Response to clopidogrel and its association with chronic kidney disease in noncardiogenic ischemic stroke patients

Ilaprazole and Clopidogrel Resistance in Acute Stroke Patients

Clopidogrel, an antiplatelet agent used for secondary prevention of cerebrovascular diseases, is often taken with proton pump inhibitors (PPIs). Generally, the combined use of clopidogrel and PPIs causes adverse drug–drug interactions. VerifyNow is a quick and convenient method to confirm clopidogrel resistance (CR), which compromises adequate antithrombotic effects. We aimed to confirm CR, identify its factors, and determine the influence of the combination of ilaprazole and clopidogrel on clopidogrel using VerifyNow. In this retrospective study, we examined patients who were receiving clopidogrel after three months, starting within one week from the onset of cerebral infarction symptoms. Clinical records, imaging records, and diagnostic laboratory results, including P2Y12 reaction units (PRU), were compared and analyzed to check for CR. Additionally, the groups treated with either both ilaprazole and clopidogrel or with medications other than ilaprazole were comparatively analyzed. CR was defined as a PRU ≥240 after clopidogrel for three months. Among factors influencing CR by affecting clopidogrel metabolism, positive statistical correlations with age and alcohol consumption were confirmed. The diagnostic tests revealed a lower glomerular filtration rate and platelet count of the CR-positive group. This finding proved that the combination therapy of ilaprazole and clopidogrel is safe, as it does not interfere with the metabolism of clopidogrel.

Increase in the risk of clopidogrel resistance and consequent TIMI flow impairment by DNA hypomethylation of CYP2C19 gene in STEMI patients undergoing primary percutaneous coronary intervention (PPCI)

Clopidogrel resistance is an important risk factor of ischemic event recurrence after optimal antiplatelet therapy. This study aims to investigate the role of CYP2C19 gene DNA methylation as one of the epigenetic factors for the risk of clopidogrel resistance in STEMI patients undergoing PPCI. ST-segment elevation myocardial infarction (STEMI) patients undergoing PPCI were pretreated with clopidogrel, and their platelet function was measured using VerifyNow™ assay. The criteria for high on-treatment platelet reactivity (HPR) were defined according to the expert consensus criteria (PRU >208). DNA methylation of the CYP2C19 gene was performed using bisulfite genomic sequencing technology. Furthermore, clinical, laboratory, and angiographic data including TIMI flow were collected. Among 122 patients, clopidogrel resistance was found in 22%. DNA methylation level percentage was lower in the clopidogrel resistance group (76.7 vs. 88.8, p-value .038). But, the <50% methylation group was associated with increased risk of clopidogrel resistance (OR =4.5, 95%CI =2.1-9.3, p-value = .018). This group was also found to have suboptimal post-PCI TIMI flow (OR =3.4 95%CI =1.3-8.7, p-value =.045). The lower DNA methylation level of the CYP2C19 gene increases the risk of clopidogrel resistance and subsequent poorer clinical outcome.

Clopidogrel Response Variability in Unruptured Intracranial Aneurysm Patients Treated with Stent-Assisted Endovascular Coil Embolization : Is Follow-Up Clopidogrel Response Test Necessary?

Objective

The purpose of this study was to analyze the variability of clopidogrel responses according to duration of a clopidogrel drug regimen after stent-assisted coil embolization (SAC), and to determine the correlation between the variability of clopidogrel responses and thromboembolic or hemorrhagic complications.

Methods

A total of 47 patients who underwent SAC procedures to treat unruptured intracranial aneurysms were enrolled in the study. Preoperatively, patients received more than seven days of aspirin (100 mg) and clopidogrel (75 mg), daily. P2Y12 reaction unit (PRU) was checked with the VerifyNow test one day before the procedure (pre-PRU) and one month after the procedure (post-PRU). PRU variability was calculated as the difference between the initial response and the follow-up response. Patients were sorted into two groups based on their response to treatment : responsive and hypo-responsive.

Results

PRU variability was significantly greater in the hypo-responsive group when compared to the responsive group (p=0.019). Pre-PRU and serum platelets counts were significantly correlated with PRU variation (p=0.005 and p=0.004, respectively). Although thromboembolic complication had no significant correlated factors, hemorrhagic complication was correlated with pre-PRU (p=0.033).

Conclusion

In conclusion, variability of clopidogrel responses during clopidogrel medication was correlated to serum platelet counts and the initial clopidogrel response. Thromboembolic and hemorrhagic complications did not show correlation with the variability of clopidogrel response, or the clopidogrel response after one month of medication; however, hemorrhagic complication was associated with initial clopidogrel response. Therefore, it is recommended to test patients for an initial clopidogrel response only, as further tests would be insignificant.

Renal dysfunction and chronic kidney disease in ischemic stroke and transient ischemic attack: A population-based study

Background and purpose

The prevalence of chronic kidney disease (estimated glomerular filtration rate (eGFR) <60 mL/min per 1.73 m2 for ≥3 months, chronic kidney disease (CKD)) in ischemic stroke and transient ischemic attack (TIA) is unknown, as estimates have been based on single-point estimates of renal function. Studies investigating the effect of renal dysfunction (eGFR < 60 mL/min per 1.73 m2, renal dysfunction) on post-stroke outcomes are limited to hospitalized cohorts and have provided conflicting results.

Methods

We investigated rates, determinants and outcomes of renal dysfunction in ischemic stroke and TIA in the North Dublin Population Stroke Study. We also investigate the persistence of renal dysfunction in 90-day survivors to determine the prevalence of CKD. Ascertainment included hot and cold pursuit using multiple overlapping sources. Survival analysis was performed using Kaplan–Meier survival curves and Cox proportional hazards modeling.

Results

In 547 patients (ischemic stroke in 76.4%, TIA in 23.6%), the mean eGFR at presentation was 63.7 mL/min/1.73 m2 (SD 22.1). Renal dysfunction was observed in 44.6% (244/547). Among 90-day survivors, 31.2% (139/446) met criteria for CKD. After adjusting for age and stroke severity, eGFR < 45 mL/min/1.73 m2 (hazard ratio 2.53, p = 0.01) independently predicted 28-day fatality but not at two years. Poor post-stroke functional outcome (Modified Rankin Scale 3–5) at two years was more common in those with renal dysfunction (52.5% vs. 20.6%, p < 0.001). After adjusting for age, stroke severity and pre-stroke disability, renal dysfunction (OR 2.17, p = 0.04) predicted poor functional outcome.

Conclusion

Renal dysfunction and CKD are common in ischemic stroke and TIA. Renal dysfunction is associated with considerable post-stroke morbidity and mortality. Further studies are needed to investigate if modifiable mechanisms underlie these associations.

High clopidogrel dose in patients with chronic kidney disease having clopidogrel resistance after percutaneous coronary intervention

We evaluated the impact of clopidogrel 150 mg/d in patients with chronic kidney disease (CKD) having clopidogrel resistance (CR) after percutaneous coronary intervention (PCI); 1076 consecutive patients with coronary artery disease (CAD) having CKD were enrolled. Maximal platelet aggregation (MPA) was assessed before, 24 hours, and 30 days after a 300-mg loading dose of clopidogrel prior to PCI. After PCI, 370 patients with CR were randomized to receive clopidogrel 75 mg/d (n = 184) or 150 mg/d (n = 186) for 30 days. Stent thrombosis (ST), major adverse cardiac events (MACEs), and bleeding were analyzed after 1 month. Patients in the 150 mg group had significant lower rates of ST and MACE. There was no significant difference in major or minor bleeding. Patients in the 150 mg group had lower MPA and greater inhibition of platelet aggregation. One-month administration of 150 mg/d of clopidogrel decreases the rate of ST and MACE without increasing bleeding in patients with CKD having CR after PCI.

Relationship between smoking and responsiveness to clopidogrel in non-cardiogenic ischemic stroke patients

OBJECTIVE

Clopidogrel is used to prevent the recurrence of non-cardiogenic ischemic stroke, but individual responsiveness to the drug varies. Moreover, it is known that smoking, which is a risk factor for ischemic stroke, affects the drug's pharmacokinetics. The objective of the present study was to investigate a possible relationship between smoking and responsiveness to clopidogrel in non-cardiogenic ischemic stroke patients.

METHODS

The study involved 209 non-cardiogenic ischemic stroke patients who were administered oral clopidogrel at a dosage of 75 mg/day for at least 1 week. Platelet aggregation in response to adenosine diphosphate (20 μM) was measured in each patient using the VerifyNow P2Y12 Assay. Platelet aggregation and the incidence of resistance to clopidogrel were compared between a smokers group (70 patients) and a non-smokers group (139 patients). Clopidogrel resistance was defined as a P2Y12 Reaction Units (PRU) value >230 and/or % inhibition <20%.

RESULTS

The mean PRU was 128.3±85.5 in the smokers group and 167.7±86.6 in the non-smokers group (p=0.002). The incidence of PRU >230 was 12.9% (9 patients) in the smokers group and 25.9% (36 patients) in the non-smokers group (p=0.033). The mean % inhibition was 48.6±30.7% in the smokers group and 36.9±27.6% in the non-smokers group (p=0.009). The incidence of patients with % inhibition <20% was 24.3% (17 patients) in the smokers group and 34.5% (48 patients) in the non-smokers group (p=0.155).

CONCLUSION

The incidence of clopidogrel resistance was lower in the non-cardiogenic ischemic stroke patients who were smokers, thus indicating that these patients' responsiveness to this drug may be enhanced.