P2Y12 Reaction Units and Clinical Outcomes in Acute Large Artery Atherosclerotic Stroke: A Multicenter Prospective Study

Impact of CYP2C19 Genotype Status on Clinical Outcomes in Patients with Symptomatic Coronary Artery Disease, Stroke, and Peripheral Arterial Disease: A Systematic Review and Meta-Analysis

BACKGROUND

Clopidogrel is widely used for the secondary prevention of atherothrombotic events in patients with coronary artery disease (CAD), ischemic stroke, and peripheral arterial disease (PAD). CYP2C19 plays a pivotal role in the conversion of clopidogrel to its active metabolite. Clopidogrel-treated carriers of a CYP2C19 loss-of-function allele (LOF) may have a higher risk of new atherothrombotic events. Previous studies on genotype-guided treatment were mainly performed in CAD and showed mixed results.

PURPOSE

To simultaneously investigate the impact of CYP2C19 genotype status on the rate of atherothrombotic events in the most common types of atherosclerotic disease (CAD, stroke, PAD).

METHODS

A comprehensive search in Pubmed, EMBASE, and MEDLINE from their inception to July 23rd 2023 was performed. Randomized controlled trials (RCTs) comparing genotype-guided and standard antithrombotic treatment, and cohort studies and post hoc analyses of RCTs concerning the association between CYP2C19 genotype status and clinical outcomes in clopidogrel-treated patients were included. The primary efficacy endpoint was major adverse cardiovascular events (MACE) and the safety end point major bleeding. Secondary endpoints were myocardial infarction, stent thrombosis, and ischemic stroke.

RESULTS

Forty-four studies were identified: 11 studies on CAD, 29 studies on stroke, and 4 studies on PAD. In CAD, genotype-guided therapy significantly reduced the risk of MACE [risk ratio (RR) 0.60, 95% confidence interval (CI) 0.43-0.83], myocardial infarction (RR 0.53, 95% CI 0.42-0.68), and stent thrombosis (RR 0.64, 95% CI 0.43-0.94), compared with standard antithrombotic treatment. The rate of major bleeding did not differ significantly (RR 0.93, 95% CI 0.70-1.23). Most RCTs were performed in patients after percutaneous coronary intervention (9/11). In stroke, LOF carriers had a significantly higher risk of MACE (RR 1.61, 95% CI 1.25-2.08) and recurrent ischemic stroke (RR 1.89, 95% CI 1.48-2.40) compared with non-carriers. No significant differences were found in major bleeding (RR 0.90, 95% CI 0.43-1.89). In the 6955 patients with symptomatic PAD treated with clopidogrel in the EUCLID trial, no differences in MACE or major bleeding were found between LOF carriers and non-carriers. In three smaller studies on patients with PAD treated with clopidogrel after endovascular therapy, CYP2C19 genotype status was significantly associated with atherothrombotic events.

CONCLUSIONS

Genotype-guided treatment significantly decreased the rate of atherothrombotic events in patients with CAD, especially after PCI. In patients with history of stroke, LOF carriers treated with clopidogrel had a higher risk of MACE and recurrent stroke. The available evidence in PAD with regard to major adverse limb events is too limited to draw meaningful conclusions.

REGISTRATION

PROSPERO identifier no. CRD42020220284.

Differential Impact of Clinical Factors for Predicting High Platelet Reactivity on Clinical Outcomes in Acute Myocardial Infarction Patients Treated With Clopidogrel and Prasugrel

AIMS

Several scoring systems, including the ABCD-GENE and HHD-GENE scores incorporating clinical and genetic factors, have been developed to identify patients likely to have high platelet reactivity on P2Y12 inhibitors, leading to increased risks of ischemic events. However, genetic testing is not widely available in daily practice. We aimed to evaluate the differential impact of clinical factors in the scores on ischemic outcomes in patients treated with clopidogrel and prasugrel.

METHODS

This bi-center registry included 789 patients with acute myocardial infarction (MI) undergoing percutaneous coronary intervention and treated with either clopidogrel or prasugrel at discharge. The relations of the number of clinical factors included in the ABCD-GENE (age ≥ 75 years, body mass index ＞30 kg/m2, chronic kidney disease, and diabetes) and HHD-GENE (hypertension, hemodialysis, and diabetes) scores to the primary endpoint of major cardiovascular events after discharge, a composite of death, recurrent MI, and ischemic stroke, were evaluated.

RESULTS

The number of clinical factors in the ABCD-GENE score was not predictive of ischemic outcomes after discharge in patients treated with clopidogrel and/or prasugrel, while the increase in the number of clinical factors of the HHD-GENE score was associated with an increased risk of the primary endpoint in a stepwise manner in patients on a P2Y12 inhibitor.

CONCLUSIONS

Clinical factors listed in the HHD-GENE score may help stratify ischemic risks in patients with acute MI treated with clopidogrel and prasugrel, whereas risk stratification without genetic testing in patients treated with clopidogrel may be challenging.

Platelet reactivity after clopidogrel loading in patients with acute ischemic stroke

Objective

It remains unclear when sufficient antiplatelet effect is achieved after administration of a loading dose of clopidogrel in patients with acute ischemic stroke (AIS). This study aimed to evaluate the clopidogrel response in patients with AIS identified by the platelet function test (PFT).

Methods

P2Y12 reaction unit (PRU) values measured using VerifyNow at baseline and at 6, 24, and 72 h after administration of a loading dose (300 mg) of clopidogrel were compared between patients with AIS and those of other cerebrovascular diseases (CVD). The prevalence of clopidogrel abnormal response and its associated factors were examined.

Results

The PRU value was significantly reduced with time in the other CVD group (p < 0.0001), and also in the AIS group (p = 0.0073). The PRU values were significantly higher in the AIS group than in the other CVD group (p < 0.0001 between the groups, baseline: 314 ± 53 vs. 284 ± 62, p = 0.35; 6 h: 290 ± 66 vs. 214 ± 71, p = 0.016; 24 h: 270 ± 75 vs. 190 ± 70, p < 0.0001; and 72 h: 231 ± 76 vs. 163 ± 93, p = 0.105). The prevalence of clopidogrel hypo-responder (PRU > 240 at 24 h after administration) was higher in the AIS group (79 vs. 33%, p < 0.0001) and associated with the baseline PRU value but not with the cytochrome P450 2C19 genotype or clinical ischemic events.

Conclusions

Residual platelet reactivity at 24 h after clopidogrel loading was substantially higher in patients with AIS than in patients with other CVD. In addition, most patients with AIS were judged to be hypo-responders on PFT. This should be carefully interpreted in patients with AIS because of poor specificity for predicting clinical ischemic events.