1208 FEASIBILITY OF A PHARMACIST-LED INTERVENTION FOR ATRIAL FIBRILLATION IN LONG-TERM CARE: THE PIVOTALL STUDY

Introduction

Older people in care homes with atrial fibrillation (AF) have complex health needs and would benefit from taking part in research. This study assessed the feasibility of pharmacist implementation of the Atrial Fibrillation Better Care (ABC: Anticoagulation; Better symptoms; Cardiovascular comorbidity management) pathway, and collection of an AF-specific, resident-centred outcome.

Methods

Older residents (aged ≥65 years) with AF were recruited from care homes within Liverpool and Sefton and randomised to receive the pharmacist intervention, or continue their existing treatment. Resident quality of life was assessed using the Atrial Fibrillation Effect on Quality of Life Questionnaire (AFEQT).

Results

Twenty-two care homes were approached about the study, and seven signed up to take part between 28 September 2020 and 29 April 2021. Time taken to recruit care homes ranged from 0 to 122 days. There were 83 residents identified as potentially eligible to take part, but after screening only 28 residents (34%) were invited. Overall, 21 residents were recruited. Eleven residents received the pharmacist intervention and three had ABC recommendations made to their GPs. Two out of four recommendations were implemented. The pharmacist administered the AFEQT questionnaire to 17 residents with capacity and completion rates were 94% and 93% at baseline and six-months, respectively. Residents found the questionnaire difficult; most were unable to distinguish if symptoms were AF-related (n=3), or did not know they had AF (n=8), and questions related to physical activity were not applicable to any of the residents who were bed bound (n=5) or had severely limited mobility (n=12).

Conclusion

There were procedural (encountered before research starts), system (encountered during research) and resident-specific barriers that impacted this study. Barriers need addressing before wider implementation, and AF-specific quality of life measures need to be developed and validated for care home residents. A detailed commentary has been submitted for publication.

Stop and Go: Barriers and Facilitators to Care Home Research

Barriers to care home research have always existed, but have been thrown into sharp relief by the COVID-19 pandemic. Existing infrastructure failed to deliver the research, or outcomes, which care home residents deserved and we need to look, again, at how these barriers can be taken down. Barriers can be categorised as procedural (encountered before research starts), system (encountered during research) or resident-specific. To tackle these, research regulatory bodies need to adopt a standardised approach to how care home research is developed and designed, reviewed and regulated, and how such approaches can enable recruitment of as wide a range of residents and their representatives as possible, including those without the mental capacity to consent for research. Establishment of local, inter-disciplinary collaborations between universities, general practices, health and social care providers and care homes is another priority. This should be based on pre-existing models such as the 'Living lab' model developed in The Netherlands and now being implemented in the UK and Austria. These changes are critical to develop a sustainable research model. If well designed this will deliver better outcomes for residents and align with the individual and organisational priorities of those who care for them.

Management of atrial fibrillation by different medical specialties in the UK: AF-GEN-UK study

Background

The AF-GEN-UK study is an extension of the EURObservational Research Programme (EORP) Long-term Registry on patients with atrial fibrillation (AF) in the UK (AF-GEN). The study aimed to establish a registry of the contemporary management of patients with AF by cardiologists, general practitioners, stroke, acute and emergency medicine physicians at baseline and 1-year of follow-up, to allow comparison between medical specialties.

Methods

Data on patients with AF diagnosed within the previous 12-months were collected using electronic case records from 101 sites, to permit comparison of patient characteristics and treatments between medical specialties. The impact of guideline-adherent oral anticoagulation (OAC) use on outcomes was assessed using Cox regression analysis.

Results

1595 patients (mean (SD) age 70.5 (11.2) years; 60.1% male; 97.4% white) with ECG-documented AF were included (recruited between June 2017 and June 2018) and followed-up for 1-year. Overall OAC prescription rates were 84.2% at baseline and 87.1% at 1-year follow-up, with NOACs predominating (74.9% at baseline and 79.2% at 1-year) Figure, mainly apixaban. Prescription of VKA was significantly higher in primary care, with NOAC prescription higher among stroke physicians. Guideline-adherent OAC (CHA2DS2-VASc ≥2) at baseline significantly reduced risk of composite endpoint of death and stroke at 1-year (adjusted hazard ratio 0.42; 95% confidence intervals 0.25–0.70). Rhythm control was evident in approximately one-quarter, with only 1.6% receiving catheter ablation. Most patients (56.6%) reported AF symptoms, but these were severe in only 17.9%. Symptomatic patients were mainly managed by cardiologists or acute/emergency medicine; among patients managed by stroke physicians, 81.5% were asymptomatic. Quality of life did not appear significantly impaired however there was a slight but significant improvement at follow-up (70.3% vs. 71.5%; p=0.044). Symptomatic patients reported poorer quality of life related to usual activities, mental health and overall quality of life.

Conclusion

Overall OAC use was high (>80%) with NOAC prescription predominating but rates varied by specialty, with VKA prescription significantly higher in primary care. Guideline-adherent OAC therapy at baseline was associated with significant reduction in composite outcome of death and stroke at 1-year, regardless of specialty. Rhythm control management was only evident in around one-quarter despite AF symptoms being reported in 56.6%. This registry extends the knowledge of contemporary management of AF outside of cardiology by including other specialties and demonstrates good implementation of clinical guidelines for the management of AF, particularly in relation to stroke prevention.

Funding Acknowledgement

Type of funding sources: Private company. Main funding source(s): This project was supported by the BMS/Pfizer European Thrombosis Investigator Initiated Research Program

Anaemia and adverse outcomes in European patients with atrial fibrillation: a report from the ESC-EHRA EORP atrial fibrillation general long-term registry

Background

Anaemia is an independent predictor of atrial fibrillation (AF) and a common comorbidity. Real world data on the impact of anaemia on clinical outcomes, and on the benefits and risks of oral anticoagulation (OAC) are limited.

Purpose

To investigate the association of different degrees of anaemia with adverse outcomes in a cohort of European patients with AF.

Methods

We analyzed patients enrolled in the ESC-EHRA EORP-AF General Long-Term Registry with baseline hemoglobin (Hb) values. Patients were stratified according to World Health Organization (WHO) definition of anaemia: (i) No anaemia (Hb≥12.0g/dl for women and Hb≥13.0g/dl for men), Mild anaemia (Hb 11.0–11.9g/dl for women and Hb 11.0–12.9g/dl for men), and moderate-severe anaemia (Hb ≤10.9 g/dl for both sexes). Primary outcomes were all-cause death, major adverse cardiac events (MACE, as the composite of any thromboembolism (TE)/acute coronary syndrome/cardiovascular death) and major bleeding.

Results

From the original 11,096 AF patients enrolled in the Registry, 7767 (69.9%) were included in the present analysis (median age 70 years, interquartile range [IQR] 62–77, males 58.3%, CHA2DS2VASc score median 3 [2–4], HAS-BLED median 2 [1–2]). A total of 5973 (76.9%) patients did not have anaemia, 1156 (14.9%) had mild anaemia, and 638 (8.2%) had moderate/severe anaemia. Patients with anaemia were more likely to have more comorbidities, frailty, permanent AF and polypharmacy (≥5 drugs). Overall, 318 (18.4%) patients with anaemia and an indication for anticoagulation [i.e. CHA2DS2-VASc≥1 (males), or ≥2 (females)] did not receive any OAC. After a median (IQR) follow-up of 730 (692–749) days, all-cause death was 10.5% and there were 841 (11.6%) MACE and 186 (2.5%) major bleeds. Kaplan–Meier analysis showed a higher cumulative risk for patients with moderate-severe anaemia for all the outcomes considered (Figure) (Log Rank tests, all p<0.001). Adjusted Cox regression analyses revealed that patients with mild and moderate-severe anaemia had a higher risk for all-cause death (adjusted hazard ratio [aHR] 2.02, 95% confidence interval [CI] 1.71–2.40 and aHR 2.39, 95% CI 1.97–2.91, respectively), MACE (aHR 1.44, 95% CI 1.17–1.76 and aHR 1.64, 95% CI 1.30–2.07 respectively), and major bleeding (aHR 1.52, 05% CI 1.02–2.25 and aHR 3.73, 95% CI 2.59–5.37, respectively). Among patients with moderate-severe anaemia, use of OAC was associated with lower risk of all-cause mortality (HR 0.64, 95% CI 0.46–0.89) and MACE (HR 0.55, 95% CI 0.36–0.84), without a significant increased risk of major bleeding (HR 0.81, 95% CI 0.43–1.52).

Conclusions

In a large contemporary cohort of European AF patients, almost 25% have concomitant anaemia which is associated with an increased risk for all-cause mortality, MACE and major bleeding. Use of OAC was associated with a lower risk of all-cause mortality in patients with moderate-severe anaemia, without significant increased risk of major bleeding.

Funding Acknowledgement

Type of funding sources: Other. Main funding source(s): Since the start of EORP, the following companies have supported the programme: Abbott Vascular Int. (2011–2021), Amgen Cardiovascular (2009–2018), AstraZeneca (2014–2021), Bayer (2009–2018), Boehringer Ingelheim (2009–2019), Boston Scientific (2009–2012), The Bristol Myers Squibb and Pfizer Alliance (2011–2016), The Alliance Daiichi Sankyo Europe GmbH and Eli Lilly and Company (2011–2017), Edwards (2016–2019), Gedeon Richter Plc. (2014–2017), Menarini Int. Op. (2009–2012), MSD-Merck & Co. (2011–2014), Novartis Pharma AG (2014–2020), ResMed (2014–2016), Sanofi (2009–2011), SERVIER (2010–2021), and Vifor (2019–2022)

Factors associated with progression of atrial fibrillation and impact on all-cause mortality: an ancillary analysis from the ESC-EHRA EURObservational Research Programme in Atrial Fibrillation General

Background

Paroxysmal atrial fibrillation (AF) often shows a natural progression towards more sustained forms of the arrhythmia. Real-world data on clinical factors associated to AF progression and its impact on long-term outcome are limited.

Purpose

To investigate the factors associated with progression of AF and its impact on all-cause mortality in a contemporary cohort of European AF patients

Methods

We analyzed patients enrolled in the ESC-EHRA EORP-AF General Long-Term Registry. Patients with paroxysmal AF at baseline or first detected AF who underwent successful cardioversion were included. Patients with known rhythm status at 1-year were then stratified into two groups: (i) No AF progression and (ii) AF progression (as defined by transition to persistent or permanent AF). All-cause mortality at 2-year of follow-up was the primary outcome of the analysis.

Results

A total of 2688 patients were included (median age 67 years, interquartile range [IQR] 60–75, females 44.7%, CHA2DS2VASc score median 3 [1–4], HASBLED median 1 [1–2]). After 1-year of follow-up 2094 (77.9%) patients showed no AF progression while 594 (22.1%) developed AF progression. On multivariable logistic regression analysis, no physical activity (odds ratio [OR] 1.35, 95% confidence interval [CI] 1.02–1.78), valvular heart disease (OR 1.63, 95% CI 1.23–2.15), left atrium diameter (OR 1.03, 95% CI 1.01–1.05) and left ventricular ejection fraction (OR 0.98, 95% CI 0.97–1.00) were independently associated with AF progression at 1-year. At the end of 2-year of follow-up, death occurred in 80/2621 (3.1%) patients. Kaplan-Meier analysis showed a lower cumulative survival from all-cause mortality in patients with AF progression compared to non-progression AF patients (Log Rank p=0.01, Figure 1). On multivariable Cox regression analysis, adjusted for age, sex, heart failure, coronary artery disease, hypertensions, diabetes mellitus, previous thromboembolic events, peripheral artery disease, chronic kidney disease and use of oral anticoagulants, patients with AF progression had an independently higher risk for all-cause mortality (adjusted hazard ratio [aHR] 1.77, 95% CI 1.09–2.89).

Conclusions

In a contemporary cohort of European AF patients, a substantial number of patients progressed to sustained AF within 1 year. Clinical factors related to atrial structural remodeling were independently associated with arrhythmia progression. AF progression was associated with an increased risk of all-cause mortality.

Funding Acknowledgement

Type of funding sources: Other. Main funding source(s): Since the start of EORP, the following companies have supported the programme: Abbott Vascular Int. (2011–2021), Amgen Cardiovascular (2009–2018), AstraZeneca (2014–2021), Bayer (2009–2018), Boehringer Ingelheim (2009–2019), Boston Scientific (2009–2012), The Bristol Myers Squibb and Pfizer Alliance (2011–2016), The Alliance Daiichi Sankyo Europe GmbH and Eli Lilly and Company (2011–2017), Edwards (2016–2019), Gedeon Richter Plc. (2014–2017), Menarini Int. Op. (2009–2012), MSD-Merck & Co. (2011–2014), Novartis Pharma AG (2014–2020), ResMed (2014–2016), Sanofi (2009–2011), SERVIER (2010–2021), and Vifor (2019–2022).

Role of multiple- and single-pregnancy complications with incident cardiovascular diseases: a nationwide data linkage study in Wales

Background

Prior evidence has suggested that pregnancy complications are associated with a higher risk of cardiovascular disease in women. However, associations between coexisting multiple pregnancy complications and incident cardiovascular disease remains unclear.

Purpose

To examine the risk of ischemic heart disease (IHD), stroke, atrial fibrillation or heart failure among women after their first pregnancy with a history of multiple pregnancy complications and women with a history of single-pregnancy complications, compared to women without pregnancy complications.

Methods

This retrospective cohort included women aged 16–45 years who had their first pregnancy between 2000 and 2018 in Wales using the Secure Anonymised Information Linkage (SAIL) Databank. Data were extracted from various sources such as Office for National Statistics (ONS) birth and death extracts, hospital admission, outpatient, emergency department and General Practice data sources, and pregnancy related data such as maternal indicators and national community child health. Cox proportional hazard regression was used to evaluate the association between multiple or specific single pregnancy complications and incidence of cardiovascular disease.

Results

A total of 298,515 women were included in the study, of which 64,794 (21.7%) women experienced a single pregnancy complication, and 10,038 (3.38%) women experienced more than one complication during their first pregnancy. During the a median of 9.7 years of follow-up, 2,484 women developed incident cardiovascular disease. IHD had the highest incidence rate among women with multiple pregnancy complications at 9.06 (7.36–11.15) per 10,000 person-years, compared to 4.24 (3.77–4.78) among women with a single pregnancy complication and 2.40 (2.20–2.61) among women without any pregnancy complications. After adjusting for potential confounding factors, compared to no previous pregnancy complications, a history of multiple pregnancy complications was associated with a higher risk of heart failure [hazard ratio (HR) 3.18 (95% confidence interval (CI) 2.34–4.32)], IHD [HR 2.88 (95% CI 2.27–3.67)], stroke [HR 2.03 (95% CI 1.55–2.65)] and atrial fibrillation [HR 1.80 (95% CI 1.20–2.72)]. There was also a consistent trend for a higher risk of all outcomes in women with a history of single-pregnancy complications compared to women without complications during the first pregnancy (Figure 1).

Conclusion

This population-scale study used anonymised individual-level linked data from multiple routinely collected data sources. In almost 300,000 women with a previous pregnancy, multiple pregnancy complications were associated with a higher risk of incident cardiovascular disease, including heart failure, ischaemic heart disease, stroke and atrial fibrillation. Women who experience multiple pregnancy complications may benefit from targeted intervention strategies to reduce their risk of incident cardiovascular disease.

Funding Acknowledgement

Type of funding sources: Other. Main funding source(s): Saudi Arabia governmental PhD studentship

Relationship between systolic blood pressure and renal function on clinical outcomes in patients with atrial fibrillation: a report from the AF-GEN-UK registry

Background

European guidelines on AF management recommend a systolic blood pressure (SBP) target of 120–129 mmHg as this level is associated with the lowest risk of poor outcomes. Elevated blood pressure and AF both negatively affect renal function, but the interactions between SBP and renal function in patients with AF remains unclear. In the UK extension of the EURObservational Research Programme (EORP) Long-term Registry of patients with atrial fibrillation (AF) [AF-GEN-UK study], we assessed the combined impact of BP levels and renal (dys)function on mortality, thromboembolic and haemorrhagic events.

Methods

1580 patients (60.1% males, mean (SD) age 70.6 (11.2) years) from the AF-GEN-UK registry had SBP available at baseline and were stratified into groups based on SBP: 120–129 mmHg (reference group, n=289), <100 mmHg (n=165), 110–119 mmHg, (n=254), 130–139 mmHg (n=321), 140–159 mmHg (n=385), and ≥160 mmHg (n=166). Impact of SBP, renal function and their interaction on 1-year outcomes were assessed using Cox regression analysis, adjusted for age, oral anticoagulation (OAC) use and CHA2DS2-VASc score. SBP groups were compared by ANOVA (continuous data) and Chi-square test (categories) with two tailed p<0.05 deemed significant (STATA Corp, version 13).

Results

Overall OAC use was 84% and was similar between all SBP groups. Renal function (eGFR), was preserved across SBP groups; those with SBP 110–119 mmHg had the lowest level. Prevalence of heart failure was highest in those with SBP <110 mmHg. Patients with uncontrolled SBP (>140 mmHg) were older, more likely female and higher rates of hypertension, with correspondingly higher CHA2DS2VASc scores. SBP <100 mmHg (Hazard Ratio (HR) 2.36; 95% confidence intervals (CI) 1.20–4.64) and lower eGFR (HR 0.99; 95% CI 0.98–0.996) were associated with all cause-death in univariate analyses.

Adjusted Cox regression revealed that SBP <100 mmHg and OAC use were independent predictors of all-cause death (Table). No interaction between BP groups and eGFR was evident. OAC use (aHR 0.31; 95% CI 0.11–0.92) was associated with a reduced risk of thromboembolic events.

Conclusion

In anticoagulated patients with AF, SBP <110 mmHg was independently predicted of all-cause death, with no interaction with kidney function. No independent association of SBP groups with haemorrhagic and thromboembolic events was evident. OAC therapy was associated with a significant reduction in all-cause death and thromboembolic events.

Funding Acknowledgement

Type of funding sources: Private company. Main funding source(s): This project was supported by the BMS/Pfizer European Thrombosis Investigator Initiated Research Program

Associations between pregnancy complications and incident cardiovascular disease: a nationwide data linkage study in Wales

Background

Previous studies have associated pregnancy complications with a higher risk of cardiovascular disease. However, previous studies have not sufficiently evaluated the impact of broad range of pregnancy complications or common cardiovascular conditions individually. Furthermore, most previous studies have relied on data from hospital admission records only, which may not have adequately accounted for conditions that may not result in an inpatient hospital admission, such as atrial fibrillation.

Purpose

To examine the risk of ischemic heart disease (IHD), stroke, atrial fibrillation or heart failure among women after their first pregnancy with a history of pregnancy complications compared to women without pregnancy complications in a large nationwide study using linked routinely collected data.

Methods

A retrospective cohort study was conducted using the Secure Anonymised Information Linkage (SAIL) Databank and included women aged 16–45 years who had their first pregnancy between 2000 and 2018 in Wales. Data were extracted from various sources such as Office for National Statistics (ONS) birth and death extracts, hospital admission, outpatient, emergency department and General Practice data sources, and pregnancy related data such as maternal indicators and national community child health. Survival analyses were conducted using Cox proportional hazard regression models adjusted for hypertension, diabetes, hyperlipidaemia, congenital and valvular heart diseases, multifetal pregnancy ethnicity, maternal age, calendar year of first birth and index of multiple deprivation.

Results

A total of 298,515 women were included in the study, of which 74,832 (25.1%) had a history of any pregnancy complication during their first pregnancy. During a median of 9.7 years follow-up time, 2,484 women developed at least one cardiovascular condition. Among women with a history of pregnancy complication in their first pregnancy, IHD had the highest incidence rate at 4.94 (95% confidence interval (CI) 4.44–5.49) per 10,000 person-years, and atrial fibrillation was the lowest at 1.92 (95% CI 1.62–2.28). The history of any pregnancy complication during the first pregnancy was associated with a higher risk of all cardiovascular conditions examined, including heart failure [hazard ratio (HR) 1.93 95% CI 1.61–2.31)], IHD [HR 1.82 (95% CI 1.58–2.10)], stroke [HR 1.39 (95% CI 1.20–1.61)] and atrial fibrillation [HR 1.33 (95% CI 1.08–1.65) (Figure 1).

Conclusion

This population-scale study used anonymised individual-level linked data from multiple routinely collected data sources. A history of pregnancy complications during first pregnancy was associated with a higher risk of incident cardiovascular conditions, including heart failure, ischaemic heart disease, stroke and atrial fibrillation. Applying primary preventive measures and risk assessments for cardiovascular disease after the first pregnancy may mitigate the higher risk among these women.

Funding Acknowledgement

Type of funding sources: Other.

Factors associated with prescription of oral anticoagulation for atrial fibrillation in older people living in care homes in Wales: a routine data linkage study 2003–2018

Background

Prescription of oral anticoagulants (OAC) is paramount for stroke prevention in people with atrial fibrillation (AF), but treatment decisions in older care home residents are complicated by frailty, multi-morbidity and heightened stroke and bleeding risk. There is a paucity of data on factors influencing the decision to prescribe OAC in this high-risk population who are under-represented in research studies.

Purpose

To explore the factors associated with OAC prescription for care home residents aged ≥65 years with AF.

Methods

Nationwide retrospective cohort study of people aged ≥65 years entering a care home in Wales between 1 January 2003 and 31 December 2018, using anonymised individual-level electronic health record and administrative data sources available within the Secure Anonymised Information Linkage Databank. Unadjusted and adjusted logistic regression models were used to explore the association between resident characteristics and OAC prescription or non-prescription.

Results

Between 2003 and 2018, 14,493 people with AF aged ≥65 years became new residents in care homes in Wales and 7,057 (48.7%) were prescribed OAC (32.7% in 2003 compared to 72.7% in 2018), Figure 1. Increasing age and prescription of antiplatelet therapy were associated with lower odds of OAC prescription (adjusted odds ratio [aOR] 0.96 per one year age increase [95% confidence interval, 0.95 to 0.96] and aOR 0.91 [0.84 to 0.98], respectively). Conversely, prior venous thromboembolism (aOR 4.06 [3.17 to 5.20]), advancing frailty (mild: aOR 4.61 [3.95 to 5.38]; moderate: aOR 6.69 [5.74 to 7.80]; severe: aOR 8.42 [7.16 to 9.90]) and year of care home entry in the post-non-vitamin K antagonist oral anticoagulant (NOAC) era from 2011 onwards (aOR 1.91 [1.76 to 2.06]) were associated with higher odds of OAC prescription, Figure 2.

Conclusions

The proportion of care home residents prescribed OAC therapy has increased over time with the introduction of NOACs in 2011, but OAC prescription rates are still sub-optimal. Although there is an expected rise in OAC prescribing for increasingly frail people, further work is needed to investigate the interaction with deprivation and other socio-economic and demographic factors to assess potential inequalities in prescribing across these groups. Targeted educational tools for clinicians are needed to address barriers to OAC prescription for AF, such as older age and separate indications for antiplatelet therapy.

Funding Acknowledgement

Type of funding sources: None.

Prevalence and outcomes of atrial fibrillation in older people living in care homes in Wales: a routine data linkage study 2003–2018

Background

Older care home residents are a high-risk group of people with atrial fibrillation (AF) who are under-represented in clinical trials. Improved understanding of AF epidemiology and management in this population is paramount for health and social care organisations to strategically plan services.

Purpose

To determine the trends in AF prevalence and compare adverse health outcomes in older care home residents aged ≥65 years with AF compared to those without AF.

Methods

Retrospective cohort study of people entering a care home between 2003–2018 using nationwide, population-scale anonymised health and administrative data, provisioned from the Secure Anonymised Information Linkage (1 January 2000–31st December 2018). Direct standardisation was used to calculate AF prevalence by year of care entry (2010–2018). Cox regression analyses were used to estimate the risk of adverse health outcomes.

Results

Between 2003 and 2018, 86,602 people aged ≥65 years became new residents in care homes in Wales. Residents with AF (n=14,493) had a significantly higher risk (adjusted hazard ratio [aHR], 95% confidence interval [CI]) of cardiovascular (aHR 1.27 [1.17 to 1.37], p<0.001) and all-cause mortality (aHR 1.14 [1.11 to 1.17], p<0.001), Figure 1. The risk (sub-distribution hazard ratio [sHR], 95% CI) of ischaemic stroke (adjusted sHR 1.55 [1.36 to 1.76], p<0.001) and cardiovascular hospitalisation (adjusted sHR 1.28 [1.22 to 1.34], p<0.001) was also higher in residents with AF, even when mortality was considered a competing event, Figure 1. There was no significant change in age- and sex-standardised prevalence of AF between 2010 and 2018, 16.79% (95% CI 15.85 to 17.94) and 17.02% (95% CI 16.05 to 17.98), respectively (absolute change 2010–2018: 0.06% [95% CI: −1.38 to 1.50], p=0.93), Figure 2.

Conclusions

This study demonstrates unique data on the epidemiology of AF and associated outcomes in older care home residents. Whilst the prevalence of AF remained stable between 2010–2018, residents with AF had significantly higher risk of adverse health events. Treatment of AF in accordance with guidelines is critical in this population to optimise management and reduce adverse health outcomes.

Funding Acknowledgement

Type of funding sources: None.

Stroke-heart syndrome: sex-specific incidence, risk factors, and major adverse cardiovascular events in 486,515 patients with incident ischaemic stroke

Background

Newly diagnosed cardiovascular complications post-stroke, termed stroke-heart syndrome, are common and associate with worsened prognosis.

Purpose

To investigate the sex-specific incidence and 5-year major adverse cardiovascular events following stroke-heart syndrome, stratified by pre-existing risk factors (sex, age, obesity, hypertension, type 2 diabetes mellitus, and high LDL cholesterol).

Methods

A retrospective cohort study was conducted using anonymised electronic medical records from 56 participating healthcare organizations. Patients with incident ischaemic stroke aged ≥18 years with 5-years of follow-up were included. Patients diagnosed with new-onset cardiovascular complications (heart failure, severe ventricular arrhythmia, atrial fibrillation, ischaemic heart disease, takotsubo syndrome) within 4-weeks of incident ischaemic stroke (exposure) were 1:1 propensity score-matched (age, sex, ethnicity, comorbidities, cardiovascular care) with ischaemic stroke patients without newly diagnosed cardiovascular complications (control). Cox proportional hazards regression models produced hazard ratios (HR) with 95% confidence intervals (CIs) and Kaplan-Meier curves for 5-year risk of all-cause mortality, recurrent stroke, and acute myocardial infarction (AMI).

Results

Of 486,515 patients with ischaemic stroke, 18% (n=87,786) presented with stroke-heart syndrome (47% (n=41,088) female and 52% (n=45,891) male). Following propensity score matching, composite stroke-heart syndrome associated with significantly higher risk of 5-year mortality (HR 1.66 (95% CI 1.62,1.70), P<0.01), recurrent stroke (1.26 (1.24,1.28), P<0.01), and AMI (2.58 (2.50,2.67), P<0.01). These outcomes were similar for both males and females (Figure 1). The risk of mortality, recurrent stroke and AMI following stroke-heart syndrome was relatively higher for patients aged <75 compared to those >75. The risk of all adverse outcomes were relatively higher for females aged <75 compared to males aged <75. Pre-existing obesity associated with a lower risk of mortality for females and males, but a higher risk of recurrent stroke for females. Pre-existing hypertension associated with a lower risk of all outcomes, except recurrent stroke in males. Pre-existing diabetes associated with higher risks for mortality and AMI for both females and males. High LDL cholesterol associated with lower risk of mortality but a higher risk of recurrent stroke and AMI in males and females (Figure 1).

Conclusions

In this cohort study of patients with incident ischaemic stroke, stroke-heart syndrome occurred in 18% of patients. The overall incidence and subsequent 5-year major adverse cardiovascular events following stroke-heart syndrome were similar for females and males, but with important sex-specific differences when stratified by pre-existing risk factors, including age, obesity, and hypertension.

Funding Acknowledgement

Type of funding sources: None.

Cardiovascular primary prevention risk factors in a nationwide survey, ABC (atrial fibrillation, high blood pressure and high cholesterol) risk factors in the LIPIDOGRAM2015 study

Background

The National Health Service in England “Long Term Plan” aims to prevent 150,000 strokes and myocardial infarctions over the next 10 years. To achieve this, resources are being allocated to improve early detection of conditions strongly associated with cardiovascular disease. This includes working towards people routinely knowing their “ABC” risk factors (“A”: atrial fibrillation (AF), “B': hypertension and “C”: high cholesterol) (1).

Purpose

The aims of this study were to: 1) determine the proportion of participants with “A”, “B”, and “C” criteria; and 2) to identify risk factors for patients fulfilling any of these criteria.

Methods

LIPIDOGRAM2015 was a nationwide cross-sectional survey for adults in Poland. Adults were recruited in 2015 and 2016 by 438 family physicians. For the ABC criteria, “A” was defined as AF identified in the medical records of the participant, “B” was defined as either systolic blood pressure greater than 140mmHg or diastolic blood pressure greater than 90mmHg or both, and “C” was defined as total cholesterol greater than 200mg/dL (5.17mmol/L). The scaled and centred dataset underwent principal component analysis using singular value decomposition to achieve dimensionality reduction. K-means clustering was used to stratify patients with Hartigan's rule being used to identify optimal K number (2–4). The p-value for statistical significance used in this study was p<0.01 unless otherwise specified.

Results

13,724 patients were included in the study. 71.0% (n=9,747) of participants fulfilled the criteria for one or more of the “A”, “B” or “C” components (Fig. 1). 26 variables were used in this analysis with Principal Component Analysis showing 7 principal components explaining over 50% of the variance with 20 components explaining over 90%. K-means clustering was also performed, finding 39 separate clusters. Correlations and statistical significance tests showed a high degree of variability between variables. Participants with AF were older (mean (SD) 67.7 (9.5) vs 55.7 (13.7), p<0.0001), with higher prevalence of concomitant coronary heart disease (CHD) (OR 6.73, 95% CL 5.75, 7.87) and ischaemic stroke (OR 13.45, 95% CL 7.66, 23.6). Participants with hypertension were older (mean (SD) 60.1 (SD 12.4) vs 53.8 (14.0), p<0.0001), with a higher BMI (mean (SD) 29.9 (5.1) vs 27.5 (4.8), p<0.0001) and resting heart rate (mean (SD) 75.7 (10.7) vs 72.7 (8.9), p<0.0001), more likely to be male (OR 1.42, 95% CL 1.32, 1.53) and have diabetes (OR 1.61, 95% CL 1.46, 1.78). Participants with high cholesterol showed an inverse correlation with prevalence of both concomitant diabetes (OR 0.85, 95% CL 0.77, 0.94) and CHD (OR 0.85, 95% CL 0.76, 0.94) (Fig. 2).

Conclusion

Simple demographic and clinical variables could be used to guide targeted screening to increase population awareness of “ABC” status, allowing for a greater proportion of the population to be appropriately managed with cardiovascular prevention strategies.

Funding Acknowledgement

Type of funding sources: None. “ABC” Venn diagramCorrelogram and significance plot

Impact of malignancy on outcomes in European patients with atrial fibrillation: a report from the ESC-EHRA EURObservational Research Programme in Atrial Fibrillation General Long-Term Registry

Background

Management of patients with atrial fibrillation (AF) and malignancy is a clinical challenge given the paucity of evidence supporting the appropriate clinical management.

Purpose

To evaluate the outcomes of patients with active or prior malignancy in a large contemporary cohort of European AF patients.

Methods

We analyzed patients enrolled in the ESC-EHRA EORP-AF General Long-Term Registry. We stratified the population into three categories (i) No Malignancy (NoM) (ii) Prior Malignancy (PriorM) and (iii) Active Malignancy (ActM). The primary outcome for this analysis was all-cause death among the three groups. The association between anticoagulant treatment, all-cause death and haemorrhagic events was also evaluated.

Results

Among the original 11 096 AF patients enrolled, 10 383 were included in this analysis (median age 71 years (interquartile range [IQR] 63–77, males 59.7%). Of these, 9 597 (92.4%) were NoM patients, 577 (5.6%) PriorM and 209 (2%) ActM. Patients with malignancy (prior or active) had a higher median age, median CHA2DS2-VASc and HAS-BLED scores, compared to patients without malignancy (p<0.001). Lack of anticoagulation (AC) prescription occurred more commonly in ActM (21.5%) as compared with the other groups (PriorM 10.1% vs NoM 12.8%, p<0.001). In case of AC treatment, patients with ActM were treated more frequently with heparins (ActM 8.1% vs PriorM 2.4% vs NoM 2%, p<0.001).

After a median follow-up of 730 days [IQR 692–749], 982 (9.5%) patients died. Among all deaths, the proportion of cardiovascular death was different according to the three groups (40.0% in NoM, 26.0% in PrioM and 22.2% in ActM, p=0.002). For all cause-death, Kaplan-Meier analysis showed a progressively higher cumulative risk in the PriorM and ActM groups compared to NoM patients (Figure 1).

On multivariable Cox regression analysis, adjusted for CHA2DS2-VASc score, use of AC, type of AF and chronic kidney disease, ActM group was independently associated with a higher risk for all cause death (hazard ratio [HR] 2.90, 95% confidence interval [CI] 2.23–3.76) while PriorM group was not.

Among PriorM and NoM patients, multivariable adjusted Cox regression analysis found that the use of any AC was independently associated with a lower risk for all-cause death (HR 0.36, 95% CI 0.19–0.66; HR 0.66, 95% CI 0.54–0.81). No significant association between AC and all-cause death was found for ActM patients.

Conclusions

In a large contemporary cohort of European AF patients, active malignancy was found to be independently associated with all-cause death. Use of any AC was associated with a lower risk for all-cause death in patients with no malignancies and with prior malignancies, but with no significant association amongst patients with active malignancies.

Funding Acknowledgement

Type of funding sources: Other. Main funding source(s): Since the start of EORP, the following companies have supported the programme: Abbott Vascular Int. (2011–2021), Amgen Cardiovascular (2009–2018), AstraZeneca (2014–2021), Bayer (2009–2018), Boehringer Ingelheim (2009–2019), Boston Scientific (2009–2012), The Bristol Myers Squibb and Pfizer Alliance (2011–2016), The Alliance Daiichi Sankyo Europe GmbH and Eli Lilly and Company (2011–2017), Edwards (2016–2019), Gedeon Richter Plc. (2014–2017), Menarini Int. Op. (2009–2012), MSD-Merck & Co. (2011–2014), Novartis Pharma AG (2014–2020), ResMed (2014–2016), Sanofi (2009–2011), SERVIER (2010–2021), and Vifor (2019–2022). Figure 1. Kaplan-Meier for all-cause death

Epidemiology of subclinical atrial fibrillation in patients with cardiac implantable electronic devices: a systematic review and meta-analysis

Background

Sub-clinical atrial fibrillation (SCAF) and atrial high-rate episodes (AHREs), seen as high-frequency atrial tachyarrhythmias in patients with cardiac implantable electronic devices (CIEDs), have gained prominence as determinants of clinical atrial fibrillation (AF) and increased stroke risk. As a result, several studies investigating their role in predicting the onset of AF and AHRE-related outcomes have been conducted but uncertainty exists on the epidemiology of AHRE.

Purpose

To estimate the incidence of SCAF, according to presence of AHREs in patients with CIEDs, through a systematic review and meta-analysis of the available literature.

Methods

PubMed and EMBASE were searched from inception to 27th January 2021 for all studies documenting the incidence of AHREs in patients with CIEDs. We included all studies with ≥100 patients reporting data on AHREs incidence. Pooled prevalence and incidence rates were computed; we also performed meta-regressions for pooled incidence rates, according to relevant study-level characteristics. This study was registered in PROSPERO: CRD42019106994.

Results

Among the 2,515 results retrieved, we included 51 studies in the systematic review and meta-analysis, with a total of 68,414 patients. Meta-analysis of included studies showed a pooled prevalence of 28.2% (95% CI: 24.3–32.5%, I2=99%), with a pooled incidence rate (IR) of 15 new AHRE cases per 100 patient-years (95% CI: 12–19, I2=100%). Given the large heterogeneity showed in the pooled estimates we performed additional analyses. Regarding pooled prevalence, we performed several subgroup analyses, according to various studies baseline characteristics, which did not show any significant difference in any of the subgroups examined. Regarding IR, a multivariable meta-regression analysis showed that decreasing follow-up time and increasing age were the only factors significantly associated with AHRE incidence, explaining a large proportion of heterogeneity (R2=68%, p<0.001; Figure 1, Panel A and B respectively). Accordingly, the AHRE IR was highest at 1 year follow-up and in the oldest subjects. Presence of SCAF was significantly associated with older age, higher CHA2DS2-VASc score, and higher prevalence of hypertension, heart failure and history of cerebrovascular disease.

Conclusions

This systematic review and meta-regression demonstrated that SCAF is very common in patients with CIEDs, with an overall IR for AHREs of up to 15 per 100 patient-years; increasing with age and decreasing with longer follow-up time. Presence of SCAF was associated with an overall higher clinical risk profile compared to those subjects without SCAF.

Funding Acknowledgement

Type of funding sources: None. Figure 1. Meta-regression for AHRE Incidence

Impact on outcomes in Europe: a cluster analysis from the ESC-EHRA EORP AF general long-term registry

Funding Acknowledgements

Type of funding sources: None.

OnBehalf

ESC-EHRA EORP AF General Long-Term Registry Investigators

Introduction

Data derived from recent observational studies in atrial fibrillation (AF) show how the complexity of the clinical phenotype, beyond baseline thromboembolic risk, can increase risk of major adverse outcomes. Importantly, risk factors tend to occur in clusters, rather than occur individually in isolation.

Aims

To describe AF patients’ clinical phenotypes among a large contemporary European AF cohort and to analyse the differential impact of these clinical phenotypes on the occurrence of major adverse outcomes.

Methods

We performed a hierarchical cluster analysis based on Ward’s Method and using Squared Euclidean Distance using 22 clinical covariates. All variables were considered as binary. Examining the distances between cluster coefficients and by visual inspection of the dendrogram produced we identified the optimal number of clusters. Patients with data available for all 22 variables were included. We considered occurrence of cardiovascular events and all-cause death.

Results

Among the original 11096 patients included, 9363 (84.4%) were available for this analysis. The cluster analysis identified three clusters: Cluster 1 (n = 3634; 38.8%) characterized by older patients with prevalent noncardiac comorbidities; Cluster 2 (n = 2774; 29.6%) characterized by younger patients mainly admitted for first detected and paroxysmal AF with low prevalence of concomitant conditions; Cluster 3 (n = 2955; 31.6%) included patients with high prevalence of permanent AF, cardiac risk factors and comorbidities. Thromboembolic and bleeding risks were higher in Cluster 3 and progressively lower in Cluster 1 and Cluster 2 (both p < 0.001). Use of oral anticoagulant was significantly lower for Cluster 2 (83.2% vs. 86.5% and 86.7% in Cluster 1 and Cluster 3, respectively; p < 0.001). Over a mean follow-up of 22.5 (SD5.5) months, Cluster 3 had the highest rate of both cardiovascular events (10.0%) and all-cause death (13.2%), compared with Cluster 1 (6.6% and 9.4%, respectively) and Cluster 2 (3.7% and 3.8%, respectively) (both p < 0.001). Kaplan-Meier curves (Figure) show that Cluster 2 (green line) had the lowest cumulative risk of outcomes; risk was progressively higher in Cluster 1 (orange line) and Cluster 3 (yellow line). A Cox multivariable regression analysis, adjusted for type of AF, symptomatic status, CHA2DS2-VASc score and use of oral anticoagulants, showed that both Cluster 3 and Cluster 1 were associated with a significantly increased risk of cardiovascular events (HR: 1.80, 95%CI: 1.39-2.33 and HR: 1.40, 95%CI: 1.09-1.80, respectively) and all-cause death (HR: 1.80, 95%CI: 1.40-2.30 and HR: 1.66, 95%CI: 1.30-2.11) compared to Cluster 2.

Conclusions

In European AF patients, three main clinical clusters were identified, those with non-cardiac comorbidities, low risk and cardiac comorbidities. Both non-cardiac and cardiac comorbidities clusters were found to be associated with an increased risk of cardiovascular events and all-cause death. Abstract Figure. Kaplan-Meier Curves for Outcomes

Subclinical thyroid dysfunction and incident atrial fibrillation - a systematic review and meta-analysis

Funding Acknowledgements

Type of funding sources: Other. Main funding source(s): This project was supported by the MRes programme in the Institute of Life Course and Medical Sciences at The University of Liverpool.

Thyroid hormones can act directly and indirectly on the cardiovascular system and studies have demonstrated associations between overt and subclinical thyroid dysfunction and adverse cardiovascular outcomes including heart failure, myocardial infarction, and coronary heart disease. The aim of this study was to assess the association between subclinical thyroid dysfunction and atrial fibrillation (AF). 

The protocol was registered on PROSPERO (CRD42020221565). MEDLINE and Scopus were searched from inception to 13th November 2020 for studies investigating subclinical thyroid dysfunction and incident AF. Risk of bias was assessed using the Risk of Bias Assessment Tool (RoBANS). The quality of evidence was assessed using the Grading of Recommendations, Assessment, Development, and Evaluations (GRADE) tool. Subgroup analysis was performed for post-operative and non-post-operative AF.

5413 records were identified. Nine cohort studies were suitable for inclusion in the systematic review, of which seven studies were included in the meta-analysis. The meta-analysis comprised 595,058 patients. Subclinical hyperthyroidism was associated with a 99% increase in the risk of incident AF (Risk ratio (RR): 1.99; 95% confidence intervals (CI); 1.43 to 2.77; p < 0.0001; I² = 67%). Subclinical hypothyroidism was also associated with a greater risk of AF (RR: 1.24; 95% CI; 1.05 to 1.47; p = 0.01; I² = 65%). Subgroup analysis demonstrated a 76% increase in the risk of post-operative AF in patients with subclinical hypothyroidism compared to euthyroid post-operative patients (RR: 1.76; 95% CI; 1.36 to 2.28; p < 0.0001; I² = 0%). Six studies were rated as low risk of bias and three as medium risk of bias according to the RoBANS tool. The quality of evidence for AF in subclinical hyper- and hypothyroid patients was low.

Subclinical hyperthyroidism and subclinical hypothyroidism were associated with a higher risk of incident AF and post-operative AF, respectively. The quality of the current evidence is low and ideally a randomised controlled trial should be conducted to confirm these associations and assess impacts of treatments. Abstract Figure.

Pregnancy-related complications and incidence of atrial fibrillation: a systematic review and meta-analysis

Funding Acknowledgements

Type of funding sources: None.

Background

Pregnancy-related complications have been previously associated with incident cardiovascular disease. However, data are scarce on the association between pregnancy-related complications and incident atrial fibrillation (AF). This systematic review examines associations between pregnancy-related complications and incident AF.

Methods

A systematic search of the literature utilising MEDLINE and EMBASE (Ovid) was conducted from 1990 to 6 April 2020. Observational studies examining the association between pregnancy-related complications including hypertensive disorders of pregnancy (HDP), gestational diabetes, placental abruption, preterm birth, low birth weight, small-for-gestational-age and stillbirth, and incidence of AF were included. Screening and data extraction were conducted independently by two reviewers. Inverse-variance random-effects models were used to pool hazard ratios.

Results: Six observational studies met the inclusion criteria

one case-control study and five retrospective cohort studies, with four studies eligible for meta-analysis.  Sample sizes ranged from 1,839-1,303,365. Mean/median follow-up for the cohort studies ranged from 7-36 years. Most studies reported an increased risk of incident AF associated with pregnancy-related complications. The pooled summary statistic from four studies reflected a greater risk of incident AF for HDP (hazard ratio (HR) 1.47, 95% confidence intervals (CI) 1.18-1.84; I2 = 84%) and from three studies for pre-eclampsia (HR 1.71, 95% CI 1.41-2.06; I2 = 64%; Figure).

Conclusions

The results of this review suggest that pregnancy-related complications particularly pre-eclampsia appear to be associated with higher risk of incident AF. The small number of included studies and the significant heterogeneity in the pooled results suggest further large-scale prospective studies are required to confirm the association between pregnancy-related complications and AF. Abstract Figure.

Enhanced activity of an ADAMTS-13 variant (R568K/F592Y/R660K/Y661F/Y665F) against platelet agglutination in vitro and in a murine model of acute ischemic stroke

Essentials ADAMTS13 requires a substrate-induced conformational change to attain full activity in vitro. The efficacy of wild type ADAMTS13 in models of thrombosis/stroke may be enhanced by pre-activation. A pre-activated ADAMTS13 variant exhibits enhanced proteolysis of platelet agglutinates. This ADAMTS13 variant is protective in a murine model of stroke at a lower dose than WT ADAMTS13. SUMMARY: Background ADAMTS-13 circulates in a closed conformation, only achieving full proteolytic activity against von Willebrand factor (VWF) following a substrate-induced conformational change. A gain-of-function (GoF) ADAMTS-13 variant (R568K/F592Y/R660K/Y661F/Y665F) is conformationally preactivated. Objectives To establish how the hyperactivity of GoF ADAMTS-13 is manifested in experimental models mimicking the occlusive arterial thrombi present in acute ischemic stroke. Methods The ability of GoF ADAMTS-13 to dissolve VWF-platelet agglutinates was examined with an assay of ristocetin-induced platelet agglutination and in parallel-flow models of arterial thrombosis. A murine model of focal ischemia was used to assess the thrombolytic potential of GoF ADAMTS-13. Results Wild-type (WT) ADAMTS-13 required conformational activation to attain full activity against VWF-mediated platelet capture under flow. In this assay, GoF ADAMTS-13 had an EC50 value more than five-fold lower than that of WT ADAMTS-13 (0.73 ± 0.21 nm and 3.81 ± 0.97 nm, respectively). The proteolytic activity of GoF ADAMTS-13 against preformed platelet agglutinates under flow was enhanced more than four-fold as compared with WT ADAMTS-13 (EC50 values of 2.5 ± 1.1 nm and 10.2 ± 5.6 nm, respectively). In a murine stroke model, GoF ADAMTS-13 restored cerebral blood flow at a lower dose than WT ADAMTS-13, and partially retained the ability to recanalize vessels when administration was delayed by 1 h. Conclusions The limited proteolytic activity of WT ADAMTS-13 in in vitro models of arterial thrombosis suggests an in vivo requirement for conformational activation. The enhanced activity of the GoF ADAMTS-13 variant translates to a more pronounced protective effect in experimental stroke.

Factor V Leiden (FV R506Q) in Families with Inherited Antithrombin Deficiency

We investigated the presence of the gene mutation of factor V, FV R506Q or factor V Leiden, responsible for activated protein C resistance, in DNA samples of 127 probands and 188 relatives from 128 families with antithrombin deficiency. The factor V mutation was identified in 18 families. Nine families were available to assess the mode of inheritance and the clinical relevance of combined defects.

The factor V and antithrombin genes both map to chromosome 1. Segregation of the defects on opposite chromosomes was observed in three families. Co-segregation with both defects on the same chromosome was demonstrated in four families. In one family a de novo mutation of the antithrombin gene and in another a crossing-over event were the most likely explanations for the observed inheritance patterns.

In six families with type I or II antithrombin deficiency (reactive site or pleiotropic effect), 11 of the 12 individuals with both antithrombin deficiency and the factor V mutation developed thrombosis. The median age of their first thrombotic episode was 16 years (range 0-19); this is low compared with a median age of onset of 26 years (range 20-49) in 15 of 30 carriers with only a defect in the antithrombin gene. One of five subjects with only factor V mutation experienced thrombosis at 40 years of age. In three families with type II heparin binding site deficiencies, two of six subjects with combined defects experienced thrombosis; one was homozygous for the heparin binding defect.

Our results show that, when thrombosis occurs at a young age in antithrombin deficiency, the factor V mutation is a likely additional risk factor. Co-segregation of mutations in the antithrombin and factor V genes provides a molecular explanation for severe thrombosis in several generations. The findings support that combinations of genetic risk factors underly differences in thrombotic risk in families with thrombophilia.

Antithrombin III: A Database of Mutations

Elucidation of the molecular defects reponsible for antithrombin III deficiency is proceeding rapidly. In order that a record is kept of the new and duplicated mutations that are found, we have compiled a database that we plan to update annually. In this, the first report of the database, we list 6 antithrombin III locus sequence polymorphisms and 94 recorded mutations causing functional deficiency of the protein, 38 of which are novel. As is the case with mutations affecting other protein genes, most mutations of antithrombin III involve a CG to TG or CA change.

Dose Finding Study of a Low Molecular Weight Heparin, Innohep, in Haemodialysis

A pilot investigation was performed with Innohep, a low molecular weight (LMWH) preparation (peak maximum molecular mass 3,000-6,000), to determine possible dose regimens for patients undergoing regular maintenance haemodialysis for chronic renal failure. Results from this study suggested that suppression of macroscopic clot formation and fibrinopeptide A (FPA), a marker of fibrin formation, could be achieved following bolus injections rather than bolus injections and an infusion. On the basis of these preliminary findings, a randomised crossover study was performed in eight patients undergoing regular maintenance haemodialysis for 5-7 h to determine the effective antithrombotic dose of this LMWH. Single i.v. bolus doses of 1,250 AFXa u, 2,500 AFXa u and 5,000 AFXa u (n = 7-8) were compared to an UFH regime of 5,000 iu + 1,500 iu/h. Excessive clot formation in the dialyser bubble trap, necessitating additional UFH to enable completion of a prolonged (up to 7 h) dialysis, was observed in all patients on the 1,250 AFXa u dose (mean duration of dialysis prior to UFH, 3 h) but in a single patient only receiving the other LMWH doses. A dose-related response in the AFXa activity, measured by chromogenic substrate (CS) assay was seen in the three LMWH groups, with levels declining significantly (p <0.05) from 1-7 h. This contrasted with the constant levels maintained during dialysis with UFH. FPA levels were significantly elevated after 2 h following the 1,250 AFXa u bolus and after 4 h following the 2,500 AFXa u bolus. There was no significant difference in FPA levels between the 5,000 AFXa u bolus and UFH. β-thromboglobulin (pTG) levels rose significantly towards the end of dialysis in all LMWH groups and, at 5 h, were significantly increased following the 5,000 AFXa u and 2,500 AFXa u doses when compared to the UFH regime. AFXa levels correlated negatively with FPA levels (r = -0.62; p <0.01). In conclusion, for administration of Innohep, a bolus dose of 2,500 AFXa u would appear to be sufficient for dialyses of short duration (up to 4 h), whilst a 5,000 AFXa u bolus is as effective as UFH for a 6 h dialysis. AFXa activity measured by CS assay is related to inhibition of fibrin formation and can be used for monitoring purposes.

Plasma D Dimer: A Useful Marker of Fibrin Breakdown in Renal Failure

D dimer and other large fragments produced during the breakdown of crosslinked fibrin may be measured by enzyme immunoassay using monoclonal antibodies. In 91 patients with renal disease and varying degrees of renal dysfunction, plasma D dimer showed no correlation with renal function, whereas FgE antigen, a fibrinogen derivative which is known to be cleared in part by the kidney, showed a significant negative correlation with creatinine clearance. Plasma concentrations of D dimer were, however, increased in patients with chronic renal failure (244 ± 3l ng/ml) (mean ± SEM) and diabetic nephropathy (308 ± 74 ng/ml), when compared with healthy controls (96 ± 13 ng/ml), and grossly elevated in patients with acute renal failure (2,451 ± 1,007 ng/ml). The results indicate an increase in fibrin formation and lysis, and not simply reduced elimination of D dimer by the kidneys, and are further evidence of activated coagulation in renal disease. D dimer appears to be a useful marker of fibrin breakdown in renal failure.

Homozygous Antithrombin Deficiency: Report of Two New Cases (99 Leu to Phe) Associated with Arterial and Venous Thrombosis

Inherited antithrombin deficiency is associated with an increased risk of thrombosis, primarily venous rather than arterial. Most affected individuals have inherited only a single copy of an abnormal antithrombin (AT) gene. Homozygously affected individuals, although rare, have a severe thrombotic history of early onset and often affecting the arteries. We report two new cases of type II HBS (heparin binding site) deficiency in which the propositi are homozygous for the previously reported mutation 99 Leu to Phe, and who have a severe thrombotic history. These cases are considered alongside existing homozygote and compound heterozygote cases.

Antithrombin Milano, Single Amino Acid Substitution at the Reactive Site, Arg393 to Cys

Antithrombin Milano is an unusual antithrombin variant, exhibiting an abnormal, fast moving component on crossed immunoelectrophoresis (in the absence of heparin). Antithrombin isolated from the propositus could be resolved into two peaks on anion-exchange chromatography; anti thrombin Milano peak 1 of Mr ∼60,000 which could inhibit thrombin, and antithrombin Milano peak 2 of Mr ∼120,000 which was inactive. The latter component also reacted with antisera to both antithrombin and albumin on immunoblotting. Under reducing conditions, the ∼120,000 Mr component migrated on SDS-PAGE as two distinct bands with Mr ∼60,000, one of which reacted with antiserum to antithrombin and the other (of slower mobility) of which reacted with antiserum to albumin only. These and other results established the ∼120,000 Mr component to be an inactive, disulphide-linked variant antithrombin and albumin complex. The variant antithrombin was isolated, following reduction and S-carboxy-methylation, by reverse-phase HPLC and then it was fragmented with CNBr. A major CNBr pool containing the sequence Gly339-Met423 was treated with trypsin, followed by V8 protease. The resulting peptides were analysed by fast atom bombardment mass spectrometry (Fab-MS) mapping. A peptide of molecular mass 1086, corresponding to the normal sequence Ala382-Arg393, was almost absent from the mass spectrum, but an additional peptide of mass number 1772 was present. These results are almost identical to those found in another variant antithrombin, North-wick Park (Erdjument et al., J Biol Chem, 262: 13381, 1987; Erdjument et al., J Biol Chem, 263: 5589-5593, 1988), indicating the same single amino acid substitution of Arg393 to Cys.

Detection of Enhanced In Vivo Platelet α-Granule Release in Different Patient Groups - Comparison of β-Thromboglobulin, Platelet Factor 4 and Thrombospondin Assays

During the platelet release reaction β-thromboglobulin (βTG), platelet factor 4 (PF4) and thrombospondin (TSP) are released from the platelet into plasma and assays of these proteins can be used to monitor in vivo platelet activation. We have assessed their relative merits as markers of the in vivo platelet α-granule release reaction in a number of patient groups which have previously been shown to have elevated plasma βTG and/or PF4 levels. It is concluded that in diseases or conditions not complicated by its reduced clearance, βTG is the most sensitive marker of in vivo platelet α-granule release. However, the TSP assay may be the least ambiguous when monitoring the platelet α-granule release reaction in patients with renal failure who are undergoing haemodialysis with heparin anticoagulation. Under these circumstances plasma βTG, but not PF4 or TSP, levels are elevated because of impaired renal catabolism, and the presence of a heparin-releasable reservoir of PF4 on the endothelium complicates the use of the PF4 assay. In liver failure none of these assays may accurately reflect platelet α-granule release because of impaired hepatic or renal elimination of the proteins.

The Anticoagulant Effect of Heparinoid Org 10172 During Haemodialysis: An Objective Assessment

The heparinoid of natural origin Org 10172 has anti-factor Xa activity but minimal anti-thrombin activity, and little effect upon broad spectrum assays such as the KCCT in vitro. Its anticoagulant effects have been compared to those of commercial heparin in 7 patients undergoing haemodialysis for chronic renal failure. Commercial heparin was administered in a dose (5,000 iu bolus + 1,500 iu/hour continuous iv infusion) previously shown to inhibit fibrin formation during haemodialysis. This produced mean anti-factor Xa levels in plasma between 0.7-1.0 iu/ml and largely suppressed fibrin formation for 5 h dialysis measured as mean FPA levels in plasma. Administration of Org 10172 as a bolus of 1,350 anti-factor Xa u or 2,000-2,400 anti-factor Xa u produced plasma anti-factor Xa levels of less than 0.5 u/ml and allowed fibrin clot and FPA generation during dialysis. Org 10172 administered as a bolus dose of 4,000-4,800 anti-factor Xa u produced mean anti-factor Xa levels of greater than 0.5 u/ml, allowed dialysis of 6 patients for 5 h and appreciably suppressed FPA generation during dialysis, with little effect on the KCCT.

It is concluded that the anti-factor Xa activity of Org 10172 may reflect its ability to inhibit fibrin during dialysis and that single bolus injection of Org 10172 may be a useful alternative method of achieving anticoagulation.

In Vivo Platelet Release in Myeloproliferative Disorders

The in vivo platelet release reaction in 22 patients with myeloproliferative disorders has been studied by measuring plasma concentrations of the platelet release product β-throm-boglobulin (βTG). Mean βTG and mean βTG:whole blood platelet count ratio were significantly raised in the patient group taken as a whole compared to an age matched control group. No significant increases were observed in the plasma concentrations of thrombin and plasmin sensitive fibrinogen fragments fibrinopeptide A (FpA) and Bβ1-42. The patients were divided into those who had normal, increased or decreased responses to in vitro ADP-induced platelet aggregation. Mean βTG and the mean βTG:whole blood platelet count ratio were higher in the increased and decreased responders to ADP than in the normal aggregation group, but the differences in means were not statistically significant. Aspirin given to six patients at a dose sufficient to eliminate the secondary phase of ADP-induced platelet aggregation reduced mean βTG and the mean βTG : whole blood platelet count ratio but did not alter mean FpA and Bβ1-42. It is concluded that the enhanced platelet release reaction seen in myeloproliferative disorders is independent of plasma protease activity that arises when coagulation and fibrinolytic systems are activated.

Gene Mutations in 21 Unrelated Cases of Phenotypic Heterozygous Protein C Deficiency and Thrombosis

Mutations have been identified in the protein C gene in 21 patients with venous thromboembolism and phenotypic heterozygous protein C deficiency. In 20 probands, single mutations were the only abnormalities identified by sequencing all coding regions, intron exon boundaries and the promoter region back to -1540. In one proband 2 mutations were identified and in another family 2 mutations were identified (but not both in the proband). Of the 23 mutations, 18 resulted in predicted amino acid substitutions, 3 were mutations resulting in stop codons, one was a mutation within a consensus splice sequence and another a 9 base pair insertion within exon 5 (this region within exon 5 is proposed as a deletion/insertion hot spot). A novel polymorphism was also, uniquely, identified in the propeptide region of the molecule (Pro-21 Pro; CCT to CCC) in a kindred from Hong Kong. Cosegregation of the protein C gene mutation with protein C deficiency could be determined in 13 families. In a further family, phenotypic protein C deficiency and the genetic mutation cosegregated in only 4/5 members.

The first thrombotic incident occurred in the probands between the ages of 11 and 59 years and 12 individuals suffered recurrent thrombosis. Thrombosis occurred in at least one other family member in 9/21 families, but in 2 of these it was inconsistently associated with protein C deficiency. An independent genetic risk factor, factor V Arg506Gln (FV Leiden) was identified in 2 probands (and 3 family members) and in 4 protein C deficient members of a third family but not in the proband. The results suggest that in the majority of probands with thrombosis and phenotypic protein C deficiency, a single protein C gene mutation is associated with thrombosis. However, it is also possible that additional unknown genetic risk factors contribute to the thrombotic risk. An added, acquired, risk factor leads to thrombosis at an early age (< 25 years).

High Purity Factor IX and Prothrombin Complex Concentrate (PCC): Pharmacokinetics and Evidence that Factor IXa Is the Thrombogenic Trigger in PCC

Recent studies using assays for surrogate markers of thrombogenic-ity in man have demonstrated that activation of the coagulation system occurs following infusion of clinical doses of prothrombin complex concentrates (PCC) but not after the same doses of high-purity factor IX concentrates (HP-FIX) in patients with haemophilia B. Here we have investigated the mechanism of such thrombogenesis by applying assays that detect early-through to late-events in coagulation system activation in a pharmacokinetic cross-over study of 50 IU/kg PCC and a new HP-FIX product in haemophilia B patients. Satisfactory recoveries and half-lives were observed for both concentrates.

HP-FIX caused no increases in thrombin-antithrombin III complex (TAT), prothrombin activation peptide fragment F1+2 (F1+2), factor X activation peptide (FXAP) or factor Vila (FVIIa). In contrast the same dose of factor IX in the form of PCC was followed by significant increases over pre-infusion levels of TAT, F1+2 and FXAP, but not FVIIa. Elevations of FIXAP occurred after both HP-FIX and PCC but did not reach normal levels and were attributed to normalisation of the FIX concentration in those patients whose levels of FIXAP were initially low. We conclude that the thrombogenic trigger associated with PCC infusion occurs at the level of factor X activation. In the absence of any increase in FVIIa, we would attribute this to the likely presence of FIXa in the PCC.

Antithrombotic Properties of Dermatan Sulphate (MF 701) in Haemodialysis for Chronic Renal Failure

The therapeutic potential of the glycosaminoglycan (GAG), dermatan sulphate (DS), as an antithrombotic agent in humans has yet to be established. We have performed dose ranging studies of DS to determine its effectiveness as an antithrombotic agent in patients (n = 6–8) undergoing haemodialysis for chronic renal failure. In an initial study, Study 1, i.v. bolus doses of 2–4 mg/kg and 5–6 mg/kg DS were given to patients dialysing with polyacrylonitrile hollow fibre (PAN HF) membranes. In a second crossover study, Study 2, performed using cuprophane hollow fibre (CHF) membranes, i. v. bolus doses of 3 mg/kg and 6 mg/kg DS were compared to a standard unfractionated heparin (UFH) regime that has been shown previously to inhibit fibrin formation. Further infusion studies, Study 3 and Study 4 evaluated the antithrombotic efficacy of an i. v. DS bolus of 3 mg/kg plus an i. v. infusion of DS 0.6 mg kg-1 h-1 and a DS bolus of 5 mg/ kg plus an infusion of 1 mg kg-1 h-1 over 5 h, respectively. These studies were compared to standard UFH regimes in a randomised crossover design. Plasma levels of fibrinopeptide A (FPA) and thrombin-antithrombin (TAT) were used as markers of fibrin formation and thrombin generation during dialysis using both membranes.

The changes in DS concentration following administration of the different doses were similar in Studies 1 and 2. However, the effectiveness of DS as an anticoagulant appeared to depend markedly on the different dialyser types used in the two studies. In Study 1, 13/14 dialyses required additional UFH to complete a normal ~6 h session and DS was unable to prevent thrombin and fibrin formation, as determined by measurement of plasma FPA and TAT. However, some dose related effects were observed in the levels of these markers. Furthermore, DS levels correlated with those of FPA and TAT. In Study 2, increasing doses of DS (3 mg/kg and 6 mg/kg), allowed longer dialysis sessions (mean 4.57 h c.f. 5.25 h), approaching that obtained with UFH regime (5.86 h). FPA and TAT generation were incompletely suppressed by both doses of DS; FPA rose significantly compared to that observed with the UFH regime, while TAT did not. While no significant differences in the activation markers were observed between the two DS doses, DS levels, taken as a whole, showed significant negative correlations with those of FPA and TAT Little effect on the KCCT was seen.

In Study 3, 3/6 patients required additional UFH (mean dialysis duration with DS 4.33 h c. f. 5.67 h with UFH). Mean DS levels were maintained between 35–40 µg/ml. Mean plasma FPA levels were maintained at constant levels throughout dialysis following DS administration but were higher than those observed following the UFH regime. In Study 4 mean DS levels were

Low Molecular Weight Heparin in Haemodialysis for Chronic Renal Failure: Dose Finding Study of CY222

A dose finding study of the very low molecular weight heparin CY222 (MW 2500) in patients (n = 8) with chronic renal failure undergoing dialysis has been carried out to (i) establish an effective dose and (ii) determine the relationship between ex vivo anti-factor Xa levels in plasma and the anticoagulant effect (in vivo suppression of FPA levels). Doses of CY222 were compared to a dose (5000 iu bolus + 1500 iu/hr) of unfractionated heparin (UFH) that has been shown to suppress FPA levels during prolonged (>5 hr) dialysis (Ireland et ah, J Lab Clin Med 103, 643, 1984). CY222 given iv in increasing doses produced a dose related increase in anti-factor Xa levels (measured as Institute Choay u/ml, with CY222 itself as standard) and suppression of FPA levels. When given in its highest dose, 20,000 Institute Choay u bolus + 1500 Institute Choay u/hr, there was little effect upon KCCT, FPA levels were statistically indistinguishable from those of the UFH regime (indicating comparable anticoagulant effect), but anti-factor Xa levels (expressed in Institute Choay u/ ml) were 2-3 times those of UFH (expressed in iu/ml). All samples were also assayed for anti-factor Xa level against the proposed low MW Heparin Standard. Plasma levels of CY222 were then found to be 2.78 times lower, so that the anti-factor Xa levels of CY222 required to produce comparable anticoagulant effect were then indistinguishable from those of UFH. Clinically, doses of CY222 exceeding 10,000 Institute Choay u bolus were effective, although increasing amounts of fibrin were visible in the drip chamber of the dialyser circuit with decreasing dose. These results indicate that CY222 is an effective anticoagulant for haemodialysis that can be monitored by its anti-factor Xa level in plasma (in conjunction with the appropriate standard). For prolonged dialysis a dose of 20,000 Institute Choay u bolus + 1500 Institute Choay u/hr is effective at suppressing fibrin formation, while the maintenance infusion may be unnecessary for short frequent dialyses.

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.

ADAMTS-13 and von Willebrand factor: a dynamic duo

von Willebrand factor (VWF) is a key player in hemostasis, acting as a carrier for factor VIII and capturing platelets at sites of vascular damage. To capture platelets, it must undergo conformational changes, both within its A1 domain and at the macromolecular level through A2 domain unfolding. Its size and this function are regulated by the metalloproteinase ADAMTS-13. Recently, it has been shown that ADAMTS-13 undergoes a conformational change upon interaction with VWF, and that this enhances its activity towards its substrate. This review summarizes recent work on these conformational transitions, describing how they are controlled. It points to their importance in hemostasis, bleeding disorders, and the developing field of therapeutic application of ADAMTS-13 as an antithrombotic agent in obstructive microvascular thrombosis and in cardiovascular disease.

Conformational quiescence of ADAMTS-13 prevents proteolytic promiscuity

Essentials Recently, ADAMTS-13 has been shown to undergo substrate induced conformation activation. Conformational quiescence of ADAMTS-13 may serve to prevent off-target proteolysis in plasma. Conformationally active ADAMTS-13 variants are capable of proteolysing the Aα chain of fibrinogen. This should be considered as ADAMTS-13 variants are developed as potential therapeutic agents. Click to hear Dr Zheng's presentation on structure function and cofactor-dependent regulation of ADAMTS-13 SUMMARY: Background Recent work has revealed that ADAMTS-13 circulates in a 'closed' conformation, only fully interacting with von Willebrand factor (VWF) following a conformational change. We hypothesized that this conformational quiescence also maintains the substrate specificity of ADAMTS-13 and that the 'open' conformation of the protease might facilitate proteolytic promiscuity. Objectives To identify a novel substrate for a constitutively active gain of function (GoF) ADAMTS-13 variant (R568K/F592Y/R660K/Y661F/Y665F). Methods Fibrinogen proteolysis was characterized using SDS PAGE and liquid chromatography-tandem mass spectrometry (LC-MS/MS). Fibrin formation was monitored by turbidity measurements and fibrin structure visualized by confocal microscopy. Results ADAMTS-13 exhibits proteolytic activity against the Aα chain of human fibrinogen, but this is only manifest on its conformational activation. Accordingly, the GoF ADAMTS-13 variant and truncated variants such as MDTCS exhibit this activity. The cleavage site has been determined by LC-MS/MS to be Aα chain Lys225-Met226. Proteolysis of fibrinogen by GoF ADAMTS-13 impairs fibrin formation in plasma-based assays, alters clot structure and increases clot permeability. Although GoF ADAMTS-13 does not appear to proteolyse preformed cross-linked fibrin, its proteolytic activity against fibrinogen increases the susceptibility of fibrin to tissue-type plasminogen activator (t-PA)-induced lysis by plasmin and increases the fibrin clearance rate more than 8-fold compared with wild-type (WT) ADAMTS-13 (EC50 values of 3.0 ± 1.7 nm and 25.2 ± 9.7 nm, respectively) in in vitro thrombosis models. Conclusion The 'closed' conformation of ADAMTS-13 restricts its specificity and protects against fibrinogenolysis. Induced substrate promiscuity will be important as ADAMTS-13 variants are developed as potential therapeutic agents against thrombotic thrombocytopenic purpura (TTP) and other cardiovascular diseases.

Use of non-vitamin K antagonist oral anticoagulants in atrial fibrillation patients: insights from a specialist atrial fibrillation clinic

BACKGROUND

Non-vitamin K antagonist oral anticoagulants (NOACs) are broadly preferable to vitamin K antagonists (VKAs) for stroke prevention in non-valvular atrial fibrillation (AF) given their overall net clinical benefit. We report an audit of the profile of OAC usage and adverse events in patients attending a specialist AF clinic.

METHODS

Patients attending our specialist AF clinic who were commenced on NOACs for SPAF between January 2013 and August 2014 were included and electronic medical records were retrospectively reviewed between August 2014 and November 2014, to collect demographic, clinical and outcome data. Outcomes included cerebrovascular and bleeding events, death, switching between NOACs or to VKA, dose changes, cessation of NOACs and the reasons for these. To provide perspective, descriptive comparisons were made with a historical cohort of warfarin users attending the specialist AF clinic prior to the introduction of NOACs.

RESULTS

We report data on 813 patients as follows: (i) 233 consecutive patients (mean (standard deviation) age 74 (10) years, 45.1% female) initiated on NOACs, with median (interquartile range) CHA2 DS2 -VASc score 3 (2-5) and HAS-BLED score 1 (1-2); and (ii) a historical cohort of 580 patients on warfarin (mean (SD) age 75 (10) years, 42.1% female) with broadly similar demographics. Overall, 54.5% (127/233) were started on rivaroxaban, 22.7% (53/233) on dabigatran and 22.7% on apixaban. Two patients experienced a transient ischaemic attack; 31 patients (13%) contributed to 37 documented bleeding events of which five bleeds (in four patients, 1.7%) were classified as major. There were seven deaths; cause of death was not available for three and the others were not related to NOACs. Eighteen (7.7%) patients switched NOACs, 2 (0.9%) patients switched to warfarin and 8 (3.4%) had their NOACs stopped. There were no ischaemic strokes in the NOAC cohort, compared with nine in the warfarin cohort, with a similar rate of major bleeding (1.7% for NOACs and 1.6% for warfarin). There were more gastrointestinal haemorrhages in the NOAC cohort (3.4% vs. 0.7% with warfarin).

CONCLUSION

In this specialist AF clinic, patients prescribed NOACs had a favourable adverse event profile with good efficacy for stroke prevention, with a low rate of cessation or switch to warfarin.

Plasma ADAMTS-13 levels and the risk of myocardial infarction: an individual patient data meta-analysis

BACKGROUND

Low ADAMTS-13 levels have been repeatedly associated with an increased risk of ischemic stroke, but results concerning the risk of myocardial infarction are inconclusive.

OBJECTIVES

To perform an individual patient data meta-analysis from observational studies investigating the association between ADAMTS-13 levels and myocardial infarction.

METHODS

A one-step meta-analytic approach with random treatment effects was used to estimate pooled odds ratios (ORs) and corresponding 95% confidence intervals (CIs) adjusted for confounding. Analyses were based on dichotomous exposures, with the 5th and 1st percentiles of ADAMTS-13 antigen levels as cut-off values. Quartile analyses, with the highest quartile as a reference category, were used to assess a graded association between levels and risk ('dose' relationship). Additionally, we assessed the risk of the combined presence of low ADAMTS-13 and high von Willebrand factor (VWF) levels.

RESULTS

Five studies were included, yielding individual data on 1501 cases and 2258 controls (mean age of 49 years). Low ADAMTS-13 levels were associated with myocardial infarction risk, with an OR of 1.89 (95% CI 1.15-3.12) for values below the 5th percentile versus above, and an OR of 4.21 (95% CI 1.73-10.21) for values below the 1st percentile versus above. Risk appeared to be restricted to these extreme levels, as there was no graded association between ADAMTS-13 levels and myocardial infarction risk over quartiles. Finally, there was only a minor synergistic effect for the combination of low ADAMTS-13 and high VWF levels.

CONCLUSIONS

Low ADAMTS-13 levels are associated with an increased risk of myocardial infarction.

Gender differences in stroke prevention in atrial fibrillation in general practice: using the GRASP-AF audit tool

BACKGROUND

Women represent a large proportion of patients with atrial fibrillation (AF) and tend to have higher risk of stroke.

AIMS

This study examines gender differences in the utilisation of oral anticoagulation (OAC) and prognosis (i.e. stroke and death) in AF patients in UK general practice.

DESIGN

Retrospective observational study.

METHODS

The Guidance on Risk Assessment and Stroke Prevention in Atrial Fibrillation (GRASP-AF) tool was employed to identify AF patients from 11 general practices in Darlington, England.

RESULTS

Two thousand two hundred and fifty-nine AF patients (mean±SD age 76 ± 12 years; 46% female) were identified. Based on CHA2 DS2 -VASc score 95% of women and 90% of men were at moderate-high risk of stroke. Women with moderate-high risk of stroke were treated with OAC less frequently than men (47% vs. 52%, p = 0.006). Overall rates of stroke and all-cause mortality were higher among women than men (p = 0.02 and p < 0.001). However, there was no significant gender difference in these outcomes in patients receiving OAC (p = 0.52 for stroke, p = 0.18 for death). Among people not receiving OAC where indicated, female gender was associated with an increased risk of stroke before (p = 0.01), and after (p = 0.04), adjustment for stroke risk factors. Women not receiving OAC had a higher risk of death on univariate regression analysis (p = 0.002), but not after adjustment for stroke risk factors (p = 0.53).

CONCLUSION

Women with AF are at higher risk of stroke than men without OAC. The gender-related differences in risk of stroke disappear if OAC is used. Despite this, women are more likely not to receive OAC.

Dabigatran adherence in atrial fibrillation patients during the first year after diagnosis: a nationwide cohort study

BACKGROUND

There is a perception among physicians that lack of routine monitoring with non-vitamin K antagonist oral anticoagulants (NOACs) may lead to poor adherence to medication. We studied adherence during the first year of usage in a cohort of patients with newly diagnosed non-valvular atrial fibrillation (AF) started on the NOAC, dabigatran etexilate.

METHODS AND RESULTS

Nationwide Danish patient and prescription purchase registries were used to identify newly diagnosed AF patients taking dabigatran, comorbidities, and refill patterns under a twice-daily, one pill regimen. Adherence was characterized among remaining users (N = 2960) after 1 year using the proportion of days covered (PDC), gap rates and restart rates. The overall 1-year PDC was 83.9%, with 76.8% of patients having a 1-year PDC in excess of 80%. Patients with a CHA2 DS2 -VASc score ≥ 2 were more adherent to medication regimes than patients with a CHA2 DS2 -VASc score of 1 (PDC ratio, 1.12; 95% confidence interval [CI], 1.08-1.17) and generally patients with higher morbidity showed more adherence. Patients with prior bleeding were not less adherent to medication regimes than patients with no prior bleeding (PDC ratio, 1.02; 95% CI, 0.98-1.06). The overall gap rate was 1.4 gaps per year. There were no clear tendencies in gap rates among subgroups, although patients with higher morbidity tended to have slightly more, but shorter, gap periods.

CONCLUSIONS

More than 75% of patients were showed > 80% adherence to medication regimes during the first year. Patients with higher morbidity, including patients with a higher risk of stroke or bleeding, exhibited better adherence. This improvement may be attributable to more regular contact with the healthcare system.

Is female sex a risk factor for stroke and thromboembolism in patients with atrial fibrillation? A systematic review and meta-analysis

BACKGROUND

Atrial fibrillation (AF) increases the risk of stroke, but this risk is not homogenous. Many risk factors contribute to stroke risk however, the evidence for female sex as a risk factor is less well-established.

AIM

To perform a systematic review and meta-analysis of the available evidence to establish if female sex is a risk factor for stroke/thromboembolism among patients with AF.

METHODS

A systematic literature search was conducted using Medline. The search term 'atrial fibrillation' was used in combination with 'stroke risk', 'thromboembolism', 'female' and 'gender differences' and returned 735 articles, of which 17 were appraised and included. Females with AF were compared with males with AF for the outcome of stroke/thromboembolism.

RESULTS

Seventeen studies, 5 randomized-controlled trials and 12 prospective observational studies were included; 10 demonstrated an increased risk of stroke in women. Meta-analysis of the 17 studies revealed a 1.31-fold (95% confidence intervals (CIs) 1.18-1.46) elevated risk of stroke in women with AF; the risk appearing greatest for women aged ≥75 years. Only three studies compared entirely anticoagulated populations; stroke rates among these patients varied from 1.2-1.44% per-patient year for men and 2.08-2.43% per-patient year for women. Risk of stroke in women appeared similar regardless of oral anticoagulation therapy [risk ratio (95% CI 1.29 (1.09-1.52) and 1.49 (1.17-1.90) in non-anticogulated vs. anticoagulated/mixed cohorts, respectively).

CONCLUSIONS

Women with AF are at increased risk of stroke, particularly elderly women. Comprehensive stroke risk assessment, including sex as a risk factor, should be undertaken in all AF patients.