P = 0.006). According to the ADP-induced platelet aggregation, patients with high platelet reactivity had a significantly higher rate of ischemic events between the two groups (P = 0.012).

CYP2C19 LOF alleles are associated with diminished platelet responses to clopidogrel treatments. The patients who received clopidogrel and with CYP2C19 LOF alleles may trend towards a poor prognosis after endovascular procedures.