Heparin dosing in patients with Impella-supported cardiogenic shock

BACKGROUND

Impella™ is increasingly used in cardiogenic shock. However, thromboembolic and bleeding events are frequent during percutaneous mechanical circulatory support (pMCS).

OBJECTIVE

Therefore, we aimed to explore the optimal anticoagulation regime for pMCS to prevent thromboembolism and bleedings.

METHODS

This hypothesis-generating multi-center cohort study investigated 170 patients with left-Impella™ support. We (A) compared bleeding/thrombotic events in two centers with therapeutic range (TR-aPTT) activated partial thromboplastin time (60-80s) and (B) compared events of these centers with one center with intermediate range aPTT (40-60s).

RESULTS

After matching, there were no differences in patients' characteristics. In centers aiming at TR-aPTT, major bleeding was numerically lower with aPTT <60s within 48 h of left-Impella™ support, versus patients that achieved the aimed aPTT of ≥60s [aPTT ≥60s: 22 (37.3%) vs. aPTT<60s 14 (23.7%); Hazard ratio [HR], 0.62 (95%) CI, 0.28-1.38; p = 0.234]. Major cardiovascular and cerebrovascular adverse events (MACCE) did not differ between groups. In comparison of centers, TR-aPTT strategy showed higher major bleeding rates [TR: 8 (47.1%) vs. intermediate range: 1 (5.9%); HR, 0.06 (95%) CI, 0.01-0.45; p = 0.006]. MACCE were lower in the intermediate range aPTT group as well [TR 12 (70.6%) vs. intermediate range 5 (29.4%) HR, 0.32 (95%) CI, 0.11-0.92; p = 0.034].

CONCLUSION

This pilot analysis showed that lowering UFH-targets in left-Impella™ supported CS patients seems to be a safe and promising strategy for reducing major bleedings without increasing MACCE. This needs to be validated in larger, randomized clinical trials.

Transformation or replacement - Effects of hormone therapy on cardiovascular risk

Hormone therapy (HT) is important and frequently used both regarding replacement therapy (HRT) and gender affirming therapy (GAHT). While HRT has been effective in addressing symptoms related to hormone shortage, several side effects have been described. In this context, there are some studies that show increased cardiovascular risk. However, there are also studies reporting protective aspects of HT. Nevertheless, the exact impact of HT on cardiovascular risk and the underlying mechanisms remain poorly understood. This article explores the relationship between diverse types of HT and cardiovascular risk, focusing on mechanistic insights of the underlying hormones on platelet and leukocyte function as well as on effects on endothelial and adipose tissue cells.

Sphingosine-1-phosphate suppresses GLUT activity through PP2A and counteracts hyperglycemia in diabetic red blood cells

Red blood cells (RBC) are the major carriers of sphingosine-1-phosphate (S1P) in blood. Here we show that variations in RBC S1P content achieved by altering S1P synthesis and transport by genetic and pharmacological means regulate glucose uptake and metabolic flux. This is due to S1P-mediated activation of the catalytic protein phosphatase 2 (PP2A) subunit leading to reduction of cell-surface glucose transporters (GLUTs). The mechanism dynamically responds to metabolic cues from the environment by increasing S1P synthesis, enhancing PP2A activity, reducing GLUT phosphorylation and localization, and diminishing glucose uptake in RBC from diabetic mice and humans. Functionally, it protects RBC against lipid peroxidation in hyperglycemia and diabetes by activating the pentose phosphate pathway. Proof of concept is provided by the resistance of mice lacking the S1P exporter MFSD2B to diabetes-induced HbA1c elevation and thiobarbituric acid reactive substances (TBARS) generation in diabetic RBC. This mechanism responds to pharmacological S1P analogues such as fingolimod and may be functional in other insulin-independent tissues making it a promising therapeutic target.

SYSTEMI - systemic organ communication in STEMI: design and rationale of a cohort study of patients with ST-segment elevation myocardial infarction

BACKGROUND

ST-segment elevation myocardial infarction (STEMI) still causes significant mortality and morbidity despite best-practice revascularization and adjunct medical strategies. Within the STEMI population, there is a spectrum of higher and lower risk patients with respect to major adverse cardiovascular and cerebral events (MACCE) or re-hospitalization due to heart failure. Myocardial and systemic metabolic disorders modulate patient risk in STEMI. Systematic cardiocirculatory and metabolic phenotyping to assess the bidirectional interaction of cardiac and systemic metabolism in myocardial ischemia is lacking.

METHODS

Systemic organ communication in STEMI (SYSTEMI) is an all-comer open-end prospective study in STEMI patients > 18 years of age to assess the interaction of cardiac and systemic metabolism in STEMI by systematically collecting data on a regional and systemic level. Primary endpoint will be myocardial function, left ventricular remodelling, myocardial texture and coronary patency at 6 month after STEMI. Secondary endpoint will be all-cause death, MACCE, and re-hospitalisation due to heart failure or revascularisation assessed 12 month after STEMI. The objective of SYSTEMI is to identify metabolic systemic and myocardial master switches that determine primary and secondary endpoints. In SYSTEMI 150-200 patients are expected to be recruited per year. Patient data will be collected at the index event, within 24 h, 5 days as well as 6 and 12 months after STEMI. Data acquisition will be performed in multilayer approaches. Myocardial function will be assessed by using serial cardiac imaging with cineventriculography, echocardiography and cardiovascular magnetic resonance. Myocardial metabolism will be analysed by multi-nuclei magnetic resonance spectroscopy. Systemic metabolism will be approached by serial liquid biopsies and analysed with respect to glucose and lipid metabolism as well as oxygen transport. In summary, SYSTEMI enables a comprehensive data analysis on the levels of organ structure and function alongside hemodynamic, genomic and transcriptomic information to assess cardiac and systemic metabolism.

DISCUSSION

SYSTEMI aims to identify novel metabolic patterns and master-switches in the interaction of cardiac and systemic metabolism to improve diagnostic and therapeutic algorithms in myocardial ischemia for patient-risk assessment and tailored therapy.

TRIAL REGISTRATION

Trial Registration Number: NCT03539133.

The Clinical Frailty Scale for mortality prediction of old acutely admitted intensive care patients: a meta-analysis of individual patient-level data

BACKGROUND

This large-scale analysis pools individual data about the Clinical Frailty Scale (CFS) to predict outcome in the intensive care unit (ICU).

METHODS

A systematic search identified all clinical trials that used the CFS in the ICU (PubMed searched until 24th June 2020). All patients who were electively admitted were excluded. The primary outcome was ICU mortality. Regression models were estimated on the complete data set, and for missing data, multiple imputations were utilised. Cox models were adjusted for age, sex, and illness acuity score (SOFA, SAPS II or APACHE II).

RESULTS

12 studies from 30 countries with anonymised individualised patient data were included (n = 23,989 patients). In the univariate analysis for all patients, being frail (CFS ≥ 5) was associated with an increased risk of ICU mortality, but not after adjustment. In older patients (≥ 65 years) there was an independent association with ICU mortality both in the complete case analysis (HR 1.34 (95% CI 1.25-1.44), p < 0.0001) and in the multiple imputation analysis (HR 1.35 (95% CI 1.26-1.45), p < 0.0001, adjusted for SOFA). In older patients, being vulnerable (CFS 4) alone did not significantly differ from being frail. After adjustment, a CFS of 4-5, 6, and ≥ 7 was associated with a significantly worse outcome compared to CFS of 1-3.

CONCLUSIONS

Being frail is associated with a significantly increased risk for ICU mortality in older patients, while being vulnerable alone did not significantly differ. New Frailty categories might reflect its "continuum" better and predict ICU outcome more accurately.

TRIAL REGISTRATION

Open Science Framework (OSF: https://osf.io/8buwk/ ).

Revealing concealed cardioprotection by platelet Mfsd2b-released S1P in human and murine myocardial infarction

Antiplatelet medication is standard of care in acute myocardial infarction (AMI). However, it may have obscured beneficial properties of the activated platelet secretome. We identify platelets as major source of a sphingosine-1-phosphate (S1P) burst during AMI, and find its magnitude to favorably associate with cardiovascular mortality and infarct size in STEMI patients over 12 months. Experimentally, administration of supernatant from activated platelets reduces infarct size in murine AMI, which is blunted in platelets deficient for S1P export (Mfsd2b) or production (Sphk1) and in mice deficient for cardiomyocyte S1P receptor 1 (S1P₁). Our study reveals an exploitable therapeutic window in antiplatelet therapy in AMI as the GPIIb/IIIa antagonist tirofiban preserves S1P release and cardioprotection, whereas the P2Y12 antagonist cangrelor does not. Here, we report that platelet-mediated intrinsic cardioprotection is an exciting therapeutic paradigm reaching beyond AMI, the benefits of which may need to be considered in all antiplatelet therapies.

Optimal Antithrombotic Regimen in Left Atrial Appendage Occlusion: The Gordian Knot?

Percutaneous left atrial appendage occlusion (LAAO) is an option to reduce the risk of stroke in patients with atrial fibrillation and high bleeding risk. However, device-related thrombosis (DRT) post LAAO is feared as complication. Simard et al. found a very high incidence of DRT compared to other trials. However, antithrombotic regimen and used devices have not been compared between studies. We compared DRT formation, antithrombotic regimen and used device in the recent DRT study, the Amplatzer IDE trial, and the Düsseldorf (DUS) LAAO registry. Occluder thrombosis occurred in 25.3% in the DRT study, 3.8% in the Amulet IDE trial, and 3.3% in the DUS LAAO registry (p < 0.0001). Oral anticoagulation-based regimen was more frequent in the DRT study compared to the DUS LAAO registry, whereas dual antiplatelet regimen was more frequent in the DUS LAAO registry (p < 0.0001). Amplatzer amulet was more frequently used in the DUS LAAO registry as compared to the DRT study (p < 0.0001). DRT is a feared complication after LAAO and seems to be dependent on antiplatelet treatment and underlying device. A clinical study controlling for device and antithrombotic regimen is needed to smash this Gordian knot.

High On-Treatment Platelet Reactivity: Aspirin versus Clopidogrel

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.

Sphingosine-1-phosphate improves outcome of no-reflow acute myocardial infarction via sphingosine-1-phosphate receptor 1

AIMS

Therapeutic options targeting post-ischaemic cardiac remodelling are sparse. The bioactive sphingolipid sphingosine-1-phosphate (S1P) reduces ischaemia/reperfusion injury. However, its impact on post-ischaemic remodelling independently of its infarct size (IS)-reducing effect is yet unknown and was addressed in this study.

METHODS AND RESULTS

Acute myocardial infarction (AMI) in mice was induced by permanent ligation of the left anterior descending artery (LAD). C57Bl6 were treated with the S1P lyase inhibitor 4-deoxypyridoxine (DOP) starting 7 days prior to AMI to increase endogenous S1P concentrations. Cardiac function and myocardial healing were assessed by cardiovascular magnetic resonance imaging (cMRI), murine echocardiography, histomorphology, and gene expression analysis. DOP effects were investigated in cardiomyocyte-specific S1P receptor 1 deficient (S1PR1 Cardio Cre+) and Cre- control mice and S1P concentrations measured by LC-MS/MS. IS and cardiac function did not differ between control and DOP-treated groups on day one after LAD-ligation despite fourfold increase in plasma S1P. In contrast, cardiac function was clearly improved and myocardial scar size reduced, respectively, on Day 21 in DOP-treated mice. The latter also exhibited smaller cardiomyocyte size and reduced embryonic gene expression. The benefit of DOP treatment was abolished in S1PR1 Cardio Cre+.

CONCLUSIONS

S1P improves cardiac function and myocardial healing post AMI independently of initial infarct size and accomplishes this via the cardiomyocyte S1PR1. Hence, in addition to its beneficial effects on I/R injury, S1PR1 may be a promising target in post-infarction myocardial remodelling as adjunctive therapy to revascularization as well as in patients not eligible for standard interventional procedures.

Excess mortality in Aspirin and Dipyrone (Metamizole) co-medicated in patients with cardiovascular disease: a nationwide study

Background

Pain is a serious issue in our aging society. Metamizole is one of the most commonly used analgesics. In addition, metamizole has been shown to attenuate the pharmacodynamics response to aspirin as measured by platelet function tests. However, the extent to which this laboratory effect translates to clinical outcome in patients is unknown.

Methods

We conducted a nationwide analysis based on health insurance database including 9.2 million patients in Germany. All patients with a cardiovascular event in 2014 and subsequent secondary prevention with aspirin were followed up for 36 months. Inverse probability of treatment weighting (IPTW) analysis was performed to examine mortality rates between patients on aspirin-metamizole co-medication and aspirin medication alone. Myocardial infarction (MI) and stroke/transient ischemic attack (TIA) events were also documented.

Results

26,200 patients received continuous aspirin medication alone and 5,946 received co-medication with aspirin and metamizole. In the IPTW analysis, significantly increased mortality was observed in the co-medication group (15.6% vs. 24.4%, hazard ratio (HR)=1.66, 95% confidence interval (CI) 1.56–1.76; p&lt;0.0001). MI and stroke/TIA were also increased (MI: 1,370 [5.2%] vs. 355 [5.9%]; HR=1.18, 95% CI 1.05–1.32; p=0.0066, relative risk (RR) 1.14, absolute risk increase (ARI) 0.71%, number needed to harm (NNH) 140. Stroke/TIA: 1,901 [7.3%] vs. 506 [8.5%]; HR=1.22, 95% CI 1.11–1.35; p&lt;0.0001, RR 1.17, ARI 1.21%, NNH 82).

Conclusion

In this nationwide observational study, aspirin-metamizole co-medication was associated with excess mortality. This was partly due to ischemic events (MI and stroke/TIA), which were also more frequent in the co-medication patients. Therefore, metamizole should be used with caution in aspirin-treated patients for secondary prevention

Funding Acknowledgement

Type of funding sources: None.

Impaired Cardioprotection by HDL in CAD and Diabetes in Ischemia/Reperfusion Injury: role of S1P and SR-BI

Background

HDL dysfunction rather than HDL-cholesterol concentration is involved in the pathogenesis of coronary artery disease (CAD) and type-2 diabetes (T2DM). While causes and consequences of HDL dysfunction are manifold, reduced concentrations of HDL-sphingosine-1-phsophate (S1P) are partially responsible for impaired vasodilation and suppression of inflammation by CAD-HDL. Administration of healthy human HDL prior to coronary ischemia/reperfusion (I/R) in mice reduced infarct size (IS) due to HDL-S1P. The role of major HDL receptor SR-BI is unexplored in this context.

Purpose

In this study, we, a) investigated the cardioprotective properties of healthy versus CAD-HDL and T2DM-HDL in a murine model of acute myocardial infarction (AMI), b) tested the effect of S1P loading of CAD-HDL in cardioprotection, and c) detected the relevant HDL receptor of this cardioprotection.

Methods

HDL were isolated from plasma of healthy volunteers, CAD, and T2DM patients by density ultra-centrifugation and injected (43 mg HDL protein/KG) in the tail vein of C57Bl/6J mice 5 minutes prior to 30 minutes of ischemia. Cardiac function was assessed after 24 hours of reperfusion by echocardiography. IS was analyzed by TTC staining and S1P concentration measured by LC-MS/MS, respectively.

Results

Administration of human healthy HDL reduced IS by 23% and increased ejection fraction (EF) by 22% 24 hours after I/R (IS: Control 43.8±6.9% [n=17] vs. healthy HDL 32.9±3.6% [n=9]; EF: Control 34.5±5.7% vs. healthy HDL 41.9±4.1%). In contrast, CAD-HDL in the same dosage had no protective effect (IS: 40.1±5.7% [n=12]; EF: 31.9±8.4%). As HDL-S1P concentrations were 33% lower in CAD-HDL compared to healthy HDL, we tested whether S1P-loading may correct CAD-HDL's defective cardioprotection. Indeed, S1P-loading (38 μg S1P/kg in 43 mg HDL protein/KG) completely restored CAD-HDL cardioprotection to levels achieved by healthy HDL. S1P-loading of healthy HDL had no additional benefit. Administration of T2DM-HDL prior to I/R led to 28% larger IS and 22% worse EF compared to healthy HDL (IS: healthy HDL 33.0±4.3% [n=6] vs. T2DM-HDL 42.4±8.9% [n=13]; EF: healthy HDL 38.5±5.8% [n=6] vs. T2DM-HDL 33.1±.4.0%). Compared to healthy HDL, T2DM-HDL exhibited a 19% decrease in S1P content. We thus tested whether the major HDL receptor SR-BI is involved in HDL-S1P mediated cardioprotection using global SR-BI deficient mice (Scarb1−/−). Remarkably, cardioprotection by HDL administration was completely absent in Scarb1−/− mice but intact in wild type controls. (IS Scarb1++: Vehicle 38.6±8.3% [n=12] vs. HDL 29.9±8.5% [n=11], Scarb1−/−: Vehicle 31.4±5.6% [n=12] vs. HDL 31.1±6.9% [n=17])

Conclusion

We have identified: (a) impaired cardioprotection after I/R as new characteristic of HDL dysfunction in CAD and T2DM; (b) low HDL-S1P as its cause and the possibility of its therapeutic correction by S1P loading, and (c) SR-BI as the HDL receptor responsible for HDL-S1P-mediated cardioprotection.

Funding Acknowledgement

Type of funding sources: None.

S1P lyase inhibition improves post-ischemic cardiac remodeling independently of infarct size via S1P receptor 1

Background

Revascularization of the infarct vessel is the golden standard in acute myocardial infarction (AMI). Even in Western countries, more than ten percent of AMI patients are so-called “latecomers” and it is controversial if revascularization of the infarct vessel is beneficial in these patients. Current guidelines even discourage revascularization of the infarcted artery if symptom onset was &gt;48 hours and the patient is asymptomatic. These patients are at high risk for cardiovascular events and heart failure with reduced ejection fraction (HFrEF). HFrEF has an enormous socio-economic impact, high morbidity, and mortality.

Purpose

Therapeutic options targeting post-ischemic cardiac remodeling are sparse. The bioactive sphingolipid sphingosine-1-phosphate (S1P) reduces ischemia/reperfusion injury when administered in advance. However, its impact on post-ischemic remodeling independently of its infarct size (IS)-reducing effect is yet unknown.

Methods

Acute myocardial infarction (AMI) in mice was induced by permanent ligation of the left anterior descending artery (LAD). C57Bl/6J were treated with the S1P lyase inhibitor 4-deoxypyridoxine (DOP) starting seven days prior to AMI to increase endogenous S1P concentrations. Cardiac function and myocardial healing were assessed by cardiovascular magnetic resonance imaging (cMRI), histomorphology and gene expression analysis. DOP effects were investigated in cardiomyocyte-specific S1P receptor 1 deficient (S1PR1 Cardio Cre+ and Cre− control) mice, and S1P concentrations measured by LC-MS/MS.

Results

S1P concentrations in plasma before induction of AMI were increased fourfold by DOP (Control 0.97±0.09μM [n=6] vs. DOP 3,80±0,09μM [n=6]). Scar size determined by MRI, as well as ejection fraction (EF), did not differ 24 h post AMI. In contrast, after 21 days, there was a clear difference between the two groups (scar size vehicle: 19.3±6.2% vs. DOP 13.4±5.7%; EF: Vehicle: 26.4±8.7% vs. DOP 38.2±11.8%). In addition, in the remote area 21 days post AMI in the DOP-treated animals, a reduced gene expression of brain natriuretic peptide, atrial natriuretic peptide and collagen 1a2. Finally, cardiomyocyte diameter in the remote myocardium was 21% smaller in DOP-treated (Vehicle: 21.95±1.59μm vs. DOP 17.35±0.77μm). The benefit of DOP-treatment was abolished in cardiomyocyte-specific S1PR1-deficient mice.

Conclusion

S1P improves cardiac function and myocardial healing post AMI independently of initial infarct size via S1PR1. Hence, in addition to its beneficial effects on I/R injury, S1PR1 may be a promising target in post-infarction myocardial remodeling as adjunctive therapy to revascularization and in patients who are not eligible for standard interventional procedures.

Funding Acknowledgement

Type of funding sources: None.

Left ventricular-aortic angle is associated with platelet reactivity in patients with aortic stenosis

The impact of aortic stenosis on platelet reactivity is unclear. Previous studies reported contradicting results. The reason for this is unknown. It is known that flow alterations enhance platelet reactivity. A steep left ventricular-aortic angle (LV-AO-angle) is associated with turbulent flow in the aorta ascendens. Therefore, in this study, we hypothesized that LV-AO-angle is associated with platelet reactivity in patients with severe aortic stenosis. We included 289 patients with severe aortic stenosis and performed cardiac computertomography to assess the LV-AO-angle. Platelet function was evaluated by light transmission aggregometry. Platelet reactivity was higher in patients with a steep LV-AO-angle (ADP: <160°: 66.99% ± 20.72% vs. ≥160°: 60.66% ± 19.85%, P  = 0.009; collagen: <160°: 78.67% ± 13.19% vs. ≥160°: 73.85% ± 14.44%, P  = 0.003). Using Spearman correlation, ADP and collagen-induced aggregation was associated with LV-AO-angle (ADP: r  = -0.19, P  = 0.0009, R2  = 0.022; collagen: r  = -0.21, P  = 0.0004, R2  = 0.027). Apart from platelet reactivity, body weight, history of myocardial infarction and other factors were associated with steep LV-AO-angle. However, multivariate cox-regression (including body weight, comorbidities, history of MI and cardiac surgery, kidney function and laboratory parameters) revealed that LV-AO angle was a robust predictor of ADP and collagen-induced platelet aggregation. Steep LV-AO-angle is associated with enhanced platelet reactivity in patients with aortic stenosis. This could be the reason of contradicting results regarding platelet function in patients with aortic stenosis in previous studies. In addition, enhanced platelet reactivity in steep LV-AO-angle aortic stenosis patients might be a promising target in pathogenesis of aortic stenosis.

Excess Mortality in Aspirin and Dipyrone (Metamizole) Co-Medicated in Patients With Cardiovascular Disease: A Nationwide Study

Background

Pain is a major issue in our aging society. Dipyrone (metamizole) is one of the most frequently used analgesics. Additionally, it has been shown to impair pharmacodynamic response to aspirin as measured by platelet function tests. However, it is not known how this laboratory effect translates to clinical outcome.

Methods and Results

We conducted a nationwide analysis of a health insurance database in Germany comprising 9.2 million patients. All patients with a cardiovascular event in 2014 and subsequent secondary prevention with aspirin were followed up for 36 months. Inverse probability of treatment weighting analysis was conducted to investigate the rate of mortality, myocardial infarction, and stroke/transient ischemic attack between patients on aspirin‐dipyrone co‐medication compared with aspirin‐alone medication. Permanent aspirin‐alone medication was given to 26,200 patients, and 5946 patients received aspirin–dipyrone co‐medication. In the inverse probability of treatment weighted sample, excess mortality in aspirin–dipyrone co‐medicated patients was observed (15.6% in aspirin‐only group versus 24.4% in the co‐medicated group, hazard ratio [HR], 1.66 [95% CI, 1.56–1.76], P<0.0001). Myocardial infarction and stroke/transient ischemic attack were increased as well (myocardial infarction: 1370 [5.2%] versus 355 [5.9%] in aspirin‐only and co‐medicated groups, respectively; HR, 1.18 [95% CI, 1.05–1.32]; P=0.0066, relative risk [RR], 1.14; number needed to harm, 140. Stroke/transient ischemic attack, 1901 [7.3%] versus 506 [8.5%] in aspirin‐only and co‐medicated groups, respectively; HR, 1.22 [95% CI, 1.11–1.35]; P<0.0001, RR, 1.17, number needed to harm, 82).

Conclusions

In this observational, nationwide analysis, aspirin and dipyrone co‐medication was associated with excess mortality. This was in part driven by ischemic events (myocardial infarction and stroke), which occurred more frequently in co‐medicated patients as well. Hence, dipyrone should be used with caution in aspirin‐treated patients for secondary prevention.

Platelet reactivity is higher in e-cigarette vaping as compared to traditional smoking

INTRODUCTION

Vaping emerges as alternative to standard tobacco smoking. However, there is evidence for critical cardiovascular, gastrointestinal and respiratory side effects. Nevertheless, long-term vaping effects on thrombocyte reactivity have not been investigated. Therefore, we investigated the influence of vaping on thrombocyte reactivity in comparison to standard smoking and non-smoking.

METHODS

Platelet function was measured by Multiplate Impedance Aggregometry as area under the curve (AUC). Smoking habits and characteristics were assessed by questionnaire. Results were analyzed using inverse probability of treatment weighting (IPTW) and conventional t-tests to test for robustness.

RESULTS

After IPTW adjustment, participants in all groups were balanced by age, gender, body height and weight. Collagen-induced aggregation was higher in vapers compared to non-smokers (non-smokers 52.55 ± 23.97 vs. vapers 66.63 ± 18.96 AUC, p = 0.002) and to smokers (vapers vs. smokers 49.50 ± 26.05 AUC, p < 0.0001). ADP-induced aggregation in vapers was higher compared to non-smokers (non-smokers 33.16 ± 16.61 vs. vapers 45.27 ± 18.67 AUC, p = 0.001) and was numerically increased compared to smokers (vapers vs. smokers 40.09 ± 19.80 AUC, p = 0.08). These findings remained robust in t-test analysis.

CONCLUSION

This study provides first evidence that vaping leads to enhanced platelet reactivity compared to standard smoking and non-smoking. This suggests health effects of vaping might be more severe than previously assumed. Whether this effect translates to clinical outcome with a higher incidence of major cardiovascular events, should be evaluated in large-scaled clinical studies.

Rapid pacing is an independent predictor for high implantation depth using self-expandable devices in TAVR

Background/Introduction

Optimizing valve implantation depth (ID) plays a crucial role in minimizing conduction disturbances and achieving optimal functional integrity. Until now, the impact of intraprocedural fast (FP) or rapid ventricular pacing (RP) on the implantation depth has not been investigated.

Purpose

Therefore, we aimed to 1) evaluate the impact of different pacing maneuvers on ID, and 2) identify the independent predictors of deep ID.

Methods

562 TAVR patients with newer-generation self-expandable devices were retrospectively enrolled and further separated into patients undergoing TAVR under FP (n=331; 58.9%) and RP (n=231; 41.1%). The final ID was analyzed, and the underlying functional, anatomical, and procedural conditions were evaluated by univariate and multivariate analysis.

Results

The highest ID was reached under RP in severe aortic valve calcification and valve size 26 mm. Multivariate analysis identified left ventricular outflow (LVOT) calcification (OR 0.56 [0.37–0.85], p=0.006*), a bicuspid valve (OR 0.34 [0.11–1.0], p=0.049*), valve size 26 mm (OR 0.47 [0.28–0.81], p=0.006*), and RP (OR 0.57 [0.37–0.87], p=0.010*) as independent and highly preventable predictors for deep valve deployment. Independent risk factors for deep ID were the use of a 34 mm device (OR 1.96 [1.22–3.15], p=0.005*) and mild aortic valve calcification (OR 1.62 [0.01–2.61], p=0.046*). In a model of protective factors, ID was significantly reduced with the number of protective criteria (0–2 criteria: −5.6±2.6 mm vs. 3–5 criteria: −4.5±2.0 mm; p&lt;0.0001*).

Conclusion

Data from this retrospective analysis indicate that RP is an independent predictor to reach a higher implantation depth using self-expandable devices.

Funding Acknowledgement

Type of funding sources: None.

Impact of high on-treatment platelet reactivity after angioplasty in patients with critical limb ischemia

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.

Aspirin I.V. Loading during Elective Percutaneous Coronary Intervention

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.

Factors associated with a high or low implantation of self-expanding devices in TAVR

OBJECTIVES

Optimizing valve implantation depth (ID) plays a crucial role in minimizing conduction disturbances and achieving optimal functional integrity. Until now, the impact of intraprocedural fast (FP) or rapid ventricular pacing (RP) on the implantation depth has not been investigated. Therefore, we aimed to (1) evaluate the impact of different pacing maneuvers on ID, and (2) identify the independent predictors of deep ID.

METHODS

473 TAVR patients with newer-generation self-expanding devices were retrospectively enrolled and one-to-one propensity-score-matching was performed, resulting in a matching of 189 FP and RP patients in each cohort. The final ID was analyzed, and the underlying functional, anatomical, and procedural conditions were evaluated by univariate and multivariate analysis.

RESULTS

The highest ID was reached under RP in severe aortic valve calcification and valve size 26 mm. Multivariate analysis identified left ventricular outflow (LVOT) calcification [OR 0.50 (0.31-0.81) p = 0.005*], a "flare" aortic root [OR 0.42 (0.25-0.71), p = 0.001*], and RP (OR 0.49 [0.30-0.79], p = 0.004*) as independent highly preventable predictors of a deep ID. In a model of protective factors, ID was significantly reduced with the number of protective criteria (0-2 criteria: - 5.7 mm ± 2.6 vs. 3-4 criteria - 4.3 mm ± 2.0; p < 0.0001*).

CONCLUSION

Data from this retrospective analysis indicate that RP is an independent predictor to reach a higher implantation depth using self-expanding devices. Randomized studies should prove for validation compared to fast and non-pacing maneuvers during valve delivery and their impact on implantation depth.

TRAIL REGISTRATION

Clinical Trial registration: NCT01805739.

STUDY DESIGN

Evaluation of the impact of different pacing maneuvers (fast ventricular pacing-FP vs. rapid ventricular pacing-RP) on implantation depth (ID). After one-to-one-propensity-score-matching, independent protective and risk factors for a very deep ID beneath 6 mm toward the LVOT (< - 6 mm) were identified. Stent frame pictures as a courtesy by Medtronic^®. AVC aortic valve calcification.

Rivaroxaban reduces thromboxane induced platelet aggregation - the forgotten Compass Arm?

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 COMPASS trial, a reduction of MACCE appeared for low-dose rivaroxaban alone compared to aspirin as well. It was recently shown that FXa induces platelet aggregation via protease activated receptor 1 (PAR-1) which is in turn attenuated by rivaroxaban. However, a potential impact of rivaroxaban on TX B2 formation is unclear.Methods and Results: TX B2 levels were measured in supernatant from washed platelets after FXa (52 µg/ml) induced platelet aggregation. TX B2 levels were significantly higher in supernatant from FXa-stimulated platelets compared to unstimulated control (Control 23.53 ± 14.15 ng/ml vs. FXa stimulated 77.4 ± 64.14 ng/ml; p = .0025). This effect was abolished in the presence of 100pM rivaroxaban (Control 23.53 ± 14.15 ng/ml vs. FXa stimulated and rivaroxaban 22.15 ± 24.74 ng/ml; p = .5142). Next, we investigated the effects of 100pM rivaroxaban on platelet aggregation induced by U46619 (TX receptor agonist) using light transmission aggregometry. Platelet aggregation quantified by maximum of aggregation (MoA%) was significantly lower in presence of rivaroxaban (U46619 40.18 ± 20.51% vs. U46619+ rivaroxaban 19.26 ± 15.46%; p = .0274).Conclusion: Our results indicate direct effects of rivaroxaban on the cyclooxygenase-1- TX axis during platelet aggregation. Hence, it seems reasonable that the 'forgotten compass arm' (rivaroxaban alone) might be an alternative to the rivaroxaban plus aspirin combination in CCS patients.

Risk prediction of bleeding and MACCE by PRECISE-DAPT score post-PCI

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 < 25 and 470 patients PD ≥ 25 (47%). Rate of major and minor bleeding was higher in the PD ≥ 25 group (major bleeding: Hazard ratio [HR] 2.9, 95% confidence interval [Cl] 1.01–8.16, p = 0.049; minor bleeding: HR 3.94, 95% Cl 1.36–9.19, p = 0.0096). Rate of MACCE, death and myocardial infarction were higher as well (MACCE: HR 2.0, 95% Cl 1.52–2.71, p < 0.0001; death: HR 3.9, 95% Cl 2.12–5.68, p < 0.0001; MI: HR 2.1, 95% Cl 1.26–3.43, p = 0.0041). Rate of stroke/transient ischemic attack did not differ between groups. Discriminative potency to predict major and minor bleeding, MACCE, death and MI were high with nearly equal cut-off values calculated by Youden’s index (YI) (major bleeding: Area under the curve [AUC] 0.66; p = 0.026; YI 32; minor bleeding: AUC 0.72; p = 0.001; YI 28; MACCE: AUC 0.62; p < 0.0001; YI 24).

Conclusion

In our cohort, PD score predicted bleeding moderately in post-PCI patients. In this study, ischemic events were predicted as well. Adaption of antiplatelet therapy duration by PD score is accurate. Nevertheless, it should be well-balanced with patient-related risk for ischemic events.

Impact of Transcatheter Aortic Valve Implantation on Thrombin Generation and Platelet Function

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.

Sphingosine-1-phosphate: A mediator of the ARB-MI paradox?

BACKGROUND

Angiotensin converting enzyme inhibitors (ACEI) and angiotensin II receptor blockers (ARB) are important in the prevention of cardiovascular disease. The "ARB-MI paradox" implies that no risk reduction of myocardial infarction (MI) was found in ARB-treated patients despite target blood pressure control. Sphingosine-1-phosphate (S1P) is a cardioprotective sphingolipid which is released by platelets during activation. In this study we aimed to investigate differences of S1P homeostasis mediated by bradykinin and sphingosine kinases during ACEI/ARB treatment.

METHODS

In this hypothesis generating pilot study, we investigated S1P plasma concentrations in 34 patients before and 3 months after ARB/ACEI medication. S1P levels were measured via liquid chromatography-tandem mass spectrometry. Bradykinin levels were measured by an enzyme-linked immunosorbent assay.

RESULTS

Patient characteristics were not different between the ACEI and ARB group. Baseline S1P plasma concentrations were similar before ARB and ACEI treatment (7.4 SD 1.9 pmol vs. 7.8 SD 2.7 pmol, p = 0.54). After 3 months, S1P plasma levels were significantly higher in ACEI (9.3 SD 2.2 pmol) as compared to ARB treated patients (7.4 SD 2.4 pmol, p = 0.001). Pearson correlation showed no significant association between bradykinin and S1P levels before (r = -0.219; 95% CI [-0.54-0.15]; p = 0.245) or after three months of treatment with ACEI or ARB (r = -0.015; 95% CI [-0.48-0.45]; p = 0.95).

CONCLUSIONS

S1P plasma concentrations are higher in ACE treated patients as compared to ARB treatment. This leads to the hypothesis, that differences in S1P metabolism might partially explain the ARB-MI paradox. This needs to be tested in clinical trials.

Optimal antithrombotic regimen in patients with cardiogenic shock on ImpellaTM mechanical support: less might be more

Background

Bleeding and ischemic complications are the main cause of morbidity and mortality in critically ill cardiogenic shock patients, supported by short-term percutaneous mechanical circulatory support (pMCS) devices. Hence, finding the optimal antithrombotic regimen is challenging. Bleeding not only occurs because of heparin and antiplatelet therapy (both required in the prevention of pump and acute stent thrombosis) but also because of device- and disease related coagulopathy. To prevent clotting-related device failure, most centers target full therapeutic heparin anticoagulation levels in left ventricular (LV) Impella™ supported patients in analogy with Veno-Arterial Extracorporeal Membrane Oxygenation. We aimed to investigate the safety (related to bleeding and thrombotic complications) of targeting low-dose versus therapeutic heparin levels in left Impella™-supported cardiogenic shock patients on dual antiplatelet therapy (DAPT).

Methods

In this hypothesis generating pilot study, we investigated 114 patients supported for at least two days by LV Impella™ mechanical support due to cardiogenic shock at three tertiary ICUs, highly specialized in mechanical support. Low-dose heparin (aPTT 40–60s or anti-Xa 0.2–0.3) was compared to standard of care (aPTT 60–80s or anti-Xa 0.3–0.5). Major adverse cardio- and cerebrovascular events (MACCE; composite of death, myocardial infarction, stroke/transient ischemic attack) and BARC bleeding (bleeding academic research consortium classification) during 30 day follow-up were assessed. Inverse probability of treatment weighting (IPTW) analysis was calculated with age, gender, arterial hypertension, diabetes mellitus, smoking, chronic kidney disease, previous stroke, previous myocardial infarction, previous coronary arterial bypass grafting, hypercholesterolemia and DAPT as matching variables. COX regression analysis was conducted to test for robustness.

Results

IPTW revealed 52 patients in the low-dose heparin group and 62 patients in the therapeutic group. Mean age of patients after IPTW was 62±16 years in the intermediate and 62±13 years in the therapeutic group (p=0.99). 25% and 42.2% were male (p=0.92). Overall bleeding events and major (BARC3b) bleeding events were higher in the therapeutic heparin group (overall bleeding: Hazard ratio [HR]=2.58, 95% confidence interval [CI] 1.2–5.5; p=0.015; BARC 3b: HR=4.4, 95% CI 1.4–13.6, p=0.009). Minor bleeding (BARC3a) as well as MACCE and its single components (ischemic events) did not differ between both groups. These findings were robust in the COX regression analysis.

Conclusion

In this pilot analysis, low-dose heparin in 114 LV Impella™ cardiogenic shock patients was associated with less bleeding without increased ischemic events, adjusted for DAPT. Reducing the target heparin levels in critically ill patients supported by LV Impella™ might improve the outcome of this precarious group. These findings need to be validated in randomized clinical trials.

Funding Acknowledgement

Type of funding source: None

MTX Treatment Does Not Improve Outcome in Mice with AMI

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.

Platelet reactivity in patients with aortic stenosis depends on LV-AO angle

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 &lt;160° in comparison to patients with an angle ≥160° (&lt;160°: 66.99±20.72% vs. ≥160°: 60.66±19.85%, p=0.009). Collagen-induced platelet reactivity was significant higher in patients with a LV-AO-angle &lt;160° in comparison to patients with an angle ≥160° (&lt;160°: 78.67±13.19% vs. ≥160°: 73.85±14.44%, p=0.003). Multivariate cox-regression revealed that LV-AO angle &lt;160 was a robust predictor of ADP- and collagen-induced platelet aggregation

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

Noncanonical Effects of Oral Thrombin and Factor Xa Inhibitors in Platelet Activation and Arterial Thrombosis

Nonvitamin K oral anticoagulants (NOACs) or direct oral anticoagulants comprise inhibitors of factor Xa (rivaroxaban, apixaban, edoxaban) or factor IIa (dabigatran). Both classes efficiently interfere with the final or penultimate step of the coagulation cascade and showed superior net clinical benefit compared with vitamin K antagonists for prevention of thromboembolic events in patients with AF and for prevention and therapy of deep vein thrombosis and pulmonary embolism. None the less, accumulating data suggested, that there may be differences regarding the frequency of atherothrombotic cardiovascular events between NOACs. Thus, the optimal individualized NOAC for each patient remains a matter of debate. Against this background, some basic and translational analyses emphasized NOAC effects that impact on platelet activity and arterial thrombus formation beyond inhibition of plasmatic coagulation. In this review, we will provide an overview of the available clinical and translational evidence for so-called noncanonical NOAC effects on platelet activation and arterial thrombosis.

A novel mechanism of ACE inhibition-associated enhanced platelet reactivity: disproof of the ARB-MI paradox?

PURPOSE

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.

METHODS

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.

RESULTS

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).

CONCLUSION

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.

Targeting the human microbiome and its metabolite TMAO in cardiovascular prevention and therapy

The human gut microbiota is the most important active part of the intestinal micro-ecosystem. Lifestyle modification, drug intake and nutrition have an impact on the composition of the gut microbiota and its metabolites. This review focuses on the effects of changes in the gut microbiota as well as the important metabolite Trimethylamine-N-oxide (TMAO). Furthermore, relevant therapeutic options to target the human microbiome in patients with cardiovascular disease are presented.

Impact of high on-treatment platelet reactivity after angioplasty in patients with peripheral arterial disease

Objective: High on-treatment platelet reactivity (HTPR) to dual antiplatelet therapy (DAPT) predicts adverse events in coronary artery disease patients. In peripheral artery disease (PAD) patients, data concerning the clinical impact of HTPR are limited. Therefore, we evaluated the incidence of (i) HTPR to DAPT and (ii) its impact on 6 months outcome after angioplasty.Methods and results: In this prospective single center analysis, we investigated 102 consecutive patients with PAD from 2016 to 2017. All patients underwent peripheral endovascular treatment due to intermittent claudication (Fontaine IIb). Clopidogrel effects were measured using vasodilator-stimulated protein phosphorylation (VASP) assay, aspirin effects by light-transmission aggregometry (LTA). Major adverse limb events (MALE), major adverse cardiac and cerebrovascular events (MACCE) and BARC bleeding (bleeding academic research consortium classification) within 6 months were assessed. HTPR to clopidogrel (n = 37, 36%), to aspirin (n = 11, 11%) and to both (n = 11, 11%) were frequent. Compared to sufficient platelet inhibition by aspirin and clopidogrel (n = 43, 42%), patients with dual HTPR showed a higher risk of MALE at 6 months (27% vs. 7%; hazard ratio [HR]: 4.45; 95% confidence interval [CI]: 1.1 to 67.8; p = .03). This was independent of diabetes, creatinine, body mass index, and age as well as of procedural details in a multivariate logistic regression analysis. MACCE (n = 2) and BARC bleeding rates (n = 2) were low.Conclusion: In this small exploratory study, HTPR was frequent in PAD patients. Furthermore, the results are suggestive that MALE might be associated with dual HTPR. This leads to the hypothesis that optimized antithrombotic regimens post percutaneous transluminal angioplasty should be tested in clinical trials.

Rivaroxaban Reduces Arterial Thrombosis by Inhibition of FXa-Driven Platelet Activation via Protease Activated Receptor-1

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.

P957Survival benefits of routine glycoprotein IIb/IIIa inhibitors during primary PCI in ST-segment elevation myocardial infarction: A meta-analysis of randomised controlled trials

Background

Cardiovascular guidelines recommend adjunct glycoprotein IIb/IIIa inhibitors (GPI) only in selected patients with acute ST-segment elevation myocardial infarction (STEMI).

Purpose

This study aimed to evaluate routine GPI use in STEMI treated with primary PCI.

Methods

Online databases were systematically searched for randomised controlled trials (RCTs) of routine GPI vs. control therapy in STEMI. Data from retrieved studies were abstracted and evaluated in a comprehensive meta-analysis using Mantel-Haenszel estimates of risk ratios (RR) as summary statistics.

Results

After systematic review, twenty-one RCTs with 8,585 patients were included: ten trials randomized tirofiban (T), nine abciximab (A), one eptifibatide (E), one trial used A+T; only one trial used DAPT with prasugrel/ ticagrelor. Routine GPI were associated with a significant reduction in all-cause mortality at 30 days (2.4% (GPI) vs. 3.2%; risk ratio (RR) 0.72; p=0.01) and 6 months (3.7% vs. 4.8%; RR 0.76; p=0.02), and a reduction in recurrent MI (1.1% vs. 2.1%; RR 0.55; p=0.0006), repeat revascularization (2.5% vs. 4.1%; RR 0.63; p=0.0001), TIMI flow <3 after PCI (5.4% vs. 8.2%; RR 0.61; p<0.0001) and ischemic stroke (RR 0.42; p=0.04). Major (4.7% vs. 3.4%; RR 1.35; p=0.005) and minor bleedings (7.2% vs. 5.1%; RR 1.39; p=0.006) but not intracranial bleedings (0.1% vs. 0%; RR 2.7; p=0.37) were significantly increased under routine GPI.

Conclusions

Routine GPI administration during primary PCI in STEMI resulted in mortality reduction, driven by reductions in recurrent ischemic events – however predominantly in trials pre-prasugrel/ticagrelor. Trials in contemporary STEMI management are needed to confirm these findings.

Routine Glycoprotein IIb/IIIa Inhibitor Therapy in ST-Segment Elevation Myocardial Infarction: A Meta-analysis

BACKGROUND

Guidelines recommend adjunct glycoprotein IIb/IIIa inhibitors (GPIs) only in selected patients with acute ST-segment elevation myocardial infarction (STEMI). This study aimed to evaluate routine GPI use in STEMI treated with primary percutaneous coronary intervention.

METHODS

Online databases were searched for randomized controlled trials of routine GPI vs control therapy in STEMI. Data from retrieved studies were abstracted and evaluated in a comprehensive meta-analysis. Twenty-one randomized controlled trials with 8585 patients were included: 10 trials randomized tirofiban, 9 abciximab, 1 trial eptifibatide, and 1 trial used abciximab+tirofiban; only 1 trial used dual antiplatelet therapy with prasugrel/ticagrelor.

RESULTS

Routine GPI use was associated with a significant reduction in all-cause mortality at 30 days (2.4% [GPI] vs 3.2%; risk ratio [RR], 0.72; P = 0.01) and 6 months (3.7% vs 4.8%; RR, 0.76; P = 0.02), and a reduction in recurrent myocardial infarction (1.1% vs 2.1%; RR, 0.55; P = 0.0006), repeat revascularization (2.5% vs 4.1%; RR, 0.63; P = 0.0001), thrombolysis in myocardial infarction flow <3 after percutaneous coronary intervention (5.4% vs 8.2%; RR, 0.61; P < 0.0001), and ischemic stroke (RR, 0.42; P = 0.04). Major (4.7% vs 3.4%; RR, 1.35; P = 0.005) and minor bleedings (7.2% vs 5.1%; RR, 1.39; P = 0.006) but not intracranial bleedings (0.1% vs 0%; RR, 2.7; P = 0.37) were significantly increased under routine GPI.

CONCLUSIONS

Routine GPI administration in STEMI resulted in a reduction in mortality, driven by reductions in recurrent ischemic events-however predominantly in pre-prasugrel/ticagrelor trials. Trials with contemporary STEMI management are needed to confirm these findings.

Cardioprotection by very mild hypothermia in mice

Target temperature management is recommended in post-resuscitation care. Additionally, hypothermia is a promising option in adjunctive therapy of acute myocardial infarction (MI). However, first in men data are contradicting. There are still many open questions to identify the optimal regimen and target temperature. In this study, we aimed to investigate the effect of very mild hypothermia on infarct size (IS) in mice. Mice underwent cardiac ischemia by temporary occlusion of the left anterior descending (LAD) artery under conditions of very mild hypothermia (34-36 °C). Hypothermia was reached within the first 5 minutes of ischemia (temperature: 34.6±0.5 vs. 36.8±1.1 °C, P=0.035). Very mild hypothermia reduced IS in mice undergoing 30 minutes ischemia [IS/area at risk (AAR): 45±12% vs. 22±4%, P=0.018] as well as mice undergoing 60 minutes ischemia [IS/AAR: 67±7% vs. 28±2%, P=0.0003]. Very mild hypothermia reduces IS. This new approach in adjunctive therapy of patients with acute MI should be investigated in clinical trials.

Malondialdehyde Assay in the Evaluation of Aspirin Antiplatelet Effects

Aspirin is essential in secondary prevention of patients after myocardial infarction and with coronary artery disease. However, impaired pharmacodynamic response to aspirin is frequent (high on-treatment platelet reactivity [HTPR]). This leads to an enhanced prevalence of cardiovascular events and to an impaired clinical outcome. The current specific assays to evaluate aspirin antiplatelet effects are complex, time-consuming and demand for a high laboratory expertise. Therefore, we developed a potentially bedside assay based on the determination of malondialdehyde (MDA). MDA is a by-product of the thromboxane (TX) formation, which is synthesized in equimolar concentrations. In this study, we compared this MDA assay to the conventional assays in determination of pharmacodynamic aspirin response. For this, aspirin antiplatelet effects were measured in 22 healthy individuals and 63 aspirin treated patients using TX B2 formation enzyme-linked antibody assay, arachidonic acid induced light transmission aggregometry (LTA) and the new fluorometric MDA assay. In patients, MDA levels correlated well with TX formation (R = 0.81; 95% CI 0.69-0.88; p < 0.001) and LTA (R = 0.84; CI 0.74-0.91; p < 0.001). Receiver operating characteristic analyses revealed that the MDA assay does detect HTPR to aspirin sufficiently (area under the curve: 0.965; p < 0.001). The optimal cut-off was > 128 nmol/L (sensitivity of 100%, specificity of 91%). The new MDA assay is reliable in detecting HTPR. It is highly specific in the evaluation of antiplatelet effects by aspirin. This promising and potential bedside assay needs to be evaluated in clinical practice.

Non-vitamin K oral anticoagulants (NOAC) and the risk of myocardial infarction: Differences between factor IIa and factor Xa inhibition?

Guidelines already recommend non-vitamin K oral anticoagulants (NOAC) over vitamin-K antagonists (VKA) for stroke prevention in patients with atrial fibrillation. However, recommendations are lacking with respect to which NOAC to use. At the moment, NOACs may employ two different molecular mechanisms: Factor IIa inhibition (dabigatran) and factor Xa inhibition (apixaban, edoxaban, rivaroxaban). The focus of this review is to compare and contrast potential differences between factor IIa- and factor Xa inhibition with respect to risk of myocardial infarction and to detail underlying mechanisms.