Significance of clopidogrel resistance related to the stent-assisted angioplasty in patients with atherosclerotic cerebrovascular disease

Hyperacute in-Stent Thrombosis Causing Large Vessel Occlusion after Stent-Assisted Aneurysm Coiling Secondary to Complete Clopidogrel and Prasugrel Resistance: a Case Report

Dual antiplatelet therapy (DAPT) is standard treatment for endoluminal stent insertion, and complete resistance to DAPT is rare. A case of in-stent thrombosis occurring 3 hours after stent-assisted coiling of internal carotid artery aneurysm is presented despite compliance with DAPT. Platelet function tests (PFTs) revealed complete clopidogrel and prasugrel resistance.

Association between CYP2C19 polymorphisms and clinical outcomes in patients undergoing stent procedure for cerebral artery stenosis

We investigated the effect of CYP2C19 polymorphisms on the clinical outcomes of clopidogrel therapy in patients after stenting procedure for cerebral artery stenosis in northeast China. 568 patients performed CYP2C19 genotype screening in the neurosurgery department of our hospital; 154 patients were finally recruited according to the inclusion and exclusion criteria, and followed-up for 6 months. Ischemic events including (1) transient ischemic attack (TIA); (2) stent thrombosis; (3) ischemic stroke; and (4) death were defined as primary clinical endpoints. The frequencies of CYP2C19*1, *2 and *3 alleles in 568 patients were 63.1%, 31.1% and 5.8%, respectively. 154 patients were classified into extensive (65 patients; 42.2%), intermediate (66 patients; 42.9%), and poor (23 patients; 14.9%) metabolizer groups. A χ2 test showed a significant difference in primary clinical endpoints at 6 months (P = 0.04), and a multivariate Cox regression analysis indicated that the CYP2C19 loss-of-function (LOF) alleles associated with post-procedure prognosis. The Kaplan-Meier curve revealed that there was no significant difference in ischemic events between *2 and *3 alleles carriers. Our study verifies that CYP2C19 *2 and *3 have significant impact on the clinical outcomes of clopidogrel therapy in patients with stenting procedure for cerebral artery stenosis in China.

Variants in clopidogrel-relevant genes and early neurological deterioration in ischemic stroke patients receiving clopidogrel

BACKGROUND

Early neurological deterioration (END) is common in acute ischemic stroke (IS). However, the underlying mechanisms for END are unclear. The aim of this study was to evaluate the associations of 16 variants in clopidogrel-relevant genes and interactions among these variants with END in acute IS patients receiving clopidogrel treatment.

METHODS

We consecutively enrolled 375 acute IS patients between June 2014 and January 2015. Platelet aggregation was measured on admission and after the 7-10 days of clopidogrel treatment. The 16 variants in clopidogrel-relevant genes were examined using mass spectrometry. The primary outcome was END within the 10 days of admission. Gene-gene interactions were analyzed by generalized multifactor dimensionality reduction (GMDR) methods.

RESULTS

Among the 375 patients, 95 (25.3%) patients developed END within the first 10 days of admission. Among the 16 variants, only CYP2C19*2 (rs4244285) AA/AG was associated with END using single-locus analytical approach. GMDR analysis revealed that there was a synergistic effect of gene-gene interactions among CYP2C19*2 rs4244285, P2Y12 rs16863323, and GPIIIa rs2317676 on the risk for END. The high-risk interactions among the three variants were associated with the higher platelet aggregation and independent predictor for END after adjusting for the covariates (hazard ratio: 2.82; 95% confidence interval: 1.36-7.76; P = 0.003).

CONCLUSIONS

END is very common in patients with acute IS. The mechanisms leading to END are most likely multifactorial. Interactions among CYP2C19*2 rs4244285, P2Y12 rs16863323, and GPIIIa rs2317676 may confer a higher risk for END. It was very important to modify clopidogrel therapy for the patients carrying the high-risk interactive genotypes.

CLINICAL TRIAL REGISTRATION INFORMATION

The study described here is registered at http://www.chictr.org/ (unique Identifier: ChiCTR-OCH-14004724). The date of trial registration was May 30, 2014.

Response to clopidogrel is associated with early neurological deterioration after acute ischemic stroke

Purpose

The relationship between response to clopidogrel and early neurological deterioration (END) after acute ischemic stroke (IS) is not well defined. The aim of present study was to evaluate the associations of clopidogrel resistance (CR) with END, and stratified analyze the effectiveness of clopidogrel alone and clopidogrel plus aspirin for the prevention of END.

Results

A total of 375 patients, 144 patients were received clopidogrel alone, 231 patients took clopidogrel plus aspirin. CR occurred in 153 patients (40.8%). 95 (25.3%) patients developed END within the first 10 days. Platelet aggregation was higher on admission, and inhibition of platelet aggregation was significantly lower in patients with END than patients without END. Diabetes mellitus, CR, and clopidogrel plus aspirin were independently associated with END. Dual antiplatelet therapy with aspirin and clopidogrel can inhibit both arachidonic acid (AA)-induced and ADP-induced platelet aggregation

Methods

This was a prospective, two-center study. A total of 375 IS patients taking clopidogrel alone or clopidogrel plus aspirin were enrolled. Platelet aggregation was measured before and after the 7–10 day treatment. CR was assessed by adenosine diphosphate (ADP)-induced platelet aggregation. The primary endpoint was END within the 10 days after admission. The secondary endpoint was a composite of recurrent ischemic stroke, myocardial infarction, and death during the 10 days after admission.

Conclusions

CR and END are fairly common after acute IS. CR is associated with higher risk of END. Clopidogrel plus aspirin combination therapy provides greater inhibition of platelet aggregation, and may afford protection against END.

Endovascular treatment of wide-neck intracranial bifurcation aneurysms with 'Y'-configuration, double Neuroform® stents-assisted coiling technique: Experience in a single center

Background Intracranial wide-neck aneurysms at the arterial bifurcations, especially in the aneurysms where the bifurcating branches emanate directly from the base of the aneurysm, have been particularly difficult on which to perform endovascular treatment. The 'Y'-configuration, double stent-assisted coil embolization is an option for the treatment of these difficult aneurysms, allowing the closure of the aneurysm, preserving the parent arteries. Material and methods In a nine-year period, 546 intracranial aneurysms in 493 patients were treated at our center by endovascular approach. We have reviewed the medical records and arteriographies from November 2007 to January 2017 of 45 patients who were treated using 'Y'-configuration double Neuroform® stent-assisted coil embolization. Results All patients were successfully treated. The location of the aneurysms were: middle cerebral artery (MCA) 20 (44.4%), anterior communicating artery (AComA) 17 (37.7%), basilar four (8.9%), internal carotid artery (ICA) bifurcation three (6.6%) and posterior communicating artery (PComA) one (2.2%). The mRS at hospital discharge was: mRS 0: 42 (93.3%), mRS 1: 1 (2.2%), mRS 2: 1 (2.2%) and mRS 5: 1 (2.2%). The Modified Raymond-Roy Occlusion Classification, in the control at six months, was: Class I: 41 (91.1%), Class II: 2 (4.4%), Class IIIa: 1 (2.2%) and Class IIIb: 1 (2.2%). Forty-four (97.8%) patients had a good outcome (mRS < 2) at six months. One (2.2%) patient had a poor outcome (mRS > 2) at six months that was due to sequelae of SAH. There was no mortality at six months. Conclusions This technique is safe and effective for the endovascular treatment of difficult wide-neck bifurcation aneurysms, allowing the stable closure of the aneurysm, preserving the parent arteries.

Association of VEGFR-2 Gene Polymorphisms With Clopidogrel Resistance in Patients With Coronary Heart Disease

Vascular endothelial growth factor receptor 2 (VEGFR-2) plays a central role in atherogenesis. We investigated the correlation between VEGFR-2 polymorphisms and the risk of clopidogrel resistance (CR) in patients with coronary heart disease (CHD). The study involved 275 patients with CHD undergoing percutaneous coronary intervention and on antiplatelet clopidogrel therapy. The participants were divided into CR group (n = 59) and non-CR group (NCR, n = 216) based on maximum platelet aggregation measurements. VEGFR-2 gene polymorphisms, +1192C>T (rs2305948), +1416T>A (rs1870377), and -271A>G (rs7667298), were genotyped using polymerase chain reaction-restriction fragment length polymorphism. Enzyme-linked immunosorbent assay was used to measure serum transforming growth factor, beta receptor 2 levels. CR was found in 59 patients (20.45%). A significantly higher proportion of patients in the CR group had a history of diabetes mellitus compared with the NCR group (P < 0.05). Genotype and allele frequency of VEGFR-2 +1192C>T (rs2305948) was significantly higher in the CR group than in the NCR group (all P < 0.01). In the VEGFR-2 +1192C>T (rs2305948), the angina pectoris, recurrent myocardial infarction, and combined end point events were significantly more prevalent in the TT carriers than in the CC + CT carriers. In VEGFR-2 -271A>G (rs7667298), the GG carriers had a lower proportion of target lesion revascularization and angina pectoris in contrast to the AA + AG carriers (all P < 0.05). Based on our results, VEGFR-2 +1192C>T (rs2305948) polymorphism is strongly associated with increased CR and main adverse cardiovascular event incidence in patients with CHD undergoing percutaneous coronary intervention. Additionally, patients with CHD with diabetes mellitus history were more likely to develop CR. The associations of +1416T>A (rs1870377) and -271A>G (rs7667298) polymorphisms with CR were inconclusive and will need to be examined further.

Interaction of CYP2C19, P2Y12, and GPIIIa Variants Associates With Efficacy of Clopidogrel and Adverse Events on Patients With Ischemic Stroke

Objective:

Clopidogrel is a clinically important oral antiplatelet agent for the treatment or prevention of cerebrovascular disease. However, different individuals have different sensitivities to clopidogrel. This study assessed variants of different genes for association with response to clopidogrel, clinical outcome, and side effects in patients with ischemic stroke (IS).

Methods:

We consecutively enrolled 375 patients with IS after they received clopidogrel therapy, and venous blood samples were subjected to genotyping allelic variants of genes modulating clopidogrel absorption (ATP binding cassette subfamily B1, ABCB1), metabolic activation (cytochrome P450[CYP] 3A and CYP2C19), and biologic activity (platelet membrane receptor [ P2Y12, P2Y1)], and glycoprotein IIIa [ GPIIIa]) and statistically analyzing their interactions with clopidogrel sensitivity (CS) and adverse events, risk of IS recurrence, myocardial infarction, and death during 6 months of follow-up.

Results:

Adverse events occurred in 37 patients (31 had IS recurrence, 4 died, and 2 had myocardial infarction) during the first 6 months of follow-up. Single locus analysis showed that only the CYP2C19*2(rs4244285) variant was independently associated with CS and risk of adverse events after adjusting covariates. However, there was significant gene–gene interaction among CYP2C19*2(rs4244285), P2Y12(rs16863323), and GPIIIa (rs2317676) analyzed by generalized multifactor dimensionality reduction methods. The rate of adverse events among patients with the 3-loci interaction was 2.82 times the rate among those with no interaction (95% confidence interval: 2.04-8.63).

Conclusion:

Sensitivity of patients with IS to clopidogrel and clopidogrel-induced adverse clinical events may be multifactorial but is not determined by single gene polymorphisms.

The first six-month clinical outcomes and risk factors associated with high on-treatment platelet reactivity of clopidogrel in patients undergoing coronary interventions

OBJECTIVE

This study attempted to fill the gaps in evidence related to response to clopidogrel treatment in the Turkish population. The study aimed to determine the prevalence, associated risk factors, and clinical outcomes of high on-treatment platelet reactivity (HTPR) of clopidogrel in patients undergoing percutaneous coronary intervention (PCI) in a tertiary cardiovascular hospital in Turkey.

METHODS

In this prospective studied a total of 1.238 patients undergoing PCI were included in the present study. Blood samples were analyzed using a Multiplate analyzer. All patients were examined in the outpatient clinics at the end of the first and sixth months for recording drug therapy compliance and study endpoints.

RESULTS

Among the study population, 324 (30.2%) patients were found to have HTPR (mean age 58.03±11.88 years, 71.7% men). The incidence of HTPR was higher amongst females than amongst males (38.3% vs. 27%, p=0.010). Hypertension and diabetes mellitus were more frequently observed in the HTPR group (57.7% vs. 48.7%, p=0.004; 35% vs. 29.1%, p=0.040, respectively). When the recorded data were analyzed using multinomial regression analysis, hypertension, hemoglobin level, platelet, lymphocyte, and eosinophil count were independently associated with HTPR.

CONCLUSION

On the basis of the results obtained from our study, we conclude that 30.2% of the Turkish population has HTPR. Our results also led us to believe that hypertension is an associated risk factor and decreased hemoglobin level as well as increased platelet counts are laboratory parameters that are strongly associated with the presence of HTPR. However, no differences were observed with regard to cardiovascular mortality and stent thrombosis.

Clopidogrel Resistance Increases Rate of Recurrent Stroke and Other Vascular Events in Chinese Population

BACKGROUND

Research regarding clopidogrel resistance (CR) and ischemic stroke (IS) recurrence related to IS is scanty. The aim of the present study was to determine the incidence of CR and the association between CR and IS recurrence and other vascular events in patients with IS receiving clopidogrel.

METHODS

CR was assessed by platelet aggregation assay in 535 IS patients receiving clopidogrel. All patients continued taking clopidogrel after discharge and were followed up for 6 months. The primary outcome was a composite of recurrent ischemic stroke (RIS), myocardial infarction, and death. The secondary outcome was the degree of disability as measured by modified Rankin Scale (mRS).

RESULTS

Out of 535 IS patients, 208 (38.88%) were CR and 327 (61.12%) were clopidogrel sensitive (CS). Diabetes was independently associated with risk of CR (odds ratio: 2.42, 95% confidence interval [CI], 1.22-4.97, P <.01). During the follow-up period, the incidence of ischemic vascular events was higher in the CR group than in the CS group; the proportion of patients with mRS score of 0-2 points at 6 months was significantly lower in CR group than in CS group. CR (hazard ratio [HR]: 2.82, 95% CI, 1.23-6.94, P <.01), diabetes (HR: 1.61, 95% CI, 1.01-3.49, P = .02), and hypertension (HR: 1.84, 95% CI, 1.12-4.72, P = .03) were independent risk factors for ischemic vascular events.

CONCLUSION

The incidence of CR in IS patients taking clopidogrel is relatively high in the Chinese population. CR is associated with ischemic vascular events, including RIS, and poor neurological recovery.

[Neurosurgery in a patient on dual antiplatelet therapy. Case report and the review of the literature]

INTRODUCTION

A neurosurgical intervention in a patient on dual antiplatelet therapy is a serious challenge for both the neurosurgeon and anesthesiologist..

MATERIAL AND METHODS

The article describes a clinical case of a successful urgent neurosurgical intervention (ventriculoperitoneostomy for obstructive hydrocephalus caused by a large meningioma of the posterior surface of the petrous pyramid) in a patient on dual antiplatelet therapy (DAT) due to a recently placed coronary stent..

CONCLUSION

Given a high risk of coronary stent thrombosis, the surgery was performed in the presence of ongoing DAT. There were no intracranial hemorrhagic complications, but subcutaneous hemorrhagic complications developed. The article discusses the features of managing similar patients whose number is growing.

Association between CYP2C19 Polymorphisms and Outcomes in Cerebral Endovascular Therapy

BACKGROUND AND PURPOSE

Differing responses to clopidogrel following endovascular treatment of cerebrovascular diseases may increase the risk of vascular complications. CYP2C19 gene polymorphisms influence clopidogrel activity. We aimed to study the clinical impact of CYP2C19 gene polymorphisms in patients undergoing endovascular treatment.

MATERIALS AND METHODS

This was a prospective, longitudinal, observational study. Information on demographics and cerebrovascular status was collected as baseline. Clopidogrel response was tested by the VerifyNow P2Y12 assay. CYP2C19 genotyping was undertaken by polymerase chain reaction-restriction fragment length polymorphism. Three-month follow-up data included vascular complications, mortality, and modified Rankin Scale score. Associations were investigated among CYP2C19 genotypes, clopidogrel responsiveness, and clinical outcomes.

RESULTS

One hundred and eight participants were included. Median age was 56 years (interquartile range, 48.8-65.0 years), and 35 (32.4%) were male. Forty-four participants were classified into group 1 (homozygous CYP2C19*1/*1); 31, into group 2 (25 with CYP2C19*1/*2, two with CYP2C19*1/*3, three with CYP2C19*3/*3, one with CYP2C19*2/*3); 28, into group 3 (24 with CYP2C19*1/*17, four with CYP2C19*17/*17); and 5, into group 4 (CYP2C19*2/*17). A significantly higher proportion of participants in group 3 experienced ischemic events (9 of 28, 32.1%) compared with group 1 (5 of 44, 11.4%; P = .04; odds ratio, 3.7; 95% confidence interval, 1.1-12.6). There was no significant difference in clopidogrel response among the 4 genotype groups.

CONCLUSIONS

Individuals with CYP2C19*17 may have increased risk of ischemic events following endovascular treatment, independent of clopidogrel responsiveness. Larger studies are required to confirm the influence of CYP2C19*17 on clinical outcomes and to understand the mechanisms for increased ischemic events.

Genetic determinations of variable responsiveness to clopidogrel and implications for neurointerventional procedures

Endovascular intervention is emerging as a substitute for open surgical procedures for the treatment of cerebrovascular disease. However, up to 9% of patients undergoing neurointerventional procedures develop thromboembolic complications. Strategies to reduce periprocedural thromboembolic events are dominated by the use of dual antiplatelet therapy (DAT) which has been validated based on studies of peripheral vascular and coronary intervention. Of note, DAT decreases adverse vascular outcomes by 75-80% in patients undergoing percutaneous coronary intervention (PCI). It follows that similar treatment effects would be observed in neurointerventional populations. However, a growing body of evidence demonstrates that a subgroup of patients respond suboptimally to DAT, and in particular to clopidogrel (termed clopidogrel hyporesponders). These patients may be at an increased risk of thromboembolic complications such as in-stent thrombosis following neurointerventional procedures. Previous studies report 5-30% suboptimal response to clopidogrel in the cardiovascular population, while a higher prevalence is seen in populations undergoing neurointerventional procedures, i.e. as much as 66%. Knowledge of the mechanism leading to clopidogrel hyporesponsiveness is accumulating. A number of genetic polymorphisms, in particular CYP 2C19*2, have been associated with clopidogrel hyporesponsiveness and clinical outcomes. In addition, there are significant differences in the prevalence of CYP 2C19*2 across racial groups. Approximately 50% of Asians and 25% of Caucasians harbor the CYP 2C19*2 allele. While no prospective randomized trials currently exist to demonstrate improved clinical outcomes with genotype-based treatment for carriers of the CYP 2C19*2 polymorphism, a number of studies show that an increased dose of clopidogrel improves platelet inhibition in hyporesponders. The aim of the review is to examine the current understanding of the genetic basis of clopidogrel hyporesponsiveness in patients undergoing neurointerventional procedures and to explore current efforts using genotype and phenotype testing as well as alternative strategies to overcome the clopidogrel hyporesponsiveness.

High on-treatment platelet reactivity in peripheral endovascular procedures

The use of aspirin is considered the "gold standard" for the decrease of major adverse cardiovascular events in patients with atherosclerosis, including peripheral arterial disease (PAD), whereas a dual-antiplatelet regimen with aspirin and clopidogrel is usually indicated for such patients after angioplasty and stent deployment. However, a substantial number of subsequent adverse events still occur, even in patients who receive double-antiplatelet therapy. The "high on-treatment platelet reactivity" (HTPR) phenomenon has been lately recognized and plays a major role in the management of patients with PAD. Greater and more rapid inhibition of platelet aggregation has become the goal for new antiplatelet agents with the expectation of further improving outcomes for percutaneous intervention for PAD. The purpose of this review article is to highlight current evidence regarding the prevalence, aetiology, and clinical implications of HTPR in PAD as well as to discuss the possibilities of novel alternative antiplatelet regiments.

Clopidogrel responsiveness in patients undergoing peripheral angioplasty

PURPOSE

To investigate the incidence and clinical significance of platelet responsiveness in patients receiving clopidogrel after peripheral angioplasty procedures.

MATERIALS AND METHODS

This prospective study included patients receiving antiplatelet therapy with clopidogrel 75 mg after infrainguinal angioplasty or stenting and who presented to our department during routine follow-up. Clopidogrel responsiveness was tested using the VerifyNow P2Y12 Assay. Patients with residual platelet reactivity units (PRU) ≥ 235 were considered as nonresponders (NR group NR), whereas patients with PRU < 235 were considered as normal (responders [group R]). Primary end points were incidence of resistance to clopidogrel and target limb reintervention (TLR)-free survival, whereas secondary end points included limb salvage rates and the identification of any independent predictors influencing clinical outcomes.

RESULTS

In total, 113 consecutive patients (mean age 69 ± 8 years) with 139 limbs were enrolled. After clopidogrel responsiveness analysis, 61 patients (53.9 %) with 73 limbs (52.5 %) were assigned to group R and 52 patients (46.1 %) with 66 limbs (47.5 %) to group NR. Mean follow-up interval was 27.7 ± 22.9 months (range 3-95). Diabetes mellitus, critical limb ischemia, and renal disease were associated with clopidogrel resistance (Fisher's exact test; p < 0.05). According to Kaplan-Meier analysis, TLR-free survival was significantly superior in group R compared with group NR (20.7 vs. 1.9 %, respectively, at 7-year follow-up; p = 0.001), whereas resistance to clopidogrel was identified as the only independent predictor of decreased TLR-free survival (hazard rate 0.536, 95 % confidence interval 0.31-0.90; p = 0.01). Cumulative TLR rate was significantly increased in group NR compared with group R (71.2 % [52 of 73] vs. 31.8 % [21 of 66], respectively; p < 0.001). Limb salvage was similar in both groups.

CONCLUSION

Clopidogrel resistance was related with significantly more repeat interventions after peripheral angioplasty procedures.

Superficial temporal artery-middle cerebral artery anastomosis for internal carotid artery occlusion by subacute in-stent thrombosis after carotid artery stenting

Alternative to carotid endarterectomy, carotid artery stenting (CAS) can be performed for symptomatic severe stenosis of internal carotid artery, especially for high-risk patients. Among several complications after CAS, subacute in-stent thrombosis is rare but important, because patient's condition can deteriorate rapidly. Subacute in-stent thrombosis with carotid artery occlusion can be managed by superficial temporal artery-middle cerebral artery (STA-MCA) anastomosis. We report two cases of STA-MCA anastomosis for internal carotid artery occlusion by subacute in-stent thrombosis after CAS.