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Background: Antithrombotic regimen in patients on oral anticoagulation (OAC) post-percutaneous coronary intervention (PCI) is challenging. At least, one antiplatelet agent in combination with OAC is recommended after PCI for 6–12 months. Clopidogrel is used most frequently in this setting. However, data comparing P2Y12 inhibition with clopidogrel versus cyclooxygenase inhibition by acetylsalicylic acid (ASA, aspirin) is missing. It is well known that the antiplatelet effects of ASA and clopidogrel are frequently impaired (high on-treatment platelet reactivity [HTPR]). In this pilot investigation, we compared the antiplatelet effects of clopidogrel versus ASA. Methods: In this retrospective single-center database analysis, we investigated platelet reactivity by light transmission aggregometry in patients under different antiplatelet regimes. Results were presented as maximum of aggregation (MoA). HTPR to ASA and to clopidogrel were assessed. Results: 755 patients were enrolled. 677 were on ASA, 521 were on clopidogrel, and 198 had OAC. Overall mean age was 73 ± 13.4 years, and 458 (60.7%) were male. HTPR to ASA occurred in 94/677 patients (13.9%), and mean arachidonic acid-induced MoA was 14.15 ± 19.04%. HTPR to clopidogrel occurred in 241/521 patients (46.3%), and mean adenosine diphosphate-induced MoA was 50.06 ± 20.42%. HTPR to clopidogrel was significantly more frequent than HTPR to ASA; single antiplatelet therapy (SAPT)-mono ASA: 27/199 (13.6%) versus mono clopidogrel: 6/18 (33.3%); p = 0.037; SAPT with OAC-OAC with ASA: 8/35 (22.9%) versus OAC with clopidogrel: 27/60 (45%); p = 0.046. Same difference in HTPR contingency could be shown in subgroups of dual antiplatelet therapy and ASA + clopidogrel + OAC therapy. Conclusion: Impaired pharmacodynamic response to clopidogrel was more frequent as HTPR to ASA. Hence, ASA should be tested in combination with OAC post-PCI.

Journal of Clinical Medicine 11(13), 3853 (2022). doi:10.3390/jcm11133853, Published by MDPI, Basel

Additional loading dose of acetylsalicylic acid (ASA) during percutaneous coronary interventions (PCIs) despite permanent oral ASA medication is frequently applicated. The impact on platelet reactivity and clinical events is not known. In this pilot study, we aimed to analyze high on-treatment platelet reactivity (HTPR) to aspirin in patients undergoing elective PCI. Platelet reactivity was measured using light-transmission aggregometry in 100 patients on permanent low-dose ASA medication undergoing elective PCI. Platelet reactivity measured by arachidonic acid-induced maximum of aggregation (MoA) in patients with versus without additional peri-procedural ASA loading (500 mg i.v.) was compared. HTPR was defined as MoA >20% for ASA. Major adverse cerebro- and cardiovascular events (MACCEs) and bleeding events were evaluated during hospital course. HTPR rate was similar in both groups (HTPR to ASA: loading vs. control 6% vs. 16%, odds ratio [OR] = 0.33, 95% confidence interval [CI] 0.08–1.35, p = 0.12). In-hospital MACCEs were not different between groups (MACCE: loading vs. control: 0 vs. 0 patient, OR = 1.32, 95% CI 0.03–67.95, p = 0.89). Thrombolysis in myocardial infarction minimal bleedings were numerically higher in patients without ASA loading dose. In this pharmacodynamic pilot study, additional ASA loading did not reduce HTPR to ASA. Furthermore, ASA loading did not increase in-hospital MACCE and bleeding complications.

Background: Targeting inflammation in patients with coronary artery disease and/or acute myocardial infarction (AMI) is a matter of debate. Methotrexate (MTX) is one of the most widely used immunosuppressants. Cardiovascular Inflammation Reduction Trial (CIRT) recently failed to demonstrate reduced cardiovascular events in MTX-treated patients. However, it is not known if long-term MTX treatment improves cardiac outcome in AMI. Therefore, in this study, we investigated the postischemic phase in MTX-treated mice undergoing AMI. Methods: Wild-type mice received MTX medication intraperitoneally for 2 weeks. Afterward, AMI was induced by transient left anterior ascending artery ligation. Postischemic cardiac damage after 24 h was assessed. Results: MTX treatment did not affect infarct size as compared to control (IS/AAR: Con 76.20% ± 12.37%/AAR vs. MTX 73.51 ± 11.72%/AAR, p = 0.64). Moreover, systolic function and structural parameters did not differ between groups (24hejection fraction: Con 36.49 ± 3.23% vs. MTX 32.77 ± 2.29%, p = 0.41; 24hLVID; d: Con 3.57 ± 0.17 mm vs. MTX 3.19 ± 0.13 mm, p = 0.14). Platelets were increased by MTX (Con 1,442 ± 69.20 × 103/mm3 vs. MTX 1,920 ± 68.68 × 103/mm3, p < 0.0001). White blood cell and RBC as well as rate of monocytes, granulocytes, lymphocytes, and serum amyloid P levels were equal. Conclusion: MTX medication did not improve postischemic cardiac damage in a murine model of AMI. Future trials are needed to identify and investigate other anti-inflammatory targets to improve cardiovascular outcome.

ACE inhibitors (ACEI) and angiotensin II receptor blockers (ARB) are important drugs in cardiovascular disease. However, little is known about which of these drug class is to be preferred. First analyses show that the blockade of the renin-angiotensin-aldosterone system (RAAS) influences platelet reactivity. Therefore, we evaluated the effects of ACEI and ARB on platelet reactivity and thrombin generation. We conducted a time series analysis in 34 patients. We performed light transmission aggregometry (LTA) to evaluate platelet reactivity. Results are given as maximum of aggregation (MoA). Thrombin generation was measured as endogenous thrombin potential (ETP) via calibrated automated thrombogram. Flow cytometry was used to analyze protease-activated receptor (PAR)-1 expression. ACEI treatment significantly increased platelet reactivity already 4 h after initiation of treatment (prior vs. 4 h post ACEI: MoA 41.9 ± 16.2% vs. 55.2 ± 16.7%; p = 0.003). After switching from ACEI to ARB treatment, platelet reactivity decreased significantly (3 months after switching: MoA 34.7 ± 20.9%; p = 0.03). ACEI reduced endogenous thrombin potential significantly from before to 3 months after ACEI (ETP 1527 ± 437 nM × min vs. 1088 ± 631 nM × min; p = 0.025). Platelet thrombin receptor (PAR1) expression increased from 37.38 ± 10.97% before to 49.53 ± 6.04% after ACEI treatment (p = 0.036). ACEI enhanced platelet reactivity. This can be reversed by changing to ARB. The mechanism behind RAAS influencing platelet function seems to be associated with PAR-1 expression.

Rationale: A reduced rate of myocardial infarction has been reported in patients with atrial fibrillation treated with FXa (factor Xa) inhibitors including rivaroxaban compared with vitamin K antagonists. At the same time, low-dose rivaroxaban has been shown to reduce mortality and atherothrombotic events in patients with coronary artery disease. Yet, the mechanisms underlying this reduction remain unknown. Objective: In this study, we hypothesized that rivaroxaban’s antithrombotic potential is linked to a hitherto unknown rivaroxaban effect that impacts on platelet reactivity and arterial thrombosis. Methods and Results: In this study, we identified FXa as potent, direct agonist of the PAR-1 (protease-activated receptor 1), leading to platelet activation and thrombus formation, which can be inhibited by rivaroxaban. We found that rivaroxaban reduced arterial thrombus stability in a mouse model of arterial thrombosis using intravital microscopy. For in vitro studies, atrial fibrillation patients on permanent rivaroxaban treatment for stroke prevention, respective controls, and patients with new-onset atrial fibrillation before and after first intake of rivaroxaban (time series analysis) were recruited. Platelet aggregation responses, as well as thrombus formation under arterial flow conditions on collagen and atherosclerotic plaque material, were attenuated by rivaroxaban. We show that rivaroxaban’s antiplatelet effect is plasma dependent but independent of thrombin and rivaroxaban’s anticoagulatory capacity. Conclusions: Here, we identified FXa as potent platelet agonist that acts through PAR-1. Therefore, rivaroxaban exerts an antiplatelet effect that together with its well-known potent anticoagulatory capacity might lead to reduced frequency of atherothrombotic events and improved outcome in patients.

Purpose During resuscitation of patients with severe trauma, guidelines recommend permissive hypotension prior to surgical bleeding control. However, hypotension may be associated with reduced organ perfusion and multiple organ dysfunction, e.g. myocardial injury. The association between hypotension and myocardial injury in trauma patients is underexplored. We hypothesized that hypotension is associated with myocardial injury in this population. Materials and methods This retrospective study included patients ≥ 18 years suffering from severe trauma [defined as Injury Severity Score (ISS) ≥ 16] that were treated in the emergency department resuscitation room between 2016 and 2019. Primary endpoint was the incidence of myocardial injury defined as high-sensitive troponin T > 14 ng/l. Main exposure was the duration of arterial hypotension during resuscitation period defined as mean arterial pressure Results Out of 368 patients screened, 343 were analyzed (73% male, age: 55 ± 21, ISS: 28 ± 12). Myocardial injury was detected in 143 (42%) patients. Overall in-hospital mortality was 26%. Multivariate binary logistic regression with forced entry of nine predefined covariables revealed an odds ratio of 1.29 [95% confidence interval 1.16–1.44]; p = 0.012) for the association between the duration of hypotension and myocardial injury. Conclusion The duration of hypotension during resuscitation period is independently associated with the incidence of myocardial injury in patients with severe trauma.

Background: Severe trauma potentially results in end-organ damage such as myocardial injury. Data suggest that myocardial injury is associated with increased mortality in this cohort, but the association with the incidence of in-hospital major adverse cardiac events (MACE) remains undetermined. Methods: Retrospective cohort study including adult patients with severe trauma treated at the University Hospital Duesseldorf between January 2016 and December 2019. The main exposure was myocardial injury at presentation. Endpoints were in-hospital incidence of MACE and incidence of acute kidney injury (AKI) within 72 h. Discrimination of hsTnT for MACE and AKI was examined by the receiver operating characteristic curve (ROC) and the area under the curve (AUC). We conducted multivariate logistic regression analysis. Results: We included 353 patients in our final analysis (72.5% male (256/353), age: 55 ± 21 years). The AUC for hsTnT and MACE was 0.68 [95% confidence interval (CI): 0.59–0.78]. The AUC for hsTnT and AKI was 0.64 [95% (CI): 0.55–0.72]. The adjusted odds ratio (OR) for myocardial injury and MACE was 2.97 [95% (CI): 1.31–6.72], and it was 2.14 [95% (CI): 1.03–4.46] for myocardial injury and AKI. Conclusion: Myocardial injury at presentation in patients with severe trauma is independently associated with the incidence of in-hospital MACE and AKI.

Purpose Severe trauma can lead to end organ damages of varying severity, including myocardial injury. In the non-cardiac surgery setting, there is extensive evidence that perioperative myocardial injury is associated with increased morbidity and mortality. The impact of myocardial injury on outcome after severe trauma has not been investigated adequately yet. We hypothesized that myocardial injury is associated with increased in-hospital mortality in patients with severe trauma. Materials/methods This retrospective cohort study included patients ≥ 18 years with severe trauma [defined as injury severity score (ISS) ≥ 16] that were admitted to the resuscitation room of the Emergency Department of the University Hospital Duesseldorf, Germany, between 2016 and 2019. The main endpoint was in-hospital mortality. Main exposure was myocardial injury at arrival [defined as high-sensitive troponin T (hsTnT) > 14 ng/l]. For statistical analysis, receiver operating characteristic curve (ROC) and multivariate binary logistic regression were performed. Results Out of 368 patients, 353 were included into statistical analysis (72.5% male, age: 55 ± 21, ISS: 28 ± 12). Overall in-hospital mortality was 26.1%. Myocardial injury at presentation was detected in 149 (42.2%) patients. In-hospital mortality of patients with and without myocardial injury at presentation was 45% versus 12.3%, respectively. The area under the curve (AUC) for hsTnT and mortality was 0.76 [95% confidence interval (CI) 0.71–0.82]. The adjusted odds ratio of myocardial injury for in-hospital mortality was 2.27 ([95%CI 1.16–4.45]; p = 0.017). Conclusion Myocardial injury after severe trauma is common and independently associated with in-hospital mortality. Thus, hsTnT might serve as a new prognostic marker in this cohort.

Background: Recent guidelines only recommend ‘vascular dose’ rivaroxaban in combination with aspirin in chronic coronary syndrome (CCS) patients with high risk of ischemic events However, in the CO...

Background Transcatheter aortic valve implantation (TAVI) is an evolving treatment of severe aortic valve stenosis. However, thromboembolic events such as stroke are common, predominantly early after TAVI. Optimal periprocedural antithrombotic regime is unknown. Especially, as antithrombotic medication enhances bleeding risk, thrombin generation and platelet function are crucial in the pathogenesis of ischemic events. However, the impact of the TAVI procedure on thrombin formation and platelet reactivity is not known by now. Methods We evaluated thrombin levels using thrombin–antithrombin (TAT) complexes and prothrombin fragments (PTFs) using enzyme-linked immunosorbent assay. Furthermore, platelet reactivity was measured via light transmission aggregometry before and 2 hours after TAVI in 198 patients. Results TAT complexes and PTF F1 + 2 substantially increased during TAVI. Postprocedurally, TAT complexes and PTF were significantly higher after TAVI compared with percutaneous coronary intervention due to acute myocardial infarction, while preprocedural TAT complexes and PTF F1 + 2 did not differ. In contrast, platelet reactivity was not altered early after TAVI. Only adenosine diphosphate-induced aggregation was reduced, reflecting preprocedural loading with clopidogrel. Conclusion In this pilot study, we were able to demonstrate that thrombin generation is significantly increased early after TAVI, while platelet function is not affected. Increased thrombin concentrations may contribute to the high risk of postprocedural thromboembolic events. This leads to the hypothesis that extended peri-interventional anticoagulation early after TAVI may be an approach to reduce thromboembolic events.

Dual platelet inhibition (DAPT) is crucial after percutaneous coronary intervention (PCI), especially for diabetes mellitus (DM) patients. Guidelines recommend 3-12 months of DAPT post PCI (1). However, prolongation up to 30 months is discussed. Moreover, additional vascular-dose rivaroxaban has been shown to reduce mortality (2). The associated increased bleeding risk, however, is fairly neglected. Several studies showed enhanced (3, 4), while others found equal or decreased bleeding risk in DM (5-8). This has direct implications for DAPT. Therefore, we investigated bleeding in post PCI patients with DM.

Background The pathogenesis of aortic stenosis (AS) is not fully understood. However, local inflammation of the valve appears to be a main player. Except haemostasis, platelets contribute to inflammatory processes in various ways. Furthermore, platelet function is altered in patients with AS. Moreover, a steep angle between the left ventricle and the aorta (LV-AO-angle) leads to turbulent blood flow. However, it is not known if platelet reactivity is associated with steep LV_AO angle in patients with AS. Methods We included 289 patients with severe AS and performed cardiac computertomography to assess the LV-AO-angle. Platelet function was evaluated by light transmission aggregometry by using collagen and adenosine-diphosphate to induce platelet activation Results ADP- and collagen induced aggregation showed a significant negative correlation with LV-AO-angle (ADP: r=−0.19, p=0.0009, R2=0.022; collagen: r=−0.21, p=0.0004, R2=0.027). ADP-induced MoA was significant higher in patients with a LV-AO-angle Conclusion A steep LV-AO-angle is associated with enhanced platelet reactivity in patients with AS. Platelet activation is known to lead to local inflammation. Therefore, enhanced platelet reactivity could play crucial in the progression of AS. The clinical significance of a steep LV-AO-angle needs be evaluated in further trials. Funding Acknowledgement Type of funding source: Foundation. Main funding source(s): German Research Foundation

Objectives Dual antiplatelet therapy (DAPT) with aspirin and clopidogrel is standard of care in patients with peripheral artery disease (PAD) after percutaneous transluminal angioplasty (PTA). However, high on treatment platelet reactivity (HTPR) to DAPT is frequent and associated with major adverse limb events (MALE) in PAD patients. Nevertheless, association of MALE and HTPR in patients with critical limb ischemia (CLI) is not known. Moreover, comorbidities might confound response to antiplatelet medication further. Hence, in this trial we analyzed pharmacodynamic responses to DAPT and clinical events in CLI patients post PTA. Methods In this prospective single center pilot analysis, we included 71 CLI patients. Patients received DAPT after PTA. Antiplatelet effect were measured by light transmission aggregometry (LTA) and vasodilator-stimulated protein phosphorylation assay (VASP). MALE, major adverse cardiac and cerebrovascular events (MACCE) and BARC bleeding within 12 months follow-up were assessed. Results Mean age of patients was 73.37 ± 7.36 years and 47 (66.2%) were male. Overall HTPR appeared in 46 patients (64.8%). MALE and MACCE showed no differences between patients with and patients without HTPR. However, bleeding was higher in patients with sufficient pharmacodynamic response to DAPT (Bleeding - HTPR: 13.4% vs. no HTPR: 36.0%; log-rank HR: 0.32; 95% CI 0.1079 to 0.9396 p = 0.0217). This finding remained robust in multivariate analysis. Conclusion HTPR to DAPT is frequent in CLI patients. However, bleeding was higher in patients with sufficient response to DAPT. Ischemic events did not differ. Hence, CLI patients might benefit from an alternative antithrombotic approach.

Background ACE inhibitors (ACEI) and angiotensin II receptor blockers (ARB) are beneficial for patients with cardiovascular disease. However, little is known about whether one of these drugs is superior. First analyses show that the inhibition of the renin-angiotensin-aldosterone system (RAAS) affects platelet reactivity. Therefore we evaluated the effects of ACEI and ARB on platelet reactivity and thrombin generation. Methods In a time series analysis, samples of 24 patients before, 4h and 24h after initial intake of ACEI were analysed. Also we included 10 patients with permanent ACEI treatment and 4h, 24h and 3 months after switching to ARB. Platelet reactivity was measured via light transmission aggregometry (LTA). Thrombin generation was measured as endogenous thrombin potential (ETP) by calibrated automated thrombogram. Protease-activated receptor (PAR) expression was analysed by flow cytometry. Thrombin-antithrombin (TAT) complexes were measured with an enzyme-linked immunosorbent assay. Results TRAP-6 induced platelet reactivity increased during ACEI treatment (prior vs. 4h post ACEI: 41.9±16.2% vs. 55.2±16.7%; p=0.003, prior vs. 24h post ACEI: 52.3±12.7%; p=0.003). Switching from chronic ACEI to ARB treatment decreased platelet reactivity (permanent ACEI vs. 3 months after switching: 50.3±20.9% vs. 34.7±20.9%; p=0.033). ACEI reduced ETP from prior to 3 months post ACEI (1527±437 nM*min vs. 1088±631 nM*min; p=0.025). ARB did not affect ETP (1526±587 nM*min vs. 1369±516 nM*min; p=0.3). PAR1 levels rose from 37.38±10.97% before to 49.53±6.04% after ACEI treatment (p=0.036). ARB did not have an effect on PAR1 (33.16±11.73 vs. 32.86±8.99; p=0.89). ACEI slightly decreased plasma thrombin concentration. ARB treatment showed a minor but again not significant decrease in TAT complexes as well. (TAT complexes prior vs. 3 months post ACEI: 8.4±11.9 μg/l vs. 6.3±6.8 μg/l; p=0.99, permanent ACEI vs. 3 months after switching to ARB: 4.3±1.9 μg/l vs. 3.0±1.0 μg/l; p=0.3). Conclusion ACEI increased platelet reactivity. This can be reversed by switching to ARB. The mechanism behind RAAS influencing platelet function needs to be further investigated in larger trials. Acknowledgement/Funding Medical Faculty of the Heinrich-Heine-University Düsseldorf

Background: Guidelines recommend the PRECISE-DAPT (PD) score to adapt duration of dual antiplatelet therapy due to bleeding risk. However, there is first evidence that PD predicts mortality and ischemic events as well. Methods: We investigated PD Score in 994 patients after percutaneous coronary intervention (PCI). PD was correlated with clinically frequently used scores. Major adverse cardiac and cerebrovascular events (MACCE) and Thrombolysis in Myocardial Infarction (TIMI) bleeding were assessed during one-year follow-up. Results: 524 patients had PD

Background The optimal antithrombotic strategy after interventional left atrial appendage closure (LAAC) is controversial. Dual antiplatelet therapy with aspirin and clopidogrel is the most frequently used regiment. However, pharmacodynamic response to antiplatelet medication differs significantly between individuals. Therefore, we aimed to analyse pharmacodynamic response to aspirin and clopidogrel after LAAC. Methods In this study, we included 129 patients undergoing interventional LAAC. Primary end point was pharmacodynamic response to antiplatelet medication. Platelet reactivity was measured by light transmittance aggregometry and vasodilator stimulated protein phosphorylation assay. Secondary endpoints were TIMI bleeding events and MACCE during hospital course and one-year follow-up. Results Insufficient pharmacodynamic response (high on-treatment platelet reactivity — HTPR) to clopidogrel occurred in 67 patients (52%); HTPR to aspirin in 15 patients (12%); low on-treatment platelet reactivity — LTPR — to clopidogrel in 13 patients (10%). No occluder thrombosis or stroke occurred during one year follow-up. Pharmacodynamic response to antiplatelet medication was not associated with MACCE. However, the incidence of TIMI minor bleeding was increased in patients with LTPR to clopidogrel. Conclusions Impaired clopidogrel antiplatelet effects were very frequent in patients after LAAC. No stroke or occluder thrombosis occurred. Patients with LTPR to clopidogrel showed more minor bleeding events. Therefore, this hypothesis generating pilot study raises the question if clopidogrel early after LAAC is needed. This question should be addressed in large scale trials.

Dipyrone comedication in aspirin-treated patients is associated with impaired pharmacodynamic response to aspirin (high on-treatment platelet reactivity [HTPR]). Additionally, in small observational studies, an association with impaired outcome has been described. In this uncontrolled, hypothesis-generating study, we aimed to investigate strategies to prevent this drug-drug interaction in patients with coronary artery disease (CAD).We analyzed pharmacodynamic response to aspirin in 80 dipyrone co-medicated CAD patients. Aspirin antiplatelet effects were measured using arachidonic acid (AA)-induced light-transmission aggregometry (LTA). Platelet reactivity was associated with daily dose, administration form, and frequency. Additionally, we conducted a time-series analysis in patients with HTPR to aspirin with re-evaluation of pharmacodynamic response to aspirin after 5 days.Patients' mean age was 75.5 ± 9.8 years. Forty-three (54%) were male, 22 (27.5%) obese, and 38 (47.5%) diabetics. Baseline characteristics, cardiovascular risk factors, comorbidities, comedication, or laboratory parameters did not differ between patients with or without HTPR. HTPR to aspirin occurred in 34 out of 80 patients (42.5%). The incidence of HTPR was associated with dipyrone daily dose ( 1 g/day: HTPR 20% vs. 3 g/day: HTPR 50%, p 0.0001) and form of administration (i.v. 87.5% vs. oral 37.5%; p 0.0001). A strict order of intake (aspirin 30 min prior to dipyrone) restored aspirin antiplatelet effects in all patients (HTPR before 100% vs. HTPR after 0%, p = 0.0002).This study shows that dipyrone should be used with caution in aspirin-treated patients. If dipyrone seems indispensable, the lowest effective dose and a strict order of intake seem favorable.