Platelet Function Testing In Patients Research Articles

Abstract Number: LBA4 Platelet Function Testing and Acute Thrombotic Events in Intracranial Aneurysm Patients Undergoing Flow Diversion

Introduction Introduction The role of platelet function testing in patients with intracranial aneurysms undergoing flow diversion remains controversial with limited evidence of its influence on thrombotic outcomes. We report an observational cohort analysis evaluating the association of P2Y12 assay testing with thrombotic events in patients undergoing flow diversion. Methods We performed a retrospective review of our prospectively maintained procedural database to identify patients who underwent flow diversion between January 2020 and July 2022. One physician within our practice never performs P2Y12 assay testing. All other physicians utilize P2Y12 assay testing as part of routine practice. These two different patient cohorts were compared. Acute thrombotic events were our primary outcome. Secondary outcomes included delayed intracerebral hemorrhage, intimal hyperplasia without clinical sequalae, and transient neurologic deficits. Results We identified 150 patients who underwent flow diversion at our institution between January 2020 and July 2022. Median age was 59 years old (Interquartile range (IQR) 49–67), with 113 females (82.5%) and 24 males (17.5%). Out of 150 patients, 93 (62.0%) patients were treated by physicians who performed routine pre and postoperative testing of aspirin and Plavix assays, with subsequent adjustment of antithrombotic dosing accordingly, while 57 patients (38.0%) were treated by the single physician who prescribes aspirin and clopidogrel pre‐operatively without testing. In all, seven out of 150 patients (4.7%) had an acute thrombotic event requiring intraarterial anti‐thrombotic infusion or urgent thrombectomy, or both. Of these, six where from the 93 patient testing cohort (6.5%), and one in 57 patients non‐testing cohort (1.8%) (p = 0.2). Patients who had a thrombotic event were more likely to have underlying atrial fibrillation (28.6% vs 4.9%, p = 0.01) but otherwise had similar demographics, vascular risk factors, maximal aneurysmal diameter, and parent vessel diameter (Table 1). In a multivariable analysis adjusting for age, maximal aneurysm diameter, ruptured aneurysms, and atrial fibrillation, P2Y12 sensitivity assay testing was not significantly associated with acute thrombotic events in aneurysm patients undergoing flow diversion (Odds Ratio (OR) = 0.15, 95% Confidence Interval (CI) = 0.01‐2.67), p = 0.2). Secondary outcomes were also comparable between both groups; transient neurologic deficits were noted in 4/93 in the testing group (4.3%), and 6/57 in the non‐testing group (10%) (p = 0.14), intracranial hemorrhage occurred in only 2 patients, both in the testing group (p = 0.3), and mild intimal hyperplasia was observed in 18.3% in the testing group versus 12.3% in the non‐testing group (p = 0.33). Conclusions Platelet function testing showed no significant correlation with thrombotic events or outcomes in our cohort. The role of platelet function testing remains controversial, albeit widely used in patients undergoing flow diversion of intracranial aneurysms.

Platelet reactivity testing in peripheral artery disease.

Oral antiplatelet therapy is routinely used to prevent adverse cardiovascular events in patients with peripheral artery disease (PAD). Several laboratory tests are available to quantify the degree of platelet inhibition following antiplatelet therapy. This article aims to provide a review of the literature surrounding platelet functional testing in patients with PAD receiving oral P2Y12 inhibitors and to offer guidance to clinicians for the use and interpretation of these tests. A literature search of PubMed and the Web of Science Core Collection database was conducted. All studies that performed platelet function testing and reported clinical outcomes in patients with PAD were included. Evaluation of the data suggests that, among the available testing strategies, the VerifyNow platelet reactivity unit (PRU) test is the most widely used. Despite numerous investigations attempting to define a laboratory threshold indicating suboptimal response to antiplatelet therapy, controversy exists about which PRU value best correlates with cardiovascular outcomes (ie, mortality, stent thrombosis, etc). In the PAD literature, the most commonly used PRU thresholds are 208 or higher and 235 or higher. Nonetheless, adjusting antiplatelet regimens based on suboptimal P2Y12 reactivity values has yet to be proven useful in reducing the incidence of adverse cardiovascular outcomes. This review examines platelet function testing in patients with PAD and discusses the interpretation and application of these tests when monitoring the safety and efficacy of P2Y12 inhibitors. Although platelet functional tests may be simple to use, clinical trials thus far have failed to show benefit from therapy adjustments based on test results. Clinicians should be cautioned against relying on this test result alone and should instead consider a combination of laboratory, clinical, and patient-specific factors when adjusting P2Y12 inhibitor therapy in clinical practice.

THE STUDY OF INFLUENCE OF PLATELET DYSFUNCTION ON CLINICAL PHENOTYPE OF HEMOPHILIA

Background: Hemophilia is an X-linked heritable coagulopathy with an overall prevalence of approximately 1 in 10,000 individuals. Hemophilias are rare X linked hereditary bleeding disorders. Platelets may be among the determinants of variability in bleeding phenotype. Objective: To evaluate the platelet function tests in patients with hemophilia, and to explore the influence of platelet dysfunction on hemophilia bleeding score. Patients and Methods: The study was conducted on 40 hemophilic patients and 20 normal persons as a control in outpatient clinics at Kafr El-Sheikh Governorate Hospitals and Al-Azhar University Hospitals (Al-Hussein and Sayed Galal) to evaluate the platelet function tests in patients with hemophilia, and to explore the influence of platelet dysfunction on hemophilia bleeding score. Results: The majority of cases (35 patients 87.5%) were type A and (5 patients 12.5%) were type B. As regard to hemophilia scoring system (HSS), 3 patients (7.5%) were type 1, 19 patients (47.5%) were type 2 and 18 patients (45%) were type 3. Bleeding from the knee occurred in the majority of patients (77.5%), from the elbow occurred in 32.5%, from the ankle occurred in 5%, from the vagina occurred in 15% and from the nose and the gum occurred in 7.5%. Platelets and maual platelet count showed insignificant difference between both groups. Platelets aggregation tests (ADP) test, collagen and restocetin agonists test) were significantly lower in cases group than control group. Prothrombin time (PT), international normalized ratio (INR), bleeding time (BT) showed insignificant differences between both group. On the other hands, activated partial thromboplastin time (APTT) significantly prolonged cases group than control group. No hemophilia C cases were detected in our study. Conclusion: There was a statistical significant relationship between bleeding phenotype in hemophilia B and platelet function. Diagnosis of hemophilia was confirmed by factor VIII assay for hemophilia A and factor IX assay for hemophilia B.

Investigation of platelet function in patients with chronic kidney disease stages IV-V.

Patients with renal failure are at increased risk of both bleeding and thrombosis. Further descriptions of laboratory investigations in these patients are required. Investigation of 24 patients with chronic kidney disease (CKD) stages IV-V with light transmission aggregometry, platelet secretion assays and platelet nucleotide analysis. Patients were in a nonbleeding state and not on antiplatelet medication. Results were compared with our local reference range used within the clinical haematology service. Of the 24 patients, two had decreased responses to arachidonic acid, adenosine diphosphate, collagen, thrombin receptor activator peptide-6 and one had decreased responses to high dose ristocetin, and one had increased response to low dose ristocetin. 11 and 13 out of 24 had abnormal platelet secretion release to collagen and thrombin, respectively. Platelet nucleotide analysis in patients was normal with the exception of a reduction in ADP content in one patient and ATP/ADP ratio in one patient. In our collection of patients with CKD investigated for platelet function in the nonbleeding state, they generally had normal light transmission aggregometry and nucleotide analysis but around 50% had decreased platelet secretion assays. These results could be important in determining the significance of platelet function tests in patients with bleeding symptoms and renal failure. Further characterization of platelet function tests in future will help characterize haemostasis in renal failure further.

Platelet function testing in patients with post-operative tonsillectomy bleeding may be a useful early identifier of inherited platelet function disorders.

Post-tonsillectomy bleeding is the most frequent complication of tonsillectomy. Inherited platelet function disorders have an estimated prevalence of 1 per cent. Any association between post-tonsillectomy bleeds and undiagnosed inherited platelet function disorders has not been investigated before. To assess the prevalence of inherited platelet function disorders in a cohort of post-tonsillectomy bleed patients. An observational cohort study was conducted using hospital digital records. Platelet function analyser 100 ('PFA-100') closure time was tested on post-tonsillectomy bleed patients who presented to hospital. Between 2013 and 2017, 9 of 91 post-tonsillectomy bleed patients who underwent platelet function analyser 100 testing (9.89 per cent) had positive results. Five patients (5.49 per cent) had undiagnosed inherited platelet function disorders. Four patients had false positive results secondary to a non-steroidal anti-inflammatory drug effect (specificity of 95.3 per cent) proven by repeat testing six weeks later, off medication. The false negative rate was 0 per cent. The prevalence of inherited platelet function disorders in our post-tonsillectomy bleed cohort is five-fold higher than in the general population. Platelet function analyser 100 testing when patients present with a post-tonsillectomy bleed allows management of their inherited platelet function disorder.

Platelet Function Testing in Patients on Antiplatelet Therapy before Cardiac Surgery.

Bleeding and transfusion, common challenges in cardiac surgery, are influenced by comorbidity, the complexity of surgery, hypothermia, and the specifics of cardiopulmonary bypass inducing hemodilution, thrombin generation, fibrinolysis, and platelet dysfunction.1-4 Nearly 11% of patients with acute coronary syndromes undergo coronary artery surgery during dual antiplatelet therapy.5 Although preoperative P2Y12 receptor inhibitor therapy may reduce ischemic events, late preoperative exposure to P2Y12 receptor inhibitors increases the risk of surgery-associated bleeding and reoperation for bleeding.2,6-8.

Utility of P2Y12 Reactive Unit Assessment on Ticagrelor in Cerebral Aneurysms Treated with Intracranial Stenting and Flow Diversion: Cohort Study and Case Report From Two Neurovascular Centers

Dual antiplatelet therapy consisting of aspirin and clopidogrel is the standard of care for neurointerventional stenting and flow diversion. Platelet function testing has been increasingly performed to identify patients with a hypo- or hyper-response to clopidogrel. Ticagrelor has been a popular alternative antiplatelet agent for such patients. We assessed the role of platelet function testing in patients receiving ticagrelor and undergoing stenting or flow diversion. The data from patients who had undergone stent-assisted coiling or Pipeline flow diversion of a cerebral aneurysm with ticagrelor therapy at any point during their treatment course from May 2017 to August 2019 at a single academic institution in the United States were retrospectively reviewed. Platelet function testing was used to determine the P2Y12 reactive units (PRUs), and the results were correlated with the procedural complications. A total of 28 patients with 29 aneurysms were treated while receiving ticagrelor. Of the 29 aneurysms, 16 (55.2%) were treated with flow diversion and 13 (44.8%) with stent-assisted coiling. Four thromboembolic complications (13.8%) and no hemorrhagic complications developed. Of the 8 patients with ≥1 PRU value >100, 4 (50%) had experienced a thromboembolic complication. The patients without a PRU value >100 did not experience any complications. A risk of thromboembolic complications exists for patients receiving ticagrelor, which correlated with the PRUs in the present preliminary study. The findings from the present study suggest that the safe PRU range for patients receiving ticagrelor should be shifted to 0-100, which is lower than that of clopidogrel, thought to be 60-210. Further validation of the optimal PRU range for patients receiving ticagrelor is necessary.

The Effects of loW Dose tIcagrelor on Platelet Function Testing in Patients With Stable Coronary arTery Disease

The Effects of loW Dose tIcagrelor on Platelet Function Testing in Patients With Stable Coronary arTery Disease

Is There a Role for Preoperative Platelet Function Testing in Patients Undergoing Cardiac Surgery During Antiplatelet Therapy?

Up to 11% of patients presenting with acute coronary syndromes undergo coronary artery bypass grafting. Guidelines largely recommend a one-size-fits-all preoperative discontinuation period for P2Y12 receptor blockers to avoid bleeding. These recommendations do not account for highly variable pharmacodynamic responsiveness and for variable recovery of platelet reactivity following discontinuation of P2Y12 receptor blockers. Several observational studies have demonstrated that an objective measurement of platelet function among these patients may reduce the waiting period while mitigating the risk of bleeding. Based on these findings, 2 recent guidelines included a Class IIa and IIb recommendation for platelet function testing in patients undergoing cardiac surgery. The following review article describes the rationale for discontinuation of dual antiplatelet therapy before cardiac surgery and the limitations with this approach, available platelet function assays to assess pharmacodynamic effects, and the association between platelet inhibition and other clinical factors with surgery-related bleeding. The information will assist the reader in determining which patients undergoing cardiac surgery might benefit from preoperative platelet function monitoring.

On-treatment platelet reactivity in the era of new ADP receptor blockers: data from a real-world clinical practice

Abstract Objectives: Several studies have questioned the need for platelet function testing in patients treated with new ADP receptor blockers (ADPRB). The aim of this study was to evaluate the prevalence of high on-treatment platelet reactivity (HTPR) among acute ST-elevation myocardial infarction (STEMI) patients treated with newer ADPRB. Methods: A prospective study enrolling 44 acute previously ADPRB naive STEMI patients (31 men, 13 women) undergoing primary percutaneous coronary intervention (pPCI) was performed. Among the studied population 23 patients received prasugrel and 21 patients received ticagrelor. Antiplatelet response was tested with light transmission aggregometry (LTA) and vasodilator-stimulated phosphoprotein phosphorylation (VASP-P) flow cytometry assay. Samples were taken prior to coronary angiography (sample 1) and on the day after this procedure (sample 2). Results: The mean platelet aggregation after induction with ADP was 51.7 ± 24.8% in sample 1 and 25.3 ± 20.1% in sample 2. An examination of VASP-P showed a mean platelet reactivity index of 56.8 ± 25.7% in sample 1 and 23.8 ± 23.1% in sample 2, respectively. The study identified 11.4% of patients in sample 2 as ADP receptor blocker non-responders. No significant differences were found between prasugrel-treated to ticagrelor-treated patients. Conclusions: This pilot study demonstrated HTPR among acute STEMI patients treated with newer ADPRB.

P5733Comparison of three different platelet function tests in patients on P2Y12 inhibitors in correlation to genetic background

P5733Comparison of three different platelet function tests in patients on P2Y12 inhibitors in correlation to genetic background

Individualized dual antiplatelet therapy based on platelet function testing in patients undergoing percutaneous coronary intervention: a meta-analysis of randomized controlled trials

BackgroundHigh on-treatment platelet reactivity (HPR) represents a strong risk factor for thrombotic events after PCI. We aim to evaluate the efficacy and safety of individualizing intensified dual antiplatelet therapy (DAPT) in PCI-treated patients with HPR based on platelet function testing (PFT).MethodsElectronic databases were searched for randomized control trials that reported the clinical outcomes of using an intensified antiplatelet protocol with P2Y12 receptor inhibitor comparing with standard maintenance dose of clopidogrel on the basis of platelet function testing. Clinical endpoints were assessed.ResultsFrom 2005 to 2016, thirteen clinical studies comprising 7290 patients were included for analysis. Compared with standard antiplatelet therapy with clopidogrel, the intensified protocol based on platelet function testing was associated with a significant reduction in major adverse cardiovascular events (RR:0.55, 95% CI: 0.36–0.84, p = 0.005), cardiovascular death (RR:0.60, 95% CI: 0.38–0.96, p = 0.03), stent thrombosis (RR:0.58, 95% CI: 0.36–0.93, p = 0.02) and target vessel revascularization (RR:0.33, 95% CI: 0.14–0.76, p = 0.009). No significant difference was found in the rate of bleeding events between intensified and standard protocol.ConclusionsCompared with standard clopidogrel therapy, individualized intensified antiplatelet therapy on the basis of platelet reactivity testing reduces the incidence of cardiovascular events in patient undergoing PCI, without increasing the risk of bleeding.

Platelet Function Testing in Patients with Acute Ischemic Stroke: An Observational Study

The measurement of platelet reactivity in patients with stroke undergoing antiplatelet therapies is not commonly performed in clinical practice. We assessed the prevalence of therapy responsiveness in patients with stroke and further investigated differences between patients on prevention therapy at stroke onset and patients naive to antiplatelet medications. We also sought differences in responsiveness between etiological subtypes and correlations between Clopidogrel responsiveness and genetic polymorphisms. A total of 624 stroke patients on antiplatelet therapy were included. Two different groups were identified: "non-naive patients", and "naive patients". Platelet function was measured with multiple electrode aggregometry, and genotyping assays were used to determine CYP2C19 polymorphisms. Aspirin (ASA) responsiveness was significantly more frequent in naive patients compared with non-naive patients (94.9% versus 82.6%, P < .0010). A better responsiveness to ASA compared with Clopidogrel or combination therapy was found in the entire population (P < .0010), in non-naive patients (P < .0253), and in naive patients (P < .0010). Multivariate analysis revealed a strong effect of Clopidogrel as a possible "risk factor" for unresponsiveness (odds ratio 3.652, P < .0001). No difference between etiological subgroups and no correlations between responsiveness and CYP2C19 polymorphisms were found. In our opinion, platelet function testing could be potentially useful in monitoring the biological effect of antiplatelet agents. A substantial proportion of patients with stroke on ASA were "resistant", and the treatment with Clopidogrel was accompanied by even higher rates of unresponsiveness. Longitudinal studies are needed to assess whether aggregometry might supply individualized prognostic information and whether it can be considered a valid tool for future prevention strategies.

Applying the Cell-Based Coagulation Model in the Management of Critical Bleeding

The cell-based coagulation model was proposed 15 years ago, yet has not been applied commonly in the management of critical bleeding. Nevertheless, this alternative model may better explain the physiological basis of current coagulation management during critical bleeding. In this article we describe the limitations of the traditional coagulation protein cascade and standard coagulation tests, and explain the potential advantages of applying the cell-based model in current coagulation management strategies. The cell-based coagulation model builds on the traditional coagulation model and explains many recent clinical observations and research findings related to critical bleeding unexplained by the traditional model, including the encouraging results of using empirical 1:1:1 fresh frozen plasma:platelets:red blood cells transfusion strategy, and the use of viscoelastic and platelet function tests in patients with critical bleeding. From a practical perspective, applying the cell-based coagulation model also explains why new direct oral anticoagulants are effective systemic anticoagulants even without affecting activated partial thromboplastin time or the International Normalized Ratio in a dose-related fashion. The cell-based coagulation model represents the most cohesive scientific framework on which we can understand and manage coagulation during critical bleeding.

Antiplatelet strategies in elderly people: still a long way to go

Outcomes of patients with acute coronary syndrome undergoing percutaneous coronary intervention have been significantly improved with the potent P2Y12 receptor inhibitors prasugrel and ticagrelor. 1 Wiviott SD Braunwald E McCabe CH et al. Prasugrel versus clopidogrel in patients with acute coronary syndromes. N Engl J Med. 2007; 357: 2001-2015 Crossref PubMed Scopus (5562) Google Scholar , 2 Wallentin L Becker RC Budaj A et al. Ticagrelor versus clopidogrel in patients with acute coronary syndromes. N Engl J Med. 2009; 361: 1045-1057 Crossref PubMed Scopus (5545) Google Scholar Elderly patients comprise a growing subset of the acute coronary syndrome population. This subset is characterised by multiple organ changes and various comorbidities, which altogether culminate in an increased risk of both ischaemic and bleeding complications after percutaneous coronary intervention. Platelet function testing has been established and validated to predict ischaemic and bleeding events in patients treated with percutaneous coronary intervention. 3 Aradi D Kirtane A Bonello L et al. Bleeding and stent thrombosis on P2Y12-inhibitors: collaborative analysis on the role of platelet reactivity for risk stratification after percutaneous coronary intervention. Eur Heart J. 2015; 36: 1762-1771 Crossref PubMed Scopus (268) Google Scholar , 4 Tantry US Bonello L Aradi D et al. Consensus and update on the definition of on-treatment platelet reactivity to adenosine diphosphate associated with ischemia and bleeding. J Am Coll Cardiol. 2013; 62: 2261-2273 Summary Full Text Full Text PDF PubMed Scopus (756) Google Scholar However, previous studies, 5 Collet JP Cuisset T Range G et al. Bedside monitoring to adjust antiplatelet therapy for coronary stenting. N Engl J Med. 2012; 367: 2100-2109 Crossref PubMed Scopus (759) Google Scholar , 6 Aradi D Storey RF Komocsi A et al. Expert position paper on the role of platelet function testing in patients undergoing percutaneous coronary intervention. Eur Heart J. 2014; 35: 209-215 Crossref PubMed Scopus (213) Google Scholar enrolling mostly low-risk patients with little use of potent antiplatelet drugs, have been unable to show clinical superiority of strategies that implemented platelet function testing for treatment guidance. Nevertheless, elderly patients undergoing percutaneous coronary intervention represent a high-risk cohort that might derive clinical benefit from platelet function testing to monitor and adjust the level of platelet inhibition. Platelet function monitoring to adjust antiplatelet therapy in elderly patients stented for an acute coronary syndrome (ANTARCTIC): an open-label, blinded-endpoint, randomised controlled superiority trialPlatelet function monitoring with treatment adjustment did not improve the clinical outcome of elderly patients treated with coronary stenting for an acute coronary syndrome. Platelet function testing is still being used in many centres and international guidelines still recommend platelet function testing in high-risk situations. Our study does not support this practice or these recommendations. Full-Text PDF

Platelet Function Testing in Patients on Antiplatelet Medications.

Guidelines provide a Class IA recommendation for the use of dual antiplatelet therapy in patients undergoing percutaneous coronary intervention (PCI). However, there is interindividual variability in the pharmacodynamic response to antiplatelet medications. Some patients present with a status of high on-treatment platelet reactivity (HPR) during platelet function testing after standard doses of antiplatelet drugs, reflecting a failure to achieve adequate platelet inhibition. As an example, patients with HPR on clopidogrel are at increased risk for thrombotic events, particularly for stent thrombosis and myocardial infarction, but cardiovascular mortality is also elevated. On the contrary, low on-treatment platelet reactivity or an enhanced response to antiplatelet medications has been linked to a higher risk for bleeding. Although both thrombotic and bleeding events are multifactorial in origin, there is supportive evidence for the prognostic value of platelet function testing for risk prediction of both sides of the coin. However, although small studies have provided evidence that treatment adjustments based on platelet function testing results may improve clinical outcomes, the available randomized controlled trials showed no benefit of modifying antiplatelet treatment based on platelet function testing. This review presents the current evidence regarding platelet function testing in patients undergoing PCI. The prognostic value of platelet function testing regarding ischemic and bleeding events is highlighted. Furthermore, the value of platelet function testing for guiding treatment and possible explanations for the so-far negative trial results are presented. The possible future role of platelet function testing for individualized antiplatelet treatment regimens in high-risk patients will be also discussed.

Association of MicroRNAs and YRNAs With Platelet Function.

Platelets shed microRNAs (miRNAs). Plasma miRNAs change on platelet inhibition. It is unclear whether plasma miRNA levels correlate with platelet function. To link small RNAs to platelet reactivity. Next-generation sequencing of small RNAs in plasma revealed 2 peaks at 22 to 23 and 32 to 33 nucleotides corresponding to miRNAs and YRNAs, respectively. Among YRNAs, predominantly, fragments of RNY4 and RNY5 were detected. Plasma miRNAs and YRNAs were measured in 125 patients with a history of acute coronary syndrome who had undergone detailed assessment of platelet function 30 days after the acute event. Using quantitative real-time polymerase chain reactions, 92 miRNAs were assessed in patients with acute coronary syndrome on different antiplatelet therapies. Key platelet-related miRNAs and YRNAs were correlated with platelet function tests. MiR-223 (rp=0.28; n=121; P=0.002), miR-126 (rp=0.22; n=121; P=0.016), and other abundant platelet miRNAs and YRNAs showed significant positive correlations with the vasodilator-stimulated phosphoprotein phosphorylation assay. YRNAs, miR-126, and miR-223 were also among the small RNAs showing the greatest dependency on platelets and strongly correlated with plasma levels of P-selectin, platelet factor 4, and platelet basic protein in the population-based Bruneck study (n=669). A single-nucleotide polymorphism that facilitates processing of pri-miR-126 to mature miR-126 accounted for a rise in circulating platelet activation markers. Inhibition of miR-126 in mice reduced platelet aggregation. MiR-126 directly and indirectly affects ADAM9 and P2Y12 receptor expression. Levels of platelet-related plasma miRNAs and YRNAs correlate with platelet function tests in patients with acute coronary syndrome and platelet activation markers in the general population. Alterations in miR-126 affect platelet reactivity.

Predicting Bleeding Risk by Platelet Function Testing in Patients Undergoing Heart Surgery.

Predicting bleeding events in patients with coronary artery bypass grafting (CABG) represents an unmet medical need that may improve CABG outcomes. To assess the potential link between platelet function testing and bleeding risk in patients undergoing CABG. Platelet aggregation and clinical outcomes in 478 patients treated with aspirin and/or clopidogrel were retrospectively analyzed. Platelet activity was assessed prior to CABG with arachidonic acid (ASPI Test), and adenosine diphosphate(ADP Test) utilizing multiple-electrode aggregometry. In the study group of 478 patients, mean age was 65.2±15.2 years; 138 were women. The majority of patients (n = 198) underwent on-pump surgery, with 162 undergoing off-pump and 30 undergoing minimally invasive surgery. Forty-eight patients received artificial valve implantation alone, and 40 received valve implantation in combination with CABG. The analysis of the entire pool revealed that an ASPI test value <407 area under curve per minute (AUC*min) may be useful in predicting postoperative drainage. In CABG patients only, an ASPI test value <271 AUC*min predicted the need for red blood cell concentrate transfusion following surgery. In patients who stopped clopidogrel for up to 5 days before surgery, the ADP test failed to exhibit prognostic utility for predicting bleeding risk. In patients undergoing heart surgery, an ASPI test value <407 AUC*min may predict higher postoperative drainage, whereas <271 AUC*min may be linked to postoperative use of red blood cell concentrate.

P-025 does platelet function testing have a role in patients undergoing pipeline embolization device deployment: Abstract P-025 Table 1

Introduction/purpose There are conflicting reports regarding the utility of platelet function tests in patients undergoing treatment with Pipeline Embolization Device (PED) for intracranial aneurysms. Herein, we report the correlation between platelet function testing and the incidence of complications in a series of patients who underwent PED placement. Unlike prior reports, patient procedures at our institutions were not canceled or postponed based on platelet function tests. Materials and methods A retrospective analysis of the patients with unruptured, intracranial aneurysms treated with PED device (s) at two academic hospitals was performed between June 2012 and March 2015. Patient demographics, location of intracranial aneurysm, size and number of PEDs deployed were documented for each patient. The dual antiplatelet regimen prior to and following PED deployment was documented. All patients received Aspirin 325 mg and Plavix 75 mg daily, 5 days prior to the procedure, and continued the treatment for six months. Platelet function testing was performed on the day of or the day after PED deployment using the VerifyNow (Accumetrics) system for Aspirin (ARU) and P2Y12 Reaction Units (PRU) (Plavix). Therapeutic platelet function testing for Aspirin was defined as an ARU less than 550. PRUs > 70 or Results A total of 39 PEDs were deployed in 32 procedures performed on a total of 27 patients with unruptured, intracranial aneurysms (average age, 55 ± 14 years; 4 (15%) male). There were 3 (9%) procedures in which neither platelet function test was obtained. No procedure was delayed or canceled based on the results of platelet function testing. There were no immediate or delayed thrombotic or hemorrhagic complications. Clinical follow up ranged from 18 days to 2 years post procedure. Conclusion In our experience, the wide range of ARU and PRU values did not have any impact on the incidence of thromboembolic or hemorrhagic complications in the peri-operative or immediate post- operative period. It may be unwise to cancel or postpone PED procedures based on single PRU value measurements, since this can lead to unnecessary cost escalations for the patient and the facility. A well designed randomized control trial may offer the best answer regarding the utility of platelet function testing in the treatment of patients with intra-cranial aneurysms using flow diverters. Disclosures H. Zacharatos: None. D. Sandhu: None. R. Tummala: None. A. Grande: None. B. Jagadeesan: None.

Optimal- vs. standard-antiplatelet therapy on platelet function and long-term clinical outcomes in patients with high on-treatment platelet reactivity: 2-year outcomes of the multicentre, randomized Optimal-antiPlatelet Therapy (OPT) trial

Optimal strategy for the management of high on-treatment platelet reactivity (HPR), an independent predictor of ischaemic events, is not yet clear. The aim of this study was to explore the safety and efficacy of personalized antiplatelet therapy based on platelet function testing in patients with HPR. A total of 840 patients with HPR who underwent coronary stenting for acute coronary syndrome (ACS) were randomly assigned in a 1:2 ratio to receive standard dual-antiplatelet therapy ( n = 280) or platelet function-guided optimal-antiplatelet therapy ( n = 560). In the optimal group, patients initially received clopidogrel 150 mg/day on top of aspirin and switched to triple antiplatelet therapy with additional cilostazol if repeat platelet function assay after 3 days indicated a sustained HPR. The primary endpoint was the composite of all-cause death, myocardial infarction, clinically driven target vessel revascularization (TVR), or stroke. Optimal therapy resulted in significantly lower 30-day HPR rate (30.1 vs. 44.3%, P < 0.001). At 1-year follow up, optimal therapy was associated with significantly lower incidence of primary endpoint events (2.7 vs. 6.8%, P = 0.006) compared with standard therapy, mainly due to the reduction of TVR. These beneficial effects were sustained at 2 years (4.5 vs. 9.2%, P = 0.006), with similar bleeding event rates between groups (7.3 vs. 6.5%, P = 0.565). Optimal-antiplatelet therapy based on platelet function testing is effective in attenuating HPR and improving long-term outcomes for ACS patients with no increase in bleeding events.