Quantifying the Effect of Antiplatelet Therapy

2006 ◽  
Vol 105 (4) ◽  
pp. 676-683 ◽  
Author(s):  
Seema Agarwal ◽  
Margaret Coakely ◽  
Kalpana Reddy ◽  
Anne Riddell ◽  
Susan Mallett
Keyword(s):  
Antiplatelet Therapy ◽  
Platelet Function ◽  
Light Transmission ◽  
Point Of Care ◽  
Perioperative Bleeding ◽  
Light Transmission Aggregometry ◽  
Function Analyzer ◽  
Platelet Function Analyzer ◽  
Ischemic Events ◽  
Good Agreement

Background Antiplatelet therapy with aspirin and clopidogrel is known to confer protection against ischemic events. Increasing numbers of patients are presenting for surgery while taking these drugs. This may lead to an increase in perioperative blood loss, particularly in those who have a heightened response to the drugs. Identifying these patients preoperatively would allow us to plan appropriate management. Methods The antiplatelet effect of aspirin and/or clopidogrel was measured using two point-of-care monitors: the platelet function analyzer (PFA-100; Dade, Miami, FL) and the modified thromboelastograph (mTEG; Haemoscope Corp., Niles, IL). This was compared with optical light transmission aggregometry. Results All people taking aspirin displayed a definitive aspirin effect on aggregometry (n = 20). Ninety percent of these were identified by modified thromboelastography (n = 18). Seventy percent were identified by the platelet function analyzer (n = 14). Fifty percent of people taking clopidogrel displayed a definitive response to the drug on aggregometry. Seventy percent of these were identified on modified thromboelastography (n = 7). None were identified by the platelet function analyzer. There was good agreement between the results of the aggregometry and modified thromboelastography in clopidogrel patients (kappa = 0.81). Conclusion The search for a point-of-care monitor of platelet function has been the focus of much research. This study has shown that the modified thromboelastograph can be used for monitoring the effect of clopidogrel as well as aspirin. It potentially has a wide scope to be used for the monitoring of effectiveness of therapy as well as a possible predictor of perioperative bleeding.

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.

The use of the VerifyNow P2Y12 point-of-care device to monitor platelet function across a range of P2Y12 inhibition levels following prasugrel and clopidogrel administration

2008 ◽  
Vol 99 (02) ◽  
pp. 409-415 ◽  
Author(s):  
Christopher D. Payne ◽  
Ying G. Li ◽  
John T. Brandt ◽  
David S. Small ◽  
Nagy A. Farid ◽  
...  
Keyword(s):  
Platelet Function ◽  
Clinical Utility ◽  
Dynamic Range ◽  
Light Transmission ◽  
Point Of Care ◽  
Antiplatelet Agents ◽  
Limited Range ◽  
Treatment Regimens ◽  
Light Transmission Aggregometry

SummaryVariability in response to antiplatelet agents has prompted the development of point-of-care (POC) technology. In this study, we compared theVerifyNowTM P2Y12 (VN-P2Y12) POC device with light transmission aggregometry (LTA) in subjects switched directly from clopidogrel to prasugrel. Healthy subjects on aspirin were administered a clopidogrel 600 mg loading dose (LD) followed by a 75 mg/d maintenance dose (MD) for 10 days. Subjects were then switched to a prasugrel 60 mg LD and then 10 mg/d MD for 10 days (n=16), or to a prasugrel 10 mg/d MD for 11 days (n=19). Platelet function was measured by LTA andVN-P2Y12 at baseline and after dosing. Clopidogrel 600 mg LD/75 mg MD treatment led to a reduction in P2Y12 reaction units (PRU) from baseline. A switch from clopidogrel MD to prasugrel 60 mg LD/10 mg MD produced an immediate decrease in PRU, while a switch to prasugrel 10 mg MD resulted in a more gradual decline. Consistent with the reduction in PRU, device-reported percent inhibition increased during both clopidogrel and prasugrel regimens. Inhibition of platelet aggregation as measured by LTA showed a very similar pattern to that found with VN-P2Y12 measurement, irrespective of treatment regimens. The dynamic range of VN-P2Y12 appeared to be narrower than that of LTA. With two different thienopyridines, the VN-P2Y12 device, within a somewhat more limited range, reflected the overall magnitude of change in aggregation response determined by LTA. The determination of the clinical utility of such POC devices will require their use in clinical outcome studies.

scholarly journals The importance of tests applied to evaluate the effectiveness of antiplatelet therapy in patients with recurrent coronary stent thrombosis

2009 ◽  
Vol 66 (4) ◽  
pp. 328-332
Author(s):  
Aleksandra Grdinic ◽  
Danilo Vojvodic ◽  
Vesna Ilic ◽  
Zvonko Magic ◽  
Nina Djukanovic ◽  
...  
Keyword(s):  
Antiplatelet Therapy ◽  
Stent Thrombosis ◽  
Platelet Function ◽  
Coronary Intervention ◽  
P2y12 Receptor ◽  
Cardiac Events ◽  
Major Haplotype ◽  
Function Analyzer ◽  
Insufficient Response ◽  
Platelet Function Analyzer

Background. Stent thrombosis is potentially lethal complication with huge economic burden. The role of insufficient response to antiplatelet therapy is still unclear reason for its occurrence. Case report. We presented 54-year-old man with recurrent stent thrombosis on the 4th, 9th and 12th day after the primary percutaneous coronary intervention in spite of double antiaggregation therapy (aspirin+ clopidogrel). All possible procedural causes were excluded and reimplantation of intracoronary stent was insufficient to resolve the problem, so four platelet tests were performed: flow cytometry, Platelet Function Analyzer-100 test, aggregometry, and determination of gene polymorphism for P2Y12 receptor (directly involved in the mechanism of thienopyridine), and GPIIbIIIa receptor (final receptor in aggregation). The patient was the carrier of the major haplotype H1H1 for P2Y12 receptor and minor A1A2 for GPIIbIIIa receptor. The results of all the performed tests showed insufficient antiplatelet effect of aspirin and sufficient response to thienopyridin (not to clopidogrel, but to ticlopidine). Conclusion. Performance of platelet function tests is necessary in the case of major adverse cardiac events especially stent thrombosis, after implantation of intracoronary stent.

Comparison of current platelet functional tests for the assessment of aspirin and clopidogrel response

2016 ◽  
Vol 116 (10) ◽  
pp. 638-650 ◽  
Author(s):  
Jean-Claude Bordet ◽  
Claude Negrier ◽  
Yesim Dargaud ◽  
Sandra Le Quellec
Keyword(s):  
Platelet Function ◽  
Light Transmission ◽  
Platelet Response ◽  
Platelet Function Tests ◽  
Clopidogrel Resistance ◽  
Function Tests ◽  
Function Analyzer ◽  
Clopidogrel Therapy ◽  
Whole Blood Aggregometry ◽  
Platelet Function Analyzer

SummaryThe two most widely used antiplatelet drugs in the world are aspirin and clopidogrel. However, some patients on aspirin and/or clopidogrel therapy do not respond appropriately to either aspirin or clopidogrel. This phenomenon is usually called “aspirin/clopidogrel resistance”. Several platelet function tests have been used in various studies for the assessment of aspirin and clopidogrel resistance in healthy individuals and patients admitted in cardiology departments. An accurate assessment of platelet response to aspirin/clopidogrel could benefit patients by proposing tailored-antiplatelet therapy based on test results. However, there is a clear lack of standardisation of such techniques and their analytical variability may induce misinterpretation. After a quick report of the mechanisms responsible for aspirin/clopidogrel resistance, we describe the pre-analytical aspects and the analytical performances of current platelet function tests (Light-transmission aggregometry, whole-blood aggregometry, VerifyNow®, Platelet Function Analyzer®, thromboelastography, VASP assay) that are used for the assessment of aspirin/clopidogrel resistance in clinical studies. Considering the different variables that have to be taken into account with each of the platelet function tests, a particular attention should be paid when interpreting results.

scholarly journals The role of platelet function analyzer-200 in predicting perioperative bleeding risk

2020 ◽  
Vol 35 (5) ◽  
pp. 1199-1209
Author(s):  
Eun Sang Yu ◽  
Min Ji Jeon ◽  
Ka-Won Kang ◽  
Byung-Hyun Lee ◽  
Eun Joo Kang ◽  
...  
Keyword(s):  
Platelet Function ◽  
Bleeding Risk ◽  
Perioperative Bleeding ◽  
Function Analyzer ◽  
Platelet Function Analyzer

scholarly journals The Platelet Function Analyzer (PFA-100) as a Screening Tool in Neurosurgery

2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
Ralf Karger ◽  
Karoline Reuter ◽  
Jochen Rohlfs ◽  
Christopher Nimsky ◽  
Ulrich Sure ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Platelet Function ◽  
Prophylactic Treatment ◽  
Screening Tool ◽  
Bleeding Complications ◽  
Preoperative Screening ◽  
Perioperative Bleeding ◽  
Neurosurgical Patients ◽  
Function Analyzer ◽  
Platelet Function Analyzer

We investigated whether the inclusion of the PFA-100 in the preoperative screening of neurosurgical patients might reduce perioperative bleeding complications. Patients with intracranial space-occupying lesions who were scheduled for neurosurgery underwent routine preoperative PFA-100 testing. In case of an abnormal PFA test, patients received prophylactic treatment with desmopressin. 93 consecutive patients were compared to 102 consecutive patients with comparable characteristics operated before introduction of the PFA-100 testing. 2 patients (2.2%) in the PFA group and 2 patients (2.0%) in the non-PFA group experienced clinically relevant intracranial bleeding confirmed by computed tomography (OR 1.05, 95% CI 0.39–2.82; ). Transfusions were not significantly different between the two groups. 13 (14.0%) patients in the PFA group and 5 (4.9%) patients in the non-PFA group received desmopressin (OR 3.2, 95% CI 1.1–9.2; ). Preoperative screening with the PFA-100 did result in a significant increase in the administration of desmopressin, which could not reduce perioperative bleeding complications or transfusions.

scholarly journals Utility of the Platelet Function Analyzer in Patients with Suspected Platelet Function Disorders: Diagnostic Accuracy Study

TH Open ◽  
2020 ◽  
Vol 04 (04) ◽  
pp. e427-e436
Author(s):  
Jonas Kaufmann ◽  
Marcel Adler ◽  
Lorenzo Alberio ◽  
Michael Nagler
Keyword(s):  
Clinical Practice ◽  
Platelet Function ◽  
Diagnostic Performance ◽  
Light Transmission ◽  
Laboratory Data ◽  
Adenosine Diphosphate ◽  
Bleeding Disorders ◽  
Platelet Function Disorders ◽  
Function Analyzer ◽  
Platelet Function Analyzer

Abstract Introduction The platelet function analyzer (PFA) is widely used as a screening tool for bleeding disorders in various settings. The diagnostic performance regarding platelet function disorders (PFDs), which are among the most common inherited bleeding disorders, is however still elusive. We aimed to assess the diagnostic value of PFA for PFD in clinical practice. Methods Comprehensive clinical and laboratory data of all consecutive patients referred to a specialized outpatient between January 2012 and March 2017 with a suspected bleeding disorder were prospectively recorded. The diagnostic work-up was performed according to a prespecified protocol following current guidelines and platelet function was tested using light transmission aggregometry as well as flow cytometry. Results Five hundred and fifty-five patients were included (median age 43.7 years; interquartile range [IQR] 29.3, 61.7; 66.9% female). Possible PFD was diagnosed in 64 patients (11.5%) and confirmed PFD in 54 patients (9.7%). In patients with confirmed PFD, median closure times were 107 seconds (ADP or adenosine diphosphate; IQR 89, 130) and 169 seconds (EPI; IQR 121, 211). In patients without bleeding disorders, PFA closure times were 96 seconds (ADP; IQR 83, 109) and 137 seconds (EPI; IQR 116, 158). The sensitivity was 19.5% in case of PFA ADP (95%CI 12.6, 30.0; specificity 86.4%; 95% CI 82.4, 89.8), and 44.3% in case of PFA EPI (95% CI 34.9, 53.9; specificity 75.6%; 95% CI 70.8, 79.9). Conclusion The diagnostic performance of PFA for PFD was moderate to poor. Our results do not support the utilization of PFA for screening of PFD in clinical practice.

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