Multiplate Research Articles

Elderly patients are hyperresponsive to potent P2Y12 inhibitors

Abstract Background Aging has recently been associated with increased basal platelet activation and adenosine diphosphate (ADP) hyperreactivity on the one hand, but decreased platelet response to thrombin receptor stimulation on the other hand in individuals without antiplatelet therapy. In the current study, we investigated platelet response to agonist stimulation in elderly patients (70 years or older) on dual antiplatelet therapy with potent P2Y12 inhibitors. Methods Platelet aggregation in response to arachidonic acid (AA), ADP, collagen, the protease-activated receptor (PAR)-1 agonist SFLLRN and the PAR-4 agonist AYPGKF was assessed by multiple electrode aggregometry in 79 prasugrel- and 77 ticagrelor-treated patients 3 days after acute percutaneous coronary intervention. Results In the overall study population (n=156), patients aged ≥70 years (n=33) had lower platelet aggregation in response to AA, ADP and SFLLRN than younger patients (all p<0.05). In prasugrel-treated patients (n=79), those aged ≥70 years (n=13) showed significantly lower platelet aggregation in response to all agonists compared to younger patients (all p<0.05). In contrast, in ticagrelor-treated patients (n=77), those aged ≥70 years (n=20) only had significantly lower ADP-inducible platelet aggregation than younger patients (p=0.03), whereas platelet aggregation in response to AA, collagen, SFLLRN and AYPGKF was similar between elderly and younger patients on ticagrelor (all p>0.05). Among patients aged ≥70 years, prasugrel-treated patients showed significantly lower platelet aggregation in response to AA, collagen and AYPGKF than those receiving ticagrelor (all p<0.05). Conclusion Patients aged ≥70 years on potent P2Y12 inhibitors exhibit increased inhibition of ADP-inducible platelet aggregation. In addition, elderly patients on prasugrel show a significantly lower response to AA, collagen, SFLLRN and AYPGKF than younger patients.Platelet aggregation prasugrel patientsPlatelet aggregation ticagrelor patients

Ticagrelor 60 vs. 90 mg in elderly ACS patients undergoing PCI: a randomized, crossover trial.

Although dual antiplatelet therapy with aspirin and a potent P2Y12 receptor inhibitor is currently recommended in patients with acute coronary syndrome (ACS), its use in elderly patients remains challenging. The aim of this trial is to evaluate the pharmacodynamic and pharmacokinetic profile of ticagrelor 60 vs. 90mg twice daily among elderly patients (≥75 years) with ACS undergoing percutaneous coronary intervention (PCI). PLINY The ELDER (NCT04739384) was a randomized, crossover trial testing the non-inferiority of a lower vs. standard dose of ticagrelor with respect to the primary endpoint of P2Y12 inhibition as determined by pre-dose P2Y12 reaction units (PRU) using the VerifyNow-P2Y12 (Accumetrics, San Diego, CA, USA). Other pharmacodynamic tests included light transmittance aggregometry, multiple electrode aggregometry, and response to aspirin. Plasma levels of ticagrelor and its active metabolite AR-C124910XX were also evaluated. A total of 50 patients (mean age 79.6±4.0 years, females 44%) were included in the trial. Ticagrelor 60mg was non-inferior to ticagrelor 90mg according to VerifyNow-P2Y12 results (PRU 26.4±32.1 vs. 30.4±39.0; least squares mean difference: -4; 95% confidence interval: -16.27 to 8.06; P for non-inferiority=0.002). Other pharmacodynamic parameters were similar between the two ticagrelor doses and there were no differences in response to aspirin. Plasma levels of ticagrelor (398.29±312.36ng/mL vs. 579.57±351.73ng/mL, P=0.006) and its active metabolite were significantly lower during treatment with ticagrelor 60mg. Although plasma concentrations were lower, ticagrelor 60mg twice daily provided a similar magnitude of platelet inhibition compared with ticagrelor 90mg twice daily among elderly patients undergoing PCI.

Association of CYP2C19 genotypes with postoperative atrial fibrillation after coronary artery bypass surgery.

This cohort study aims to assess the connection between cytochrome P450 family 2 subfamily C member 19 (CYP2C19) genotyping, platelet aggregability following oral clopidogrel administration, and the occurrence of postoperative atrial fibrillation (POAF) after off-pump coronary artery bypass graft (CABG) surgery. From May 2017 to November 2022, a total of 258 patients undergoing elective first-time CABG surgery, receiving 100 mg/day oral aspirin and 75 mg/day oral clopidogrel postoperatively, was included for analysis. These patients were categorized based on CYP2C19 genotyping. Platelet aggregability was assessed serially using multiple-electrode aggregometry before CABG, 1 and 5 days after the procedure, and before discharge. The incidences of POAF were compared using the log-rank test for cumulative risk. CYP2C19 genotyping led to categorization into CYP2C19*1*1 (WT group, n = 123) and CYP2C19*2 or *3 (LOF group, n = 135). Baseline characteristics and operative data showed no significant differences between the two groups. The incidence of POAF after CABG was 42.2% in the LOF group, contrasting with 22.8% in the WT group (hazard risk [HR]: 2.061; 95% confidence interval [CI]: 1.347, 3.153; p = 0.0013). Adenosine diphosphate-stimulated platelet aggregation was notably higher in the LOF group compared to the WT group 5 days after CABG (30.4% ± 6.5% vs. 17.9% ± 4.1%, p < 0.001), remaining a similar higher level at hospital discharge (25.6% ± 6.1% vs. 12.2% ± 3.5%, p < 0.001). The presence of CYP2C19 LOF was linked to a higher incidence of POAF and relatively elevated platelet aggregation after CABG surgery under the same oral clopidogrel regimen.

Ticagrelor downregulates the expression of proatherogenic and proinflammatory miR125-b compared to clopidogrel: A randomized, controlled trial

BackgroundPlatelet P2Y12 antagonist ticagrelor reduces cardiovascular mortality after acute myocardial infarction (AMI) compared to clopidogrel, but the underlying mechanism is unknown. Because activated platelets release proatherogenic and proinflammatory microRNAs, including miR-125a, miR-125b and miR-223, we hypothesized that the expression of these miRNAs is lower on ticagrelor, compared to clopidogrel. ObjectivesWe compared miR-125a, miR-125b and miR-223 expression in plasma of patients after AMI treated with ticagrelor or clopidogrel. MethodsAfter percutaneous coronary intervention on acetylsalicylic acid and clopidogrel, 60 patients with first AMI were randomized to switch to ticagrelor or to continue with clopidogrel. Plasma expression of miR-223, miR-125a-5p, miR-125b was measured using quantitative polymerase chain reaction at baseline and after 72 h and 6 months of treatment with ticagrelor or clopidogrel in patients and one in 30 healthy volunteers. Multiple electrode aggregometry using ADP test was used to determine platelet reactivity in response to P2Y12 inhibitors. ResultsExpression of miR-125b was higher in patients with AMI 72 h and 6 months, compared to healthy volunteers (p = 0.001), whereas expression of miR-125a-5p and miR-223 were comparable. In patients randomized to ticagrelor, expression of miR-125b decreased at 72 h (p = 0.007) and increased back to baseline at 6 months (p = 0.005). Expression of miR-125a-5p and miR-223 was not affected by the switch from clopidogrel to ticagrelor. ConclusionsTicagrelor treatment leads to lower plasma expression of miR-125b after AMI, compared to clopidogrel. Higher expression of miR-125b might explain recurrent thrombotic events and worse clinical outcomes in patients treated with clopidogrel, compared to ticagrelor.

Low on-clopidogrel ADP- and TRAP-6-induced platelet aggregation in patients with atrial fibrillation undergoing percutaneous coronary intervention: an observational pilot study

High on-clopidogrel platelet reactivity (HPR) associates with ischemic risk in patients after percutaneous intervention (PCI). This study aimed to evaluate the association of HPR as assessed by multiple electrode aggregometry (MEA) with ischemic, thromboembolic, and bleeding risk in patients with atrial fibrillation (AF) undergoing PCI. Patients with AF and an indication for oral anticoagulation (OAC) were included in this prospective cohort study on day 1–3 after PCI. Platelet aggregation [U] was analyzed by MEA. HPR and low platelet reactivity (LPR) were defined as ADP-induced aggregation ≥ 46 U and ≤ 18 U, respectively. TRAP-6-induced aggregation reference was 94–156 U. The primary outcome was time to all-cause death, myocardial infarction, or stroke at 6 months. The secondary outcome was time to non-major clinically relevant bleedings or major bleedings. 159 patients were enrolled between May 2020 and May 2021. The median age was 78 years (interquartile range 72–82) and 111 (70%) were male. Median ADP- and TRAP-induced aggregation were 12 (6–17) and 49 (35–68) U, respectively. 147 (93%) patients had a low overall aggregability. HPR was detected in 2 patients (1%) and 125 (79%) had LPR. ADP-induced aggregation did not significantly associate with the primary outcome (r = 0.081, p = 0.309) but correlated inversely with bleeding risk (r = − 0.201, p = 0.011). HPR status as assessed by MEA among patients with AF after PCI was rare and overall aggregability was low. Conventional cut-off values for HPR might be inappropriate for these patients. ADP-induced aggregation might be helpful to identify patients at risk for bleeding.

Cangrelor in contemporary patients with ST-segment elevation myocardial infarction pretreated with Ticagrelor: Pharmacodynamic data from the POMPEII study

BackgroundThere are limited data to assess pharmacodynamic (PD) profiles of patients with STEMI undergoing primary percutaneous coronary intervention (PCI) and receiving cangrelor after pretreatment with ticagrelor. MethodsThe PharmacOdynaMic effects of cangrelor in PatiEnts wIth acute or chronIc coronary syndrome undergoing percutaneous coronary intervention (POMPEII) registry (NCT04790032) is a prospective study conducted at Federico II University of Naples enrolling all patients undergoing PCI receiving cangrelor at operator’s discretion. PD assessments were performed with 3 assays: (1) the gold standard light transmittance aggregometry (LTA) (20- and 5-μM adenosine diphosphate [ADP] stimuli); (2) VerifyNow P2Y12-test; (3) Multiplate electrode aggregometry (MEA), ADP-test. ResultsWe analyzed 13 STEMI patients pretreated with ticagrelor within 1 h at the time they underwent primary PCI receiving cangrelor. All patients showed low maximal platelet aggregation at 30-minute during cangrelor infusion, as well as at 3 h and 4–6 h (corresponding to 1 h and 2–4 h after stopping cangrelor infusion) with no cases of high residual platelet reactivity. These results were consistent with all assays. ConclusionsPD data show that in contemporary real-world STEMI patients pretreated within 1 h with ticagrelor undergoing primary PCI, adding cangrelor resulted in fast and potent platelet inhibition, thus suggesting that cangrelor may bridge the gap until ticagrelor reaches its effect.

Integrated microfluidic multiple electrode aggregometry for point-of-care platelet function analysis.

Point-of-care (POC) platelet function analysis can enable timely and precise management of bleeding and clotting in emergency rooms, operation rooms and intensive care units. However, POC platelet testing is currently not commonly performed, due to the complexity of sample preparation and limitations of existing technologies. Here, we report the development of an integrated microfluidic multiple electrode aggregometry (μMEA) sensor which uses multi-frequency impedance measurement of an embedded microelectrode array to perform platelet aggregometry directly from whole blood, sensing and measuring platelet activation in a label-free manner and without requiring any additional sample preparation. Additionally, the sensor incorporates blood flow during the assay to account for physiological flow and shear conditions. We show that the impedance signal from the sensor can be used to accurately detect and quantify platelet aggregation in a label-free manner, which was further validated by simultaneous fluorometric measurement and visualization of platelet aggregation. Further, we optimized the sensitivity and repeatability of the sensor using its frequency response and demonstrated that the sensor could be used to characterize drug dose-response in antiplatelet therapy with a frequency-tunable dynamic range. We also demonstrate that the sensor provides high sensitivity to perform platelet aggregometry under thrombocytopenic or low platelet count conditions. The μMEA sensor could thus enable POC platelet function analysis across several clinical applications.

Association of Impedance Aggregometry-Measured Platelet Aggregation With Thromboembolic Events in Patients Who Undergo Carotid Endarterectomy: A Pilot Study

ObjectivesThe aim of the current study was to assess the relationship between thrombin receptor activator peptide 6 (TRAP test), adenosine-5′-diphosphate (ADP test) and arachidonic acid (ASPI test) and stroke/TIA, using the multiple electrode aggregometry (Multiplate®) in patients undergoing CEA. DesignA retrospective study. SettingVascular surgery operating rooms of university hospital. ParticipantsOne hundred and thirty-one out of 474 patients undergoing CEA between November 2020 and October 2022. InterventionsNone. Measurements & Main ResultsA pre-operative blood sample of all enrolled patients was analyzed using the multiplate analyzer. Receiver operating characteristics curves were generated to test the ability of TRAP, ADP and ASPI in discriminating perioperative thromboembolic stroke/TIA. A logistic LASSO regression model was used to identify factors independently associated with stroke/TIA. Eight patients suffered of perioperative stroke/TIA. Although all the platelet functional assays showed an excellent predictive performance an ADP value exciding 72 U showed the highest specificity (87%) and sensitivity (68%) in discriminating patients who had perioperative thromboembolic stroke/TIA with a negative predictive value of 99% and a positive predictive value of 15%. After LASSO regression an ADP> 72 U and need of shunt during CEA were the only two variables independently associated with perioperative stroke/TIA. ConclusionSince the ADP test was independently associated with perioperative stroke/TIA, the assessment of platelet reactivity using Multiplate® may offer potential utility in monitoring patients undergoing CEA.

Management of Microvascular Bleeding after On-Pump Cardiac Surgery in a Patient with Perioperative Diagnosis of Impairment of Platelet Responses to Adenosine Diphosphate: A Case Report and a Literature Review.

Impairment of platelet responses to adenosine diphosphate (ADP) is typified by mild to severe bleeding diathesis, easy bruising, excessive mucosal and post-operative bleeding. Patients lack full platelet activation and aggregation in response to ADP. Following research of the literature in Scopus, PubMed/MEDLINE, ScienceDirect, and the Cochrane Library, we report only 18 patients described to date with impaired platelet response to ADP, none of whom in the high bleeding-risk surgical setting or exploring potential therapeutic options. Data regarding population, putative genetic mutations, modes of inheritance, functional defects, and related clinical manifestations were retrieved from case series and case reports. A 40-year-old woman was scheduled for on-pump cardiac surgery. Her past medical history included episodes of spontaneous mucocutaneous hemorrhages of the mild entity since childhood. Multiple electrode aggregometry (MEA, Multiplate® Roche Diagnostics, Rotkreuz, Switzerland) was used to evaluate platelet response to thrombin-activated peptide-6 (TRAP), arachidonic acid (ASPI), and ADP. An inadequate platelet aggregation induced using a high concentration of ADP with normal TRAP and ASPI tests was detected preoperatively. Therefore, intravenous desmopressin (DVVAP) 0.3 μg/kg body weight was administered to manage microvascular bleeding developed after weaning from cardiopulmonary bypass (CPB). Proper management of impaired platelet response to ADP requires a systematic assessment. The Multiplate analyzer is a valuable tool to promptly detect the disorder when a high clinical suspect is present and obtain insights during high bleeding-risk surgical procedures. DVVAP can be beneficial as first-line therapy in bleeding patients to improve platelet function.

Clopidogrel Responsiveness in Patients Undergoing Percutaneous Coronary Intervention using Multiplate Analyzer: Frequency and Outcomes

Objectives: Over and under response to dual antiplatelet therapy (DAPT) can lead to bleeding and thrombotic events in patients undergoing coronary stent placement. The present study aimed to assess the platelet response to clopidogrel in patient undergoing percutaneous coronary intervention (PCI) using Multiplate Analyzer. The primary outcome in the present study was the short-term incidence of stent thrombosis and bleeding events. Background: Multiple electrode aggregometry is a rapid and standardized tool to for diagnosis of platelet defects and monitoring response to DAPT. Methods: A hospital-based, prospective study was conducted on 431 patients who underwent PCI from September 2016 to November 2017 and received clopidogrel therapy. The platelet aggregometry was done using a Multiplate analyzer (Dynabyte, Munich, Germany). Patients were followed for 30 days to assess the incidence of stent thrombosis and bleeding. Results: The patients’ mean age was 58 ± 6.7 years. A total of 40% of the patients were diabetic and 7.7% had chronic renal failure. The rate of clopidogrel non-responders was 10.7%, while clopidogrel over-responders were 18.3%. Patients with diabetes and chronic renal failure had significantly lower platelet responsiveness (40.1% with p &lt; 0.05 and 7.7% with p &lt;0.005, respectively). Smoking was significantly associated with platelet over-responsiveness (39.4%, p &lt; 0.001). Patients with low platelet responsiveness to clopidogrel were associated with an increased risk of definite stent thrombosis (p &lt; 0.005), while increasing bleeding risk was significantly associated with over-responsiveness to patients to clopidogrel (p &lt;0.001). Conclusions: Antiplatelet responsiveness showing individual variability with increased risk of stent thrombosis among the cases with no response to the effect of clopidogrel and high risk of bleeding with the over-responsiveness group.

Association of ADP-Induced Whole-Blood Platelet Aggregation with Serum Low-Density Lipoprotein Cholesterol in Patients with Coronary Artery Disease When Receiving Maintenance Ticagrelor-Based Dual Antiplatelet Therapy.

The degree of platelet inhibition in patients undergoing dual antiplatelet therapy (DAPT) affects cardiovascular outcomes after acute coronary syndromes (ACS) and/or percutaneous coronary intervention. Our aim was to search for correlates of residual ex vivo platelet reactivity and circulating soluble P-selectin (sP-selectin), an index of in vivo platelet activation, in patients being treated by DAPT with ticagrelor. Adenosine diphosphate (ADP)-induced platelet aggregability (by multiple electrode aggregometry) and plasma sP-selectin were estimated in 62 stable post-ACS subjects (46 men and 16 women; mean age: 64 ± 10 years; 30 with type 2 diabetes (T2DM)) undergoing maintenance DAPT with ticagrelor and aspirin. These patients did not exhibit heart failure or other relevant coexistent diseases except for properly controlled T2DM, mild renal insufficiency, and hypertension. We also assessed this in 64 subjects on clopidogrel-based DAPT matched for age, sex, and T2DM status. ADP-induced platelet aggregation was below the optimal levels (190-460 arbitrary units (AU) * min) in most patients receiving ticagrelor-based DAPT, especially in those with below-median (<1.9 mmol/L) serum concentrations of low-density lipoprotein cholesterol (LDL-c) (128 ± 61 vs. 167 ± 73 AU * min for below-median and above-median LDL-c, respectively, p = 0.025). In contrast, platelet reactivity did not differ by LDL-c on clopidogrel-based DAPT (246 ± 101 vs. 268 ± 108 AU * min for below-median and above-median LDL-c, respectively, p > 0.4). Plasma sP-selectin was found to be unrelated to serum LDL-c when receiving DAPT with ticagrelor (p > 0.4) or clopidogrel (p > 0.8). In conclusion, our preliminary observational study suggests the association of lower residual ex vivo platelet aggregability with better LDL-c control in patients undergoing ticagrelor-based maintenance DAPT, which does not appear to be reflected by plasma sP-selectin. Whether the serum LDL-c level should be considered among the factors affecting the degree of platelet inhibition for those treated with ticagrelor-based DAPT needs to be investigated in larger studies.

Pilot study: The LIPL-PLATELET study postprandial LIPid paneLs and PLATELET activity in coronary heart disease after treatment with PCSK9-inhibitors

Abstract Funding Acknowledgements Type of funding sources: Private company. Main funding source(s): Sanofi AVentis Reports about a pleiotropic potential of pro-protein convertase subtilisin/kexin type 9 inhibitor are scarce. This hypothesis-generating study investigates the platelet reactivity after standardized oral fat tolerance testing (OFTT) under an optimized lipid-lowering therapy (statin plus ezetimibe) alone and during the add-on treatment with the alirocumab. We investigated ten patients with the chronic coronary syndrome (CCS). Lipid variables and markers of platelet function were assessed during the fasting state and 3 and 5 hours after OFTT using a milkshake with 90g of fat. Measurements were performed in the same CCS patients under dual lipid-lowering therapy (DLLT) alone and after three months of add-on therapy with alirocumab. Postprandial inflammatory reaction did not change, irrespective of alirocumab. Neutrophile to lymphocyte ratio increased during the OFTT more significantly when on dual lipid-lowering therapy (p=0.021). The multiplate electrode aggregometry test with ASPI reagents (p=0.037) showed a paradoxically higher platelet reactivity five hours after OFTT with the addition of alirocumab compared to the DLLT only. Platelet reactivity remained unchanged during OFTT in CCS patients before or after alirocumab therapy. Altogether, alirocumab showed a trend of decreased postprandial inflammation and an increase in platelet reactivity.

Sonorheometry versus rotational thromboelastometry in trauma: a comparison of diagnostic and prognostic performance

BackgroundRotational thromboelastometry (ROTEM) is used to rapidly identify trauma-induced coagulopathy (TIC) and direct targeted interventions in hemorrhaging trauma patients. A novel technology, Quantra System (HemoSonics), utilizes sonic estimation of elasticity via resonance sonorheometry, avoids mechanical clot interference, and may increase diagnostic accuracy, but there are limited data on bleeding in major trauma patients. ObjectivesTo compare the performance of Quantra with that of ROTEM for rapid diagnosis of TIC and prediction of transfusion requirements and mortality. MethodsSamples were collected from adult trauma patients enrolled in a perpetual cohort study upon admission to a single level 1 trauma center between 2020 and 2021. Samples were analyzed using Quantra, ROTEM, multiple electrode aggregometry, and conventional coagulation assays. ResultsSamples from 209 patients were analyzed. Correlations were strong between Quantra and ROTEM parameters (for all, p < .001): clot stiffness (CS) and tissue factor–activated ROTEM (EXTEM) clot amplitude at 5 minutes (A5) (r = 0.90); fibrinogen contribution to CS and tissue factor–activated ROTEM with cytochalasin D (FIBTEM) A5 (r = 0.85); and platelet contribution to CS and EXTEM-FIBTEM A5 (r = 0.73). Although CS showed higher discrimination than EXTEM A5 in detecting TIC (international normalized ratio, >1.2; area under the receiver operating characteristic curve, 0.83 vs 0.79; p = .038), the ability of fibrinogen contribution to CS to detect hypofibrinogenemia (a fibrinogen level of <2g/L) was good but lower than that of FIBTEM A5 (area under the receiver operating characteristic curve, 0.79 vs 0.84; p = .027). There was no difference between Quantra and ROTEM in detecting a platelet count of <150 × 109/L, predicting rapid transfusion or mortality at 6 hours. ConclusionQuantra and ROTEM have similar diagnostic performances in evaluating TIC and predicting clinically relevant outcomes. Larger studies are required to determine the utility of Quantra for goal-directed treatment of TIC.

In-vitro antiplatelet effect of melatonin in healthy individuals and patients with type 2 diabetes mellitus

PurposeThe incidence of acute myocardial infarctions (AMI) shows circadian variation typically peaking during morning hours with a decline at night. However, this variation does not occur in patients with diabetes mellitus (DM). The night’s decline of AMI may be partially explained by melatonin-related platelet inhibition. Whether this effect is absent in diabetic patients is unknown. The aim was to study the effect of melatonin on in-vitro platelet aggregation in healthy individuals and patients with type 2 DM.MethodsPlatelet aggregation was measured in blood samples from healthy individuals (n = 15) and type 2 DM patients (n = 15) using multiple electrode aggregometry. Adenosine diphosphate (ADP), arachidonic acid (ASPI) and thrombin (TRAP) were used as agonists. Aggregability for each subject was tested after adding melatonin in two concentrations.ResultsIn healthy individuals, melatonin inhibited platelet aggregation in both higher (10–5 M) and lower concentrations (10–9 M) induced by ADP, ASPI, and TRAP (p < 0.001, p = 0.002, p = 0.029, respectively). In DM patients, melatonin did not affect platelet aggregation in both concentrations induced by ADP, ASPI, and TRAP. Melatonin decreased platelet aggregation induced by ADP, ASPI, and TRAP significantly more in healthy individuals compared to patients with DM. (p = 0.005, p = 0.045 and p = 0.048, respectively).ConclusionPlatelet aggregation was inhibited by melatonin in healthy individuals. In-vitro antiplatelet effect of melatonin in type 2 DM patients is significantly attenuated.

The LIPL-PLATELET Study Postprandial LIPid Panels and PLATELET Activity in Coronary Heart Disease after Treatment with PCSK9-Inhibitors

Reports about a pleiotropic potential of pro-protein convertase subtilisin/kexin type 9 inhibitor are scarce. This hypothesis-generating study investigates the platelet reactivity after standardized Oral Fat Tolerance Testing (OFTT) under an optimized lipid-lowering therapy (statin plus ezetimibe) alone and during the add-on treatment with the alirocumab. We investigated ten patients with Chronic Coronary Syndrome (CCS). Lipid variables and markers of platelet function were assessed during the fasting state and 3 and 5 hours after OFTT using a milkshake with 90 g of fat. Measurements were performed in the same CCS patients under Dual Lipid-Lowering Therapy (DLLT) alone and after three months of add-on therapy with alirocumab. Postprandial inflammatory reaction did not change, irrespective of alirocumab. Neutrophile to lymphocyte ratio increased during the OFTT more significantly when on dual lipid-lowering therapy (p=0.021). The multiplate electrode aggregometry test with ASPI reagents (p=0.037) showed a paradoxically higher platelet reactivity five hours after OFTT with addition of alirocumab compared to the DLLT only. Platelet reactivity remained unchanged during OFTT in CCS patients before or after alirocumab therapy. Altogether, alirocumab showed a trend of decreased postprandial inflammation and increase in platelet reactivity.

Growth Differentiation Factor 15 Is Associated with Platelet Reactivity in Patients with Acute Coronary Syndrome

Bleeding events in patients with acute coronary syndrome (ACS) are a risk factor for adverse outcomes, including mortality. We investigated the association of growth differentiation factor (GDF)-15, an established predictor of bleeding complications, with on-treatment platelet reactivity in ACS patients undergoing coronary stenting receiving prasugrel or ticagrelor. Platelet aggregation was measured by multiple electrode aggregometry (MEA) in response to adenosine diphosphate (ADP), arachidonic acid (AA), thrombin receptor-activating peptide (TRAP, a protease-activated receptor-1 (PAR-1) agonist), AYPGKF (a PAR-4 agonist) and collagen (COL). GDF-15 levels were measured using a commercially available assay. GDF-15 correlated inversely with MEA ADP (r = -0.202, p = 0.004), MEA AA (r = -0.139, p = 0.048) and MEA TRAP (r = -0.190, p = 0.007). After adjustment, GDF-15 was significantly associated with MEA TRAP (β = -0.150, p = 0.044), whereas no significant associations were detectable for the other agonists. Patients with low platelet reactivity in response to ADP had significantly higher GDF-15 levels (p = 0.005). In conclusion, GDF-15 is inversely associated with TRAP-inducible platelet aggregation in ACS patients treated with state-of-the-art antiplatelet therapy and significantly elevated in patients with low platelet reactivity in response to ADP.

Optimization Of Production Capacity In Manufacturing Multi Plate 424 Products Using Promodel Simulation At Pt CMP

A good production system is one of the important factors to determine the success of production. The integration of every process in production requires that every element in the system work properly. If one of the elements in the production process is jammed, this can cause big problems in the production process, such as a lot of idle time, inappropriate production targets, and so on. One alternative to overcome this is by simulating alternative solutions that have been proposed in a visual form with Promodel student version 7.5 software. The production process of making Multi Plate 424 at PT CMP occurs an imbalance in the machines used, which results in idle time and the length of the process of making the multi plate 424. This problem occurs because there are many piles of material on each of the machines used, so that it has an impact on the length of time for the multi plate. The proposed alternative solution is to reduce the bottleneck on each machine. Based on the simulation carried out between the existing system simulation and the proposed simulation model, there are several results including the schedule time, which is 21037.28 minutes, while the proposed simulation model is 18390,22 minutes with the total entries that enter the finished goods warehouse is 630 pcs

Impact of Stereotactic Body Radiotherapy on Thrombin Generation and Platelet Aggregation in Patients with Non-Small Cell Lung Cancer.

Patients with localized non-small cell lung cancer (NSCLC) considered unfit for surgery are at substantially increased risk of venous thromboembolism. Radiotherapy may further increase this risk. We aim to investigate the impact of stereotactic body radiotherapy (SBRT) on thrombin generation and platelet aggregation. We included 110 patients with localized NSCLC treated with SBRT. Blood samples were obtained prior to SBRT, immediately after SBRT completion, and 4-6 weeks following SBRT. Ex vivo and in vivo thrombin generations were analyzed using a calibrated automated thrombogram and commercial enzyme-linked immunosorbent assays. Platelet aggregation was evaluated using multiple electrode aggregometry. No significant differences were found in ex vivo or in vivo thrombin generation between blood samples before and immediately after SBRT treatment. Platelet aggregation was lower immediately after SBRT than before SBRT (TRAP: P = 0.04 and ASPI: P = 0.02) but remained within the reference interval. SBRT did not affect in vivo and ex vivo thrombin generation or platelet aggregation. SBRT did not cause prothrombotic changes in the coagulation in this study population of SBRT-treated patients with localized NSCLC.

Multiple Electrode Aggregometry (Multiplate): Functional Assay for Vaccine-Induced (Immune) Thrombotic Thrombocytopenia (VITT).

Vaccine-induced immune thrombotic thrombocytopenia (VITT) was first described in 2021 and represents an adverse reaction to adenoviral vector COVID-19 vaccines AstraZeneca ChAdOx1 nCoV-19 (AZD1222) and Johnson & Johnson Ad26.COV2.S vaccine. VITT is a severe immune platelet activation syndrome with an incidence of 1-2 per 100,000 vaccinations. The features of VITT include thrombocytopenia and thrombosis within 4-42days of first dose of vaccine. Affected individuals develop platelet-activating antibodies against platelet factor 4 (PF4). The International Society on Thrombosis and Haemostasis recommends both an antigen-binding assay (enzyme-linked immunosorbent assay, ELISA) and a functional platelet activation assay for the diagnostic workup of VITT. Here, the application of multiple electrode aggregometry (Multiplate) is presented as a functional assay for VITT.

Functional Testing for Heparin-Induced Thrombocytopenia Using Whole Blood Multiplate Impedance Aggregometry.

Immune-mediated heparin-induced thrombocytopenia (HIT) occurs when heparin-dependent IgG antibodies bind to heparin/platelet factor 4 (H/PF4) complexes and activate platelets. There is a vast panoply of assays to investigate HIT which can be divided into two groups, antigen-based immunoassays that detect all antibodies against H/PF4 and are used as a first diagnostic step and functional assays that will identify only the antibodies capable of activating platelets and are mandatory to confirm a diagnosis of pathological HIT. The serotonin-release assay, known as SRA, has been the gold standard for decades, but in the last 10years, other easier alternatives have been described. The current chapter will focus on whole blood multiple electrode aggregometry, a validated method for the functional diagnosis of HIT.