Performance Metrics of the AGGRESTAR PL-12® Platelet Function Analyser in Patients with TIA or Ischaemic Stroke on Commonly-Prescribed Antiplatelet Regimens

2021 ◽  
Vol 5 (2) ◽  
Author(s):  
Offiah C ◽  
◽  
Delaney S ◽  
Smith DR ◽  
Murphy SJX ◽  
...  
Keyword(s):  
Combination Therapy ◽  
Ischaemic Stroke ◽  
Platelet Function ◽  
Performance Metrics ◽  
Adenosine Diphosphate ◽  
Optimal Time ◽  
Time Interval ◽  
Cross Sectional ◽  
Coefficients Of Variation ◽  
Low Shear Stress

Introduction: The optimal time interval after venepuncture to perform platelet function/reactivity testing at low shear stress on the novel AGGRESTAR PL-12® platelet function analyser in non-Chinese Cerebrovascular Disease (CVD) patients is unknown. Methods: Twelve TIA/ischaemic stroke patients were recruited to this cross-sectional, methodological study: 3 on aspirin monotherapy, aspirindipyridamole combination therapy, clopidogrel monotherapy and aspirinclopidogrel combination therapy, respectively. The PL-12 (‘mode 2’) was used to calculate the % maximum aggregation rate to fixed doses of arachidonic acid (%MARAA) and adenosine diphosphate (%MARADP). Samples were analysed every 15 minutes from 30-135 minutes, and every 30 minutes between 165-225 minutes after venepuncture to calculate the time interval providing optimal interassay Coefficients of Variation (CVs). Results: Mean CVs were ≤ 7.37% for the %MARAA assay in patients on aspirin monotherapy or combination therapy, and ≤ 10.24% for the %MARADP assay in patients on clopidogrel monotherapy or combination therapy if assays were performed between 90-120 minutes post-venepuncture. CVs ≤ 10% were also obtained from assays performed between 90-165 minutes postvenepuncture on aspirin monotherapy or combination therapy. Discussion: Reliable and reproducible platelet function/reactivity data can be obtained with the AGGRESTAR PL-12 analyser in non-Chinese CVD patients on commonly-prescribed antiplatelet monotherapy or combination therapy regimens between 90-120 minutes post-venepuncture.

Adenosine Diphosphate (ADP) Breakdown in Human Plasma with Reference to Platelet Aggregation and Uraemia

1968 ◽  
Vol 19 (03/04) ◽  
pp. 438-450
Author(s):  
I. E. T Gan ◽  
B. G Firkin
Keyword(s):  
Platelet Aggregation ◽  
Human Plasma ◽  
Platelet Function ◽  
Adenosine Diphosphate ◽  
Plasma Enzyme ◽  
Aggregation Of Platelets ◽  
Plasma Activity

Summary1. A correlation between platelet aggregation and the plasma enzyme(s) ability to degrade Adenosine Diphosphate (ADP) has been confirmed.2. This plasma activity has been shown to be reduced in 6 patients with uraemia in whom platelet aggregation was demonstrably impaired but not in two whose platelet function was normal. The incorporation of 14C labelled ADP-8-14C was also only reduced in uraemic patients with abnormal platelet aggregation.3. These findings are discussed with particular reference to possible implication in mechanism involved in ADP aggregation of platelets.

Inhibition of Platelet Function by Antiarrhythmic Drugs, Verapamil and Disopyramide

1982 ◽  
Vol 47 (02) ◽  
pp. 150-153 ◽  
Author(s):  
P Han ◽  
C Boatwright ◽  
N G Ardlie
Keyword(s):  
Platelet Aggregation ◽  
Platelet Function ◽  
Antiarrhythmic Drugs ◽  
Adenosine Diphosphate ◽  
Inhibitory Effect ◽  
Second Phase ◽  
Ionophore A23187 ◽  
High Concentrations ◽  
Artery Disease

SummaryVarious cardiovascular drugs such as nitrates and propranolol, used in the treatment of coronary artery disease have been shown to have an antiplatelet effect. We have studied the in vitro effects of two antiarrhythmic drugs, verapamil and disopyramide, and have shown their inhibitory effect on platelet function. Verapamil, a calcium channel blocker, inhibited the second phase of platelet aggregation induced by adenosine diphosphate (ADP) and inhibited aggregation induced by collagen. Disopyramide similarly inhibited the second phase of platelet aggregation caused by ADP and aggregation induced by collagen. Either drug in synergism with propranolol inhibited ADP or collagen-induced platelet aggregation. Disopyramide at high concentrations inhibited arachidonic add whereas verapamil was without effect. Verapamil, but not disopyramide, inhibited aggregation induced by the ionophore A23187.

Platelet Function in Experimentally Induced Pancreatitis in the Dog

1986 ◽  
Vol 55 (02) ◽  
pp. 197-200 ◽  
Author(s):  
R M Jacobs ◽  
R J Murtaugh ◽  
R H Fertel
Keyword(s):  
Platelet Function ◽  
Disseminated Intravascular Coagulation ◽  
Degradation Products ◽  
Plasma Concentrations ◽  
Adenosine Diphosphate ◽  
Intravascular Coagulation ◽  
Fibrin Degradation Products ◽  
Functional Defect ◽  
And Function ◽  
Experimentally Induced

SummaryEvidence suggests that changes in prostaglandins and disseminated intravascular coagulation accompany pancreatitis. Both may induce changes in platelet function. We wished to determine if experimentally induced pancreatitis in the dog was associated with altered platelet number and function, and whether there were concomitant changes in prostaglandins. Evidence for disseminated intravascular coagulation in the dogs with pancreatitis were red blood cell fragmentation, increased platelet turnover indicated by macro-platelets and the transient presence of fibrin degradation products in urine. There were no significant changes in platelet count. The platelets from dogs with pancreatitis showed a functional defect characterized by significantly decreased aggregation in response to adenosine diphosphate, arachidonic acid, and collagen. Release of adenosine triphosphate from platelets was reduced in collagen-stimulated aggregation. There were no changes in the plasma concentrations of thromboxane B2, 6-Keto-PGF1a, and PGE2. This defect may have been due to the generation of fibrin degradation products and platelet “exhaustion”.

scholarly journals Preferences for life-sustaining treatment in Korean adults: a cross-sectional study

BMJ Open ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. e039470
Author(s):  
HyunChul Youn ◽  
Suk-young Lee ◽  
Han-yong Jung ◽  
Shin-Gyeom Kim ◽  
Seung‑Hyun Kim ◽  
...  
Keyword(s):  
Cross Sectional Study ◽  
Left Ventricular ◽  
Self Report ◽  
Ventricular Assist Devices ◽  
Optimal Time ◽  
Left Ventricular Assist Devices ◽  
Sectional Study ◽  
Cross Sectional ◽  
Ventricular Assist ◽  
Life Sustaining Treatment

ObjectivesLife-sustaining treatment is any treatment that serves to prolong life without reversing the underlying medical conditions, and includes cardiopulmonary resuscitation, mechanical ventilation, haemodialysis and left ventricular assist devices. This study aimed to investigate the thoughts on life-sustaining treatment of Koreans and to assess the factors associated with deciding to not receive life-sustaining treatment if they develop a terminal disease.DesignCross-sectional study.SettingGuro-gu centre for dementia from 1 May 2018 to 31 December 2019.ParticipantsIn total, 150 individuals participated in this study.Outcome measuresThe questionnaire consisted of self-report items with some instructions, demographic characteristics, thoughts on life-sustaining treatment and psychosocial scales. The preferences of the participants were investigated on the assumption that they develop terminal cancer. The psychosocial scales included the Generalised Anxiety Disorder-7 (GAD-7), Patient Health Questionnaire-9 (PHQ-9), Connor–Davidson Resilience Scale and Multidimensional Scale of Perceived Social Support (MSPSS).ResultsWe classified our participants into two groups: individuals who wanted to receive life-sustaining treatment (IRLT) and individuals who wanted to not receive life-sustaining treatment (INLT). There were twice as many participants in the INLT group than there were in the IRLT. In making this decision, the INLT group focused more on physical and mental distress. Additionally, 32.7% of participants responded that terminal status was an optimal time for this decision, but more participants want to decide it earlier. The GAD-7 and PHQ-9 scores were significantly higher in the INLT group than in the IRLT group. However, the INLT group had significantly lower MSPSS family scores.ConclusionOur findings can help assess issues regarding advance directives and life-sustaining treatment, and will be a reference for designing future studies on this issue.

scholarly journals Adequate Platelet Function Inhibition Confirmed by Two Inductive Agents Predicts Lower Recurrence of Ischemic Stroke/Transient Ischemic Attack

2017 ◽  
Vol 2017 ◽  
pp. 1-5 ◽  
Author(s):  
Lulu Zhang ◽  
Xiaowei Hu ◽  
Juehua Zhu ◽  
Xiuying Cai ◽  
Yan Kong ◽  
...  
Keyword(s):  
Ischemic Stroke ◽  
Antiplatelet Therapy ◽  
Platelet Function ◽  
Adenosine Diphosphate ◽  
Aggregation Rate ◽  
Function Analyzer ◽  
Ischemic Attack ◽  
Platelet Function Analyzer ◽  
Platelet Functions

Background. The correlation between platelet function and recurrent ischemic stroke or TIA remains uncertain. Objective. To investigate two inductive agents to detect platelet functions and assess associations with recurrent ischemic stroke/TIA. Method. The study included 738 ischemic stroke/TIA patients. On days 0, 3, and 9 after antiplatelet therapy, platelet function tests were determined by maximum aggregation rate (MAR) using a PL-11 platelet function analyzer and phase matching reagents. Two induction agents were used: arachidonic acid (AA) and adenosine diphosphate (ADP). At 3-month follow-up, recurrence of stroke/TIA was recorded. Result. Cut-off values of adequate platelet function inhibition were MARADP < 35% and MARAA < 35%. Data showed that antiplatelet therapy could reduce the maximum aggregation rate. More importantly, adequate platelet function inhibition of either MARADP or MARAA was not associated with the recurrence of stroke/TIA, but adequate platelet function inhibition of not only MARADP but also MARAA predicts lower recurrence (0/121 (0.00%) versus 18/459 (3.92%), P = 0.0188). Conclusion. The platelet function tested by PL-11 demonstrated that adequate inhibition of both MARADP and MARAA could predict lower risk of ischemic stroke/TIA recurrence.

scholarly journals Impact of an in-house emergency radiologist on report turnaround time

CJEM ◽  
2015 ◽  
Vol 17 (1) ◽  
pp. 21-26 ◽  
Author(s):  
Leslie Lamb ◽  
Paria Kashani ◽  
John Ryan ◽  
Guy Hebert ◽  
Adnan Sheikh ◽  
...  
Keyword(s):  
Patient Care ◽  
Emergency Radiology ◽  
Time Frame ◽  
Turnaround Time ◽  
Time Interval ◽  
Final Report ◽  
Radiology Resident ◽  
Cross Sectional ◽  
Patient Disposition ◽  
Report Turnaround Time

AbstractBackgroundOne of the many challenges facing emergency departments (EDs) across North America is timely access to emergency radiology services. Academic institutions, which are typically also regional referral centres, frequently require cross-sectional studies to be performed 24 hours a day with expedited final reports to accelerate patient care and ED flow.ObjectiveThe purpose of this study was to determine if the presence of an in-house radiologist, in addition to a radiology resident dedicated to the ED, had a significant impact on report turnaround time.MethodsPreliminary and final report turnaround times, provided by the radiology resident and staff, respectively, for patients undergoing computed tomography or ultrasonography of their abdomen/pelvis in 2008 (before the implementation of emergency radiology in-house staff service) were compared to those performed during the same time frame in 2009 and 2010 (after staffing protocols were changed).ResultsA total of 1,624 reports were reviewed. Overall, there was no statistically significant decrease in the preliminary report turnaround times between 2008 and 2009 (p = 0.1102), 2009 and 2010 (p = 0.6232), or 2008 and 2010 (p = 0.0890), although times consistently decreased from a median of 2.40 hours to 2.08 hours to 2.05 hours (2008 to 2009 to 2010). There was a statistically significant decrease in final report turnaround times between 2008 and 2009 (p < 0.0001), 2009 and 2010 (p < 0.0011), and 2008 and 2010 (p < 0.0001). Median final report times decreased from 5.00 hours to 3.08 hours to 2.75 hours in 2008, 2009, and 2010, respectively. There was also a significant decrease in the time interval between preliminary and final reports between 2008 and 2009 (p < 0.0001) and 2008 and 2010 (p < 0.0001) but no significant change between 2009 and 2010 (p = 0.4144).ConclusionOur results indicate that the presence of a dedicated ED radiologist significantly reduces final report turnaround time and thus may positively impact the time to ED patient disposition. Patient care is improved when attending radiologists are immediately available to read complex films, both in terms of health care outcomes and regarding the need for repeat testing. Providing emergency physicians with accurate imaging findings as rapidly as possible facilitates effective and timely management and thus optimizes patient care.

The platelet P2Y12 receptor for adenosine diphosphate: congenital and drug-induced defects

Blood ◽  
2011 ◽  
Vol 117 (7) ◽  
pp. 2102-2112 ◽  
Author(s):  
Marco Cattaneo
Keyword(s):  
Platelet Function ◽  
Cardiovascular Events ◽  
Thrombus Formation ◽  
Adenosine Diphosphate ◽  
New Drugs ◽  
Drug Induced ◽  
P2y12 Inhibitors ◽  
Major Cardiovascular Events ◽  
Platelet Receptor ◽  
Net Clinical Benefit

Abstract P2Y12, the Gi-coupled platelet receptor for adenosine diphosphate (ADP), plays a central role in platelet function. Patients with congenital P2Y12 defects display a mild to moderate bleeding diathesis, characterized by mucocutaneous bleedings and excessive post-surgical and post-traumatic blood loss. Defects of P2Y12 should be suspected when ADP, even at high concentrations (≥ 10μM), is unable to induce full, irreversible platelet aggregation. Tests that evaluate the degree of inhibition of adenylyl cyclase by ADP should be used to confirm the diagnosis. Drugs that inhibit P2Y12 are potent antithrombotic drugs, attesting the central role played by P2Y12 in platelet thrombus formation. Clopidogrel, the most widely used drug that inhibits P2Y12, is effective both in monotherapy and in combination with acetylsalicylic acid. The most important drawback of clopidogrel is its inability to inhibit adequately P2Y12-dependent platelet function in approximately one-third of patients who are therefore not protected from major cardiovascular events. New drugs, such as prasugrel and ticagrelor, which effectively inhibit P2Y12 in the majority of patients, proved to be more efficacious than clopdidogrel in preventing major cardiovascular events. Although they increase the incidence of major bleedings, the net clinical benefit is in favor of the new P2Y12 inhibitors.

scholarly journals The aptamer BT200 blocks von Willebrand factor and platelet function in blood of stroke patients

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Katarina D. Kovacevic ◽  
Stefan Greisenegger ◽  
Agnes Langer ◽  
Georg Gelbenegger ◽  
Nina Buchtele ◽  
...  
Keyword(s):  
Platelet Function ◽  
Von Willebrand Factor ◽  
Stroke Prevention ◽  
Adenosine Diphosphate ◽  
Target Range ◽  
Large Artery ◽  
Dependent Manner ◽  
Secondary Stroke Prevention ◽  
Von Willebrand ◽  
Willebrand Factor

AbstractThe effect of conventional anti-platelet agents is limited in secondary stroke prevention, and their effects are blunted under high shear stress in the presence of increased levels of circulating von Willebrand factor (VWF). VWF is critically involved in thrombus formation at sites of stenotic extracranial/intracranial arteries. A third generation anti-VWF aptamer (BT200) has been generated which could be useful for secondary stroke prevention. To characterize the effects of BT200 in blood of patients with large artery atherosclerosis stroke (LAA). Blood samples were obtained from 33 patients with acute stroke or transient ischemic attack to measure inhibition of VWF activity and VWF-dependent platelet function. Patients who received clopidogrel or dual antiplatelet therapy did not differ in VWF dependent platelet function tests from aspirin treated patients. Of 18 patients receiving clopidogrel with or without aspirin, only 3 had a prolonged collagen adenosine diphosphate closure time, and none of the patients had ristocetin induced aggregation in the target range. BT200 concentration-dependently reduced median VWF activity from 178 to < 3%, ristocetin induced platelet aggregation from 40U to < 10U and prolonged collagen adenosine diphosphate closure times from 93 s to > 300 s. Baseline VWF activity correlated (r = 0.86, p < 0.001) with concentrations needed to reduce VWF activity to < 20% of normal, indicating that BT200 acts in a target concentration-dependent manner. Together with a long half-life supporting once weekly administration, the safety and tolerability observed in an ongoing phase I trial, and the existence of a reversal agent, BT200 is an interesting drug candidate.

scholarly journals Influence of Hepatocellular Carcinoma on Platelet Aggregation in Cirrhosis

Cancers ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 1150
Author(s):  
Alberto Zanetto ◽  
Marco Senzolo ◽  
Elena Campello ◽  
Cristiana Bulato ◽  
Sabrina Gavasso ◽  
...  
Keyword(s):  
Hepatocellular Carcinoma ◽  
Platelet Count ◽  
Platelet Aggregation ◽  
Platelet Function ◽  
Adenosine Diphosphate ◽  
Compensated Cirrhosis ◽  
Impedance Aggregometry ◽  
Child Class ◽  
Von Willebrand ◽  
Willebrand Factor

Hyper-functional platelets are being proposed as a potential therapeutic target in multiple cancers. Whether this can be considered in patients with cirrhosis and hepatocellular carcinoma (HCC) is unknown as their platelet function has not yet been investigated. We evaluated platelet function in cirrhosis patients with HCC. Patients with cirrhosis with and without HCC were prospectively recruited. Platelet aggregation, a marker of platelet function, was assessed by impedance aggregometry with adenosine diphosphate (ADP), arachidonic acid (ASPI), and thrombin (TRAP) stimulation. Plasmatic levels of Von Willebrand factor antigen (VWF) were also determined. One-hundred patients were recruited (50 cirrhotics with and 50 without HCC). Cirrhosis severity by Child class and platelet count were comparable between cirrhotics with and without HCC. Cirrhotics with HCC had higher ADP- (45 vs. 28; p < 0.001), ASPI- (47 vs. 28; p < 0.001), and TRAP- (85 vs. 75; p = 0.01) induced platelet aggregation than cirrhotics without HCC, all indicative of platelet hyper-function. The relatively increased platelet aggregation in patients with HCC was confirmed after adjusting the analysis for platelet count/severity of thrombocytopenia. Levels of VWF were higher in patients with vs. without HCC (348 vs. 267; p = 0.006), particularly in compensated cirrhosis. In patients with cirrhosis, HCC is associated with increased platelet aggregation and higher VWF. The clinical implications of these findings deserve further investigation.

The impact of the workability of an automated technological system on the effective implementation of the production program when processing tools in glow discharge plasma generators

2021 ◽  
pp. 58-65
Author(s):  
V.A. Logvin ◽  
◽  
S.A. Sheptunov ◽  
Keyword(s):  
Glow Discharge ◽  
Discharge Plasma ◽  
Functional Dependence ◽  
Plasma Generator ◽  
Glow Discharge Plasma ◽  
Optimal Time ◽  
Time Interval ◽  
Production Program ◽  
The Impact ◽  
Plasma Generators

The conditions for the hardening of tools in accordance with the author’s technological routes in the optimal time interval are considered using the functional dependence of the serviceability of plasma generators. This dependence takes into account the workability of the technical devices involved in processing the laying batch of tools in the speci ed time interval. The probability of performing the production process in the estimated time is represented by the product of the trouble-free operation of each glow discharge plasma generator involved in the nishing processing of tools that require a different type of plasma exposure in a certain sequence and duration.

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