Polimorfisme COX-1 terhadap Agregasi Platelet pada Pasien Penyakit Jantung Koroner

Polimorfisme genetik COX-1 (Cyclooxygenase 1) menjadi salah satu faktor penyebab variasi respon terhadap agregasi platelet. Variasi tersebut dapat menimbulkan Coronary Arthery Disease (CAD) pada pasien penyakit jantung koroner (PJK). Penelitian ini dilakukan di RSUD Sidoarjo di Jawa Timur selama 1 bulan yaitu terhitung mulai bulan November hingga Desember 2017 dengan melibatkan 30 pasien. Metode penelitian yang digunakan yaitu Polymerase Chain Reaction (PCR) agar pemeriksaan polimorfisme COX-1 dan metode Light Transmittance Aggregometry (LTA) untuk pengukuran agregasi platelet. Dari 30 pasien yang terlibat dengan penelitian ini didapatkan jenis polimorfisme COX-1 homozygout (wild type) sebanyak 4 pasien dengan nilai bp pada kisaran rentang 233-243dan Heterozygot sebanyak 26 pasien dengan kisaran rentang 244-294. Analisis yang dilakukan agar mengetahui hubungan antara polimorfisme COX-1 terhadap agregasi platelet pada pasien PJK yaitu analisis inferensial, dimana diperoleh nilai p=0,423. Dari hasil uji analisis yang diperoleh, maka dapat diambil kesimpulan bahwa tidak hubungan antara polimorfisme COX-1 terhadap agrgasi platelet.

Platelet Reactivity in Hepatitis C Virus–Infected Patients on Dual Antiplatelet Therapy for Acute Coronary Syndrome

Background Coronary artery disease (CAD) has been recognized as a serious and potentially life‐threatening complication of Hepatitis C Virus (HCV) infection. High on‐treatment platelet reactivity has been associated with high risk of ischemic events in patients with CAD, but data regarding the association with HCV infection are still lacking. This post hoc analysis aims to assess high on‐treatment platelet reactivity, severity of CAD, and long‐term outcomes of patients with acute coronary syndrome (ACS) who were infected with HCV. Methods and Results Patients with ACS who were infected with HCV (n=47) were matched to patients with ACS and without HCV (n=137) for age, sex, diabetes mellitus, hypertension, and renal function. HCV‐infected patients with ACS had higher levels of platelet reactivity (ADP 10 –light transmittance aggregometry, 56±18% versus 44±22% [ P =0.002]; arachidonic acid–light transmittance aggregometry, 25±21% versus 16±15% [ P =0.011]) and higher rates of high on‐treatment platelet reactivity on clopidogrel and aspirin compared with patients without HCV. Moreover, HCV‐infected patients with ACS had higher rates of multivessel disease (53% versus 30%; P =0.004) and 3‐vessel disease (32% versus 7%; P <0.001) compared with patients without HCV. At long‐term follow‐up, estimated rates of major adverse cardiovascular events (cardiac death, nonfatal myocardial infarction, and ischemia‐driven revascularization) were 57% versus 34% ( P =0.005) in HCV‐ and non–HCV‐infected patients with ACS, respectively. In addition, thrombolysis In Myocardial Infarction (TIMI) major bleeding rates were higher in HCV‐infected patients (11% versus 3%; P =0.043) compared with noninfected patients. Multivariable analysis demonstrated that HCV infection was an independent predictor of high on‐treatment platelet reactivity, severity of CAD, and long‐term outcome. Conclusions In this hypothesis‐generating study, patients with ACS and HCV infection showed increased on‐treatment platelet reactivity, more severe CAD, and worse prognosis compared with patients without HCV.

Comparison of acetylsalicylic acid and clopidogrel non-responsiveness assessed by light transmittance aggregometry and PFA-100® in patients undergoing neuroendovascular procedures

ObjectivesDual platelet inhibition is commonly used for prevention of cardiovascular events in patients undergoing neuroendovascular procedures. Non-responsiveness to platelet inhibitors may be associated with adverse outcomes. The aim of this study was to evaluate the reliability of the platelet function analyzer PFA-100® in comparison to light transmittance aggregometry (LTA) for monitoring clopidogrel and acetylsalicylic acid (ASA) non-responsiveness in a cohort of patients treated for intracranial aneurysm or cranial artery stenosis.MethodsNon-responsiveness to clopidogrel and ASA was assessed by LTA using adenosine diphosphate (ADP) and arachidonic acid and by PFA-100® with the ADP/prostaglandin E1 (PGE1) and collagen/epinephrine cartridges, respectively.ResultsA total of 203 patients (145 females; median age, 57 years) were analyzed. Agreement between the two tests was poor for clopidogrel non-responsiveness (ƙ=0.19) and not better than chance for ASA non-responsiveness (ƙ=0.01). Clopidogrel non-responsiveness by LTA and PFA-100® was associated with higher von Willebrand factor antigen and activity levels. ADP-induced platelet disaggregation was lower in patients with clopidogrel non-responsiveness as assessed by PFA-100®. Clopidogrel non-responsiveness by LTA was associated with a higher prevalence of diabetes and a higher body mass index (BMI). Adverse outcomes (death, thromboembolism, or in-stent thrombosis) occurred in 13% (n=26) of all patients independently of ASA and clopidogrel non-responsiveness as assessed by both devices.ConclusionsOur results show that LTA and PFA-100® are not interchangeable in the assessment of ASA and clopidogrel non-responsiveness in patients undergoing neuroendovascular interventions.

Point of Care Tests VerifyNow P2Y12 and INNOVANCE PFA P2Y Compared to Light Transmittance Aggregometry After Fibrinolysis

Detection of high on-treatment platelet reactivity (HPR) by point-of-care tests has not been validated after successful fibrinolysis for ST-elevation myocardial infarction. We assessed the validity of the point-of-care VerifyNow P2Y12 (VN) and INNOVANCE PFA P2Y (PFA) tests on HPR compared to light transmittance aggregometry (LTA) in these patients. The HPR was identified in 10 (34.5%) patients, 15 (51.7%) patients, and 14 (50%) patients using LTA, VN, and PFA, respectively. Discrepancies were observed between the tests despite significant correlations between platelet reactivity measures by LTA and VN ( r = 0.74; P < .0001) and LTA and PFA ( r = .75; P < .0001). Compared to LTA, VN and PFA were associated with a 92% and 53% and 92% and 64% positive predictive value (PPV) and negative predictive value (NPV), respectively, in detecting HPR. When combined, VN and PFA results yielded 90% and 100% PPV and NPV values if discrepancies between the 2 tests were considered as non-HPR. The VN or PFA identify patients without HPR correctly but overestimate the proportion of HPR patients. The association of the 2 tests, in case of HPR, improves the accuracy of the detection of HPR.

Thromboxane Formation Assay to Identify High On-Treatment Platelet Reactivity to Aspirin

Platelet inhibition by aspirin is indispensable in the secondary prevention of cardiovascular events. Nevertheless, impaired aspirin antiplatelet effects (high on-treatment platelet reactivity [HTPR]) are frequent. This is associated with an enhanced risk of cardiovascular events. The current gold standard to evaluate platelet hyper-reactivity despite aspirin intake is the light-transmittance aggregometry (LTA). However, pharmacologically, the most specific test is the measurement of arachidonic acid (AA)-induced thromboxane (TX) B2 formation. Currently, the optimal cut-off to define HTPR to aspirin by inhibition of TX formation is not known. Therefore, in this pilot study, we aimed to calculate a TX formation cut-off value to detect HTPR defined by the current gold standard LTA. We measured platelet function in 2,507 samples. AA-induced TX formation by ELISA and AA-induced LTA were used to measure aspirin antiplatelet effects. TX formation correlated nonlinearly with the maximum of aggregation in the AA-induced LTA (Spearman's rho R = 0.7396; 95% CI 0.7208-0.7573, p < 0.0001). Receiver operating characteristic analysis and Youden's J statistics revealed 209.8 ng/mL as the optimal cut-off value to detect HTPR to aspirin with the TX ELISA (area under the curve: 0.92, p < 0.0001, sensitivity of 82.7%, specificity of 90.3%). In summary, TX formation ELISA is reliable in detecting HTPR to aspirin. The calculated cut-off level needs to be tested in trials with clinical end points.

Rationale and Design of ST-ON-SET: Assessment of Antiplatelet Effect after Ticagrelor Loading Dose in STEMI pPatients and NSTEMI Patients

<p>Background: Delayed platelet inhibition by ticagrelor has been initially documented in STEMI subjects. To the best of our knowledge, no data exists about the direct description of early onset of platelet inhibition after ticagrelor loading dose (LD) in different clinical forms of ACS, especially in Chinese patients. The ST-ON-SET study is designed to address this unmet need.</p><p><br /> Method/Design: The ST-ON-SET study is a single center, prospective, observational, open-label, investigator-initiated study. Platelet inhibition assessed by Light transmittance aggregometry (LTA) and plasma concentrations of ticagrelor and its metabolites would be investigated serially. The primary outcome is the inhibition of platelet aggregation measured by LTA at 2 hours after ticagrelor LD. Moreover, baseline inflammatory and thrombotic biomarkers would be measured to investigate the potential underlying influences of platelet inhibition.</p>Conclusion: The study is designed to characterize pharmacokinetic and pharmacodynatic profiles of ticagrelor LD in Chinese STEMI and NSTEMI patients. Furthermore, preliminary investigation of the underlying mechanism of initial delayed platelet inhibition by ticagrelor would be conducted.