Patients on vitamin K treatment: is switching to direct-acting oral anticoagulation cost-effective? A target trial on a prospective cohort

AIMS

Direct-acting oral anticoagulants (DOACs) have, to a substantial degree, replaced vitamin K antagonists (VKA) as treatments for stroke prevention in atrial fibrillation (AF) patients. However, evidence on the real-world causal effects of switching patients from VKA to DOAC is lacking. We aimed to assess the empirical incremental cost-effectiveness of switching patients to DOAC compared with maintaining VKA treatment.

METHODS

The target trial approach was applied to the prospective observational Swiss-AF cohort, which enrolled 2415 AF patients from 2014 to 2017. Clinical data, healthcare resource utilisation and EQ-5D-based utilities representing quality of life were collected in yearly follow-ups. Health insurance claims were available for 1024 patients (42.4%). Overall survival, quality-of-life, costs from the Swiss statutory health insurance perspective and cost-effectiveness were estimated by emulating a target trial in which patients were randomly assigned to switch to DOAC or maintain VKA treatment.

RESULTS

228 patients switching from VKA to DOAC compared with 563 patients maintaining VKA treatment had no overall survival advantage over a 5-year observation period (HR 0.99, 95% CI 0.45, 1.55). The estimated gain in quality-adjusted life years (QALYs) was 0.003 over the 5-year period at an incremental costs of CHF 23 033 (€ 20 940). The estimated incremental cost-effectiveness ratio was CHF 425 852 (€ 387 138) per QALY gained.

CONCLUSIONS

Applying a causal inference method to real-world data, we could not demonstrate switching to DOACs to be cost-effective for AF patients with at least 1 year of VKA treatment. Our estimates align with results from a previous randomised trial.

Thrombin Generation Is Associated with Venous Thromboembolism Recurrence, but Not with Major Bleeding and Death in the Elderly: A Prospective Multicenter Cohort Study

It is currently unknown whether thrombin generation is associated with venous thromboembolism (VTE) recurrence, major bleeding, or mortality in the elderly. Therefore, our aim was to prospectively study the association between thrombin generation and VTE recurrence, major bleeding, and mortality in elderly patients with acute VTE. Consecutive patients aged ≥65 years with acute VTE were followed for 2 years, starting from 1 year after the index VTE. Primary outcomes were VTE recurrence, major bleeding, and mortality. Thrombin generation was assessed in 551 patients 1 year after the index VTE. At this time, 59% of the patients were still anticoagulated. Thrombin generation was discriminatory for VTE recurrence, but not for major bleeding and mortality in non-anticoagulated patients. Moreover, peak ratio (adjusted subhazard ratio 4.09, 95% CI, 1.12-14.92) and normalized peak ratio (adjusted subhazard ratio 2.18, 95% CI, 1.28-3.73) in the presence/absence of thrombomodulin were associated with VTE recurrence, but not with major bleeding and mortality after adjustment for potential confounding factors. In elderly patients, thrombin generation was associated with VTE recurrence, but not with major bleeding and/or mortality. Therefore, our study suggests the potential usefulness of thrombin generation measurement after anticoagulation completion for VTE to help identify among elderly patients those at higher risk of VTE recurrence.

Association of chocolate consumption with neurological and cardiovascular outcomes in atrial fibrillation: data from two Swiss atrial fibrillation cohort studies (Swiss-AF and BEAT-AF)

AIM

To assess the associations of chocolate consumption with neurocognitive function, brain lesions on magnetic resonance imaging (MRI), and cardiovascular outcome in patients with atrial fibrillation (AF).

METHODS

We analysed data from patients of two prospective multicentre Swiss atrial fibrillation cohort studies (Swiss-AF) and (BEAT-AF). Assessments of MRI findings and neurocognitive function were performed only in the Swiss-AF population (in 1727 of 2415 patients [71.5%] with a complete data set), as patients enrolled in BEAT-AF were not systematically evaluated for these outcomes. Otherwise, the two cohorts had an equivalent set of clinical assessments. Clinical outcome analysis was performed in 3931 patients of both cohorts. Chocolate consumption was assessed by questionnaire. Patients were categorised as no/low chocolate consumption (No/Low-Ch) ≤1 servings/week, moderate chocolate consumption (Mod-Ch) >1-6 servings/week, and high chocolate consumption (High-Ch) >6 servings/week, respectively. Brain lesions were evaluated by MRI. Assessment of cognitive function was performed by neurocognitive functional testing and included global cognition measurement with a cognitive construct score. Cerebral MRI and cognition were evaluated at baseline. Cross-sectional associations between chocolate consumption and MRI findings were analysed by multivariate logistic regression models and associations with neurocognitive function by multivariate linear regression models. Clinical outcome events during follow-up were recorded and assessed by a clinical event committee. The associations between chocolate consumption and clinical outcomes were evaluated by Cox regression models. The median follow-up time was 6 years.

RESULTS

Chocolate consumption was not associated with prevalence or volume of vascular brain lesions on MRI, nor major adverse cardiac events (ischaemic stroke, myocardial infarction, cardiovascular death). However, No/Low-Ch was independently associated with a lower cognitive construct score compared to Mod-Ch (No/Low-Ch vs. Mod-Ch: coeff. -0.05, 95% CI -0.10-0), whereas other neurocognitive function tests were not independently associated with chocolate consumption categories. In addition, there was a higher risk of heart failure hospitalisation (No/Low-Ch vs. Mod-Ch: HR 1.24, 95% CI 1.01-1.52) and of all-cause mortality (No/Low-Ch vs. Mod-Ch: HR 1.29, 95% CI 1.06-1.58) in No/Low-Ch compared to Mod-Ch. No significant associations with the evaluated outcomes were observed when High-Ch was compared to Mod-Ch.

CONCLUSION

While chocolate consumption was not associated with MRI findings and major adverse cardiac events in an atrial fibrillation population, No/Low-Ch was associated with a lower cognitive construct score, higher risk of heart failure hospitalisation and increased all-cause mortality compared to Mod-Ch.

CLINICALTRIALS

gov Identifier: NCT02105844.

Mid-term changes in cognitive functions in patients with atrial fibrillation: a longitudinal analysis of the Swiss-AF cohort

Background

Longitudinal association studies of atrial fibrillation (AF) and cognitive functions have shown an unclear role of AF-type and often differ in methodological aspects. We therefore aim to investigate longitudinal changes in cognitive functions in association with AF-type (non-paroxysmal vs. paroxysmal) and comorbidities in the Swiss-AF cohort.

Methods

Seven cognitive measures were administered up to five times between 2014 and 2022. Age-education standardized scores were calculated and association between longitudinal change in scores and baseline AF-type investigated using linear mixed-effects models. Associations between AF-type and time to cognitive drop, an observed score of at least one standard deviation below individual's age-education standardized cognitive scores at baseline, were studied using Cox proportional hazard models of each cognitive test, censoring patients at their last measurement. Models were adjusted for baseline covariates.

Results

2,415 AF patients (mean age 73.2 years; 1,080 paroxysmal, 1,335 non-paroxysmal AF) participated in this Swiss multicenter prospective cohort study. Mean cognitive scores increased longitudinally (median follow-up 3.97 years). Non-paroxysmal AF patients showed smaller longitudinal increases in Digit Symbol Substitution Test (DSST), Cognitive Construct Score (CoCo)and Trail Making Test part B (TMT-B) scores vs. paroxysmal AF patients. Diabetes, history of stroke/TIA and depression were associated with worse performance on all cognitive tests. No differences in time to cognitive drop were observed between AF-types in any cognitive test.

Conclusion

This study indicated preserved cognitive functioning in AF patients, best explained by practice effects. Smaller practice effects were found in non-paroxysmal AF patients in the DSST, TMT-B and the CoCo and could indicate a marker of subtle cognitive decline. As diabetes, history of stroke/TIA and depression-but not AF-type-were associated with cognitive drop, more attention should be given to risk factors and underlying mechanisms of AF.

Physical activity and brain health in patients with atrial fibrillation

BACKGROUND AND PURPOSE

Vascular brain lesions, such as ischemic infarcts, are common among patients with atrial fibrillation (AF) and are associated with impaired cognitive function. The role of physical activity (PA) in the prevalence of brain lesions and cognition in AF has not been investigated.

METHODS

Patients from the multicenter Swiss-AF cohort study were included in this cross-sectional analysis. We assessed regular exercise (RE; at least once weekly) and minutes of weekly PA using a validated questionnaire. We studied associations with ischemic infarcts, white matter hyperintensities, cerebral microbleeds, and brain volume on brain magnetic resonance imaging and with global cognition measured with a cognitive construct (CoCo) score.

RESULTS

Among 1490 participants (mean age = 72 ± 9 years), 730 (49%) engaged in RE. In adjusted regression analyses, RE was associated with a lower prevalence of ischemic infarcts (odds ratio [OR] = 0.78, 95% confidence interval [CI] = 0.63-0.98, p = 0.03) and of moderate to severe white matter hyperintensities (OR = 0.78, 95% CI = 0.62-0.99, p = 0.04), higher brain volume (β-coefficient = 10.73, 95% CI = 2.37-19.09, p = 0.01), and higher CoCo score (β-coefficient = 0.08, 95% CI = 0.03-0.12, p < 0.001). Increasing weekly PA was associated with higher brain volume (β-coefficient = 1.40, 95% CI = 0.65-2.15, p < 0.001).

CONCLUSIONS

In AF patients, RE was associated with a lower prevalence of ischemic infarcts and of moderate to severe white matter disease, with larger brain volume, and with better cognitive performance. Prospective studies are needed to investigate whether these associations are causal. Until then, our findings suggest that patients with AF should be encouraged to remain physically active.

Differential endothelial senescence elicited by AQP1 regulation of epigenetic/metabolic responses

Introduction

Accumulation of senescent endothelial cells with age is an important driver of vascular aging and related cardiovascular disease. However, little is known about the mechanisms and signaling pathways that underpin endothelial cell senescence. Aquaporin-1 (AQP1) has been implicated in sensing hydrogen peroxide (H2O2), which differentially modulates endothelial signal transduction. Nonetheless, the role of AQP1 in the regulation of metabolism and function in young and old vascular cells remains elusive.

Purpose

We sought to investigate whether 1) AQP1 differentially regulates vascular senescence and angiogenesis through epigenetic/metabolic response, senescence-associated secretory phenotype (SASP), and 2) AQP1 knockdown/inhibition rejuvenates senescent endothelial cells and restores angiogenesis.

Methods

We assessed the role of AQP1 in endothelial cell senescence and impaired angiogenesis through mitochondrial metabolic disorder, epigenetic alteration, and the SASP in human aortic endothelial cells and aortas from wild-type C57BL/6 mice. For these, we conducted AQP1 knockdown (with siRNA) or blockade of AQP1 (with Bacopaside-II, 10 μM) to inhibit H2O2 transport.

Results

Here we show the upregulation of AQP1 in the senescent endothelial cells (SEC, p.15) and aorta from old mice (&gt;24 months) (p&lt;0.01 and p&lt;0.0001, respectively), facilitating outside-in H2O2 transport. Interestingly, AQP1 knockdown/inhibition reverses both replicative (increased SA-β-galactosidase positive cells) and stress-induced senescence (increased cell-cycle arrest markers p16, p19, and p21; and SASP markers IL1α, IL1β, and IL6) in SEC, whereas it triggers the senescence processes in the proliferating endothelial cells (PEC, p.5) (for each, p&lt;0.05, n=6). Unlike in PEC or young aorta (3-month-old), AQP1 knockdown/inhibition restores angiogenesis in both SEC and old aortas. The interventions increased mitochondrial OXPHOS (represented by enhanced oxygen consumption rate (OCR)) in SEC, which is accompanied by marked increase in CaMKKβ-regulated AMPKT172 phosphorylation (for each, p&lt;0.05, n=6) and in histone deacetylase-4 (HDAC4) phosphorylation at Ser632 (p&lt;0.05) and further histone 3 (H3) acetylation (p&lt;0.01). The HDAC4 phosphorylation leads to significant increase in Mef2A-mediated eNOS phosphorylation at Ser1177 (p&lt;0.05). By contrast, AQP1 knockdown/inhibition induced a senescent-like state by a decrease in mitochondrial OCR and the phosphorylation of CaMKKβ-AMPK and HDAC4-Mef2A regulation of eNOS activity.

Conclusion

Our studies identify AQP1 as essential regulator of EC proliferation that differentially regulates angiogenesis via epigenetic/metabolic response and SASP modulation. Moreover, genetic or pharmacological inhibition of AQP1 reverses endothelial senescence and restores angiogenesis, representing a potential therapeutic target for vascular rejuvenation.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Swiss National Science Foundation (SNSF)SwissLife Jubiläumsstiftung

Trimethylamine N-oxide is associated with impaired cognitive function in patients with atrial fibrillation

Introduction

Since patients with atrial fibrillation (AF) are predisposed to suffer from major adverse cerebrovascular events (MACE), they are more likely to suffer MACE linked sequelae, such as cognitive impairment. We hypothesised that the gut microbiome derivate trimethylamine N-oxide (TMAO) may amplify this pathomechanism given its hypercoagulative, proinflammatory and proatherogenic effects.

Methods

Patients of the Swiss-AF cohort with determined TMAO plasma levels, cognitive scores (n=2'379) and cerebral magnetic resonance imaging (cMRI) (n=1'722) collected at baseline were included. TMAO levels were measured by liquid chromatography-mass spectrometry (HPLC). Overall cognitive performance was evaluated using the Cognitive Construct (CoCo) score reflecting different cognitive functions measured by four validated neuropsychological assessments, namely the Montreal Cognitive Assessment (MoCA), Trail Making Test (TMT parts A and B), Semantic Fluency Test (SFT) and Digital Symbol Substitution Test (DSST). The scores were compared with the quartiles of patients' TMAO plasma levels (Q1: 0.6–4, Q2: 4–5.8, Q3: 5.8–9.1, Q4: 9.1–164μmol/l) in linear effect models. All models were adjusted for multiple covariates correlating with this association: For TMAO (overall meat consumption &gt;3 times per week, physical activity, glomerular filtration rate, presence of diabetes mellitus), cognitive function (EQ-5D-5L score, geriatric depression scale, education level) and cerebral affects (white matter lesions volume and total brain volume in cMRI). The relevance of high TMAO plasma levels in different stroke groups in cMRI (i.e., clinically overt, silent, or no stroke) were analysed in a subgroup analysis. The subgroups were additionally adjusted for total brain volume to eliminate the effect of simultaneous decrease of cerebral white matter.

Results

After multivariable adjustment, AF patients in the highest quartile of TMAO levels performed significantly poorer in the global cognitive score (CoCo: estimate −0.11, 95% CI [−0.17, −0.05], p=0.002) compared to patients in the lowest quartile. This was observed also in the MoCA, SFT, DSST, TMT-A and TMT-B.

In the subgroup analysis, an association between the highest TMAO quartile (compared with the lowest quartile) and lower CoCo score was found in the group of patients with overt strokes (−0.18, 95% CI [−0.33, −0.04], p=0.012). Weak evidence of the same association was found in the group of patients with silent strokes (−0.13, 95% CI [−0.25, 0.002], p=0.053) and patients with no strokes (−0.08, 95% CI [−0.16, 0.01], p=0.07).

After adjustment for decreased brain volume, the association remained for silent strokes (−0.14, 95% CI [−0.28, −0.01], p=0.036) indicating the impact of TMAO in this subgroup.

Conclusion

TMAO plasma levels were associated with cognitive impairment in patients with AF. Longitudinal data will clarify dynamics and likely causality between TMAO and cognitive impairment.

Funding Acknowledgement

Type of funding sources: Public Institution(s). Main funding source(s): Swiss National Science Foundation

Comparison of severe hypercholesterolemia patients with and without pathogenic variants

Introduction

A pathogenic variant causally related to familial hypercholesterolemia (FH) is found in less than half of adults with severe hypercholesterolemia. The characteristics of adults with severe hypercholesterolemia without pathogenic variant have been poorly described, and it remains unclear whether intensive preventive strategies should be recommended. In this study we compared the characteristics of adults with severe hypercholesterolemia with and without pathogenic variant for FH.

Methods

Between November 2020 and February 2022, we recruited individuals older than 16 years with a Dutch Lipid Clinic Network (DLCN) score ≥6 and genotyped LDLR, APOB and PCSK9. Participants were part of the multicenter CATCH study, testing the implementation of genetic cascade screening for FH in Switzerland. All genetic analyses were performed in a single central laboratory. Variants classified as likely pathogenic or pathogenic were interpreted as FH-causing. We also assessed socio-economic status, cardiovascular risk factors, lifestyle behavior, and use of lipid-lowering drugs.

Results

In total, 150 non-related adults with a DLCN score of ≥6 were included, out of whom 62 (41.3%) had genetically confirmed FH. Most variants were found in the LDLR gene (77%). Overall, 70% were using a lipid-lowering drug and 20% were current smokers. Compared to adults with genetically confirmed FH, those without pathogenic variants were older (57.6 vs 50.4 years old), had lower untreated LDL-cholesterol levels (p&lt;0.001), higher triglyceride levels (p=0.032), higher BMI (p=0.014), and had more frequently hypertension (62.5% vs 36.1%). No socio-economic differences were observed. Although adherence to Mediterranean diet was higher among adults without pathogenic variant, they reached less frequently the recommended level of physical activity than adults with genetically confirmed FH (66.2% vs 82.1%). Xanthomas or xanthelasmas, but not corneal arcus, were more frequent among genetically confirmed FH (5.7% vs 20.3%).

Conclusions

Adults with severe hypercholesterolemia and without a pathogenic FH variant had less optimal control of cardiovascular risk factors than genetically confirmed FH. One fifth were smokers and one third of all patients included in this study were not taking any lipid-lowering drugs, regardless of the presence of a pathogenic variant.

Funding Acknowledgement

Type of funding sources: Foundation. Main funding source(s): Swiss Heart Foundation

SGLT-2 inhibition by empagliflozin exerts neutral effects on experimental arterial thrombosis in a murine model of low-grade inflammation

Introduction

Low-grade inflammation couples dysmetabolic states to insulin resistance and atherosclerotic cardiovascular disease (ASCVD). Selective sodium-glucose co-transporter 2 (SGLT-2) inhibition by empagliflozin improves clinical outcomes in patients with ASCVD independently of glucose-lowering. Yet, its mechanism of action remains largely undetermined.

Purpose

We aimed to test whether empagliflozin affects arterial thrombus formation in baseline conditions or low-grade inflammation, a systemic milieu shared among patients with ASCVD.

Methods

Sixteen-week-old C57BL/6 mice were randomly assigned to acute administration of empagliflozin (25 mg/kg BW) or vehicle, of which a subgroup was pre-treated biweekly over 4 weeks with super-low-dose lipopolysaccharide (LPS; 5 ng/kg BW), before carotid thrombosis was induced by photochemical injury. The translational value of these findings was investigated in primary human aortic endothelial cells (HAECs) and plasma samples of patients randomized to empagliflozin therapy.

Results

The between-group difference in doppler-flow probe detected time-to-occlusion (TTO) remained within the predefined equivalence margin (Δ=|10.50|), irrespective of low-grade inflammation (95% confidence interval [CI], −9.82 to 8.85 and −9.20 to 9.69), while glucose dropped by 1.64 and 4.84 mmol/l, respectively (Fig. 1). Ex vivo platelet aggregometry suggests similar platelet activation status, corroborated by unchanged circulating platelet-factor 4 (PF4) plasma levels. In concert, carotid PAI-1 expression and TF activity remained unaltered upon SGLT-2 inhibition, and no difference in plasma D-dimer levels was detected, suggesting comparable coagulation cascade activation and fibrinolytic activity (Fig. 1). In HAECs pre-treated with LPS, empagliflozin neither changed TF activity nor PAI-1 expression (Fig. 2). Accordingly, among patients with established ASCVD or at high cardiovascular (CV) risk randomized to 10 mg empagliflozin daily signatures of thrombotic (i.e., TF) and fibrinolytic activity (i.e., PAI-1) remained unchanged, while plasma glucose declined significantly during 3 months of follow-up (Fig. 2).

Conclusion

SGLT-2 inhibition by empagliflozin does not impact experimental arterial thrombus formation, neither under baseline conditions nor during sustained low-grade inflammation, and has no impact on proxies of thrombotic/fibrinolytic activity in patients with ASCVD. The beneficial pleiotropic effects of empagliflozin are likely independent of pathways mediating thrombosis.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Swiss National Science FoundationSwiss Heart FoundationFoundation for Cardiovascular Research–Zurich Heart House

Towards personalized antithrombotic management with drugs and devices across the cardiovascular spectrum

Intravascular thrombus formation and embolization are among the most frequent events leading to a number of cardiovascular conditions with high morbidity and mortality. The underlying causes are stasis of the circulating blood, genetic and acquired coagulation disorders, and reduced antithrombotic or prothrombotic properties of the vascular wall (Virchow's triad). In the venous system, intravascular thrombi can cause venous thrombosis and pulmonary and even peripheral embolism including ischaemic stroke [through a patent foramen ovale (PFO)]. Thrombi in the left atrium and its appendage or ventricle form in the context of atrial fibrillation and infarction, respectively. Furthermore, thrombi can form on native or prosthetic aortic valves, within the aorta (in particular at sites of ulcers, aortic dissection, and abdominal aneurysms), and in cerebral and peripheral arteries causing stroke and critical limb ischaemia, respectively. Finally, thrombotic occlusion may occur in arteries supplying vital organs such the heart, brain, kidney, and extremities. Thrombus formation and embolization can be managed with anticoagulants and devices depending on where they form and embolize and on patient characteristics. Vitamin K antagonists are preferred in patients with mechanical valves, while novel oral anticoagulants are first choice in most other cardiovascular conditions, in particular venous thromboembolism and atrial fibrillation. As anticoagulants are associated with a risk of bleeding, devices such as occluders of a PFO or the left atrial appendage are preferred in patients with an increased bleeding risk. Platelet inhibitors such as aspirin and/or P2Y12 antagonists are preferred in the secondary prevention of coronary artery disease, stroke, and peripheral artery disease either alone or in combination depending on the clinical condition. A differential and personalized use of anticoagulants, platelet inhibitors, and devices is recommended and reviewed in this article.

In vitro fertilization exacerbates stroke size and neurological disability in wildtype mice

BACKGROUND AND PURPOSE

Assisted reproductive technologies (ART) induce premature vascular aging in human offspring. The related alterations are well-established risk factors for stroke and predictors of adverse stroke outcome. However, given the young age of the human ART population there is no information on the incidence and outcome of cerebrovascular complications in humans. In mice, ART alters the cardiovascular phenotype similarly to humans, thereby offering the possibility to study this problem.

METHODS

We investigated the morphological and clinical outcome after ischemia/reperfusion brain injury induced by transient (45 min) middle cerebral artery occlusion in ART and control mice.

RESULTS

We found that stroke volumes were almost 3-fold larger in ART than in control mice (P < 0.001). In line with these morphological differences, neurological performance assessed by the Bederson and RotaRod tests 24 and 48 h after artery occlusion was significantly worse in ART compared with control mice. Plasma levels of TNF-alpha, were also significantly increased in ART vs. control mice after stroke (P < 0.05). As potential underlying mechanisms, we identified increased blood-brain barrier permeability evidenced by increased IgG extravasation associated with decreased tight junctional protein claudin-5 and occludin expression, increased oxidative stress and decreased NO-bioactivity in ART compared with control mice.

CONCLUSIONS

In wildtype mice, ART predisposes to significantly worse morphological and functional stroke outcomes, related at least in part to altered blood-brain barrier permeability. These findings demonstrate that ART, by inducing premature vascular aging, not only is a likely risk factor for stroke-occurrence, but also a mediator of adverse stroke-outcome.

TRANSLATIONAL PERSPECTIVE

This study highlights that ART not only is a likely risk factor for stroke-occurrence, but also a mediator of adverse stroke-outcome. The findings should raise awareness in the ever-growing human ART population in whom these techniques cause similar alterations of the cardiovascular phenotype and encourage early preventive and diagnostic efforts.

JCAD enhances arterial thrombosis by regulating endothelial plasminogen activator inhibitor-1 and tissue factor expression

Introduction

Arterial thrombosis underlies most acute CV events. Variants of the Junctional cadherin 5 associated (JCAD) locus were consistently shown to associate with increased risk of acute coronary syndrome. Being a component of cell junctions, JCAD protein is highly expressed in endothelial cells and was shown to promote atherosclerosis by acting on the Hippo pathway through LATS2 kinase.

Purpose

This project investigated the effect of JCAD in arterial thrombosis by using an established in vivo mouse model of carotid injury. The translational value of animal findings was assessed in primary human aortic endothelial cells (HAECs) as well as in CV patients.

Methods

JCAD knock-out (Jcad−/−) mice were exposed to photochemically-induced carotid artery endothelial injury to trigger thrombosis. Primary HAECs treated with JCAD small-interfering RNA (si-JCAD), LATS2-silencing RNA (si-LATS2) or control siRNA (si-SCR) were employed for in vitro assays. Plasma JCAD was measured in patients with chronic coronary syndrome (CCS) or ST-elevation myocardial infarction (STEMI).

Results

Compared to wild-type, Jcad−/− mice displayed reduced thrombus formation as underlined by delayed time to occlusion following endothelial-specific carotid damage. Suggesting a blunted activation of the extrinsic coagulation cascade, Jcad−/− animals showed reduced tissue factor (TF) protein expression and activity in carotid artery lysates (Fig. 1). Increased thrombus embolization episodes and D-dimer further suggested an increased activation of the fibrinolytic system in Jcad−/− mice. Indeed, Jcad−/− mice displayed reduced vascular expression of the fibrinolysis inhibitor plasminogen activator inhibitor (PAI)-1. In contrast, platelets aggregation in response to collagen and thrombin was similar in Jcad−/− and Jcad+/+ mice (Fig. 1). In line with the in vivo data, JCAD-silencing of HAECs inhibited TF and PAI-1 gene and protein expression. In accordance with previous literature, JCAD-silenced HAECs displayed increased levels of LATS2 Kinase, which blunts the Hippo pathway by increasing YAP phosphorylation. Yet, double JCAD and LATS2 silencing did not retrieve the phenotype of control HAECs. Of interest, si-JCAD HAECs showed increased levels of Akt phosphorylation, known to downregulate procoagulant expression and to directly phosphorylate YAP. Treatment with the Akt inhibitor Wortmannin prevented the effect of JCAD silencing on TF and PAI-1 indicating a causative role for this pathway (Fig. 2). Recapitulating in vitro findings, p-Akt and p-YAP levels were higher in arterial tissue of Jcad−/− animals as compared to WT (Fig. 1). Patients with STEMI showed significantly higher plasma levels of JCAD as compared to CCS (Fig. 2).

Conclusions

JCAD promotes arterial thrombosis by selectively modulating coagulation and fibrinolysis, but not platelet aggregation through endothelial TF and PAI-1. Our findings support the importance of JCAD as a novel therapeutic target for CV prevention.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Swiss National Science Foundation

Lifelong dietary omega-3 fatty acid reverses cardiac and vascular dysfunction via MMP-2 modulation in aged mice

Background

Aging has a remarkable effect on the cardiovascular system, and negatively causes structural and functional changes in the heart including diastolic/systolic dysfunction and left ventricular (LV) dyssynchrony, as well as, arterial stiffness which may develop to heart failure with preserved ejection fraction (HFpEF) in aged adults. We recently showed that the plant-derived omega-3-fatty-acid α-linolenic-acid (ALA) has emerged to confer potential protective effects against cardiovascular disease. Since cardiovascular aging is a chronic process, we hypothesized that a lifelong effective dietary supplementation with ALA will reverse or prevent age-related diastolic and arterial dysfunction during aging.

Purpose

Here, we test the hypotheses that (1) lifelong dietary ALA will prevent LV diastolic and arterial dysfunction in aged mice and that (2) lifelong dietary ALA will prevent the age-related cardiovascular dysfunction through modiulation of matrix-metalloproteinase-2 (MMP-2) in the heart and arteries.

Methods and results

6-month-old (young) wild-type C57BL/6J mice were fed a low (0.03%), as control, or high ALA (7.3%) diet for more than 12 months. Our results show that aged (&gt;18 months) mice on low ALA diet recapitulate major hallmarks of HFpEF, including diastolic dysfunction with preserved left ventricular ejection fraction, cardiac interstitial fibrosis, impaired acetylcholine-induced relaxation of aortic segments, and arterial stiffness. Intriguingly, we revealed that lifelong ALA-rich diet prevents diastolic dysfunction, vascular relaxation capacity, reduced pulse wave velocity, interstitial fibrosis, and coincident hemodynamic abnormalities in aged mice. Lifelong dietary ALA-in the prevention strategy-was associated with remarkably reduced cardiac and aortic MMP-2 and COX-2 expression, lower levels of pro-inflammatory cytokine TNF-α, and increased isocitrate dehydrogenase 2 (Idh2) expression, decreased function of which has previously been associated with cardiac dysfunction.

Conclusions

Our data support that lifelong ALA-rich diet restores normal cardiac and vascular function in aged mice with LV diastolic and arterial dysfunction and prevents development of age-related cardiovascular dysfunction through the modulation of MMP-2 signaling.

Funding Acknowledgement

Type of funding sources: Public Institution(s). Main funding source(s): 1. Swiss National Science Foundation (number 324730_182328)2. the Kardio Stiftung, Baden, Switzerland

MMP-2 gene silencing attenuates age-dependent carotid stiffness via reduction of elastin degradation and increased eNOS activation

Background and aims

Arterial stiffness is a hallmark of vascular aging. Being characterized by a loss of elasticity of large arterial walls, arterial stiffness is associated with an increased risk of cardiovascular disease (CVD). The age-dependent arterial stiffness is primarily attributed to alterations in the elastic and collagen deposition that is regulated by a number of enzymes, including matrix metalloproteinase-2 (MMP-2). Nevertheless, the mechanistic link between age-dependent arterial stiffness and MMP-2 remains unclear.

In this study, we investigated the effect and efficacy of therapeutic MMP-2 knockdown using small interfering RNA (siRNA) on age-dependent arterial stiffness.

Methods

Pulse wave velocity (PWV) was assessed in the right carotid artery of wild-type (WT) mice of different age groups. MMP-2 levels and activity in the carotid artery and plasma of young (3 months) and aged (20–25 months) WT mice were determined. Old WT mice (18–21 months) were treated for 4 weeks with either MMP-2 or scrambled siRNA, in which carotid PWV was assessed at baseline, 2 and 4 weeks after the start of the treatment. Elastin to collagen ratio, desmosin (DES) level, and endothelial nitric oxide synthase (eNOS) pathways were also evaluated and compared. Lastly, levels of circulating MMP-2 and DES, the breakdown product of elastin, were measured in a human cohort (23–86 years old), in whom carotid-femoral PWV was assessed.

Results

Carotid PWV, as well as both vascular and circulating MMP-2 levels, were elevated with increasing age in WT mice (Figure 1). Therapeutic MMP-2 knockdown in aged WT mice reduced the vascular MMP-2 expression and attenuated age-dependent carotid stiffness. Increased elastin to collagen ratio and a lower plasma DES level were observed on MMP-2 silenced treated animals (Figure 2). Moreover, siMMP-2 treated mice showed enhanced eNOS phosphorylation on Ser1177. A direct interaction between MMP-2 and eNOS was also observed, which, interestingly, is augmented with age. Finally, collected human data showed a higher level of circulating MMP-2 levels on the elderly subjects. In addition, plasma DES level is positively correlated with age and aortic PWV, indicating the involvement of vascular elastin catabolism on arterial stiffness.

Conclusions

Therapeutic MMP-2 gene silencing, specifically targeting vascular MMP-2, attenuates age-dependent carotid stiffness. This effect is mediated by augmenting eNOS activation and reducing elastin degradation. Thus, our findings indicate MMP-2 as a potential therapeutic target to mitigate age-dependent arterial stiffness and CVD.

Funding Acknowledgement

Type of funding sources: Foundation. Main funding source(s): Swiss National Science Foundation,Foundation for Cardiovascular Research–Zurich Heart House Figure 1

Increased risk of severe clinical course of COVID-19 in carriers of HLA-C*04:01

BACKGROUND

Since the beginning of the coronavirus disease 2019 (COVID-19) pandemic, there has been increasing urgency to identify pathophysiological characteristics leading to severe clinical course in patients infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Human leukocyte antigen alleles (HLA) have been suggested as potential genetic host factors that affect individual immune response to SARS-CoV-2. We sought to evaluate this hypothesis by conducting a multicenter study using HLA sequencing.

METHODS

We analyzed the association between COVID-19 severity and HLAs in 435 individuals from Germany (n = 135), Spain (n = 133), Switzerland (n = 20) and the United States (n = 147), who had been enrolled from March 2020 to August 2020. This study included patients older than 18 years, diagnosed with COVID-19 and representing the full spectrum of the disease. Finally, we tested our results by meta-analysing data from prior genome-wide association studies (GWAS).

FINDINGS

We describe a potential association of HLA-C*04:01 with severe clinical course of COVID-19. Carriers of HLA-C*04:01 had twice the risk of intubation when infected with SARS-CoV-2 (risk ratio 1.5 [95% CI 1.1-2.1], odds ratio 3.5 [95% CI 1.9-6.6], adjusted p-value = 0.0074). These findings are based on data from four countries and corroborated by independent results from GWAS. Our findings are biologically plausible, as HLA-C*04:01 has fewer predicted bindings sites for relevant SARS-CoV-2 peptides compared to other HLA alleles.

INTERPRETATION

HLA-C*04:01 carrier state is associated with severe clinical course in SARS-CoV-2. Our findings suggest that HLA class I alleles have a relevant role in immune defense against SARS-CoV-2.

FUNDING

Funded by Roche Sequencing Solutions, Inc.

Blood Omega-3 Fatty Acids Are Inversely Associated With Albumin-Creatinine Ratio in Young and Healthy Adults (The Omega-Kid Study)

Background: Omega-3 fatty acids are associated with a lower risk of cardiovascular disease (CVD) and with beneficial effects on CV risk factors. The albumin-creatinine ratio (ACR) is a risk factor for CVD, all-cause mortality and accelerated glomerular filtration rate (GFR) decline in the general population. We aimed to investigate the association between n-3 PUFAS and ACR in heathy individuals with preserved GFR. Design and Methods: The present cross-sectional analysis is part of the GAPP study, a population-based cohort of healthy adults aged 25-41 years. Individuals with known CVD, diabetes, or a BMI >35 kg/m² were excluded. eGFR was calculated according to the combined Creatinine/Cystatin C CKD-EPI formula. ACR was obtained from a fasting morning urine sample. The Omega-3 Index (relative amount of EPA and DHA of total fatty acids in %) was obtained from whole blood aliquots. Results: Overall, 2001 participants (median age 37 years IQR 31; 40, 53% female) were included in this analysis. Median Omega-3 Index was 4.59 (IQR 4.06; 5.25) and median eGFR 111 ml/min/1.73 m² (IQR 103; 118). Median ACR was 0.14 mg/mmol (IQR 0; 0.43). We found a significant inverse association of the Omega-3 Index with ACR (ratio 0.84, 95%CI 0.73-0.96; p = 0.011) which remained after comprehensive adjustment (ratio 0.86, 95%CI 0.74-1.00; p = 0.048). No association of the Omega-3 Index with eGFR was found. The adjusted difference in eGFR per 1-unit increase in Omega3-Index was -0.21 (95%CI -0.76; 0.35; p = 0.47). Conclusions: A higher Omega-3 Index was significantly associated with lower ACR in this young and healthy population with preserved eGFR. Omega-3 fatty acids may exhibit cardio- and nephroprotective effects in healthy individuals through modulation of ACR.

Heart rate and adverse outcomes in patients with prevalent atrial fibrillation

Objective

The optimal target heart rate in patients with prevalent atrial fibrillation (AF) is not well defined. The aim of this study was to analyse the associations between heart rate and adverse outcomes in a large contemporary cohort of patients with prevalent AF.

Methods

From two prospective cohort studies, we included stable AF outpatients who were in AF on the baseline ECG. The main outcome events assessed during prospective follow-up were heart failure hospitalisation, stroke or systemic embolism and death. The associations between heart rate and adverse outcomes were evaluated using multivariable Cox regression models.

Results

The study population consisted of 1679 patients who had prevalent AF at baseline. Mean age was 74 years, and 24.6% were women. The mean heart rate on the baseline ECG was 78 (±19) beats per minute (bpm). The median follow-up was 3.9 years (IQR 2.2–5.0). Heart rate was not significantly associated with heart failure hospitalisation (adjusted HR (aHR) per 10 bpm increase, 1.00, 95% CI 0.94 to 1.07, p=0.95), stroke or systemic embolism (aHR 0.95, 95% CI 0.84 to 1.07, p=0.38) or death (aHR 1.02, 95% CI 0.95 to 1.09, p=0.66). There was no evidence of a threshold effect for heart rates <60 bpm or >100 bpm.

Conclusions

In this large contemporary cohort of outpatients with prevalent AF, we found no association between heart rate and adverse outcome events. These data are in line with recommendations that strict heart rate control is not needed in otherwise stable outpatients with AF.

Association of psychosocial factors with all-cause hospitalizations in patients with atrial fibrillation

Background

A high burden of cardiovascular comorbidities puts patients with atrial fibrillation (AF) at high risk for hospitalizations, but the role of other factors is less clear.

Hypothesis

To determine the relationship between psychosocial factors and the risk of unplanned hospitalizations in AF patients.

Methods

Prospective observational cohort study of 2378 patients aged 65 or older with previously diagnosed AF across 14 centers in Switzerland. Marital status and education level were defined as social factors, depression and health perception were psychological components. The pre‐defined outcome was unplanned all‐cause hospitalization.

Results

During a median follow‐up of 2.0 years, a total of 1713 hospitalizations occurred in 37% of patients. Compared to patients who were married, adjusted rate ratios (aRR) for all‐cause hospitalizations were 1.28 (95% confidence interval [CI], 0.97‐1.69) for singles, 1.31 (95%CI, 1.06‐1.62) for divorced patients, and 1.02 (95%CI, 0.82‐1.25) for widowed patients. The aRRs for all‐cause hospitalizations across increasing quartiles of health perception were 1.0 (highest health perception), 1.15 (95%CI, 0.84‐1.59), 1.25 (95%CI, 1.03‐1.53), and 1.66 (95%CI, 1.34‐2.07). No different hospitalization rates were observed in patients with a secondary or primary or less education as compared to patients with a college degree (aRR, 1.06; 95%CI, 0.91‐1.23 and 1.05; 95%CI, 0.83‐1.33, respectively). Presence of depression was not associated with higher hospitalization rates (aRR, 0.94; 95%CI, 0.68‐1.29).

Conclusions

The findings suggest that psychosocial factors, including marital status and health perception, are strongly associated with the occurrence of hospitalizations in AF patients. Targeted psychosocial support interventions may help to avoid unnecessary hospitalizations.

Trial registration

ClinicalTrials.gov Identifier NCT02105844.

A factor score reflecting cognitive functioning in patients from the Swiss Atrial Fibrillation Cohort Study (Swiss-AF)

Background

Atrial fibrillation (AF), the most common sustained cardiac arrhythmia, is considered as risk factor for the development of mild cognitive impairment (MCI) and dementia. However, dynamics of cognitive functions are subtle, and neurocognitive assessments largely differ in detecting these changes. We aimed to develop and evaluate a score which represents the common aspects of the cognitive functions measured by validated tests (i.e., “general cognitive construct”), while reducing overlap between tests and be more sensitive to identify changes in overall cognitive functioning.

Methods

We developed the CoCo (cognitive construct) score to reflect the cognitive performance obtained by all items of four neurocognitive assessments (Montreal Cognitive Assessment (MoCA); Trail Making Test; Semantic Fluency, animals; Digital Symbol Substitution Test). The sample comprised 2,415 AF patients from the Swiss Atrial Fibrillation Cohort Study (Swiss-AF), 87% aged at least 65 years. Psychometric statistics were calculated for two cognitive measures based on (i) the full set of items from the neurocognitive test battery administered in the Swiss-AF study (i.e., CoCo item set) and (ii) the items from the widely used MoCA test. For the CoCo item set, a factor score was derived based on a principal component analysis, and its measurement properties were analyzed.

Results

Both the MoCA item set and the full neurocognitive test battery revealed good psychometric properties, especially the full battery. A one-factor model with good model fit and performance across time and groups was identified and used to generate the CoCo score, reflecting for each patient the common cognitive skill performance measured across the full neurocognitive test battery. The CoCo score showed larger effect sizes compared to the MoCA score in relation to relevant clinical variables.

Conclusion

The derived factor score allows summarizing AF patients’ cognitive performance as a single score. Using this score in the Swiss-AF project increases measurement sensitivity and decreases the number of statistical tests needed, which will be helpful in future studies addressing how AF affects the risk of developing cognitive impairment.

A significant increase in exercise test performance with virtual group motivation: a randomised open-label controlled trial

AIMS

Exercise stress testing is frequently used for the assessment of coronary artery disease. As the validity of the test result is highly dependent on the patient&rsquo;s cooperation and motivation, we hypothesised that virtual group motivation would result in a higher exercise capacity and may increase the test&rsquo;s validity.

METHODS

108 patients at a Swiss teaching hospital with an indication for exercise testing were included in a controlled, open-label trial and randomised 1:1 to treadmill exercise testing whilst either watching a video of a walking group (video group, n = 43), or watching a static image of flowers (image group, n = 43). The video showed a group of five amateur runners, giving the patients the impression of running within the group. As primary outcomes, the performance achieved and the perceived level of comfort during the test were analysed.

RESULTS

The video group achieved significantly higher percentages of their age-predicted METs (149 &plusmn; 32% vs 135 &plusmn; 29%, p = 0.041) and longer exercise durations (11:12 &plusmn; 2:54 min vs 08:54 &plusmn; 02:39 min, p &lt;0.001). Levels of comfort (8.4 &plusmn; 1.4 vs 7.5 &plusmn; 1.7 analogue scale, p = 0.011) and closeness to their physical limits (8.9 &plusmn; 0.8 vs 8.1 &plusmn; 1.5, p = 0.005) were rated significantly higher by patients in the video group.

CONCLUSIONS

Patients watching a video of a running group achieved significantly higher maximum exercise levels and longer test durations. This may have implications for the test&rsquo;s validity. Furthermore, the virtual setting enhanced patient comfort. (This trial was formally registered at clinicaltrials.gov: trial ID NCT03704493.).

483Blood pressure and white matter lesions in patients with atrial fibrillation

Background

Hypertension (HTN) is one of the most common cardiovascular risk factors in patients with atrial fibrillation (AF). As a potential risk factor for cerebral white matter lesions (WML), HTN might explain the increased risk of cognitive dysfunction in AF patients.

Methods

In a multicenter cohort study of patients with documented AF in Switzerland, systolic and diastolic blood pressure (SBP, DBP) was measured up to three times in a supine position and the mean was calculated. HTN was defined as controlled, when SBP was <140 and DBP <90 mmHg with treatment, and uncontrolled when SBP was ≥140 or DBP ≥90 mmHg with treatment. All patients underwent brain magnetic resonance imaging. Volumes of WML were assessed and graded using the Fazekas scale. A Fazekas score of ≥2 was defined as moderate or severe WML. Multivariable adjusted regression models were used to assess the association between BP and WML.

Results

Overall, 1738 patients were enrolled in this cross-sectional analysis (mean age 73 years, 73% males). Mean BP was 135/79 mmHg, 69% had a history of HTN. Any WMLs were found in 99% of the patients and 54% had at least moderate WMLs. The prevalence of Fazekas ≥2 was 47%, 50% and 61% among AF patients with SBP <120, 120–140 and ≥140mmHg (p<0.001), respectively. Volumes of WMLs significantly increased across the same SBP categories (2943, 3512 and 4988 mm3, p<0.001). Among patients with normotension, controlled and uncontrolled HTN, moderate or severe WMLs were present in 173 (42.5%), 345 (55%) and 307 (61%), respectively. SBP was associated with Fazekas ≥2 and WML volume after multivariable adjustment (Table). Compared to normotension, both controlled and uncontrolled HTN were significantly associated with higher WML volume (Table).

Association between blood pressure and white matter lesions Blood pressure Fazekas ≥2 OR (95% CI) Volume WML β-coefficient (95% CI) <120 mmHg Ref Ref 120–140 mmHg 1.17 (0.88; 1.55) 0.14 (−0.01; 0.30) ≥140 mmHg 1.49 (1.11; 2.00) 0.28 (0.12; 0.43) Continuous, per SD 1.20 (1.09; 1.36), p<0.001 0.12 (0.06; 0.18), p<0.001 Normotension Ref Ref Treated hypertension 1.26 (0.94; 1.68), p=0.12 0.22 (0.07; 0.38), p=0.005 Treated, uncontrolled hypertension 1.52 (1.13; 2.05), p=0.005 0.38 (0.21; 0.54), p<0.001 Regression analyses were adjusted for age, sex, BMI, smoking status, stroke, diabetes, coronary heart disease, AF type, and antihypertensive treatment. One standard Deviation (SD) of SBP = 18 mmHg. Volume of WML was log-transformed.

Conclusion

Moderate or severe cerebral WMLs are highly prevalent in AF patients and strongly associated with SBP. Our data suggests that optimal treatment of HTN might play an essential role in preventing WMLs.

Acknowledgement/Funding

Swiss National Science Foundation

P6286Old age significantly worsens stroke outcome in old mice through a mechanism of inflamm-aging successfully countered by the tumour necrosis factor alpha antibody infliximab

Background

Stroke is the second leading cause of death and the number one cause of adult disability worldwide. As a strongly age-dependant disease, its prevalence is expected to rise along with the average age in western populations. While the epidemiological evidence linking stroke to age is non-refutable, the specific and independent effects of age on stroke remain elusive.

This presents an important missing link for developing targeted treatments tailored to the growing elderly population.

A potential mechanism pertinent to stroke outcome in the elderly is a chronic low-grade inflammatory state, coined “inflamm-aging”. Such a phenomenon could not only increase the risk for stroke, but also negatively affect its outcome and thus offers both preventive and therapeutic value.

Purpose

To determine the specific effects of age on the outcome after stroke in mice and delineate culprit molecular pathways with a focus on inflammatory mediators and to assess the efficacy of specific anti-inflammatory treatment with the TNF-α antibody Infliximab in this setting.

Methods

Old (18–20 months) C57BL/6 wildtype mice were compared to young (12 weeks) controls. Baseline levels of inflammatory cytokines were assayed in plasma and brain homogenates by ELISA. Ischemic stroke was induced by transient middle cerebral artery occlusion (30 minutes/48 h). Neurological function was assessed by a Bederson based score and the RotaRod test. Anti-inflammatory treatment with Infliximab was administered to a subset of old mice via weekly intraperitoneal injections (10 mg/kg) for 4 weeks prior to stroke induction. Young and old control animals received vehicle.

Results

At baseline (prior to stroke), old animals showed significantly higher plasma levels of TNF-α compared to young (Fig. 1A), while IL-6 and IL-1β remained below detection level in both groups. In brain homogenates of healthy old and young animals, TNF-α and IL-1β did not differ, while IL-6 was below detection level.

Old mice showed significantly larger stroke sizes (Fig.1B), performed worse neurologically (Fig. 1C) and suffered from higher post-stroke mortality compared to young (Fig. 1D). Pre-treatment with the TNF-α inhibitor Infliximab significantly decreased stroke size, neurological impairment and mortality in old animals (Fig1B-D).

Figure 1

Conclusions

In a model lacking additional confounding factors, we demonstrate a direct adverse effect of age per se on stroke outcome and mortality. Elevated TNF-α plasma levels in old mice outline the mechanism of “inflamm-aging” as a possible culprit. This concept is strongly supported by the beneficial effect of Infliximab on stroke outcome in old animals. Further investigation of the downstream mediators of the observed effect could help in tailoring treatments to the particularly vulnerable and growing elderly population.

2182Sirtuin 5 regulates arterial thrombosis by modulating endothelial plasminogen activator inhibitor-1

Introduction

Arterial thrombosis as a result of plaque rupture or erosion is a crucial event in myocardial infarction and stroke. Oxidative stress and inflammation promote endothelial dysfunction and play a pivotal role in destabilization of the atherosclerotic plaque. Sirtuin 5 (SIRT5) is a member of the sirtuin protein family with function as a NAD+-dependent protein desuccinylase and demalonylase. Being implicated in the regulation of different pathophysiological processes among which production of reactive oxygen species and transcription of inflammatory mediators, SIRT5 plays a role in the development of several cardiovascular diseases such as myocardial infarction and stroke. To date, the possible involvement of SIRT5 as a mediator of arterial thrombosis remains to be investigated.

Purpose

In this study we investigate the putative role of this protein in arterial thrombosis by using an established in vivo mouse model. The translational value of animal findings as well as the molecular mechanism underlying the observed effect will be investigated also in primary human aortic endothelial cells (HAECs).

Methods

SIRT5 knockout (KO) as well as SIRT5 transgenic (TG) animals were used for in vivo experiments. HAECs treated with SIRT5 silencing RNA (si-SIRT5) and stimulated with tumor necrosis factor (TNF)-α were used for in vitro assays.

Results

When compared to WT animals, SIRT5 KO mice display blunted carotid artery thrombus formation as underlined by delayed time to occlusion in a photochemical injury model. Oppositely, in SIRT5 TG mice the formation of an occlusive thrombus is accelerated (Fig 1). Mechanistically, SIRT5 KO and WT animals show no difference in terms of vascular tissue factor (TF) activity, TF concentration in plasma and expression of TF pathway inhibitor (TFPI) in the aorta. In line with the observed reduced thrombogenicity, SIRT5 KO animal express reduced level of the pro-thrombotic plasminogen activator-1 (PAI-1), as assessed by western blot in aorta lysate. Of interest, SIRT5 genetic deletion does not affect platelet aggregation, as assessed by ex-vivo collagen-induced aggregometry. In HAECs, SIRT5-silencing inhibits PAI-1 expression in response to TNF-α. Real-time polymerase chain reaction revealed that inhibition of PAI-1 expression occurs at the mRNA level. This effect is mediated by reduced activation of the MAP kinase Erk 1/2, but not JNK (Fig 1).

Conclusions

SIRT5 mediates arterial thrombosis by increasing endothelial PAI-1 expression. Hence, SIRT5 may be an effective therapeutic target in the context of atherothrombosis.

2287Endothelial SIRT6 exerts a beneficial role in cerebral ischemia/reperfusion injury by preserving blood-brain barrier integrity

Introduction

Stroke is a major cause of mortality and morbidity worldwide. Yet, therapeutic strategies are limited to the early reperfusion which can, on the other hand, worsen the brain damage trough ischemia/reperfusion (I/R) injury. Post-stroke blood-brain barrier (BBB) impairment is associated with worsened outcome. Aging is a major risk factor for stroke and genes regulating lifespan also contribute to the determination of cerebral damage during I/R injury.

Purpose

Given the pivotal role of endothelial cells in BBB, we hypothesized that the endothelial-specific expression of the longevity gene SIRT6 may protect the BBB from ischemia/reperfusion damage thus having a beneficial role on stroke outcome.

Methods

Endothelial-specific SIRT6 knockout (eSIRT6−/−) mice and control littermates (CTRL) underwent transient middle cerebral artery occlusion (tMCAO) for 45 min followed by 48 hours of reperfusion. Immunohistochemistry (IHC) was used to investigate BBB permeability by IgG extravasation and molecular mechanisms. Primary human brain microvascular endothelial cells (HBMVECs) transfected with either SIRT6 (siSIRT6) or scrambled (siSCR) small interfering RNA were subjected to hypoxia/reoxygenation (H/R). An in vitro BBB model consisting of a monolayer of siRNA-treated HBMVECs was established and barrier function was assessed by 48 h-lasting transendothelial electrical resistance measurement. SIRT6 expression in monocytes from stroke patients was correlated with the short-term neurological outcome [ΔNIHSS% = (NIHSS discharge-NIHSS admission)/ NIHSS admission*100].

Results

eSIRT6−/− displayed higher infarct volumes and lower survival rate compared to WT mice 48 h after tMCAO. The increased infarct volume was functionally relevant as eSIRT6−/− also showed worse post-stroke neurological impairment. Analysis of brain sections revealed increased BBB damage and increased endothelial expression of cleaved caspase-3 in eSIRT6−/− as compared to control littermates. In vitro, H/R reduced SIRT6 expression in HBMVECs. Mirroring the animal results, SIRT6 silencing impaired the barrier function of HBMVECs 48 h after exposure to H/R. In line with this, SIRT6-silenced HBMVECs showed reduced viability, increased cleaved caspase-3 expression and reduced activation of the anti-apoptotic survival pathway Akt as compared to control cells after H/R. The direct interaction between SIRT6 and Akt was confirmed by co-immunoprecipitation. In ischemic stroke patients, SIRT6 expression was higher in those with short-term neurological improvement (ΔNIHSS% >0) and negatively correlated with ΔNIHSS%.

Conclusion

Endothelial SIRT6 exerts a beneficial role in ischemic stroke by blunting I/R-mediated BBB damage. Specifically, SIRT6 reduces endothelial I/R-induced apoptotic death through activation of the protective Akt pathway. The longevity gene SIRT6 may represent a novel therapeutic target for the treatment of ischemic stroke.

Acknowledgement/Funding

Swiss National Science Foundation

P1898Prevalence and risk of DOACs inappropriate dosing in atrial fibrillation. An analysis of the Swiss-AF and BEAT-AF registries

Background

Direct oral anticoagulants (DOACs) have a similar efficacy in terms of stroke and mortality reduction as compared to Vitamin K-Antagonists (VKAs) and improved safety with regards to intracranial haemorrhage in patients with non-valvular atrial fibrillation (AF). Dose of DOACs needs to be adjusted according to age, weight, renal function and concomitant medication. Yet, off-label dosages have been reported in 11 - 45% of patients (on average 20%).

Purpose

To assess the prevalence of inappropriate DOAC-dosing according to the official prescribing information in two large prospective Swiss AF cohorts (Swiss-AF and BEAT-AF) and to evaluate its correlation with adverse clinical outcomes.

Methods

All 3267 patients taking oral anticoagulants were stratified at baseline as receiving DOACs (adequately dosed, under- or overdosed) or VKAs. Appropriateness of DOAC dosing was assessed based on age (≥80 years), weight (≤60kg) and renal function (serum creatinine ≥133μmol/l [apixaban]; creatinine clearence ≤50ml/min [all other DOACs]). Clinical outcomes were collected during a median follow-up of 2.96 years. Major adverse clinical events (MACE) consisted of a combination of myocardial infarction, cardiac death, ischemic stroke and systemic embolism. Safety was assessed by occurrence of any bleeding event.

Results

1902 patients (58%) were on VKAs and 1365 on DOACs (42%). In the DOAC group, 1149 patients received a dose consistent with drug labelling (84%), 133 (10%) received an inappropriately high and 83 (6%) an inappropriately low dose. Overdosed patients were older than those adequately treated and more likely female, had a lower BMI and a higher CHA2DS2-VASc score (4 vs. 3 points) (p<0.001 for all). Underdosed patients were more likely to have concomitant antiplatelet therapy (p<0.001). Both off-label groups were more likely to have a history of coronary artery disease, heart failure and chronic kidney disease (p<0.001). Kaplan-Meier cumulative incidence rates for the first occurrence of MACE or bleedings are provided in Figure 1. Overdosed patients had an almost two-fold higher risk of bleeding (9.0 vs. 5.0 events per 100 patient-years compared to correctly dosed DOACs and to VKAs) and a higher rate of MACE (5.1 vs. 2.3 events per 100 patient years compared to correctly dosed DOACs and 5.1 vs. 3.4 compared to VKAs). Underdosing did not seem to be associated with a relevant increase in ischemic or bleeding events as compared to correctly dosed DOACs and VKAs (see Figure 1).

Figure 1. Kaplan-Meier incidence curves

Conclusion

Inadequate DOACs dosing was found in 1 in 6 patients and correlated with a higher burden of comorbidities at baseline. Underdosing correlated with concomitant antiplatelet therapy. Overdosing was associated with adverse clinical outcome for ischemic and bleeding events.

P1876Atrial fibrillation related symptoms and cardiovascular outcomes

Background

Comprehensive information on the impact of atrial fibrillation (AF)-related symptoms and quality of life (QoL) on adverse outcomes is sparse.

Purpose

We aimed to investigate whether AF-related symptoms and/or QoL are associated with cardiovascular outcomes in a large cohort of AF patients.

Methods

A total of 3902 participants with documented AF from two nationwide prospective cohort studies in Switzerland were included. Information on AF-related symptoms was assessed yearly by standardized questionnaires, QoL was quantified using a visual analog scale (0–100, with higher scores indicating better QoL). The primary endpoint was a composite of stroke and systemic embolism. The secondary endpoint was a composite of cardiovascular death, hospitalization for heart failure and myocardial infarction. We assessed associations using multivariable, time-updated Cox proportional-hazards models including age, sex, study cohort, history of heart failure, hypertension, diabetes, prior stroke, prior myocardial infarction, vascular disease and prior catheter ablation for AF as covariates.

Results

Mean age was 72 years, and 72% were male. The median QoL score was 75 points, and 2572 (66%) participants had AF-related symptoms. Symptomatic individuals were younger (71 vs 75 years) and had more often paroxysmal AF (29 vs 23%) (p for both <0.001). The most frequent symptoms were palpitations (42%), dyspnea (25%) and fatigue (18%). In multivariable, time-updated models, the hazard ratio (HR) was 1.24 (95% confidence intervals (CI) 0.72; 2.11, p=0.43) for the primary endpoint and HR 0.83 (95% CI 0.65; 1.06, p=0.14) for the secondary endpoint in symptomatic vs non-symptomatic individuals. There was a significant, inverse association for a 5-point increase in the QoL score with both the primary (HR 0.94 (95% CI 0.88; 0.99), p=0.04) and secondary (HR 0.91 (95% CI 0.88; 0.93), p<0.0001) endpoints.

Conclusions

AF-related symptoms are not associated with adverse cardiovascular events in AF patients. In contrast, QoL is inversely associated with to adverse cardiovascular outcomes.

P3782Frailty to predict unplanned hospitalizations, stroke, bleeding and death in atrial fibrillation

Aim

We investigated the prevalence of frailty, and the relationships between frailty and the risk of adverse clinical outcomes in patients with atrial fibrillation (AF).

Methods

Patients with known AF were enrolled in a nation-wide observational cohort study in Switzerland. Information on medical history, medication, lifestyle factors and clinical measurements were obtained. The primary outcome was unplanned hospitalizations, secondary outcomes were all-cause mortality, bleeding and stroke. The frailty index (FI) was measured using a cumulative deficit approach according to previously published criteria. Participants were divided into three groups (non-frail, pre-frail and frail) according to their FI at study entry. The association between frailty and clinical outcomes was assessed using multivariable adjusted Cox proportional hazard models.

Results

We included 2369 patients with a mean age of 73±8 years (27.3% female). The prevalence of frailty and pre-frailty was 10.6% and 60.7%, respectively. Frailty was associated with unplanned hospitalization (adjusted hazard ratio [HR] 3.59; 95% confidence interval [95% CI], 2.78–4.63; p<0.001), all-cause mortality (adjusted HR 16.72; 95% CI 7.75–36.05; p<0.001), bleeding (adjusted HR 2.46; 95% CI 1.61–3.77; p<0.001), and stroke (adjusted HR 3.29; 95% CI 1.29–8.39; p=0.01) (Figure). Similarly, pre-frailty was significantly associated with unplanned hospitalization (adjusted HR 1.82; 95% CI 1.49–2.22; p<0.001), all-cause mortality (adjusted HR 5.07; 95% CI 2.43–10.59; p<0.001) and bleeding (adjusted HR 1.53; 95% CI 1.11–2.13; p=0.01), but not with stroke.

Cumulative incidence of adverse events

Conclusion

In our cohort, more than two thirds of AF patients were either pre-frail or frail. These patients have a high risk of unplanned hospitalizations and other adverse outcomes, indicating that frailty is a powerful tool to predict adverse clinical outcomes in AF patients.

Acknowledgement/Funding

Swiss National Science Foundation; Foundation for Cardiovascular Research Basel; University of Basel

P4468Dietary plant derived omega-3 fatty acid alpha linolenic acid prevents age-dependent arterial stiffness and improves outcome after stroke in mice

Background

A fundamental determinant of cardio- and cerebrovascular diseases is vascular aging, characterized by arterial stiffness. Arterial stiffness is an independent predictor of adverse cardio- and cerebrovascular events and mortality.

Fish-derived omega-3 fatty acids (n3-FA) have been described to decrease cardiovascular events in high risk populations. Little is known on the effects of the plant-derived n3 FA alpha-linolenic acid (ALA). More insight is urgently needed, because of the low costs and abundant global supply of ALA. Thus, we aimed to investigate the effects of a long-term dietary intervention with ALA on age-dependent arterial stiffness and the magnitude of these effects on a specific vascular endpoint – ischemic stroke – in a mouse model of aging.

Methods

C57BL/6 wildtype males were either fed an ALA-rich (high ALA, 7.3 g%) or a respective control (0.3 g%) diet for 12 months, starting from 6 months of age.

At 9, 15 and 18 months, arterial stiffness was assessed by measuring pulse wave velocity (PWV) in the right common carotid artery using a Vevo 3100 system (VisualSonics, Fig. 1A).

At 18 months, ischemic stroke was induced by transient middle cerebral artery occlusion (30 mins/48 h). Stroke size was assessed by triphenyl tetrazolium chloride staining and neurological function by a Bederson based score.

Results

Arterial stiffness steadily and significantly increased in controls over time, while ALA clearly and effectively prevented it (PWV at 9 vs. 18 months: controls + 95%; p<0,0001 vs. High ALA + 15%; ns) (Fig 1A).

Stroke size at 18 months was significantly decreased in ALA-fed animals compared to controls (28.39 mm3 vs. 51.77 mm3 p=0.0017) (Fig. 1B). In line with the morphological changes, controls performed significantly worse neurologically (Fig. 1C). Additionally, post-stroke survival at 48 h was improved in ALA-fed animals compared to controls, with 85% survival compared to 57% (Fig. 1D).

Figure 1

Conclusion

We demonstrate that long-term dietary supplementation with the plant-derived ALA fully prevents the development of age-dependent arterial stiffness.

The magnitude of this effect is clearly reflected in biologically relevant decreased stroke size, improved neurological performance and even post-stroke survival.

This study not only demonstrates vasoprotective effects of ALA, but also links them to improved outcome of a specific clinical endpoint. Future analyses will aim at delineating the molecular basis of the observed benefits. This will result in a better understanding of some ambiguous results from clinical trials and likely define the population which benefits from ALA.

Risk stratification of elderly patients with acute pulmonary embolism

BACKGROUND

Combining high-sensitivity cardiac Troponin T (hs-cTnT), NT-pro-B-type natriuretic peptide (NT-proBNP) and high-sensitivity C-reactive protein (hs-CRP) may improve risk stratification of patients with pulmonary embolism (PE) beyond the PESI risk score.

METHODS

In the prospective multicentre SWITCO65+ study, we analysed 214 patients ≥ 65 years with a new submassive PE. Biomarkers and clinical information for the PESI risk score were ascertained within 1 day after diagnosis. Associations of hs-TnT, NT-proBNP, hs-CRP and the PESI risk score with the primary endpoint defined as 6-month mortality were assessed. The discriminative power of the PESI risk score and its combination with hs-cTnT, NT-proBNP and hs-CRP for 6-month mortality was compared using integrated discrimination improvement (IDI) index and net reclassification improvement (NRI).

RESULTS

Compared with the lowest quartile, patients in the highest quartile had a higher risk of death during the first 6 months for hs-cTnT (adjusted HR 10.22; 95% CI 1.79-58.34; P = 0.009) and a trend for NT-proBNP (adjusted HR 4.3; 95% CI 0.9-20.41; P = 0.067) unlike hs-CRP (adjusted HR 1.97; 95% CI 0.48-8.05; P = 0.344). The PESI risk score (c-statistic 0.77 (95% CI 0.69-0.84) had the highest prognostic accuracy for 6-month mortality, outperforming hs-cTnT, NT-proBNP and hs-CRP (c-statistics of 0.72, 0.72, and 0.54), respectively. Combining all three biomarkers had no clinically relevant impact on risk stratification when added to the PESI risk score (IDI = 0.067; 95% CI 0.012-0.123; P = 0.018; NRI = 0.101 95% CI -0.099-0.302; P = 0.321).

CONCLUSIONS

In elderly patients with PE, 6-month mortality can adequately be predicted by the PESI risk score alone.

Tumour Necrosis Factor-α Inhibition Improves Stroke Outcome in a Mouse Model of Rheumatoid Arthritis

Rheumatoid Arthritis (RA) is a chronic inflammatory disorder where incidence and severity of myocardial infarction are increased. Data on the incidence and outcome of stroke are conflicting. Thus, we investigated outcome after Ischemia/Reperfusion (I/R) brain injury in a mouse model of RA and assessed for the role of the tumour necrosis factor-α (TNF-α) inhibitor Infliximab herein. We used a TNF-α reliant mouse model of RA. RA and wildtype (WT) animals were treated with vehicle (RA/WT) or Infliximab (RA Infliximab) for 4 weeks, before undergoing I/R brain injury. RA-animals displayed larger strokes and poorer neurological performance. Immunohistochemistry on brain sections revealed increased numbers of resident and peripheral innate immune cells (microglia and macrophages); increased Blood-Brain-Barrier (BBB)-disruption; decreased levels of the tight junction proteins (TJPs) claudin-5 and occludin; increased expression of matrix-metalloproteinases (MMP)-3 and -9 and enhanced lipid peroxidation. Treatment with Infliximab corrected these alterations. We show that RA associates to worse stroke-outcome via exacerbated BBB degradation by decrease of the TJPs claudin-5 and occludin. We identified MMPs-3 and -9 and increased oxidative stress as potential mediators thereof. Increased numbers of resident and peripheral innate immune cells (microglia and macrophages) may in turn contribute to all these effects. Infliximab-treatment restored the phenotype of RA-mice to baseline. Our data provide evidence clearly linking RA to adverse stroke-outcome in mice and indicate an approved TNF-α inhibitor as a potential strategy to reduce stroke-burden in this setting.

Quantitative and Qualitative Analysis of Platelet GPIb and von Willebrand Factor in Liver Cirrhosis

Numerous abnormalities of plasmatic coagulation and platelet function may contribute to the bleeding in liver cirrhosis with a defective platelet-von Willebrand factor interaction being a potential mechanism. To analyze GPIb and von Willebrand factor in cirrhosis, we quantified the number of GPIb molecules on the platelet surface by flow cytometry, assessed the total (and indirectly the internal) pool of GPIb by ELISA and measured the circulating amount of glycocalicin in plasma as a measure of proteolytic activity and platelet turnover. Von Willebrand factor was characterized by ELISA, by its ristocetin-cofactor activity and by multimer analysis. Botrocetin-induced agglutination was used for functional analysis.

The data from 8 well-characterized cirrhosis patients indicate that total GPIb is insignificantly increased to 46,000 ± 5,000 molecules/P (normal: 39,500 ± 2,000 [SEM]), surface-GPIb is normal with some variability and that the glycocalicin levels are 2-3 times higher than would be expected from the platelet count (= 100 ±5 × 109/1). Von Willebrand factor antigen levels and -activity were 400-500 % of normal with a 22% reduction of the high molecular weight multimers. A significant hyperagglutination response to botrocetin was observed with platelets from both patients and controls using patient plasma as a source of von Willebrand factor. In conclusion, a hyperresponsiveness rather than a defective platelet-von Willebrand factor interaction can be observed in cirrhosis which may compensate for other hemostatic problems and appears to be mediated primarily by increased levels of von Willebrand factor.

Whole Blood Clot Lysis: Enhanced by Exposure to Autologous but not to Homologous Plasma

A new phenomenon is described: Whole blood clots lyse faster in the plasma of the same donor than in another donor’s plasma. We have confirmed this finding in 68 healthy volunteers by a standardized, pairwise analysis and have found a mean difference in clot weights of 8.8 ± 0.99% (SEM, p<0.0001) after 6 h of urokinase-induced (200 U/ml) clot lysis. Nu difference was found in a group of 7 pairs of identical twins. Further analysis revealed that increasing concentrations of platelets in the plasma reduced the difference significantly but did not abolish it. A 1:1 mixture of autologous with homologous plasma reduced the autologous advantage by almost 50%, thus making an inhibitor unlikely. The absence of cellular components in clots of platelet- poor plasma resulted in the loss of the advantage after 2 h of lysis, but not in the early phase. We conclude that there is a clear advantage of autologous over homologous clot lysis. Potential mechanisms are discussed and include an increased affinity of enzymes for their substrates in a given individual.

Whole blood omega-3 fatty acid concentrations are inversely associated with blood pressure in young, healthy adults

BACKGROUND

Omega-3 fatty acids (n - 3 FA) may have blood pressure (BP)-lowering effects in untreated hypertensive and elderly patients. The effect of n - 3 FA on BP in young, healthy adults remains unknown. The Omega-3 Index reliably reflects an individuals' omega-3 status. We hypothesized that the Omega-3 Index is inversely associated with BP levels in young healthy adults.

METHODS

The current study (n = 2036) is a cross-sectional study investigating the baseline characteristics of a cohort, which includes healthy adults, age 25-41 years. Individuals with cardiovascular disease, known diabetes or a BMI higher than 35 kg/m were excluded. The Omega-3 Index was determined in whole blood using gas chromatography. Association with office and 24-h BP was assessed using multivariable linear regression models adjusted for potential confounders.

RESULTS

Median Omega-3 Index was 4.58% (interquartile range 4.08; 5.25). Compared with individuals in the lowest Omega-3 Index quartile, individuals in the highest had a SBP and DBP that was 4 and 2 mmHg lower, respectively (P < 0.01). A significant linear inverse relationship of the Omega-3 Index with 24-h and office BP was observed. Per 1-U increase in log-transformed Omega-3 Index the lowering in BP (given as multivariable adjusted β coefficients; 95% confidence interval) was -2.67 mmHg (-4.83; -0.51; P = 0.02) and -2.30 mmHg (-3.92; -0.68; P = 0.005) for 24-h SBP and DBP, respectively.

CONCLUSION

A higher Omega-3 Index is associated with statistically significant, clinically relevant lower SBP and DBP levels in normotensive young and healthy individuals. Diets rich in n - 3 FA may be a strategy for primary prevention of hypertension.

Long-term outcomes of elderly patients with CYP2C9 and VKORC1 variants treated with vitamin K antagonists

Essentials The long-term effects of VKORC1 and CYP2C9 variants on clinical outcomes remains unclear. We followed 774 patients ≥65 years with venous thromboembolism for a median duration of 30 months. Patients with CYP2C9 variants are at increased risk of death and non-major bleeding. Patients with genetic variants have a slightly lower anticoagulation quality only.

SUMMARY

Background The long-term effect of polymorphisms of the vitamin K-epoxide reductase (VKORC1) and the cytochrome P450 enzyme gene (CYP2C9) on clinical outcomes remains unclear. Objectives We examined the association between CYP2C9/VKORC1 variants and long-term clinical outcomes in a prospective cohort study of elderly patients treated with vitamin K antagonists for venous thromboembolism (VTE). Methods We followed 774 consecutive patients aged ≥ 65 years with acute VTE from nine Swiss hospitals for a median duration of 30 months. The median duration of initial anticoagulant treatment was 9.4 months. The primary outcome was the time to any clinical event (i.e. the composite endpoint of overall mortality, major and non-major bleeding, and recurrent VTE. Results Overall, 604 (78%) patients had a CYP2C9 or VKORC1 variant. Three hundred and thirty-four patients (43.2%) had any clinical event, 119 (15.4%) died, 100 (12.9%) had major and 167 (21.6%) non-major bleeding, and 100 had (12.9%) recurrent VTE. After adjustment, CYP2C9 (but not VKORC1) variants were associated with any clinical event (hazard ratio [HR], 1.34; 95% confidence interval [CI], 1.08-1.66), death (HR, 1.74; 95% CI, 1.19-2.52) and clinically relevant non-major bleeding (sub-hazard ratio [SHR], 1.39; 95% CI, 1.02-1.89), but not with major bleeding (SHR, 1.03; 95% CI, 0.69-1.55) or recurrent VTE (SHR, 0.95; 95% CI, 0.62-1.44). Patients with genetic variants had a slightly lower anticoagulation quality. Conclusions CYP2C9 was associated with long-term overall mortality and non-major bleeding. Although genetic variants were associated with a slightly lower anticoagulation quality, there was no relationship between genetic variants and major bleeding or VTE recurrence.

Frequency of use and acceptability of clinical prediction rules for pulmonary embolism among Swiss general internal medicine residents

INTRODUCTION

Whether clinical prediction rules for pulmonary embolism are accepted and used among general internal medicine residents remains uncertain. We therefore evaluated the frequency of use and acceptability of the Revised Geneva Score (RGS) and the Pulmonary Embolism Severity Index (PESI), and explored which factors were associated with rule use.

MATERIALS/METHODS

In an online survey among general internal medicine residents from 10 Swiss hospitals, we assessed rule acceptability using the Ottawa Acceptability of Decision Rules Instrument (OADRI) and explored the association between physician and training-related factors and rule use using mixed logistic regression models.

RESULTS

The response rate was 50.4% (433/859). Overall, 61% and 36% of the residents reported that they always or regularly use the RGS and the PESI, respectively. The mean overall OADRI score was 4.3 (scale 0-6) for the RGS and 4.1 for the PESI, indicating a good acceptability. Rule acceptability (odds ratio [OR] 6.19 per point, 95% confidence interval [CI] 3.64-10.51), prior training in emergency medicine (OR 5.14, CI 2.20-12.01), and availability of internal guidelines recommending RGS use (OR 4.25, CI 2.15-8.43) were associated with RGS use. Rule acceptability (OR 6.43 per point, CI 4.17-9.92) and rule taught at medical school (OR 2.06, CI 1.24-3.43) were associated with PESI use.

CONCLUSIONS

The RGS was more frequently used than the PESI. Both rules were considered acceptable. Rule acceptability, prior training in emergency medicine, availability of internal guidelines, and rule taught at medical school were associated with rule use and represent potential targets for quality improvement interventions.

Omega-3 fatty acids predict recurrent venous thromboembolism or total mortality in elderly patients with acute venous thromboembolism

Essentials The role of omega-3 fatty acids (n-3 FAs) in recurrent venous thromboembolism (VTE) is unknown. Association of n-3 FAs with recurrent VTE or total mortality was investigated in 826 patients. Whole blood n-3 FAs were inversely correlated with recurrent VTE or total mortality. Major and non-major bleeding was not increased in patients with higher levels of n-3 FAs.

SUMMARY

Background The role of omega-3 fatty acids (n-3 FAs) in recurrent venous thromboembolism (VTE) remains unknown. Objectives To investigate the association of n-3 FAs with recurrent VTE or total mortality at 6 months and 3 years. Methods N-3 FAs were assessed in 826 patients aged ≥ 65 years, categorized into low, medium and high based on the 25th and 75th percentile. Mean follow-up was 29 months. Results At 6 months, subjects with medium (adjusted hazard ratio [HR], 0.37; 95% confidence interval [CI], 0.22-0.62) and high n-3 FA levels (adjusted HR, 0.36; 95% CI, 0.20-0.67) were less likely to develop recurrent VTE or total mortality, compared with those with low n-3 FAs. At 3 years, medium levels (adjusted HR, 0.67; 95% CI, 0.47-0.96) were associated with lower risk of recurrent VTE or total mortality. As compared with low n-3 FAs, the adjusted sub-hazard ratio [SHR] of recurrent VTE was 0.39 (95% CI, 0.15-0.99) in patients with medium and 0.17 (95% CI, 0.03-0.82) in patients with high n-3 FAs. The cumulative incidence of recurrent VTE was lower in the medium and high n-3 FA groups as compared with the low n-3 FA groups, but seems to have worn off after 3 years. The incidence of major and non-major bleeding was not greater in the high n-3 FA group. Conclusion Higher levels of n-3 FAs were associated with a lower risk of recurrent VTE or total mortality in elderly patients with VTE, but not with greater bleeding risk.

Ticagrelor, but not clopidogrel, reduces arterial thrombosis via endothelial tissue factor suppression

AIMS

The P2Y₁₂ antagonist ticagrelor reduces mortality in patients with acute coronary syndrome (ACS), compared with clopidogrel, and the mechanisms underlying this effect are not clearly understood. Arterial thrombosis is the key event in ACS; however, direct vascular effects of either ticagrelor or clopidogrel with focus on arterial thrombosis and its key trigger tissue factor have not been previously investigated.

METHODS AND RESULTS

Human aortic endothelial cells were treated with ticagrelor or clopidogrel active metabolite (CAM) and stimulated with tumour necrosis factor-alpha (TNF-α); effects on procoagulant tissue factor (TF) expression and activity, its counter-player TF pathway inhibitor (TFPI) and the underlying mechanisms were determined. Further, arterial thrombosis by photochemical injury of the common carotid artery, and TF expression in the murine endothelium were examined in C57BL/6 mice treated with ticagrelor or clopidogrel. Ticagrelor, but not CAM, reduced TNF-α-induced TF expression via proteasomal degradation and TF activity, independently of the P2Y₁₂ receptor and the equilibrative nucleoside transporter 1 (ENT1), an additional target of ticagrelor. In C57BL/6 mice, ticagrelor prolonged time to arterial occlusion, compared with clopidogrel, despite comparable antiplatelet effects. In line with our in vitro results, ticagrelor, but not clopidogrel, reduced TF expression in the endothelium of murine arteries.

CONCLUSION

Ticagrelor, unlike clopidogrel, exhibits endothelial-specific antithrombotic properties and blunts arterial thrombus formation. The additional antithrombotic properties displayed by ticagrelor may explain its greater efficacy in reducing thrombotic events in clinical trials. These findings may provide the basis for new indications for ticagrelor.

Post-ischaemic silencing of p66Shc reduces ischaemia/reperfusion brain injury and its expression correlates to clinical outcome in stroke

AIM

Constitutive genetic deletion of the adaptor protein p66(Shc) was shown to protect from ischaemia/reperfusion injury. Here, we aimed at understanding the molecular mechanisms underlying this effect in stroke and studied p66(Shc) gene regulation in human ischaemic stroke.

METHODS AND RESULTS

Ischaemia/reperfusion brain injury was induced by performing a transient middle cerebral artery occlusion surgery on wild-type mice. After the ischaemic episode and upon reperfusion, small interfering RNA targeting p66(Shc) was injected intravenously. We observed that post-ischaemic p66(Shc) knockdown preserved blood-brain barrier integrity that resulted in improved stroke outcome, as identified by smaller lesion volumes, decreased neurological deficits, and increased survival. Experiments on primary human brain microvascular endothelial cells demonstrated that silencing of the adaptor protein p66(Shc) preserves claudin-5 protein levels during hypoxia/reoxygenation by reducing nicotinamide adenine dinucleotide phosphate oxidase activity and reactive oxygen species production. Further, we found that in peripheral blood monocytes of acute ischaemic stroke patients p66(Shc) gene expression is transiently increased and that this increase correlates with short-term neurological outcome.

CONCLUSION

Post-ischaemic silencing of p66(Shc) upon reperfusion improves stroke outcome in mice while the expression of p66(Shc) gene correlates with short-term outcome in patients with ischaemic stroke.

Platelet receptor gain-of-function single nucleotide polymorphisms in carotid and vertebral stenosis patients

The role of platelet receptor gain-of-function single nucleotide polymorphisms (SNP) in cardiovascular disease is controversial. We hypothesised that certain SNPs may accelerate the development of carotid artery stenosis. The intronic PAR-1 receptor intervening sequence-14 A/T (IVSn-14 A/T) polymorphism and three additional platelet receptor polymorphisms, i.e. GPIa (807C/T), GPIbα (5T/C) and HPA-1a/HPA-1b (Pl (A1/A2)) of GPIIIa were studied. The interaction of SNPs with conventional risk factors including male gender, hypertension, high cholesterol, diabetes, advanced age and smoking were investigated. The hypothesis was tested in 114 well-characterised patients with symptomatic carotid or vertebral stenosis from the British CAVATAS population and compared the results with 97 unrelated controls. The allele frequency of the platelet gain-of-function SNP was not significantly different in the CAVATAS population as compared to controls (PAR-1A/T (P = 0.13), GPIa C/T (P = 0.25), GPIIIa HPA-1a/HPA-1b (PlA1/A2) (P = 0.66) and GPIb T/C (P = 0.20)). In the subgroup of smokers, however, the prothrombotic GPIbα C mutated allele was found in a significantly higher frequency in the patient as compared to the control group (P = 0.04). Contrary to the primary hypothesis, the PAR-1A/T SNP as well as the other SNPs tested were not over- or underrepresented in the CAVATAS population. However, a significantly increased prevalence of GPIb-α (5C/T) was found in the subgroup of smokers and may represent an important cofactor in this patient group of our hypothesis-generating study.

[To prevent myocardial infarction with a tooth brush?]

The association of periodontal disease and cardiovascular events is discussed. Low grade inflammation, with elevated CRP and elevated fibrinogen might contribute. A recent study from Scotland in which the dental brushing was evaluated found a relative risk for a cardiovascular event of 1.69 associated with rare tooth brushing. However, there was a bias with elderly patients, male gender and low socioeconomic status.

CONCLUSION

The common risk factor is smoking; active "dentogenic" inflammation should be checked before surgery, particularly before surgery with implants.