Przemysław Paciorek

Overview of pleiotropic effects of platelet P2Y12 receptor inhibitors.

Dual antiplatelet therapy consisting of one of the P2Y12 receptor inhibitors in conjunction with aspirin is the mainstay of treatment for patients with acute coronary syndromes (ACS) and those undergoing percutaneous coronary interventions (PCI). In recent years, multiple extra-platelet features of P2Y12 receptor antagonists have been reported in numerous clinical trials. The aim of this review is to summarise reported pleiotropic effects of clopidogrel, prasugrel, ticagrelor and other P2Y12 receptor blockers. We included observations made both in human and in animal models, together with proposed mechanisms of action for described features. If confirmed in randomised studies and properly applied to everyday practice, the observed extra-platelet actions could enable us to improve efficacy of ACS and post-PCI treatment, as well as to confine mortality and occurrence rate of cardiovascular events.

Time-related changes in determinants of antiplatelet effect of clopidogrel in patients after myocardial infarction☆

Substantial variability of antiplatelet action is an important limitation of clopidogrel. The aim of this study was to evaluate time-related changes in determinants of clopidogrel responsiveness in patients after myocardial infarction. The study population comprised 191 consecutive patients treated with primary percutaneous coronary intervention for acute myocardial infarction. Follow-up visits were scheduled at 3, 6 and 9 months after discharge. ADP-induced platelet aggregation was tested with Multiplate Analyzer. Patients with ADP-PA>46.8U were defined as clopidogrel non-responders. The prevalence of clopidogrel non-responsiveness was highest during hospitalization and at 9 month follow-up visit, while it was lowest at 3 and 6 months after myocardial infarction (P=0.004). According to multivariate analysis, platelet count, mean platelet volume, concentration of hsCRP and leukocyte count influenced ADP-induced platelet aggregation in multiple assessment points. BMI, concentrations of hemoglobin, glycated hemoglobin, and BNP, hematocrit, adherence to medication, and patient׳s age were found to be independent predictors of high on-treatment ADP-induced platelet aggregation only at a single follow-up visit. Determinants of clopidogrel responsiveness in patients after myocardial infarction change within the long-term therapy. During hospitalization and early after discharge only biological factors affect ADP-induced platelet aggregation, while non-adherence to antiplatelet therapy may be a significant factor in determining clopidogrel non-responsiveness during late follow-up visits.

ACS network-based implementation of therapeutic hypothermia for the treatment of comatose out-of-hospital cardiac arrest survivors improves clinical outcomes: the first European experience

BackgroundThere is a paucity of data regarding clinical outcomes associated with the integration of a mild therapeutic hypothermia (MTH) protocol into a regional network dedicated to treatment of patients with acute coronary syndromes (ACS). Additionally, a recent report suggests that the neurological benefits of MTH therapy in interventionally managed ACS patients resuscitated from out-of-hospital cardiac arrest (OHCA) may be potentially offset by the catastrophic occurrence of stent thrombosis. The goal of this study was to share our experience with the implementation of an MTH program using a previously established ACS network in consecutive comatose OHCA survivors undergoing interventional management due to an initial diagnosis of ACS and to assess the clinical effectiveness and safety of MTH.MethodsWe conducted a retrospective historically controlled single centre study. Hospital survival with a favourable neurological outcome (Cerebral Performance Category of 1 or 2) and all-cause in-hospital mortality were the primary and secondary efficacy end points, respectively. Occurrence of definite stent thrombosis was the primary safety end point while the development of pneumonia, presence of positive blood cultures, occurrence of probable stent thrombosis, any bleeding complications, need for red blood cell transfusion and presence of rhythm and conductions disorders during hospitalisation constituted secondary safety end points.ResultsComatose OHCA survivors (n = 32) were referred to our Department based on ECG recording transmissions and/or phone consultations or admitted from the Emergency Department. Compared with controls (n = 33), they were significantly more likely to be discharged from hospital with a favourable neurological outcome (59 vs. 27%; p < 0.05; number needed to treat [NNT] = 3.11) and experienced lower all-cause in-hospital mortality (13 vs. 55%; p < 0.05; NNT = 2.38). Rates of all safety end points were similar in patients treated with and without MTH.ConclusionsOur study indicates that a regional system of care for OHCA survivors may be successfully implemented based on an ACS network, leading to an improvement in neurological status and to a reduction of in-hospital mortality in patients treated with MTH, without any excess of complications. However, our findings should be verified in large, prospective trials.

Affective temperament and executive functions in emergency medicine professionals

BACKGROUND Recent studies indicate that choice of profession is related to differences in affective temperament, which is probably due to various predispositions needed to efficiently perform particular professions. The aim of the present study was to assess affective temperament and executive functions in a sample of emergency medicine professionals. METHODS 75 emergency medicine professionals were enrolled in the study. Affective temperament was assessed by means of TEMPS-A. Executive functions were assessed by means of Trail Making Test and Stroop Color Word Interference Test. RESULTS Subjects showed significantly higher rates of hyperthymic, compared to depressive, cyclothymic, irritable and anxious temperaments. The principal component analysis revealed that hyperthymic temperament contributes to a different factor, than the remaining ones. Higher rates of depressive, cyclothymic, irritable and anxious temperaments were related to poorer performance in Trail Making Test, whereas hyperthymic temperament had the opposite effect. LIMITATIONS Due to the size of the sample, results of the present study may have lacked power to show all the relationships between tested variables. CONCLUSIONS Hyperthymic temperament promotes efficient performance of complex tasks under time pressure. Depressive, cyclothymic, irritable and anxious temperaments have the opposite effect. This makes hyperthymic temperament a desirable trait in emergency medicine professionals, performing complex medical tasks under extreme conditions.

Rationale and Design of the Effectiveness of LowEr maintenanCe dose of TicagRelor early After myocardial infarction (ELECTRA) pilot study

Aims The degree and time course of platelet inhibition using ticagrelor can vary during the acute phase and the following stable period after acute myocardial infarction (AMI). The optimal level of platelet inhibition during the various stages of AMI remains an open question. The aim of the current study is to compare the antiplatelet efficacy of two ticagrelor maintenance dose regimens (60 mg b.i.d. vs. 90 mg b.i.d.) in stable patients following an initial strategy with ticagrelor 90 mg b.i.d. during the first month after AMI. Methods and results The Effectiveness of LowEr maintenanCe dose of TicagRelor early After myocardial infarction (ELECTRA) pilot study is a phase III, single-centre, randomized, open-label, pharmacokinetic/pharmacodynamic trial. The study population will include 50 patients with AMI treated with percutaneous coronary intervention. At Day 30 post-AMI, all trial participants will be randomly assigned in 1:1 ratio to receive either reduced (60 mg b.i.d.) or standard (90 mg b.i.d.) maintenance ticagrelor dose until Day 45 post-AMI. Platelet function testing in each patient will be performed using up to two different methods (the VASP assay and multiple electrode aggregometry). Pharmacokinetics of ticagrelor and its active metabolite (AR-C124910XX) will be assessed by liquid chromatography mass spectrometry. Conclusion A de-escalation strategy with reduced dose of ticagrelor (60 mg b.i.d.) following an initial standard dose (90 mg b.i.d.) during the first month after AMI may provide equally effective platelet inhibition as compared to maintenance with the standard ticagrelor dose. ClinicalTrials. gov Identifier NCT03251859.

Comparison of bioavailability and antiplatelet action of ticagrelor in patients with ST-elevation myocardial infarction and non-ST-elevation myocardial infarction: A prospective, observational, single-centre study

Background Data from available studies suggest that the presence of ST-elevation myocardial infarction (STEMI) may be associated with delayed and attenuated ticagrelor bioavailability and effect compared with non-ST-elevation myocardial infarction (NSTEMI). Methods In a single-center, prospective, observational trial 73 patients with myocardial infarction (STEMI n = 49, NSTEMI n = 24) underwent a pharmacokinetic and pharmacodynamic assessment after a 180 mg ticagrelor loading dose (LD). Ticagrelor and its active metabolite (AR-C124910XX) plasma concentrations were determined with liquid chromatography tandem mass spectrometry, and their antiplatelet effect was measured with the VASP assay and multiple electrode aggregometry. Results During the first six hours after ticagrelor LD, STEMI patients had 38% and 34% lower plasma concentration of ticagrelor and AR-C124910XX, respectively, than NSTEMI (ticagrelor AUC(0–6): 2491 [344–5587] vs. 3991 [1406–9284] ng*h/mL; p = 0.038; AR-C124910XX AUC(0–6): 473 [0–924] vs. 712 [346–1616] ng*h/mL; p = 0.027). STEMI patients also required more time to achieve maximal concentration of ticagrelor (tmax: 4.0 [3.0–12.0] vs. 2.5 [2.0–6.0] h; p = 0.012). Impaired bioavailability of ticagrelor and AR-C124910XX seen in STEMI subjects was associated with diminished platelet inhibition in this group, which was most pronounced during the initial hours of treatment. Conclusions Plasma concentrations of ticagrelor and AR-C124910XX during the first hours after ticagrelor LD were one third lower in STEMI than in NSTEMI patients. This reduced and delayed ticagrelor bioavailability was associated with weaker antiplatelet effect in STEMI. Clinical trial registration ClinicalTrials.gov identifier: NCT02602444 (November 09, 2015)

Off-target effects of glycoprotein IIb/IIIa receptor inhibitors.

Soon after identification of the platelet membrane glycoprotein (GP) IIb/IIIa, it has become a target of antiplatelet therapy. There are 3 intravenous GP IIb/IIIa receptor inhibitors, namely- eptifibatide, tirofiban and abciximab, used in the contemporary clinical practice, particularly in patients with acute coronary syndrome undergoing percutaneous coronary intervention (PCI). The aim of the current review is to summarize available knowledge concerning off-target effects of GP IIb/IIIa receptor inhibitors. All 3 drugs have similar antithrombotic properties, but differ with respect to pharmacodynamics, pharmacokinetics and off-target effects. Eptifibatide and tirofiban are highly specific GP IIb/IIIa receptor inhibitors, while abciximab is unselectiveand cross-reacts with integrin avb3 - a vitronectin receptor and leukocyte-associatedi ntegrin Mac-1. As a result of these interactions, abciximab seems to reduce the development of clinical restenosis, decrease infarct size, inhibit adhesion of monocytes to medical steel and modulate the inflammatory response. Intracoronary administration of abciximab provides higher drug concentration in the target area, increasing dose-dependent interactions with other integrins. Off-target effects of small molecule GP IIb/IIIa receptor inhibitors (i.e. eptifibatide and tirofiban) are predominantly connected with their suppressive influence on the inflammatory response. All in all, although GP IIb/IIIa receptor inhibitors are not recommended as a routine therapy during PCI, their antiplatelet properties and potential off-target effects may bebeneficial in certain subsets of patients.

Treatment of patients with acute coronary syndrome: Recommendations for medical emergency teams: Focus on antiplatelet therapies. Updated experts’ standpoint

A group of Polish experts in cardiology and emergency medicine, encouraged by the European Society of Cardiology (ESC) guidelines, have recently published common recommendations for medical emergency teams regarding the pre-hospital management of patients with acute coronary syndrome. Due to the recent publication of the 2017 ESC guidelines for the management of acute myocardial infarction in patients presenting with ST-segment elevation and 2017 focused update on dual antiplatelet therapy in coronary artery disease the current panel of experts decided to update the previous standpoint. Moreover, new data coming from studies presented after the previous document was issued were also taken into consideration.

Anti-aggregation therapy in patients with acute coronary syndrome — recommendations for medical emergency teams. Experts’ standpoint

Jacek Kubica, Piotr Adamski, Przemysław Paciorek , Jerzy R. Ładny, Zbigniew Kalarus, Waldemar Banasiak, Wacław Kochman, Jarosław Gorący, Beata Wożakowska-Kapłon, Eliano Pio Navarese, Andrzej Kleinrok, Robert Gil, Maciej Lesiak, Jarosław Drożdż, Aldona Kubica, Krzysztof J. Filipiak, Jarosław Kaźmierczak, Aleksander Goch, Stefan Grajek, Andrzej Basiński, Łukasz Szarpak, Grzegorz Grześk, Piotr Hoffman, Wojciech Wojakowski, Zbigniew Gąsior, Sławomir Dobrzycki, Jolanta M. Siller-Matula, Adam Witkowski, Wiktor Kuliczkowski, Marcin Gruchała, Dariusz Timler, Grzegorz Opolski, Dariusz Dudek, Jacek Legutko, Marzenna Zielińska, Jarosław Wójcik

Metabolism of ticagrelor in patients with acute coronary syndromes

Ticagrelor is a state-of-the-art antiplatelet agent used for the treatment of patients with acute coronary syndromes (ACS). Unlike remaining oral P2Y12 receptor inhibitors ticagrelor does not require metabolic activation to exert its antiplatelet action. Still, ticagrelor is extensively metabolized by hepatic CYP3A enzymes, and AR-C124910XX is its only active metabolite. A post hoc analysis of patient-level (n = 117) pharmacokinetic data pooled from two prospective studies was performed to identify clinical characteristics affecting the degree of AR-C124910XX formation during the first six hours after 180 mg ticagrelor loading dose in the setting of ACS. Both linear and multiple regression analyses indicated that ACS patients presenting with ST-elevation myocardial infarction or suffering from diabetes mellitus are more likely to have decreased rate of ticagrelor metabolism during the acute phase of ACS. Administration of morphine during ACS was found to negatively influence transformation of ticagrelor into AR-C124910XX when assessed with linear regression analysis, but not with multiple regression analysis. On the other hand, smoking appears to increase the degree of ticagrelor transformation in ACS patients. Mechanisms underlying our findings and their clinical significance warrant further research.