Testing spatial working memory in pigs using an automated T-maze

Pigs are an important large animal model for translational clinical research but underutilized in behavioral neuroscience. This is due, in part, to a lack of rigorous neurocognitive assessments for pigs. Here, we developed a new automated T-maze for pigs that takes advantage of their natural tendency to alternate. The T-maze has obvious cross-species value having served as a foundation for cognitive theories across species. The maze (17' × 13') was constructed typically and automated with flanking corridors, guillotine doors, cameras, and reward dispensers. We ran nine pigs in (1) a simple alternation task and (2) a delayed spatial alternation task. Our assessment focused on the delayed spatial alternation task which forced pigs to wait for random delays (5, 60, 120, and 240 s) and burdened spatial working memory. We also looked at self-paced trial latencies, error types, and coordinate-based video tracking. We found pigs naturally alternated but performance declined steeply across delays (R2 = 0.84). Self-paced delays had no effect on performance suggestive of an active interference model of working memory. Positional and head direction data could differentiate subsequent turns on short but not long delays. Performance levels were stable over weeks in diverse strains and sexes, and thus provide a benchmark for future neurocognitive assessments in pigs.

Reducing bleeding risk in patients on oral anticoagulation therapy

INTRODUCTION

Oral anticoagulation (OAC) significantly mitigates thromboembolism risks in atrial fibrillation (AF) and venous thromboembolism (VTE) patients yet concern about major bleeding events persist. In fact, clinically relevant hemorrhages can be life-threatening. Bleeding risk is dynamic and influenced by factors such as age, new comorbidities, and drug therapies, and should not be assessed solely based on static baseline factors.

AREAS COVERED

We comprehensively review the bleeding risk associated with OAC therapy. Emphasizing the importance of assessing both thromboembolic and bleeding risks, we present clinical tools for estimating stroke and systemic embolism (SSE) and bleeding risk in AF and VTE patients. We also address overlapping risk factors and the dynamic nature of bleeding risk.

EXPERT OPINION

The OAC management is undergoing constant transformation, motivated by the primary objective of mitigating thromboembolism and bleeding hazards, thereby amplifying patient safety throughout the course of treatment. The future of OAC embraces personalized approaches and innovative therapies, driven by advanced pathophysiological insights and technological progress. This holds promise for improving patient outcomes and revolutionizing anticoagulation practices.

Longitudinal changes in CHA2DS2-VASc and HAS-BLED scores are superior to baseline score values for predicting ischemic stroke and major bleeding in atrial fibrillation patients

Background

Stroke and bleeding risks in atrial fibrillation (AF) are often assessed at baseline, as a “one-off” evaluation. However, these baseline values are usually applied to predict outcomes many years later, and therefore lack the consideration that the risk is not static.

Purpose

Our aim was to investigate if dynamic changes of CHA2DS2-VASc and HAS-BLED over time have an effect on the prediction of stroke and bleeding risks.

Methods

We included AF patients who were stable while taking vitamin K antagonists (INR 2.0–3.0) for 6 months attending a tertiary hospital (May 2007-December 2007). During 6-years of follow-up, ischemic strokes/transient ischemic attacks (TIAs), major bleeds, and all-cause deaths were recorded. CHA2DS2-VASc and HAS-BLED were recalculated every 2-years, and their predictive abilities were tested for outcomes in periods of 2-years (from year 0 to 2, year 2 to 4 and year 4 to 6).

Results

1361 patients (693 [50.9%] females, median age 76 [IQR 71–81] years, mean CHA2DS2-VASc and HAS-BLED of 4.0±1.7 and 2.9±1.2, respectively) were included. The predictive ability for ischemic stroke/TIA of the baseline CHA2DS2-VASc for 2-years events was 0.662 (0.637–0.688, p<0.001). Compared to the baseline CHA2DS2-VASc, the CHA2DS2-VASc re-calculated at 2-years presented significantly higher predictive ability for ischemic stroke/TIA during the period 2–4 years (c-indexes: 0.701 [0.675–0.727] vs. 0.604 [0.576–0.631], p<0.001). Integrated discrimination improvement (IDI) and net reclassification improvement (NRI) showed an improvement in sensitivity of 0.014 (p<0.001) and a better reclassification (0.677, p<0.001). Similarly, the CHA2DS2-VASc re-calculated at 4-years yielded significantly better predictive performance for ischemic stroke/TIA during the period 4–6 years in comparison to the baseline CHA2DS2-VASc (c-indexes: 0.761 [0.734–0.786] vs. 0.682 [0.653–0.710], p=0.026). Again, IDI reported an improvement (IDI = 0.030, p<0.001) and there was an important enhance of the reclassification ability (NRI = 0.757, p<0.001).

The c-index of the baseline HAS-BLED for events at 2-years was 0.744 (0.720–0.767, p<0.001). At 2-years, the re-calculated HAS-BLED score showed higher predictive ability compared to the baseline HAS-BLED during the period 2–4 year (c-indexes: 0.709 [0.680–0.738] vs. 0.663 [0.632–0.693], p=0.003). Accordingly, IDI and NRI demonstrated significant improvements for the re-calculated HAS-BLED compared to baseline (IDI = 0.016, p=0.001; NRI = 0.444, p<0.001). For major bleeding during the period 4–6 years, the c-index of the HAS-BLED score re-calculated at 4-years was non-significantly different to baseline HAS-BLED at baseline (0.631 [0.601–0.660] vs. 0.623 [0.593–0.652], p=0.751), although showed a slight enhance in sensitivity (IDI = 0.009, p=0.018).

Conclusions

In AF patients, stroke and bleeding risks are dynamic and change over time. The CHA2DS2-VASc and HAS-BLED scores should be regularly reassessed.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): This work was supported by the Spanish Ministry of Economy, Industry, and Competitiveness, through the Instituto de Salud Carlos III after independent peer review (research grant: PI17/01375 co-financed by the European Regional Development Fund)

Multimorbidity, frailty and malnutrition: moving beyond traditional risk factors for risk assessment in atrial fibrillation. The Murcia Atrial Fibrillation Project II

Background

The management of atrial fibrillation (AF) has evolved over the last decade with a more towards a more multidisciplinary, integrated and holistic approach. However, several conditions that may influence the prognosis and management of AF patients are still under-recognised.

Purpose

Our aim was to investigate if multimorbidity, frailty and malnutrition are associated with the risk of worse clinical outcomes in patients with recent diagnosis of AF starting oral anticoagulation (OAC) therapy.

Methods

Prospective cohort study including outpatients newly diagnosed with AF starting vitamin K antagonist (VKA) therapy from July 1, 2016 to June 30, 2018. Morbidity was assessed with the crude number of comorbidities. Frailty was assessed with the Clinical Frailty Scale (CFS). Nutrition status was assessed with the Controlling Nutritional Status (CONUT) score. During 2-years of follow-up, we recorded all ischemic strokes/transient ischemic attacks (TIAs), major bleeds (according to the 2005 International Society on Thrombosis and Haemostasis criteria), and all-cause deaths.

Results

We included 1050 patients (540 [51.4%] females, median age 77 [IQR 70–83] years), with median CHA2DS2-VASc of 4 [IQR 3–5] and median HAS-BLED of 2 [IQR 2–3]. The median crude number of comorbidities was 3 [IQR 2–5], whereas the median CFS and CONUT score were 2 [IQR 2–3] and 2 [IQR 1–3], respectively. The crude number of comorbidities, CFS and CONUT score demonstrated a significant positive correlation (p<0.001 for all correlations). After adjusting for several risk factors (age, sex, hypertension, diabetes, previous stroke, vascular disease, heart failure, chronic kidney disease, dyslipidemia, sleep apnoea, hepatic disease, and cancer), the CFS was independently associated with major bleeding (adjusted HR 1.25, 95% CI 1.07–1.45) and all-cause mortality (aHR 1.20, 95% CI 1.09–1.32). The crude number of comorbidities (aHR 1.30, 95% CI 1.14–1.49) was also associated with major bleeding, and the CONUT score (aHR 1.25, 95% CI 1.15–1.35) was associated with all-cause mortality. Any frailty degree (i.e CFS ≥5) was associated with a 3-fold higher risk of major bleeding (aHR 3.04, 95% CI 1.67–5.52) and a 2-fold higher risk of death (aHR 2.04, 95% CI 1.39–3.01), whereas the moderate/severe malnutrition (i.e. CONUT ≥5) was an independent risk factor for ischemic stroke/TIA and (aHR 2.25, 95% CI 1.11–4.56) and death (aHR 3.21, 95% CI 2.14–4.83) (Figures 1 and 2).

Conclusions

Frailty and malnutrition are important risk factors for bleeding, stroke and mortality in AF. The frailty degree and nutritional status should be assessed in all AF patients in order to address them properly and provide a truly integrated management.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): This work was supported by the Spanish Ministry of Economy, Industry, and Competitiveness, through the Instituto de Salud Carlos III after independent peer review (research grant: PI17/01375 co-financed by the European Regional Development Fund)

The ideal environment for the development of postcardiac surgery atrial fibrillation: evidence for endothelial activation and poor cell-cell interaction

Introduction

The development of post-operative atrial fibrillation (POAF) after cardiac surgeryis associated with pre-existing endothelial activation and systemic inflammation due to adhesion and transmigration of leukocytes into the interstitium. The electrical remodelling associated with AF causes changes in connexins, resulting in ineffective electrical coupling between cells and thus ineffective cell-cell communication.There is also an association between the inflammatory state, and the presence of cardiac fibrosis, oxidative stress and myocyte apoptosis.

Purpose

Our aim was to investigate the pathophysiologicaland regulatory mechanisms of AF through endothelial activation and inflammatory status, as well as cell-cell interactions (connexins) in relation to POAF amongst a cohort of patients undergoing cardiac surgery.

Methods

We studied prospective patients who underwent CABG (52.9%) or cardiac valve (47.1%) surgery without previous documented AF. Patients with permanent AF who underwent CABG or cardiac valve surgery were also included as positive controls. Plasma samples were collected at baseline and 24 hours after surgery, to assess the impact of surgery. To detect endothelial activation, vascular cell adhesion protein-1 (VCAM-1 (CD106)) was evaluated by ELISA assay in plasma samples. Expression of connexin 40 and 43 were measured by inmunohistochemistry in atrial tissue samples.

Results

We included 117 patients (75.2% males, median age 67 [IQR 59.5–73.0] years), of whom17 (14.5%) patients had permanent AF; 27 (23.1%) developed POAF and 73 (62.4%) had no AF detected.

We found higher baseline VCAM-1 levels versus 24-hour samples overall (p=0.001). When comparing groups, baseline VCAM-1 levels were higher in patients with permanent AF compared to non-AF (p=0.035); and in permanent AF compared to POAF (p=0.049). VCAM-1 levels at 24h followed the same trends between permanent AF and non-AF (p=0.001), and permanent AF versus POAF (p=0.013) (Table 1). VCAM-1 levels over the third tertile (i.e.>49.77 ng/ml) increased the risk of AF almost 3-fold (OR 2.85, 95% CI 1.06–7.70; p=0.039). There was a significant decrease in the expression of connexion 40 in patients with AF (ie. patients with permanent AF or POAF) compared to non-AF patients (1.00 [0.50–2.31] vs. 2.48 [1.94–3.00], p=0.044), while connexin 43 was non-significantly different (1.07 [0.41–1.75] vs. 2.00 [0.63–2.25], p=0.289) (Table 2).

Conclusions

VCAM-1 levels were upregulated in patients with permanent AF and POAF compared to patients without AF, and remained higher even after surgery, thus demonstrating a relevantendothelial activation. The pro-inflammatory state presented in these patients with AF, along with decreased connexin 40 expression impacting cell-to-cell conduction, suggests a potential combination for atrial remodelling and incident AF.

Funding Acknowledgement

Type of funding sources: None.

Assessment and Mitigation of Bleeding Risk in Atrial Fibrillation and Venous Thromboembolism: Executive Summary of a European and Asia-Pacific Expert Consensus Paper

While there is a clear clinical benefit of oral anticoagulation in patients with atrial fibrillation (AF) and venous thromboembolism (VTE) in reducing the risks of thromboembolism, major bleeding events (especially intracranial bleeds) may still occur and be devastating. The decision for initiating and continuing anticoagulation is often based on a careful assessment of both thromboembolism and bleeding risk. The more common and validated bleeding risk factors have been used to formulate bleeding risk stratification scores, but thromboembolism and bleeding risk factors often overlap. Also, many factors that increase bleeding risk are transient and modifiable, such as variable international normalized ratio values, surgical procedures, vascular procedures, or drug-drug and food-drug interactions. Bleeding risk is also not a static "one-off" assessment based on baseline factors but is dynamic, being influenced by aging, incident comorbidities, and drug therapies. In this executive summary of a European and Asia-Pacific Expert Consensus Paper, we comprehensively review the published evidence and propose a consensus on bleeding risk assessments in patients with AF and VTE, with a view to summarizing "best practice" when approaching antithrombotic therapy in these patients. We address the epidemiology and size of the problem of bleeding risk in AF and VTE, and review established bleeding risk factors and summarize definitions of bleeding. Patient values and preferences, balancing the risk of bleeding against thromboembolism, are reviewed, and the prognostic implications of bleeding are discussed. We propose consensus statements that may help to define evidence gaps and assist in everyday clinical practice.

Assessment and mitigation of bleeding risk in atrial fibrillation and venous thromboembolism: A Position Paper from the ESC Working Group on Thrombosis, in collaboration with the European Heart Rhythm Association, the Association for Acute CardioVascular Care and the Asia-Pacific Heart Rhythm Society

Whilst there is a clear clinical benefit of oral anticoagulation (OAC) in patients with atrial fibrillation (AF) and venous thromboembolism (VTE) in reducing the risks of thromboembolism, major bleeding events (especially intracranial bleeds) may still occur and be devastating. The decision to initiate and continue anticoagulation is often based on a careful assessment of both the thromboembolism and bleeding risk. The more common and validated bleeding risk factors have been used to formulate bleeding risk stratification scores, but thromboembolism and bleeding risk factors often overlap. Also, many factors that increase bleeding risk are transient and modifiable, such as variable international normalized ratio values, surgical procedures, vascular procedures, or drug-drug and food-drug interactions. Bleeding risk is also not a static 'one off' assessment based on baseline factors but is dynamic, being influenced by ageing, incident comorbidities, and drug therapies. In this Consensus Document, we comprehensively review the published evidence and propose a consensus on bleeding risk assessments in patients with AF and VTE, with the view to summarizing 'best practice' when approaching antithrombotic therapy in these patients. We address the epidemiology and size of the problem of bleeding risk in AF and VTE, review established bleeding risk factors, and summarize definitions of bleeding. Patient values and preferences, balancing the risk of bleeding against thromboembolism are reviewed, and the prognostic implications of bleeding are discussed. We propose consensus statements that may help to define evidence gaps and assist in everyday clinical practice.

Predictors of adverse clinical outcomes in atrial fibrillation patients with concomitant renal impairment under rivaroxaban therapy

Background

Atrial fibrillation (AF) increases the risk of stroke and mortality, and concomitant renal impairment confers a worse prognosis. However, those factors that may limit the use of direct-acting oral anticoagulants in AF patients with renal impairment have not been further investigated, as they confer a higher risk of adverse events in this patient population.

Purpose

To investigate predictors of adverse clinical outcomes in AF patients with renal impairment who were treated with rivaroxaban.

Methods

The EMIR study is an observational, multicenter study including patients with AF treated with rivaroxaban for at least the previous 6 months. During 2.5 years of follow-up, the occurrence of thromboembolic events (the composite of isquemic stroke, transient ischemic attack, systemic embolism and myocardial infarction [MI]), major bleeding (ISTH definition) and major adverse cardiovascular events (MACE: fatal/non-fatal MI, myocardial revascularization and cardiovascular death) were recorded. For the present analysis, creatinine clearance (CrCl) was estimated by using the Cockroft-Gault equation and renal impairment was defined as a CrCl <60 mL/min.

Results

1433 patients were included (44.5% female; mean age 74.2±9.7 years), of which 498 (35.1%) had CrCl <60 mL/min. The mean CHA2DS2-VASc and HAS-BLED were 3.5±1.5 and 1.6±1.0, respectively. During the follow-up, 7 (1.4%) patients with CrCl <60 mL/min suffered a thromboembolic event, 16 (3.2%) suffered major bleeding, and 19 (3.8%) suffered a MACE. Compared to patients with normal renal function, patients with CrCl <60 mL/min showed a higher annual rate of major bleeding (0.62%/year vs. 1.87%/year; p=0.003) and MACE (0.62%/year vs. 1.97%/year; p=0.002). Multivariate analyses demonstrated that the CHA2DS2-VASc score (OR 1.84; 95% CI 1.11–3.07) was associated with a higher risk of thromboembolic events; whereas the HAS-BLED score (OR 2.25; 95% CI 1.41–3.59) and any dependency level (OR 3.42; 95% CI 1.17–9.98) were associated with a higher risk of major bleeding; and male sex (OR 3.55; 95% CI 1.08–11.63) and heart failure (OR 4.67; 95% CI 1.62–13.51) with a higher risk of MACE. The use of antiplatelet agents was also independently associated with an increased risk of thromboembolic events and MACE (OR 12.28; 95% CI 2.50–60.18; and OR 8.72; 95% CI 2.86–26.59; respectively).

Conclusions

Rivaroxaban showed excellent results in moderate renal impairment. However, the annual rate of major bleeding and MACE was higher in AF patients with impaired renal function. In patients with AF and renal impairment, male sex, the presence of heart failure, dependency, the concomitant use of antiplatelets, and greater comorbidity according to the CHA2DS2-VASc and HAS-BLED, were associated with higher risk of adverse clinical outcomes.

Funding Acknowledgement

Type of funding sources: Private company. Main funding source(s): Bayer

Oral anticoagulation therapy with rivaroxaban in elderly patients with atrial fibrillation. Results from EMIR study

Background

Atrial fibrillation (AF) in elderly patients increases both bleeding and thromboembolic risks. Elderly patients benefit as much from anticoagulation therapy with positive net clinical benefit. However, there have been few studies that focused on the efficacy and safety of direct oral anticoagulants in elderly patients.

The aim of this subanalysis from EMIR study was to assess the effectiveness of rivaroxaban in patients older than 75 years old.

Methods

EMIR Study (acronym from 'Estudio observacional para la identificaciόn de los factores de riesgo asociados a eventos cardiovasculares Mayores en pacientes con fIbrilaciόn auricular no valvular tratados con un anticoagulante oral directo (Rivaroxaban)') was an observational, multicenter, post-authorization and prospective study that involved AF patients under oral anticoagulation with rivaroxaban at least 6 months before enrolment. We analyzed baseline clinical characteristics and adverse events after 2.5 years of follow up.

Results

We analyzed 1,433 patients with median age of 74.7 (67.7–81.6). Of them 691 (48.2%) were ≥75 years. Elderly patients had higher prevalence of cardiovascular risk factors such previous stroke (16.8% vs 8.5%; p<0.001), heart failure (25.0% vs 20.6%; p<0.001), higher CHA2DS2-VASc (4.4±1.3 vs 2.7±1.2; p<0.001) and HAS-BLED (1.9±1.0 vs 1.2±1.0; p<0.001) scores. After 2.5 (2.2–2.6) years of follow-up, we observed low rate of adverse events in patients under rivaroxaban therapy. We observed higher rate of adverse events in elderly population for thromboembolic events (1.13%/year vs 0.36%/year; p=0.017) and major bleeding events (1.80%/year vs 0.36%/year; p<0.001) but those adverse rates were lower than expected according to previous studies (i.e. ROCKET-AF trial, rivaroxaban group had 4.86%/year of major bleeding or in XANTUS study was 3.2%/year of major bleeding in patients >75 years). We did not observe differences between groups from MACE (1.13%/year vs 1.01%/year; p=0.875) or cardiovascular death (0.86%/year vs 0.42%/year; p=0.170).

Conclusion

In real-world elderly population, rivaroxaban showed higher rates of thromboembolic and major bleeding events in elderly patients but with annual rates lower than expected according to previous studies like ROCKET-AF or XANTUS. Similar annual rates in elderly were observed for MACE and cardiovascular mortality than in younger patients, being rivaroxaban a good therapeutic alternative even for the elderly.

Funding Acknowledgement

Type of funding sources: Private grant(s) and/or Sponsorship. Main funding source(s): Bayer Hispania S.L.

Stroke risk based on classification of atrial fibrillation: real-world vs clinical trial

Background

The most widely accepted clinical classification of atrial fibrillation (AF) is according to temporal rhythm-based patterns, reflecting the notion that most patients initially suffer from transient episodes that prolong over time due to atrial substrate remodelling as the disease progresses. Therefore, it may be speculated that patients with extended episodes of “continuous” AF (persistent, long-standing persistent and permanent AF) may be at higher risk of stroke complications compared to paroxysmal AF (pAF). However, the risk of stroke according to clinical classification of AF remains poorly defined. In this study, we assessed the impact of AF type on stroke risk in patients with AF from “real-world” and “clinical trial” cohorts.

Methods

Post-hoc analysis of patient-level data from the Murcia AF Project and AMADEUS trial. All patients were anticoagulated. Patients were grouped into those with pAF and non-pAF. pAF was defined as AF that terminates spontaneously or with intervention within seven days of onset. Non-pAF was defined as AF that lasted longer than seven days, including persistent, long-standing persistent and permanent AF subtypes. Study endpoint was the incidence rate of ischaemic stroke. A modified CHA2DS2-VAS“c” score that applied one additional point for a “c” criterion of continuous AF (i.e. non-pAF) was calculated.

Results

5,917 patients were included; 1,361 (23.0%) real-world and 4,556 (77.0%) clinical trial. Real-world patients had a median age of 76 (interquartile range [IQR] 71–81) years with 51.3% females compared to a median age of 71 (IQR 64–77) years with 33.5% females among clinical trial participants. Baseline demographics were comparable in both groups in the real-world cohort but clinical trial participants with non-pAF were older, predominantly male and had more comorbidities compared to those with pAF.

Crude stroke rates were comparable between the groups in real-world patients (incidence rate ratio [IRR] 0.72 [95% CI, 0.37–1.28], p=0.259) though clinical trial participants with non-pAF (vs. pAF) had a significantly higher crude rate of stroke events (IRR 4.66 [95% CI, 2.41–9.48], p<0.001). Using multivariable cox regression analysis, AF type was not independently associated with stroke risk in the real-world (adjusted hazard ratio [HR] 1.41 [95% CI, 0.80–2.50], p=0.239) and clinical trial (adjusted HR 1.17 [95% CI, 0.62–2.20], p=0.621) cohorts, after accounting for known risk factors using the CHA2DS2-VASc score. Using receiver operating characteristic curves analysis, we found no significant improvement in the CHA2DS2-VAS“c” compared to CHA2DS2-VASc score in either cohort (p>0.05).

Conclusion

Overall, there was no association between the temporal rhythm-based patterns of AF and stroke risk among anticoagulated patients, suggesting that this should not be a consideration when assessing the need for anticoagulation in AF.

Funding Acknowledgement

Type of funding sources: None.

Novel tool for predicting residual stroke risk in atrial fibrillation: mCARS

Funding Acknowledgements

Type of funding sources: None.

Background

Recently, CARS was proposed to predict 1-year absolute stroke risk in non-anticoagulated patients with atrial fibrillation (AF). We aimed to determine whether a modified CARS (mCARS) may be used to assess the residual stroke risk in anticoagulated AF patients.

Methods

We studied patient-level data of anticoagulated AF patients from the real-world Murcia AF Project and AMADEUS clinical trial. Individual mCARS was estimated for each patient using an estimated 64% risk reduction with anticoagulation.

Results

3,503 patients were included (2,205 [62.9%] clinical trial and 1,298 [37.1%] real-world). In the clinical trial cohort, the median age was 71 (IQR 65-77) and CHA2DS2-VASc score 3 (IQR 2-4). In the real-world cohort, the median age was 76 (IQR 70-81) and CHA2DS2-VASc score 4 (IQR 3-5).

At 1-year, there were 40 and 31 stroke events in the clinical trial and real-world cohorts, respectively. Average predicted residual stroke risk by mCARS was identical to actual stroke risk (1.8 [±1.8%] vs. 1.8% [95% CI, 1.3-2.4]) in the clinical trial, and broadly similar in the real-world (2.1 [±1.9%] vs. 2.4% [95% CI, 1.6-3.4]). Additionally, these values were comparable across the subgroups stratified by CHA2DS2-VASc score in both cohorts.

AUCs of mCARS for prediction of stroke events in the clinical trial and real-world were 0.678 (95% CI, 0.598-0.758) and 0.712 (95% CI, 0.618-0.805), respectively. In an exploratory analysis, we found that mCARS was able to refine stroke risk estimation for each point of the CHA2DS2-VASc score in both cohorts.

Conclusion

Personalised residual 1-year absolute stroke risk in anticoagulated AF patients may be estimated using mCARS. Such patients with high residual stroke risk may benefit from more aggressive interventions and follow-up. Absolute 1-year stroke risk Clinical Trial Real-World Median (IQR) Range Median (IQR) Range CHA2DS2-VASc score 0 NA 0.9 (0.6 - 1.3) 0.2 - 1.4 CHA2DS2-VASc score 1 1.1 (0.7 - 1.4) 0.2 - 2.0 1.4 (0.9 - 1.7) 0.2 - 13.0 CHA2DS2-VASc score 2 2.0 (1.5 - 2.4) 0.3 - 10.8 2.1 (1.5 - 2.6) 0.3 - 10.8 CHA2DS2-VASc score 3 2.6 (2.1 - 3.4) 0.4 - 13.3 2.8 (2.5 - 3.4) 0.9 - 13.3 CHA2DS2-VASc score 4 3.6 (2.8 - 5.6) 0.3 - 18.1 3.9 (3.3 - 5.0) 1.1 - 21.0 CHA2DS2-VASc score 5 6.7 (3.6 - 14.0) 1.9 - 20.9 4.8 (3.9 - 12.2) 1.2 - 21.0 CHA2DS2-VASc score 6 13.6 (5.5 - 15.8) 2.4 - 21.8 12.8 (4.8 - 16.7) 2.2 - 21.8 CHA2DS2-VASc score 7 15.7 (14.5 - 17.4) 4.5 - 21.9 15.6 (5.9 - 17.5) 4.1 - 23.5 CHA2DS2-VASc score 8 16.5 (14.0 - 18.5) 13.1 - 20.3 16.9 (15.7 - 19.5) 13.6 - 21.0 IQR, interquartile range; NA, not applicable.

Relationship of particular matter and temperature on the risk of adverse events in atrial fibrillation patients

Background

Ambient particulate matter (PM), is a principal component of air pollutant and the main culprit of the adverse effects of air pollution on humans' health. In particular, PM with aerodynamic diameter <10 μm (PM10) has been shown to be associated with worse clinical outcomes. Similarly, cardiovascular risk increases during colder temperatures/seasons. Thus, both, air pollution and temperature fluctuations are examples confirming how the climate change is affecting our health. However, our knowledge about the impact of air pollution and temperature in anticoagulated atrial fibrillation (AF) patients is scarce.

Purpose

Herein, we investigated if PM10 and temperature are associated with an increased risk of adverse clinical outcomes in patients with AF taking vitamin K antagonists (VKAs).

Methods

We included AF patients who were stable on VKAs (INR 2.0–3.0) for 6 months in a tertiary hospital (Murcia, South-east Spain). During a median follow-up of 6.5 (IQR 4.3–7.9) years, ischemic strokes, major bleeds, adverse cardiovascular events, and mortality were recorded. From 2007–2016, data on average temperature and PM10 (PM with aerodynamic diameter <10 μm) were obtained and related to clinical outcomes.

Results

1361 patients (48.7% male; median age 76, IQR 71–81 years) were included. High PM10 and low temperatures were associated with higher risk of major bleeding (adjusted Hazard Ratio, aHR 1.44, 95% CI 1.22–1.70 and aHR 1.03, 95% CI 1.01–1.05) and mortality (aHR 1.50, 95% CI 1.34–1.69 and aHR 1.04, 95% CI 1.02–1.06) (Table 1). PM10 was also significantly associated with ischemic stroke and temperature with cardiovascular events. The relative risk for cardiovascular events and mortality increased in months in the lower quartile (Q1) of temperature (<12.74°C) (RR 1.12, 95% CI 1.04–1.21 and RR 1.41, 95% CI 1.15–1.74; respectively). Comparing seasons, there were higher risks of cardiovascular events in spring, autumn, and winter than in summer, whereas the risk of mortality increased only in winter.

Conclusions

In AF patients taking VKAs highPM10 and low temperature were associated with an increased the risk of ischemic stroke and cardiovascular events, respectively. Both factors increased major bleeding and mortality risks, which were higher during colder months and seasons.

Table 1. Univariate and Multivariate Cox

Funding Acknowledgement

Type of funding source: None

P4800Estimated effect of NOACs compared to Vitamin K Antagonists in real-world atrial fibrillation patients: Data from FANTASIA Registry

Background

Despite of the effectiveness and safety profile of Non-vitamin K Antagonists Oral Anticoagulants (NOACs) even in real-world (RW) Atrial Fibrillation (AF) patients, Vitamin K Antagonists (VKAs) have remained widely used in clinical practice worldwide but the comparison with acenocoumarol therapy in RW is unknown.

Purpose

To estimate the potential absolute benefit in clinical adverse events if the AF patients anticoagulated with VKA therapy had been treated with NOACs.

Methods

We analyzed anticoagulated AF patients who were prospectively recruited into the multicentre FANTASIIA registry. Patients were treated with VKAs for at least 6 months prior to inclusion. The estimation of clinical adverse events avoided was calculated applying absolute risk reductions, relative risk reductions and hazard ratios from the meta-analysis of RW use of NOACs relative to VKAs.

Results

We analyzed 1,470 patients under VKA therapy (mean age 74.1±9.5 years; 56.4% male). Stroke rate with acenocoumarol treatment was 0.88%/year. The estimated rates for stroke using NOACs would be 0.80%/year for Dabigatran 150 mg; 0.76%/year for Rivaroxaban and 0.74%/year for Apixaban instead of VKA. No significant differences were observed between the different NOACs and VKA in stroke rate. Major bleeding with acenocoumarol was 3.40%/year. The estimated rates for major bleeding using NOACs would be 2.75%/year for Dabigatran 150 mg; 3.37%/year for Rivaroxaban and 2.18%/year for Apixaban instead of VKA. Apixaban was the only NOAC that showed a significant estimated reduction rates (p=0.046). Finally, the all-cause mortality rate with acenocoumarol was 4.69%/year. The estimated rates of all-cause mortality using NOACs would be 3.28%/year for Dabigatran 150mg; 4.88%/year for Rivaroxaban and 2.67%/year for Apixaban. Dabigatran and Apixaban showed significant estimated reduction rates with the highest reduction with Apixaban (Table).

Annual Rate reduction of adverse events

Conclusion

The absolute estimated effect of NOACs in the AF patients anticoagulated with VKA showed a significant reduction in adverse clinical events. Apixaban performed the highest estimated reduction in major bleeding and all-cause mortality in comparison with acenocoumarol.

Effect of CYP4F2, VKORC1, and CYP2C9 in Influencing Coumarin Dose: A Single-Patient Data Meta-Analysis in More Than 15,000 Individuals

The cytochrome P450 (CYP)4F2 gene is known to influence mean coumarin dose. The aim of the present study was to undertake a meta-analysis at the individual patients level to capture the possible effect of ethnicity, gene-gene interaction, or other drugs on the association and to verify if inclusion of CYP4F2*3 variant into dosing algorithms improves the prediction of mean coumarin dose. We asked the authors of our previous meta-analysis (30 articles) and of 38 new articles retrieved by a systematic review to send us individual patients' data. The final collection consists of 15,754 patients split into a derivation and validation cohort. The CYP4F2*3 polymorphism was consistently associated with an increase in mean coumarin dose (+9% (95% confidence interval (CI) 7-10%), with a higher effect in women, in patients taking acenocoumarol, and in white patients. The inclusion of the CYP4F2*3 in dosing algorithms slightly improved the prediction of stable coumarin dose. New pharmacogenetic equations potentially useful for clinical practice were derived.

Comparison of bleeding risk scores in patients with atrial fibrillation: insights from the RE-LY trial

BACKGROUND

Oral anticoagulation is the mainstay of stroke prevention in atrial fibrillation (AF), but must be balanced against the associated bleeding risk. Several risk scores have been proposed for prediction of bleeding events in patients with AF.

OBJECTIVES

To compare the performance of contemporary clinical bleeding risk scores in 18 113 patients with AF randomized to dabigatran 110 mg, 150 mg or warfarin in the RE-LY trial.

METHODS

HAS-BLED, ORBIT, ATRIA and HEMORR₂ HAGES bleeding risk scores were calculated based on clinical information at baseline. All major bleeding events were centrally adjudicated.

RESULTS

There were 1182 (6.5%) major bleeding events during a median follow-up of 2.0 years. For all the four schemes, high-risk subgroups had higher risk of major bleeding (all P < 0.001). The ORBIT score showed the best discrimination with c-indices of 0.66, 0.66 and 0.62, respectively, for major, life-threatening and intracranial bleeding, which were significantly better than for the HAS-BLED score (difference in c-indices: 0.050, 0.053 and 0.048, respectively, all P < 0.05). The ORBIT score also showed the best calibration compared with previous data. Significant treatment interactions between the bleeding scores and the risk of major bleeding with dabigatran 150 mg BD versus warfarin were found for the ORBIT (P = 0.0019), ATRIA (P < 0.001) and HEMORR₂ HAGES (P < 0.001) scores. HAS-BLED score showed a nonsignificant trend for interaction (P = 0.0607).

CONCLUSIONS

Amongst the current clinical bleeding risk scores, the ORBIT score demonstrated the best discrimination and calibration. All the scores demonstrated, to a variable extent, an interaction with bleeding risk associated with dabigatran or warfarin.

Cessation of oral anticoagulation in relation to mortality and the risk of thrombotic events in patients with atrial fibrillation

Bleeding risk (often perceived, rather than actual) is a common reason for cessation of oral anticoagulation with Vitamin K antagonists (VKA). We investigate clinical outcomes in a consecutive population of VKA naïve atrial fibrillation (AF) patients, who initiated VKA therapy in our clinic. We included consecutive VKA-naíve patients with non valvular AF, initiated on VKA therapy in our anticoagulation outpatient clinic in 2009. During follow-up, adverse events [thrombotic/vascular events (stroke, acute coronary syndrome, acute heart failure and cardiac death), major bleeding and death], and VKA cessation were recorded. At the end of the follow-up, we determined time within therapeutic range (TTR), using a linear approximation (Rosendaal method). We studied 529 patients (49% male, median age 76), median follow-up 835 days (IQR 719−954). During this period 114 patients stopped VKA treatment. 63 patients suffered a thrombotic/cardiovascular event (5.17%/year, 27 thrombotic/ischaemic strokes), 51 major bleeding (4.19%/year) and 48 died (3.94%/year). Median TTR was 54% (34a57). On multivariate analysis (adjusted by CHA2DS2-VASc score), VKA cessation was associated with death [Hazard Ratio (HR) 3.43; p<0.001], stroke [4.21; p=0.001] and thrombotic/cardiovascular events [2.72; p<0.001]. Independent risk factors for major bleeding were age [1.08; p<0.001], previous stroke [1.85; p=0.049], and TTR [0.97; p=0.001], but not VKA cessation. In conclusion, in AF patients AF, VKA cessation is independently associated with mortality stroke and cardiovascular events. Specifically, VKA cessation independently increased the risk of stroke, even after adjusting for CHA2DS2-VASc score. TTR was an independent risk factor for major bleeding following initiation of VKA therapy.

Note: The editorial process for this paper was fully handled by Prof Christian Weber, Editor in Chief.

Von Willebrand factor is associated with atrial fibrillation development in ischaemic patients after cardiac surgery

AIMS

Atrial fibrillation (AF) is associated with an increased morbidity and mortality after cardiac surgery. Von Willebrand factor (vWF) has been proposed as a biomarker of endothelial damage/dysfunction. We hypothesized that vWF levels could be used as valuable biomarker for AF occurrence after cardiac surgery. Moreover, we explored the potential association between vWF and tissue remodelling as possible implication in post-surgical AF.

METHODS AND RESULTS

We prospectively recruited 100 consecutive patients who undergoing programmed cardiac surgery with cardiopulmonary bypass and with no previous history of AF. Plasma vWF levels were determined from citrated plasma samples. Right atrial appendage tissue was obtained during cardiac surgery, and vWF expression as well as interstitial fibrosis was analysed by immunostaining and Masson's trichrome, respectively. We found raised vWF plasma levels in ischaemic vs. valvular patients (200.2 ± 66.3 vs. 157.2 ± 84.3 IU/dL; P = 0.015). Fibrosis degree was associated with plasma vWF levels. Plasma vWF was an independent prognostic marker for AF development in ischaemic patients [odds ratio, OR 6.44 (95% confidence interval, CI 1.40-36.57), P = 0.035].

CONCLUSION

Plasma vWF levels are associated with tissue fibrosis in patients undergoing cardiac surgery and with post-surgical AF development in ischaemic patients. These findings suggest an association among vWF levels, atrial remodelling, and AF development. It is supported by higher vWF expression in right atrial tissue in ischaemic patients, who developed post-surgical AF.

Effect of VKORC1, CYP2C9 and CYP4F2 genetic variants in early outcomes during acenocoumarol treatment

Aim: To analyze VKORC1, CYP2C9 and CYP4F2 polymorphisms in relation to the main outcomes in the first stages of acenocoumarol therapy. Patients & methods: Nine hundred and forty one patients who had started therapy and in whom time to stable dosage, time to over-anticoagulation and adverse events occurred during 3 first months were retrospectively analyzed. Results: VKORC1 AA patients needed fewer days to reach stable dosage (p = 0.017). International normalized ratio [INR] at 72 h, and VKORC1 and CYP2C9 genotypes conditioned INR values >2.5 (p < 0.001, p = 0.002 and p < 0.001, respectively), whereas CYP4F2 T carriers had a low risk of the same outcome (p = 0.009). In regards to combined genotypes, CYP4F2 had a significant effect on over-anticoagulation at the beginning of therapy except for the VKORC1 AA and CYP2C9*3 combination. Conclusion: In addition to VKORC1 and CYP2C9, CYP4F2 gene has a slight but significant role in reaching INR >2.5 during the first weeks of acenocoumarol therapy.

Original submitted 22 July 2013; Revision submitted 14 November 2013

Conventional and new oral anticoagulants in the treatment of chest disease and its complications

Oral anticoagulants block the coagulation cascade either by an indirect mechanism (e.g., vitamin K antagonists) or by a direct one (e.g., the novel oral anticoagulants). Vitamin K antagonists are widely used as treatment of venous thromboembolism and for stroke prevention in patients with atrial fibrillation. Although low molecular weight heparin remains the first line in venous thromboembolism prophylaxis, more recently the novel oral anticoagulants such as dabigatran (initial dose of 110 mg within 1-4 h after surgery, followed by the full dose of 220 mg once daily), rivaroxaban (dose of 10 mg once daily, with the first dose administered 6-10 h after the surgery), and apixaban (dose of 2.5 mg twice daily, starting 12-24 h after surgery, but available only in Europe) are approved for prophylaxis in patients undergoing major orthopedic surgery. The period in which thromboembolic risk abates remains uncertain, and trials of extended therapy are still ongoing. After showing at least noninferiority to warfarin in RE-LY, ROCKET-AF, and ARISTOTLE trials, dabigatran (110 or 150 mg twice daily), rivaroxaban (20 or 15 mg once daily), and apixaban (5 mg twice daily), respectively, were approved also for stroke prevention in patients with atrial fibrillation. While awaiting long-term safety data, the choice among all these available therapies should be based on patient preferences, compliance, and ease of administration, as well as on local factors affecting cost-effectiveness.

Novel associations of VKORC1 variants with higher acenocoumarol requirements

BACKGROUND

Algorithms combining both clinical and genetic data have been developed to improve oral anticoagulant therapy. Three polymorphisms in two genes, VKORC1 and CYP2C9, are the main coumarin dose determinants and no additional polymorphisms of any relevant pharmacogenetic importance have been identified.

OBJECTIVES

To identify new genetic variations in VKORC1 with relevance for oral anticoagulant therapy.

METHODS AND RESULTS

3949 consecutive patients taking acenocoumarol were genotyped for the VKORC1 rs9923231 and CY2C9* polymorphisms. Of these, 145 patients with a dose outside the expected range for the genetic profile determined by these polymorphisms were selected. Clinical factors explained the phenotype in 88 patients. In the remaining 57 patients, all with higher doses than expected, we sequenced the VKORC1 gene and genetic changes were identified in 14 patients. Four patients carried VKORC1 variants previously related to high coumarin doses (L128R, N = 1 and D36Y, N = 3).Three polymorphisms were also detected: rs17878544 (N = 5), rs55894764 (N = 4) and rs7200749 (N = 2) which was in linkage disequilibrium with rs17878544. Finally, 2 patients had lost the rs9923231/rs9934438 linkage. The prevalence of these variations was higher in these patients than in the whole sample. Multivariate linear regression analysis revealed that only D36Y and rs55894764 variants significantly affect the dose, although the improvement in the prediction model is small (from 39% to 40%).

CONCLUSION

Our strategy identified novel associations of VKORC1 variants with higher acenocoumarol doses albeit with a low effect size. Further studies are necessary to test their influence on the VKORC1 function and the cost/benefit of their inclusion in pharmacogenetic algorithms.

Peri-operative management of ophthalmic patients taking antithrombotic therapy

Increasing number of patients presenting for ophthalmic surgery are using oral anti-coagulant and anti-platelet therapy. The current practice of discontinuing these drugs preoperatively because of a presumed increased risk of bleeding may not be evidence-based and could pose a significant risk to the patient's health. To provide an evidence-based review on the peri-operative management of ophthalmic patients who are taking anti-thrombotic therapy. In addition, we briefly discuss the underlying conditions that necessitate the use of these drugs as well as management of the operative field in anti-coagulated patients. A semi-systematic review of literature was performed. The databases searched included MEDLINE, EMBASE, database of abstracts of reviews of effects (DARE), Cochrane controlled trial register and Cochrane systematic reviews. In addition, the bibliographies of the included papers were also scanned for evidence. The published data suggests that aspirin did not appear to increase the risk of serious postoperative bleeding in any type of ophthalmic surgery. Topical, sub-tenon, peri-bulbar and retrobulbar anaesthesia appear to be safe in patients on anti-thrombotic (warfarin and aspirin) therapy. Warfarin does not increase the risk of significant bleeding in most types of ophthalmic surgery when the INR was within the therapeutic range. Current evidence supports the continued use of aspirin and with some exceptions, warfarin in the peri-operative period. The risk of thrombosis-related complications on disruption of anticoagulation may be higher than the risk of significant bleeding by continuing its use for most types of ophthalmic surgery.

Predictive value for thrombosis of pre-chemotherapy D-Dimer in ambulatory cancer patients

e20601

Background: Elevated D-Dimer (DD) is related with activated coagulation system. We pretended to assess if high DD is predictive of thrombosis in ambulatory cancer patients. Methods: We prospectively determined DD in plasma specimens from ambulatory cancer patients, without previous thromboembolic events (TE), before chemotherapy initiation. DD was determined with an immunological test in an automated coagulometer (IL D-Dimer test, Instrumentations laboratory). The selected cut-off point for DD was 1.5 x UNL, as it was the nearest point to the median DD. All thromboembolic events were recorded. Results: Between June 2007 and December 2008 eighty four patients were included, 66% with advanced and 34% with early disease. The most frequent tumours were colorectal 31%, breast 27% and genitourinary cancers 30% (12% HR prostate and 28% non prostate cancers). Antiangiogenic drugs were included in 24% of treatments (16% Bevacizumab and 8% Sunitinib). Median ECOG was 1. With a median follow-up of 6.5 months, 12 thromboembolic events were observed (5 PE, 3 DVT and 4 Arterial thrombosis). The following variables were included in the univariate analysis: high DD (>1.5 x UNL), low haemoglobin (Hb <10 mg/dL), high leukocyte, high platelet, high BMI and tumour location. High DD (HR = 6,25, 95% CI: 1,34–29,25; p= 0,02) and low Hb (HR= 6,17, 95% CI: 1,77- 21,53; p=0,004) were associated with increased TE. The high risk group in the Khorana index was also significant (p=0.02). In multivariate analysis both high DD (HR= 5,06, 95%CI: 1,05–24,48; p=0,044) and low Hb (HR=3,77, 95%CI: 1,02–13,97; p=0,047) remained significant. Conclusions: High pre-chemotherapy DD is associated with increased risk of thrombosis in ambulatory cancer patients.

No significant financial relationships to disclose.

Antithrombin Cambridge II (A384S): an underestimated genetic risk factor for venous thrombosis

The antithrombin A384S mutation has a relatively high frequency in the British population but has not been identified in other populations. This variant has been associated with cases of thrombotic disease, but its clinical relevance in venous thrombosis remained unclear. We have conducted a secondary analysis of the prevalence of the mutation in a large case-control study, including 1018 consecutive Spanish patients with venous thromboembolism. In addition, we evaluated its functional consequences in 20 carriers (4 homozygous). This mutation, even in the homozygous state, did not affect anti-Xa activity or antigen levels, and it only slightly impaired anti-IIa activity. Thus, routine clinical methods cannot detect this anomaly, and, accordingly, this alteration could have been underestimated. We identified this mutation in 0.2% of Spanish controls. Among patients, this variant represented the first cause of antithrombin anomalies. Indeed, 1.7% patients carried the A384S mutation, but 0.6% had any other antithrombin deficiency. The mutated allele was associated with an increased risk of venous thrombosis with an adjusted OR of 9.75 (95% CI, 2.2-42.5). This is the first study supporting that antithrombin A384S mutation is a prevalent genetic risk factor for venous thrombosis and is the most frequent cause of antithrombin deficiency in white populations.

Short-term effect of miglustat in every day clinical use in treatment-naïve or previously treated patients with type 1 Gaucher's disease

In a prospective, open-label study, 25 patients with mild-to-moderate type 1 Gaucher's disease (GD1) were treated with miglustat (Zavesca), an oral glucosylceramide synthase inhibitor, over 12 months. Of the 25 patients, 10 were therapy-naïve and 15 had previously received enzyme replacement therapy (ERT). Clinical status, blood parameters, biomarkers, and organomegaly were assessed at baseline at 6 months and at 12 months. At 6 months the previously untreated patients showed a mean increase in hemoglobin of 0.77 g/dL, platelet counts improved or remaining stable, chitotriosidase and CCL18 decreased. These results were similar to those observed in 40 Spanish GD1 patients on ERT. Bone marrow infiltration cleared at 12 months. In the previously treated group, clinical and hematologic parameters and biomarkers were maintained/ improved at 12 months. Miglustat was well tolerated. The efficacy of miglustat treatment after 6 months was comparable to that of ERT.