Four detection methods for antiplatelet function of clopidogrel: A comparative study / 第二军医大学学报

Objective To assess the consistencies of VerifyNow system, thrombelastography (TEG), vasodilator-stimulated phosphoprotein (VASP), and PL-11 platelet analyzer in detecting the antiplatelet function of clopidogrel, and to discuss the clinical application values. Methods Totally 98 consecutive inpatients with ST-segment elevation myocardial infarction (STEMI), non-(NSTEMI), or coronary artery in-stent restenosis (SR) were included in this study. The patients were given a loading dose of 600-mg clopidogrel for 6 hours, 300-mg clopidogrel for at 24 hours, or chronic clopidogrel therapy (75 mg daily for ≥ 7 days) before the procedure. And then the antiplatelet effects were evaluated by VerifyNow, TEG, VASP and PL-11 platelet analyzer simultaneously, with the results of VerifyNow taken as the gold standard and P2Y12 reaction unit (PRU) ≥ 208 taken as high on-clopidogel treatment platelet reactivity (HTPR). Correlation analysis was done for the four methods, and area under ROC curve (AUC) was used to evaluate the value of each method for HTPR. Results The platelet inhibition rate detected by VerifyNow was positively correlated with that by TEG (r = 0. 234, P < 0. 05); by contrast, it was negatively correlated with the platelet reactivity index (PRI) measured by VASP, the maximum platelet aggregation rate (MAR) by PL-11 and the maximum adenosine diphosphate (MA-ADP) by TEG (r = –0. 299, P<0. 01; r = –0. 330, P< 0.05; r = –0. 237, P<0. 05). The PRU values was negatively correlated with the platelet inhibition rate detected by VerifyNow (r = –0.815, P < 0. 01). The area under ROC curve of PL-11 platelet analyzer was the highest (0. 644). Conclusion TEG, VASP, and PL-11 platelet function testing systems all have consistency with the “gold standard” VerifyNow in some extent, with PL-11 platelet analyzer showing the highest sensitivity and specificity.

Correlation Between the CYP2C19 Phenotype Status and the Results of Three Different Platelet Function Tests in Cardiovascular Disease Patients Receiving Antiplatelet Therapy: An Emphasis on Newly Introduced Platelet Function Analyzer-200 P2Y Test

BACKGROUND: An association has been reported between CYP2C19 polymorphism and the altered antiplatelet activity of clopidogrel. We investigated this association using the newly introduced platelet function analyzer (PFA)-200 (INNOVANCE PFA-200 System; Siemens Healthcare, Germany) P2Y test. METHODS: Polymorphisms of CYP2C19*2, *3, *17 and the degree of inhibition of platelet function were determined in 83 patients. Three different platelet function tests were used to evaluate the degree of platelet inhibition and to check the association with genotype. RESULTS: The post-procedure PFA-200 values of extensive metabolizers (EM) patients (285.3+/-38.8) were higher than those of intermediate metabolizers (IM) and poor metabolizers (PM) patients (227.7+/-98.3 and 133.7+/-99.2, respectively; P=0.024). Light transmittance aggregometry (LTA) and the VerifyNow system showed that the post-procedure values for EM patients were lower than those of IM and PM patients (LTA: 24.4+/-15.7, 34.1+/-17.6, and 42.2+/-16.9, respectively, P<0.001; VerifyNow: 133.2+/-60.5, 171.5+/-42.6, and 218.7+/-59.3, respectively, P<0.001). The high residual platelet reactivity (HPR) rates were significantly different among the EM, IM, and PM groups using PFA-200 (PM:IM:EM=82.4:40.6:11.8, P<0.001). CONCLUSIONS: Approximately, 59.0% of Korean patients with cardiovascular disease receiving clopidogrel had CYP2C19 loss-of-function genotypes classified as IM or PM, and the frequency was similar to the data from Asian people. The PFA-200, LTA, and VerifyNow platelet function tests revealed evidence of a significant association between the efficacy of clopidogrel and CYP2C19 genotypes.

Change of Platelet Reactivity to Antiplatelet Therapy after Stenting Procedure for Cerebral Artery Stenosis: VerifyNow Antiplatelet Assay before and after Stenting / 신경중재치료의학

PURPOSE: VerifyNow antiplatelet assays were performed before and after stenting for various cerebral artery stenoses to determine the effect of the procedure itself to the function of dual antiplatelets given. MATERIALS AND METHODS: A total of 30 consecutive patients underwent cerebral arterial stenting procedure were enrolled. The antiplatelet pretreatment regimen was aspirin (100 mg daily) and clopidogrel (300 mg of loading dose followed by 75mg daily). VerifyNow antiplatelet assay performed before and right after stenting. The two test results were compared in terms of aspirin-reaction unit (ARU), P2Y12 reaction units (PRU), baseline (BASE), and percentage inhibition. We evaluated occurrence of any intra-procedural in-stent thrombosis or immediate thromboembolic complication, and ischemic events in 1-month follow-up. RESULTS: The median Pre-ARU was 418 (range, 350-586). For clopidogrel the medians of the pre-BASE, PRU, and percent inhibition were 338 (279-454), 256 (56-325), and 27% (0-57%). The medians of the post-ARU, BASE, PRU, and percent inhibition after stenting were 469 (range, 389-573), 378 (288-453), 274 (81-370), and 26% (0-79%). There was a significant increase of ARU (p=0.045), BASE (p=0.026), and PRU (p=0.018) before and after stenting. One immediate thromboembolic event was observed in poor-response group after stenting. There was no in-stent thrombosis and ischemic event in 1-month follow-up. CONCLUSION: We observed a significant increase of platelet reactivity to dual antiplatelet therapy right after stenting procedure for various cerebral arterial stenoses.

Análise farmacogenômica de pacientes submetidos à dupla antiagregação plaquetária / Pharmacogenomics analysis of patients undergoing double platelet antiagregation

O presente estudo avaliou o perfil farmacogenômico de 338 pacientes, sob terapia antiagregante. Os pacientes foram submetidos a tratamento prévio com AAS (100mg/dia) e clopidogrel (75mg/dia) por no mínimo cinco dias antes da angioplastia coronária. Os indivíduos com resposta considerada indesejada <30% de inibição de PRU (do inglês, P2RY12 Reaction Unit) para clopidogrel e >550 ARU (do inglês, Aspirin Reaction Unit), foram considerados como não respondedores. As concentrações plasmáticas dos antiagregantes foram determinadas por cromatografia líquida acoplada à espectrometria de massa do tipo triploquadrupolo (LC-MS/MS). A taxa da inibição da agregação plaquetária foi medida utilizando-se o sistema VerifyNow®. A expressão gênica global das células totais do sangue periférico foi avaliada pela tecnologia de microarranjos de DNA Human Exon ST 1.0 Array. Características genotípicas dos pacientes também foram avaliadas pelo sistema Sequenom®. Assim, foi possível obter como resultados a identificação de 64% e 10% para pacientes não respondedores ao clopidogrel e AAS respectivamente, sendo que para o primeiro foi possível identificar a associação desta não resposta a variáveis clínicas como diabetes (p = 0,003), hipertensão (p = 0,011) e hábito de fumar (p = 0,041) e sexo (p = 0,022) e idade dos pacientes (p = 0,004) em relação à resposta ao AAS. O método de quantificação simultânea do clopidogrel, seu metabólito majoritário e do AS (metabólito do AAS), apresentou limites de quantificação entre de 2 a 500 ng/mL, 2 a 2000 ng/mL e de 20 a 2000 ng/mL, respectivamente. O estudo de associação encontrou uma relação significante da presença dos SNPs presentes nos genes CYP5A1 (rs2299890) e CYP2C19 (rs4244285 e rs3758580), com a variação na resposta ao clopidogrel, obtendo um valor de p corrigido pelo teste de permutação inferior a 0,001. Como também, uma fraca associação da variação na resposta do AAS com o SNP rs9605030 do gene COMT (p = 0,009). Os resultados do ...

This study investigated the pharmacogenomics profile of 338 patients under antiplatelet therapy. Patients undergoing pretreatment with ASA (100 mg/day) and clopidogrel (75mg/day) for at least five days prior to coronary angioplasty. Individuals with response <30% of PRU (P2RY12 reaction unit) were considering non responder for clopidogrel and >550 of ARU (aspirin reaction unit), were considered as non responders for ASA. Plasma concentrations of the antiagregation drugs were determined by liquid chromatography followed mass spectrometry of triple quadrupole detection (LC-MS/MS). The rate of inhibition of platelet aggregation was measured using the VerifyNow® system. The global gene expression of total cells in blood was assessed by DNA microarray technology Human Exon 1.0 ST Array. Genotypic characteristics of the patients were also evaluated by the Sequenom® system. Thus it was possible to obtain results such as identification of 64% and 10% for patients non responders to clopidogrel and aspirin respectively, and for the first could identify the association of this response to variables such as diabetes (p = 0.003), hypertension (p = 0.011) and smoking (p = 0.041) for clopidogrel and sex and age in relation to response to ASA (p = 0.022 and p = 0.004, respectively). The method of simultaneous quantification of clopidogrel and its major metabolite of AS (metabolite of ASA), had quantification limits between 200 to 500 ng/mL 2000-2000 ng/mL and 20 to 2000 ng/mL, respectively. The association study found a significant grating presence of SNPs present in genes CYP5A1 (rs2299890) and CYP2C19 (rs4244285 and rs3758580), with the variation in the response to clopidogrel, obtaining a corrected p value by permutation test below 0.001. As well, a weak association of variation in the response of ASA with the SNP rs9605030 of the gene COMT (p = 0.009). The results of microarray related therapeutic response to clopidogrel with genes CA2, MKRN1, ABCC3 and MBP followed by...

Implication of aspirin resistance: Simple laboratory finding or important clinical criteria? / 대한내과학회지

Aspirin resistance defined by light transmittance aggregometry (LTA) or urinary 11-dehydro-thromboxane B2 has been associated with an increased risk of adverse clinical events. However, aspirin resistance based on the point-of-care VerifyNow-Aspirin assay (aspirin reaction unit > or = 550) shows poor sensitivity compared with LTA. In aspirin-treated patients, activation by cyclooxygenase- independent pathways may be associated with residual platelet reactivity, which may cause adverse clinical outcomes in some portion. A large-scale, prospective study using several platelet function assays should be performed to establish the long-term clinical significance of antiplatelet resistance in Korean patients treated with coronary stenting. Accordingly, we can apply tailored antiplatelet therapy in resistant patients.

Incidence of Aspirin Resistance in the Patient Group of a University Hospital in Korea / 대한진단검사의학회지

BACKGROUND: Aspirin is the most common drug used for the prevention of arterial thrombosis. However, platelet responsiveness to aspirin is variable among individuals and it is important to detect aspirin resistance to improve clinical outcome. We analyzed the changes of platelet reactivity before and after aspirin treatment. We also investigated the incidence and influencing factors of aspirin resistance in Korean. METHODS: We tested platelet function in 198 patients who had been treated with aspirin in a Korean university hospital, and 59 of these patients were tested for platelet function before and after aspirin treatment. We also analyzed platelet reactivity in 136 patients who had not been treated with aspirin. Platelet function was tested using the VerifyNow Aspirin Assay (Accumetrics, USA). Platelet reactivity was expressed as aspirin reaction unit (ARU) and > or =550 ARU was defined as aspirin resistance. RESULTS: Platelet reactivity of 136 patients who had not been treated with aspirin was 632.2+/-46.3 ARU (mean+/-SD) (range, 462-675). Platelet reactivity of 198 patients who had been treated with aspirin was 472.5+/-60.0 (338-666) ARU, and 10.1% of patients were aspirin-resistant. The difference of platelet reactivity before and after aspirin treatment was 128.3+/-68.7 (-40-248) ARU. Hb level was lower and platelet count was higher in aspirin-resistant group than in aspirin-sensitive group (P<0.05). CONCLUSIONS: We demonstrated the distribution of platelet reactivity before and after aspirin treatment using the VerifyNow Aspirin Assay. The incidence of aspirin resistance was 10.1%, and low Hb level and high platelet count were related with aspirin resistance.