Secondary Stroke Prophylaxis with Clopidogrel Produces Sufficient Antiplatelet Response

Association of clopidogrel resistance and ABCD-GENE score with long-term clinical prognosis in patients with ischemic stroke or TIA

BACKGROUND

Clopidogrel resistance (CR) is associated with adverse clinical outcomes in acute ischemic stroke or transient ischemic attack (TIA) patients. However, whether CR affects the long-term clinical prognosis remains to be clarified. The ABCD-GENE score is a novel risk model that identifies CR in cardiovascular disease patients; its diagnostic ability and application in ischemic stroke or TIA remain to be studied. This study aimed to investigate the diagnostic ability of the ABCD-GENE score for CR and analyze the relationship between CR and long-term clinical prognosis in patients with ischemic stroke or TIA.

METHODS

From January 2018 to January 2021, 251 ischemic stroke or TIA patients who were treated with clopidogrel for more than three months after onset and maintained the medication until the follow-up time were enrolled, and platelet reactivity was detected by thromboelastography. CYP2C19 gene analysis was performed. Adverse clinical outcomes were recorded from 3months after onset. The median follow-up time was 878days.

RESULTS

The prevalence of CR was 33.9%. The proportion of CYP2C19 loss-of-function carriers was 62.2%. The ABCD-GENE score≥10 was independently associated with CR (OR=1.82, 95% CI: 1.02-3.24, P=0.041), and the C-statistic value of the score (as a binary and integer variable) on CR was 0.58 and 0.63, respectively. The risk of long-term adverse clinical outcomes was not significantly different between CR and clopidogrel sensitive groups (12.94% vs. 11.44%, HR=1.22, 95% CI: 0.57-2.62, P=0.603). A similar result was observed between ABCD-GENE score≥10 and ABCD-GENE score<10 groups (10.38% vs. 12.64%, HR=1.19, 95% CI: 0.55-2.60, P=0.666).

CONCLUSIONS

In ischemic stroke or TIA patients, the ABCD-GENE score could identify the risk of CR. CR was not associated with long-term adverse clinical outcomes.

Clopidogrel responder status is uninfluenced by CYP2C19*2 in Danish patients with stroke

Background

Antiplatelet therapy is a cornerstone of secondary stroke prevention, but the responsiveness to antiplatelet medication varies among patients. Clopidogrel is a pro-drug that requires hepatic transformation to reach its active metabolite. Single nucleotide polymorphisms (SNPs) in key enzymes or the target adenosine diphosphate (ADP) receptor on the platelet surface are believed to be involved in clopidogrel-mediated platelet inhibition and decreased antiplatelet effect with high-on-treatment platelet reactivity (HTPR).

Objective

This study investigated whether specific SNPs in key hepatic enzymes (CYP2C19*2, *3, *17, CYP3A4*1G, and NR1I2) or the ADP receptor (PR2Y12) are associated with HTPR to clopidogrel.

Patients & methods

This observational study included patients with ischemic stroke (IS) and transient ischemic attacks (TIAs) receiving clopidogrel at a dose of 75 mg/day. Patients were genotyped for eight different SNPs in the genes encoding CYP2C19, CYP3A4, NR1I2, and the P2Y12 receptor.

Results

Of the 103 patients that were included, 30.7% carried the CYP2C19*2 allele and had higher platelet reaction unit (PRU) values than non-carriers, but no patients showed HTPR. Carriers of the *17 allele had higher platelet inhibition but showed no difference in PRU values compared with non-carriers. The remaining SNPs were neither associated with PRU nor with platelet inhibition.

Conclusions

Patients with IS and TIAs treated with 75 mg clopidogrel/day do not have HTPR. A genetic analysis of CYP2C19*2, *3, *17, CYP3A4*1G, and NR1I2 revealed no associations with clopidogrel HTPR. CYP2C19*2 carriers and patients with HTPR in the acute phase after ischemic stroke or transient ischemic attacks exhibit higher PRU values, but not long-term treatment HTPR.