Dual antiplatelet therapy clopidogrel with low-dose cilostazol intensifies platelet inhibition in patients with ischemic stroke

Genotype-guided dual antiplatelet therapy in cerebrovascular disease: assessing the risk and benefits for ethnic populations

INTRODUCTION

Cerebrovascular disease is a leading cause of morbidity and mortality in the world and antiplatelet therapy is a main pharmacologic means of secondary prevention. Clinical information has accumulated about benefit of dual antiplatelet therapy in certain clinical scenarios, genetic causes of antiplatelet resistance and its effect on clinical outcomes, and ethnic and geographic distributions of genetic polymorphisms.

AREAS COVERED

This review covers literature related to the pharmacogenomics of antiplatelet agents with a focus on ethnic variability, antiplatelet resistance, and dual antiplatelet therapy in cerebrovascular disease.

EXPERT OPINION

Selecting patients for dual antiplatelet therapy and specific agents require consideration of multiple factors. Ethnic factors should be considered in certain circumstances, but additional research is needed to determine the generalizability of the findings.

Verifynow P2Y12 PRU-Guided Modification of Clopidogrel for Prevention of Recurrent Ischemic Stroke: A Real-World Prospective Cohort Study

INTRODUCTION

Clopidogrel resistance causes recurrent stroke. However, outcomes of modified antiplatelet medications to prevent recurrent ischemic stroke are not well known.

METHODS

Patients who received clopidogrel with and without modification as initial treatment for stroke were recruited and compared. The primary outcome was ischemic stroke and myocardial infarction at the 1-year follow-up. The secondary outcome was bleeding complications.

RESULTS

Overall, 206 patients treated with clopidogrel were enrolled and were divided into the modification (n = 39) and no modification (n = 167) groups. There was a significant difference in the incidence of severe cerebral arterial stenosis between the two groups (modification group, 16/39, 41.03%; no modification group, 36/167, 21.56%, P = 0.012) at baseline. The loss to follow-up rate was 12.14% (25/206). After adjustment for severe cerebral artery stenosis, antiplatelet modification based on the platelet reactivity unit (PRU) value significantly improved in the per protocol set (odds ratio 0.142, 95% confidential interval 0.022-0.898, P = 0.038). The area under the curve of the different PRU cutoff values were 0.630, 0.605, and 0.591 (P = 0.016, 0.051, and 0.092) for PRU 190, 208, and 235, respectively.

CONCLUSION

Verifynow P2Y₁₂ PRU-guided modification of clopidogrel for ischemic stroke significantly improved or prevented recurrence at the 1-year follow-up. Our findings suggest that clopidogrel therapy based on the PRU cutoff value of 190 should be considered to improve outcomes.

TRIAL REGISTRATION

ClinicalTrials.gov NCT02618265 (December 1, 2015).

Anticoagulant therapy for recurrent in-stent thrombosis following carotid artery stenting: A case report

We report a case in which strict anticoagulant therapy management was useful for a recurrent in-stent thrombosis after carotid artery stenting (CAS). An 84-year-old man presented with cognitive decline that progressed rapidly over two months. Head magnetic resonance imaging showed an acute-stage infarct occurring frequently in the right cerebral hemisphere, and he underwent hospitalization and treatment. On neck magnetic resonance angiography (MRA), severe stenosis was found at the origin of the right internal carotid artery. Since he took aspirin, clopidogrel, and a statin after placement of an indwelling coronary stent, we treated him by adding argatroban and edaravone drip therapy to his existing medication. CAS was performed on day 15 of the hospitalization. A small in-stent thrombosis with plaque protrusion was observed on a carotid sonogram performed at the second day after CAS, and re-examination at the seventh day confirmed enlargement of the lesion and an increase in peak systolic velocity; thus, a second CAS procedure was performed on the same day. After the second CAS, oral cilostazol was added for triple antiplatelet therapy (TAPT), but as the in-stent thrombosis increased further, we started a continuous infusion of heparin with the goal of an activated partial thromboplastin time (APTT) of 50 to 65 seconds. After starting heparin, the lesion did not progress; after 14 days of continuous heparin infusion, the patient was switched to TAPT, and regression of the plaque was confirmed. This case demonstrated to us that controlled anticoagulation therapy can be an effective treatment for cases in which a thrombus recurs within a stent after CAS.

Antiplatelet Therapy of Cilostazol or Sarpogrelate with Aspirin and Clopidogrel after Percutaneous Coronary Intervention: A Retrospective Cohort Study Using the Korean National Health Insurance Claim Database

Background/Objectives

Addition of cilostazol or sarpogrelate to the standard dual antiplatelet therapy of aspirin and clopidogrel has been implemented in patients that underwent percutaneous coronary intervention (PCI) with stents in Korea. This study aimed to evaluate the efficacy and safety of triple antiplatelet therapies.

Methods

This retrospective cohort study was performed using the Korean National Insurance Claim Data of the Health Insurance Review and Assessment Service from January 1, 2009 to December 31, 2014. The study cohort population consisted of patients with ischemic heart diseases and a history of PCI. They were treated with antiplatelet therapy of aspirin, clopidogrel (AC); aspirin, clopidogrel, cilostazol (ACCi); or aspirin, clopidogrel, sarpogrelate (ACSa) during the index period from January 1, 2010 to December 31, 2011. During the follow-up period up to December 31, 2014, the major adverse cardiac or cerebral events (MACCE) including death, myocardial infarction, target lesion revascularization, and ischemic stroke were assessed. Bleeding complications were also evaluated as adverse drug events.

Results

Out of 93,876 patients with PCI during the index period, 69,491 patients started dual (AC) or triple therapy (ACSa or ACCi). The clinical outcomes of comparing ACSa and ACCi therapy showed beneficial effects in the ACSa group in the prevention of subsequent cardiac or cerebral events. After Propensity score-matching between ACSa and ACCi groups, there were significant differences in MI and revascularization, with corresponding HR of 0.38 (95% CI, 0.20–0.73) and 0.66 (95% CI, 0.53–0.82) in ACSa vs. ACCi at 12 months, respectively. At the 24-month follow-up, the triple therapy groups (ACS or ACC) had a higher incidence of MACCE compared to the dual therapy (AC) group; ACSa vs. AC HR of 1.69 (95% CI, 1.62–1.77); ACC vs. AC HR of 1.22 (95% CI, 1.06–1.41). There was no significant difference in severe or life-threatening bleeding risk among three groups; ACSa vs. AC, HR of 0.68 (95% CI, 0.37–1.24), ACCi vs. AC, HR of 0.91 (95% CI, 0.77–1.09).

Conclusion

Sarpogrelate-containing triple antiplatelet therapy demonstrated comparable rates of MACCE prevention to the conventional dual antiplatelet therapy after PCI without significantly increasing bleeding risk during the two-year follow-up period.

Comparison of antiplatelet effect and safety of clopidogrel napadisilate with clopidogrel bisulfate in stroke patients: multicenter, randomized, open-label, phase 4, non-inferiority clinical trial

OBJECTIVE

Clopidogrel napadisilate has better chemical stability than clopidogrel bisulfate. Our trial's objective was to compare the efficacy and safety of clopidogrel napadisilate with clopidogrel bisulfate in participants with ischemic stroke.

RESEARCH DESIGN AND METHODS

The study was a phase 4, 4 week, randomized, parallel-group, non-inferiority trial. Patients with ischemic stroke were randomized to receive either clopidogrel napadisilate 75 mg or clopidogrel bisulfate 75 mg. The primary study endpoint was change from baseline in P2Y12 percentage inhibition at week 4. The primary analysis was conducted in the per-protocol population. Non-inferiority was confirmed if the lower limit of the 95% confidence interval (CI) of the treatment difference was greater than or equal to -9.0% points.

RESULTS

Sixty-one participants were randomly assigned clopidogrel napadisilate and 60 were randomly assigned clopidogrel bisulfate. Thirty-nine participants in the clopidogrel napadisilate group and 39 in the clopidogrel bisulfate group were analyzed for the primary endpoint. At 4 weeks, mean P2Y12 percentage inhibition had increased in both treatment groups. The estimated mean change from baseline was 22.3% with clopidogrel napadisilate and 21.4% with clopidogrel bisulfate; the estimated treatment difference of 0.9% (95% CI, -8.6 to 10.4) confirmed the non-inferiority of clopidogrel napadisilate to clopidogrel bisulfate.

CONCLUSIONS

Clopidogrel napadisilate was non-inferior to clopidogrel bisulfate as assessed by change in P2Y12 percentage inhibition. Rates of adverse events were similar between the two groups. Therefore, clopidogrel napadisilate is a useful alternative option for the dosing of ischemic stroke patient populations.

Optimization, ex vivo permeation, and stability study of lipid nanocarrier loaded gelatin capsules for treatment of intermittent claudication

In this study, an optimized nanodispersible oral dosage form (containing a lactate ester) was developed for cilostazol (CZL). CZL is a phosphodiesterase inhibitor used for intermittent claudication. We aimed to improve the dissolution rate and absorption of CZL giving it a better chance of oral bioavailability, and to evaluate its stability on storage. Suitable compositions of nanoemulsion preconcentrate formulations were screened via solubility and compatibility tests. Response surface methodology and a desirability approach were applied to optimize preconcentrates containing minimum amount of surfactant mixture, maximum amount of lipid, and possessing the smallest globule size, with the highest emulsification and dissolution rates and minimum risk of drug precipitation. As part of the optimization process, the main effect, interaction effects and quadratic effects of amounts of lipid, and surfactant/co-surfactant ratio on % transmittance, globule size, emulsification time, drug precipitation, and drug release were investigated. The optimized formulation consisting of 28.9% butyl lactate, 28.9% Capryol, 27.82% Solubilisant Gamma 2429, and 14.18% Transcutol possessing a globule size of 60 nm was mixed with Aerosil 200. This gave uniform free flowing granules, which were characterized for surface and powder properties. The self-nanoemulsifying granules (SNEGs) filled into hard gelatin capsules showed two- and threefold increase in CZL released compared with conventional tablet and pure drug, respectively. The amount of drug permeated using non-everted sac technique from the SNEGs was twofold higher than that permeated from the tablet suspension. The shelf life was 526 days at 25°C. Our study illustrated that the developed SNEGs, with bioenhancing ingredients, held great potential as a superior alternative to traditional oral formulations of CZL.

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

OBJECTIVE

Noncardiogenic ischemic stroke patients with chronic kidney disease (CKD) are known to have a greater rate of ischemic stroke recurrence than those without. Although clopidogrel is often used to prevent the recurrence of noncardiogenic ischemic stroke, the relationship between the response to clopidogrel and CKD is unclear. In the present study, the relationship between the response to clopidogrel and the presence of CKD was investigated in noncardiogenic ischemic stroke patients.

METHODS

A total of 129 noncardiogenic ischemic stroke patients receiving 75 mg/day of clopidogrel for ≥1 week were evaluated. The VerifyNow P2Y12 Assay was used to measure the level of platelet aggregation induced by 20 μM of adenosine diphosphate, and the degree of platelet aggregation and frequency of clopidogrel resistance were compared between 34 patients with CKD and 95 patients without CKD. Clopidogrel resistance was defined as a P2Y12 Reaction Units (PRU) value of >230 and/or % inhibition <20%.

RESULTS

The PRU value was 201.9±91.3 in the patients with CKD and 163.3±86.4 in the patients without CKD (p=0.035). The frequency of a PRU value of >230 was 44.1% (15 patients) among the patients with CKD and 17.9% (17 patients) among those without CKD (p=0.002). The percent inhibition was 29.9%±28.1% among the patients with CKD and 41.1%±28.0% among the patients without CKD (p=0.030). The frequency of % inhibition <20% was 47.1% (16 patients) among the patients with CKD and 26.3% (25 patients) among those without CKD (p=0.026).

CONCLUSION

The present study showed that noncardiogenic ischemic stroke patients with CKD have a greater frequency of clopidogrel resistance, thus suggesting that the response to clopidogrel is diminished in these patients.

Long-term clinical efficacy and safety of adding cilostazol to dual antiplatelet therapy for patients undergoing PCI: a meta-analysis of randomized trials with adjusted indirect comparisons

OBJECTIVE

To assess the long-term clinical efficacy and safety of adding cilostazol to aspirin plus clopidogrel (triple antiplatelet therapy, TAT) in patients undergoing percutaneous coronary intervention (PCI) and explore its role in the era of new generation adenosine diphosphate (ADP)-receptor antagonists.

METHODS

PUBMED, EMBASE, and the Cochrane Central Register of Controlled Trials were searched for randomized controlled trials (RCTs) comparing TAT versus dual antiplatelet therapy (DAT), followed by a manual search. Then, a meta-analysis of RCTs comparing TAT versus standard DAT in patients undergoing PCI was performed. Furthermore, indirect comparisons of TAT versus new generation ADP-receptor antagonist based DAT (prasugrel or ticagrelor based DAT) were undertaken, with standard DAT as a common comparator. The included end-points were major adverse cardiovascular event (MACE), target lesion revascularization (TLR), target vessel revascularization (TVR), death, myocardial infarction (MI), stent thrombosis, bleeding and other drug adverse events.

RESULTS

Twelve RCTs with a total of 31,789 patients were included. Compared with standard DAT (n = 2551), TAT (n = 2545) significantly reduced the incidence of MACE (OR: 0.56, 95% CI: 0.47-0.68, P < 0.00001), TLR (OR: 0.51, 95% CI: 0.34-0.75, P = 0.0006) and TVR (OR: 0.59, 95% CI: 0.46-0.75, P < 0.0001), and did not change significantly in death (OR: 0.68, 95% CI: 0.44-1.05, P = 0.08), MI (OR: 0.80, 95% CI: 0.45-1.44, P = 0.46), stent thrombosis (OR: 0.61, 95% CI: 0.27-1.36, P = 0.23), major bleeding (OR: 1.42, 95% CI: 0.52-3.85, P = 0.49) and overall bleeding (OR: 1.16, 95% CI: 0.79-1.69, P = 0.45). Compared with prasugrel (n = 6813) or ticagrelor based DAT (n = 6732), TAT (n = 2545) further reduced the incidence of MACE (OR: 0.80, 95% CI: 0.72-0.90, P = 0.0012; OR: 0.83, 95% CI: 0.75-0.92, P = 0.0003, respectively).

CONCLUSIONS

Compared with standard DAT, the long-term use of TAT in patients with PCI gives more benefits in reducing the incidence of MACE, TLR and TVR without increasing bleeding. Furthermore, it might be superior to prasugrel or ticagrelor based DAT in term of MACE, which needs to be confirmed by future studies with direct comparisons.