Clopidogrel response in ischemic stroke patients: Is polymorphism or gender more important? Results of the CRISP study

Genetic variability in stroke patients: CYP2C19 polymorphisms unraveled

OBJECTIVE

To study the distribution characteristics of CYP2C19 polymorphisms in patients suffering from stroke in Han Chinese patients.

METHOD

PCR and DNA microarray chip technology were used to detect the CYP2C19 genotype of 549 patients with stroke, and the genotype, allele frequency and metabolic type of patients with different sexes, ages and types of infarctions and the independent risk factors for clopidogrel resistance were analyzed.

RESULTS

Six genotypes were detected in these 549 patients. A total of 233 (42.44%) patients had the heterozygous allele *1/*2, which was the most prevalent, followed by the homozygous wild-type allele *1/*1 (191, 34.79%). A total of 30 (5.46%) patients possessed the heterozygous allele *1/*3, and 65 (11.84%) patients had the homozygous mutant allele *2/*2. Twenty-nine (5.28%) patients had the compound heterozygous mutant allele *2/*3, and only 1 patient had the homozygous mutant allele *3/*3. The distribution of genotypes, alleles, and metabolic types did not change significantly (P > 0.05) by sex, age, or type of stroke. In addition, no independent risk factors for clopidogrel resistance were found in this analysis.

CONCLUSION

The distribution of CYP2C19 genotypes, allele frequencies, and metabolic types in patients with stroke in Han Chinese patients were not correlated with sex, age, or infarction type. The possibilities of hyperglycemia, hypercholesterolemia, hypertriglyceridemia, hypo-HDL-cholesterolemia, hyper-LDL-cholesterolemia and high blood pressure were not statistically associated with CYP2C19 genotypes. CYP2C19 gene polymorphism detection is recommended for patients who are available, and during treatment, the CYP2C19 genotype can be used to guide personalized precise medication use in patients with stroke.

Future Perspectives to Improve CHA2DS2VASc Score: The Role of Left Atrium Remodelling, Inflammation and Genetics in Anticoagulation of Atrial Fibrillation

In 10% of ischemic strokes, non-valvular atrial fibrillation (NVAF) is detected retroactively. Milder, or even asymptomatic forms of NVAF have shown high mortality, thrombotic risk, and deterioration of cognitive function. The current guidelines for the diagnosis and treatment of AF contain "grey areas", such as the one related to anticoagulant treatment in men with CHA2DS2-VASc score 1 and women with score 2. Moreover, parameters such as renal function, patient weight or left atrium remodelling are missing from the recommended guidelines scores. Vulnerable categories of patients including the elderly population, high hemorrhagic risk patients or patients with newly diagnosed paroxysmal episodes of atrial high rate at device interrogation are at risk of underestimation of the thrombotic risk. This review presents a systematic exposure of the most important gaps in evaluation of thrombotic and hemorrhagic risk in patients with NVAF. The authors propose new algorithms and risk factors that should be taken into consideration for an accurate thrombotic and hemorrhagic risk estimation, especially in vulnerable categories of patients.

Randomized, Double-Blind, Active Comparator Pharmacodynamic Study of Platelet Inhibition with Crushed and Integral Formulations of Clopidogrel and Ticagrelor in Acute Coronary Syndrome

BACKGROUND

Crushed formulations of specific antiplatelet agents produce earlier and stronger platelet inhibition. We studied the platelet inhibitory effect of crushed clopidogrel in patients with acute coronary syndrome (ACS) and its relative efficacy compared with integral clopidogrel, crushed and integral ticagrelor.

OBJECTIVES

We aimed to compare the platelet inhibitory effect of crushed and integral formulations of clopidogrel and ticagrelor in patients with acute coronary syndrome (ACS).

METHODS

Overall, 142 patients with suspected ACS were randomly assigned to receive crushed or integral formulations of clopidogrel or ticagrelor. Platelet inhibition at baseline and 1 and 8 h was assessed using the VerifyNow assay. High on-treatment platelet reactivity (HTPR) ≥ 235 P2Y₁₂ reaction units (PRUs) 1 h after the medication loading dose was also determined.

RESULTS

The PRU and percentage inhibition median (interquartile range) at 1 h for the different formulations were as follows: crushed clopidogrel: 196.50 (155.50, 246.50), 9.36 (- 1.79, 25.10); integral clopidogrel: 189.50 (159.00, 214.00), 2.32 (- 2.67, 19.89); crushed ticagrelor: 59.00 (10.00, 96.00), 75.53 (49.12, 95.18); and integral ticagrelor: 126.50 (50.00, 168.00), 40.56 (25.59, 78.69). There was no significant difference in PRU or percentage platelet inhibition between the crushed and integral formulations of clopidogrel (p = 0.990, p = 0.479); both formulations of ticagrelor were superior to the clopidogrel formulations (p < 0.05). On paired comparison, crushed ticagrelor showed robust early inhibition of platelets compared with the integral formulation (p = 0.03). Crushed clopidogrel exhibited the maximal HTPR of 34.3%, but was < 3% for both formulations of ticagrelor.

CONCLUSIONS

The platelet inhibitory effect of crushed clopidogrel is not superior to integral preparation in patients with ACS. Crushed ticagrelor produced maximal platelet inhibition acutely. HTPR rates in ACS are similar and very low with both formulations of ticagrelor, and maximal with crushed clopidogrel. Clinical Trials Registry of India identifier number CTRI/2020/06/025647.

Association Between CYP2C19 Genotypes With Clinical Phenotypes and Adipokine Levels Among Ischemic Stroke Patients: A Prospective Observational Study

Background Cytochrome P450 system is implicated in vascular pathologies, including stroke. Besides its role as a drug metabolizer, it also plays an important role in the metabolism of several endogenous substances like fatty acids, arachidonic acid, etc., which have pro-inflammatory effects. On the other hand, leptin and adiponectin are two of the most common adipose tissue-derived cytokines (adipokines), which are pro-inflammatory and anti-inflammatory in nature, respectively. Both of them are implicated in the pathogenesis of stroke. Methods We prospectively recruited ischemic stroke patients (within three months of occurrence of an attack of stroke). The occurrence of composite outcome (recurrence of transient ischemic attack/ischemic stroke or death) was evaluated for association with genetic variants of CYP2C19 (allele *2, *17, *3, and *4, i.e., single nucleotide polymorphism (SNP) 1/2/3/4, identified using TaqMan assays and DNA sequencing). Adiponectin and leptin levels were determined using an enzyme-linked immunosorbent assay. Comparisons were made between stroke vs. control patients and between CYP2C19 intermediate metabolizer (IM)/poor metabolizer (PM) vs. extensive metabolizer (EM)/ultra metabolizer (UM) (PM: *2/*2; IM: *1/*2 vs. EM: *1/*1; UM: *1/*17). P < 0.05 was taken as the threshold for statistical significance. Results A total of 204 patients and 101 controls were recruited. With regard to the occurrence of stroke, SNP2 showed a significant positive association. Haplotypes (SNP1/SNP2) AC (OR = 1.75 (1.08-2.83), p = 0.024) and GT (OR = 3.33 (1.53-7.22), p = 0.0026) were strongly associated with the occurrence of ischemic stroke even after adjustment for age and sex (global haplotype association p-value: 0.0062). Haplotype phenotype gender interaction was evident. Among stroke patients, with regard to composite outcome, only SNP1 showed a positive association. The AC haplotype was significantly associated with the occurrence of composite outcome (OR = 2.27 (1.17-4.41), p = 0.016). Among stroke patients, a significant positive association was seen between death and SNP1 (OR = 2.35 (1.13-4.90), p = 0.021) and AC haplotype (OR = 2.73 (1.20-6.22), p = 0.018). However, none of the SNPs or haplotypes showed any association with recurrence. Significant higher leptin and lower adiponectin levels were observed among stroke patients compared to controls. Leptin levels were higher in IM/PM group. IM/PM phenotypes showed a higher incidence of occurrence of composite outcome (hazard ratio = 2.07 (0.96-4.47), p = 0.056). Conclusion CYP2C19 polymorphisms may play a significant role in the pathogenesis of stroke. Leptin could serve as a prominent biomarker of atherosclerosis and inflammation in the early post-stroke period; however, further study is warranted with a larger sample size.