Evaluation of survival and ischaemic and thromboembolic event rates in patients with non-valvar atrial fibrillation in the general population when treated and untreated with warfarin

Concomitant intra-atrial excision of the left atrial appendage during robotic-assisted minimally invasive cardiac surgery

Objective

Surgical closure of the left atrial appendage (LAA) in patients with atrial fibrillation undergoing cardiac surgery can decrease the risk of stroke and thromboembolism and should therefore be considered. In minimally invasive, thoracoscopic, or robotic-assisted mitral valve surgery, however, external procedures such as clip application or epicardial resection are not feasible due to anatomic limitations and the reduced size of the access port. Internal suture closing techniques bear the risk of recurrent LAA reperfusion, so far. We present a novel surgical technique of LAA excision and subsequent defect closure from the interior aspect of the atrium.

Methods

We developed this novel technique during robotic-assisted cardiac surgeries. In short, the LAA is invaginated into the left atrium, excised completely at the base using scissors and the stump is then closed from the inside with a two-layer looped PTFE suture. We give a detailed step-by-step description of the technique.

Results

A total of 20 patients received intra-atrial LAA excision so far. Complete resection of the LAA without any residual stump or bleeding was achieved in all cases. There were no procedure-related complications.

Conclusion

The intra-atrial LAA excision technique shows promising preliminary results regarding efficacy, safety, and reproducibility during robotic-assisted cardiac operations and could be recommended for all right-sided minimally invasive cardiac surgical procedures.

Prevalence of atrial fibrillation : The Swiss population-based CoLaus|PsyCoLaus study

BACKGROUND

Atrial fibrillation (AF) is the most common arrhythmia worldwide and is associated with increased morbi-mortality. The prevalence of AF in the Western world is increasing; however, reports on the prevalence of AF in the past decade are scarce, and whether the prevalence of AF increased during the last decade in Switzerland remains uncertain. Therefore, using data from a Swiss population-based sample, we aimed to assess the point prevalence of AF from 2014 to 2017 and to investigate determinants of AF.

METHODS

A cross-sectional analysis of 4616 Caucasian participants aged 45-86 years (55% women) from a population-based sample was designed to explore the point prevalence and determinants of cardiovascular risk factors in the population of Lausanne, Switzerland. AF was assessed using electrocardiography (ECG) between 2014 and 2017.

RESULTS

Overall, the point prevalence of AF was 0.9% (95% confidence interval [95% CI]: 0.7-1.2%) and the combined AF + atrial flutter (AFL) point prevalence was 1.1% (95% CI: 8.4-1.5%). The point prevalence of AF was higher among men (81% vs. 19% in women) and increased with age, reaching 3.1% in participants aged ≥ 80. In multivariable analysis, male gender (odds ratio and 95% CI: 4.98 [1.01-24.6]) and increasing age (2.86 [1.40-5.87] per decade) were associated with AF.

CONCLUSION

The point prevalence of AF and of AF + AFL, assessed between 2014 and 2017 in the city of Lausanne (Switzerland), was low but increased with age and in men.

Cost-effectiveness of dabigatran etexilate for the prevention of stroke and systemic embolism in atrial fibrillation: A Canadian payer perspective

Oral dabigatran etexilate is indicated for the prevention of stroke and systemic embolism in patients with atrial fibrillation (AF) in whom anticoagulation is appropriate. Based on the RE-LY study we investigated the cost-effectiveness of Health Canada approved dabigatran etexilate dosing (150 mg bid for patients <80 years, 110 mg bid for patients ≥80 years) versus warfarin and “real-world” prescribing (i.e. warfarin, aspirin, or no treatment in a cohort of warfarin-eligible patients) from a Canadian payer perspective. A Markov model simulated AF patients at moderate to high risk of stroke while tracking clinical events [primary and recurrent ischaemic strokes, systemic embolism, transient ischaemic attack, haemorrhage (intracranial, extracranial, and minor), acute myocardial infarction and death] and resulting functional disability. Acute event costs and resulting long-term follow-up costs incurred by disabled stroke survivors were based on a Canadian prospective study, published literature, and national statistics. Clinical events, summarized as events per 100 patient-years, quality-adjusted life years (QALYs), total costs, and incremental cost effectiveness ratios (ICER) were calculated. Over a lifetime, dabigatran etexilate treated patients experienced fewer intracranial haemorrhages (0.49 dabigatran etexilate vs. 1.13 warfarin vs. 1.05 “real-world” prescribing) and fewer ischaemic strokes (4.40 dabigatran etexilate vs. 4.66 warfarin vs. 5.16 “real-world” prescribing) per 100 patient-years. The ICER of dabigatran etexilate was $10,440/QALY versus warfarin and $3,962/QALY versus “real-world” prescribing. This study demonstrates that dabigatran etexilate is a highly cost-effective alternative to current care for the prevention of stroke and systemic embolism among Canadian AF patients.

Ischaemic stroke and bleeding rates in ‘real-world’ atrial fibrillation patients

Stroke prevention guidelines recommend oral anticoagulants (OAC) for atrial fibrillation (AF) patients at moderate/high risk of stroke, and antiplatelet or no therapy for those at low/moderate risk. Outcomes for AF patients receiving antiplatelet/no therapy in ‘real-life’ clinical practice were explored. This study compared clinical event rates (stroke/bleeding) for AF patients treated with OAC therapy, antiplatelets or no therapy in usual clinical practice to event rates in OAC-treated AF patients from optimally-monitored ‘real-life’ settings (anticoagulation clinics). We searched biomedical literature (1994–2010) using PubMed to identify ‘real-world’ studies of clinical event rates for AF patients receiving OAC therapy, antiplatelets, or no therapy; event rates were extracted for each treatment and setting. We identified 136 studies of thromboembolic events and 86 of bleeding events. Ischaemic stroke rates (30 studies) were higher for AF patients receiving no therapy (median: 4.45/100 person-years; range: 0.25–5.9) or antiplatelet-therapy (median: 4.45/100 person-years; range: 2.0–10) compared to OACtreated patients monitored in anticoagulation clinics (median: 1.72/100 person-years; range: 0.97–2.00), or from a non-specialized setting (median 1.66/100 person-years; range: 0–4.9). Major bleeding rates (32 studies) for patients receiving antiplatelet/no therapy were similar to OAC-treated patients from both clinical settings. As in randomised clinical trials, AF patients in ‘real-world’ clinical practice receiving antiplatelet/no therapy have higher rates of ischaemic stroke than OAC-treated patients. Antiplatelet/no therapy was associated with similar bleeding rates to OAC therapy. Increasing utilisation of anticoagulants in clinical practice could improve patient outcomes.

Risks of stroke and mortality associated with suboptimal anticoagulation in atrial fibrillation patients

Atrial fibrillation (AF) carries an increased risk of ischaemic stroke, and oral anticoagulation with warfarin can reduce this risk. The objective of this study was to evaluate the association between time in therapeutic International Normalised Ratio (INR) range when receiving warfarin and the risk of stroke and mortality. The study cohort included AF patients aged 40 years and older included in the UK General Practice Research Database. For patients treated with warfarin we computed the percentage of follow-up time spent within therapeutic range. Cox regression was used to assess the association between INR and outcomes while controlling for patient demographics, health status and concomitant medication. The study population included 27,458 warfarintreated (with at least 3 INR measurements) and 10,449 patients not treated with antithrombotic therapy. Overall the warfarin users spent 63% of their time within therapeutic range (TTR). This percentage did not vary substantially by age, sex and CHA2DS2-VASc score. Patients who spent at least 70% of time within therapeutic range had a 79% reduced risk of stroke compared to patients with ≤30% of time in range (adjusted relative rate of 0.21; 95% confidence interval 0.18–0.25). Mortality rates were also significantly lower with at least 70% of time spent within therapeutic range. In conclusion, good anticoagulation control was associated with a reduction in the risk of stroke.

A randomised, double blind comparison of tecarfarin, a novel vitamin K antagonist, with warfarin

Tecarfarin is a novel vitamin K antagonist that is metabolised by carboxyl estererase, thereby eliminating the variability associated with cytochrome-mediated metabolism. EmbraceAC was designed to compare the quality of anticoagulation with tecarfarin and warfarin as determined by time in therapeutic range (TTR). In this phase 2/3 randomised and blinded trial, 607 patients with indications for chronic anticoagulation were assigned to warfarin (n=304) or tecarfarin (n=303). Dosing of study drugs was managed by a centralised dose control centre, which had access to genotyping. The primary analysis tested superiority of tecarfarin over warfarin for TTR. Patients were recruited between May 12, 2008 and May 12, 2009. TTR with tecarfarin and warfarin were similar (72.3% and 71.5%, respectively; p=0.51). In those taking CYP2C9 interacting drugs, the TTR on tecarfarin (n=92) was similar to that on warfarin (n=87, 72.2% and 69.9%, respectively; p=0.15). In patients with mechanical heart valves, the TTR of tecarfarin (n=42) was similar to that of warfarin (n=42, 68.4% and 66.3%, respectively; p=0.51). The same was true for the TTR in patients with any CYP2C9 variant allele and on CYP2C9-interacting drugs (tecarfarin, n=24, 76.5% vs warfarin, n=31, 69.5%; p=0.09). There was no difference in thromboembolic or bleeding events. In conclusion, superiority of tecarfarin over warfarin for TTR was not demonstrated. The TTR with tecarfarin was similar to that with well-controlled warfarin and tecarfarin appeared to be safe and well tolerated with few major bleeding and no thrombotic events. Favourable trends in certain subpopulations make tecarfarin a promising oral anticoagulant that deserves further study.

Supplementary Material to this article is available online at www.thrombosis-online.com.

Impact of Baseline Stroke Risk and Bleeding Risk on Warfarin International Normalized Ratio Control in Atrial Fibrillation (from the TREAT-AF Study)

Warfarin prevents stroke and prolongs survival in patients with atrial fibrillation and flutter (AF, collectively) but can cause hemorrhage. The time in international normalized ratio (INR) therapeutic range (TTR) mediates stroke reduction and bleeding risk. This study sought to determine the relation between baseline stroke, bleeding risk, and TTR. Using data from The Retrospective Evaluation and Assessment of Therapies in Atrial Fibrillation (TREAT-AF) retrospective cohort study, national Veterans Health Administration records were used to identify patients with newly diagnosed AF from 2003 to 2012 and subsequent initiation of warfarin. Baseline stroke and bleeding risk was determined by calculating CHA₂DS₂-VASc and HAS-BLED scores, respectively. Main outcomes were first-year and long-term TTR and INR monitoring rate. In 167,190 patients, the proportion of patients with TTR (>65%) decreased across increasing strata of CHA₂DS₂-VASc and HAS-BLED. After covariate adjustment, odds of achieving TTR >65% were significantly associated with high CHA₂DS₂-VASc or HAS-BLED score. INR monitoring rate was similar across risk strata. In conclusion, increased baseline stroke and bleeding risk is associated with poor INR control, despite similar rates of INR monitoring. These findings may paradoxically limit warfarin's efficacy and safety in high-risk patients and may explain observed increased bleeding and stroke rates in this cohort.

Systematic review of observational studies assessing bleeding risk in patients with atrial fibrillation not using anticoagulants

Background

Patients with atrial fibrillation considering use of anticoagulants must balance stroke reduction against bleeding risk. Knowledge of bleeding risk without the use of anticoagulants may help inform this decision.

Purpose

To determine the rate of major bleeding reported in observational studies of atrial fibrillation patients not receiving Vitamin K antagonists (VKA).

Data Sources

We searched MEDLINE, EMBASE and CINAHL to October 2011 and examined reference lists of eligible studies and related reviews.

Study Selection

All longitudinal cohort studies that included over 100 adult patients with atrial fibrillation not receiving VKA.

Data Extraction

Teams of two reviewers independently and in duplicate adjudicated eligibility, assessed risk of bias and abstracted study characteristics and outcomes.

Data Synthesis

Twenty-one eligible studies included 96,448 patients. Major bleeding rates varied widely, from 0 to 4.69 events per 100 patient-years. The pooled estimate in 13 studies with 78839 patients was 1.59 with a 99% confidence interval of 1.10 to 2.3 and median 1.42 (interquartile range 0.62–2.70). Pooled estimates for fatal bleeding and non-fatal bleeding from 4 studies that reported these outcomes were, respectively, 0.40 (0.34 to 0.46) and 1.18 (0.30 to 4.56) per 100 patient-years. In 9 randomized controlled trials (RCTs) the median rate of major bleeding in patients not receiving either anticoagulant or antiplatelet therapy was 0.6 (interquartile 0.2 to 0.90), and in 12 RCTs the median rate of major bleeding in patients receiving a single antiplatelet agent was 0.75 (interquartile 0.4 to 1.4).

Conclusion

Results suggest that patients with atrial fibrillation not receiving VKA enrolled in observational studies represent a population on average at higher risk of bleeding.

Dabigatran for the prevention of stroke and systemic embolism in atrial fibrillation: A NICE single technology appraisal

The National Institute for Health and Clinical Excellence (NICE) invited the manufacturer of dabigatran etexilate (Boehringer Ingelheim Ltd, UK) to submit evidence for the clinical and cost-effectiveness of this drug for the prevention of stroke and systemic embolism in patients with non-valvular atrial fibrillation (AF) as part of the NICE single technology appraisal process. The Centre for Reviews and Dissemination and the Centre for Health Economics at the University of York were commissioned to act as the evidence review group (ERG). This article presents a summary of the manufacturer's submission, the ERG report and the subsequent development of NICE guidance for the use of dabigatran within the UK National Health Service. Dabigatran was granted marketing authorisation by the European Medicines Agency for a sequential dosing regimen (DBG sequential), in which patients under 80 years are treated with dabigatran 150 mg twice daily (DBG150) and patients 80 years and over are given dabigatran 110 mg twice daily (DBG110). NICE decisions are bound by the marketing authorisation; therefore, the decision problem faced by the committee was whether the DBG sequential regimen was effective and cost-effective compared with warfarin or aspirin for patients with non-valvular AF and one or more risk factors. The RE-LY trial, a large multi-centre non-inferiority randomised clinical trial, was the primary source of clinical evidence. DBG150 was shown to be non-inferior, and subsequently superior to warfarin, for the primary outcome of all stroke/systemic embolism. DBG110 was found to be non-inferior to warfarin. Results were presented for a post hoc subgroup analysis for patients under and over 80 years of age, where DBG110 showed a statistically significant reduction of haemorrhagic stroke and intracranial haemorrhage in comparison to warfarin in patients over 80 years of age. This post hoc subgroup analysis by age was the basis for the licensed DBG sequential regimen. The economic evaluation compared the costs and outcomes of DBG110, DBG150 and DBG sequential against warfarin, aspirin, and aspirin plus clopidogrel. Across the three dosing regimens, dabigatran was associated with greater costs and better health outcomes than warfarin; however, DBG150 offered the most benefits and dominated DBG110 and DBG sequential (i.e. less costly and more effective). The cost-effectiveness of DBG150 was less favourable for patients well controlled on warfarin. In the first appraisal meeting, the committee issued a 'minded no' decision until additional analyses on the licensed DBG sequential regimen were presented by the manufacturer. These additional analyses indicated that the incremental cost-effectiveness ratio (ICER) of the DBG sequential regimen compared with warfarin ranged from £8,388 to £18,987 per quality-adjusted life year (QALY) gained depending on the level of monitoring costs assumed for warfarin. Patients on warfarin would need to be within therapeutic range 83-85 % of the time for the ICER to exceed £30,000 per additional QALY. Following consideration of the additional evidence and the responses from a large number of consultees and commentators, the committee recommended dabigatran as DBG sequential as an option for the prevention of stroke and systemic embolism in people with non-valvular AF with one or more risk factors for ischaemic stroke.

Benchmark for time in therapeutic range in venous thromboembolism: a systematic review and meta-analysis

INTRODUCTION

The percentage of time within the target INR range 2.0 to 3.0 (TTR) in patients treated with vitamin K antagonists varies considerably among efficacy-studies of novel anticoagulants. In order to properly asses the quality of anticoagulant control in upcoming cost-effectiveness studies and real life registries this systematic review reports a benchmark of TTR for different treatment durations in patients with venous thromboembolism and discusses ways to calculate TTR.

METHODS

Medline and Embase were searched for studies published between January 1990 and May 2012. Randomized controlled trials and cohort studies reporting the TTR in patients with objectively confirmed venous thromboembolism treated with vitamin K antagonists (VKA) were eligible. Duplicate reports, studies only reporting INR during initial treatment or with VKA treatment less than 3 months were excluded. Three authors assessed trials for inclusion and extracted data independently. Discrepancies were resolved by discussion between the reviewers. A meta-analysis was performed by calculating a weighted mean, based on the number of participants in each included study, for each time-period in which the TTR was measured since the confirmation of the diagnosis of VTE.

RESULTS

Forty studies were included (26064 patients). The weighted means of TTR were 54.0% in the first month since the start of treatment, 55.6% in months 1 to 3, 60.0% in months 2 to 3, 60.0% in the months 1 to 6+ and 75.2% in months 4 to 12+. Five studies reported TTR in classes. The INR in these studies was ≥ 67% of time in therapeutic range in 72.0% of the patients.

CONCLUSION

Reported quality of VKA treatment is highly dependent on the time-period since the start of treatment, with TTR ranging from approximately 56% in studies including the 1(st) month to 75% in studies excluding the first 3 months.

The use of epidemiological measures to estimate the impact of primary prevention interventions on CHD, stroke and cancer outcomes: experiences from Herefordshire, UK

Background: CHD, stroke and cancers are the major causes of mortality in the UK and are responsible for significant amounts of morbidity and healthcare costs. This study examines the proportion of CHD, stroke and cancer owing to specific risk factors in Herefordshire, UK. It estimates the population impact of a number of interventions being implemented to reduce these risk factors, through the NHS Health Check program and the Herefordshire Health Improvement Plan. The present study also aims to demonstrate the value of epidemiological measures in providing evidence-based public health information in policy-making to aid decision makers when prioritizing investments and optimal use of resources.

Methods: The epidemiological measures–‘Population Attributable Risk’ and ‘Population Impact Measures’–were used to assess the impact of interventions to reduce the burden of CHD, stroke and cancer.

Results: Implementation of the NHS Health Check program will prevent 63 CHD events, 90 MI events and 125 stroke events, and one lung cancer over a period of 5 years. Reducing specific risk factors by 5% annually through the Health Improvement Plan will prevent 65 CHD events, 25 MI events, 140 stroke events, four lung cancer, one breast cancer and four colorectal cancer cases in Herefordshire if targets are met over a period of 5 years.

Conclusion: Physical inactivity and obesity are the major causes of CHD and stroke events (incidence and mortality) in Herefordshire. Their impact is greater than the combined effect of hypercholesterolemia and hypertension.

Epidemiological measures used in this study proved to be excellent tools in providing evidence-based public health information. Their use is strongly recommended to support prioritization of primary prevention interventions.

Atrial fibrillation: its prevalence and risk factor profile in the German general population

BACKGROUND

Atrial fibrillation (AF) is an increasingly common problem in primary care, but little is known about its prevalence and the distribution of AF risk factors in the general population.

METHODS

We determined the prevalence of AF and the distribution of known AF risk factors among persons participating in the population-based Gutenberg Health Study. To this end, we used interview data about the medical diagnosis of AF and electrocardiograms (ECGs) that were performed for the study in 5000 persons aged 35 to 74. The response rate was 60.4%.

RESULTS

There were 5000 persons in the study sample (age 52.2 ± 11 years; 50.6% were women). The prevalence of AF, weighted for the age and sex distribution of the general population, was 2.5%. AF was found to be more common in older persons, with a more pronounced increase in men: whereas its prevalence was 0.7% in 35- to 44-year-old men, the corresponding figure for the age group 65- to 74 was as high as 10.6%. Twenty five participants (15.5% of AF cases) received their initial diagnosis of AF on the basis of the study ECG. Compared to persons without AF, persons with AF were older and more commonly male, and they had a higher burden of cardiovascular risk factors. 14.3% of persons with AF had none of the well-established risk factors for AF (systolic blood pressure, antihypertensive medication, increased body-mass-index, heart failure). 42.7% of persons with AF were not taking either anticoagulants or platelet inhibitors.

CONCLUSION

These data indicate that the prevalence of AF in the middle-aged general population is 2.5% overall, and higher in the elderly. AF is thus a significant public health problem, and greater awareness of it is needed.

Development and comparison of a warfarin-dosing algorithm for Korean patients with atrial fibrillation

BACKGROUND

The pharmacokinetics and pharmacodynamics of warfarin are affected by polymorphisms in the genes coding for cytochrome P450 2C9 (CYP2C9) and vitamin K epoxide reductase complex subunit 1 (VKORC1).

OBJECTIVE

The objective of this study was to develop a pharmacogenetic dosing algorithm for warfarin in Korean patients with atrial fibrillation and to compare it with the published pharmacogenetic dosing algorithms for accuracy to predict warfarin maintenance dose.

METHODS

Clinical and genetic data from 130 Korean patients with atrial fibrillation (mean [SD] age: 66.2 [13.3] years; gender, male/female: 86/44; mean body weight: 66.6 [11.6] kg) were used to create a dosing algorithm, which was validated against an independent group of patients (n = 108; mean age: 67.4 [10.1] years; gender, male/female: 69/39; mean body weight: 66.0 [10.9] kg). Validation cohort data for the 12 previously published dosing algorithms incorporating CYP2C9 and VKORC1 genotype information were also applied.

RESULTS

A multivariate regression model including the variables of age, VKORC1 and CYP2C9 genotype, body surface area, and statin status produced the best model for estimating the warfarin dose (R(2) = 0.62). Among the 12 algorithms that were compared, the predicted doses using algorithms derived from both the Swedish Warfarin Genetics (WARG) study and the Korean population study showed the best correlation with actual warfarin doses. Comparing the percentage of patients whose predicted dosages were within 20% of actual dosages, these algorithms showed similar overall performance.

CONCLUSIONS

This study derived and validated a multivariate regression model for daily warfarin dose requirements in Korean patients with atrial fibrillation. As no algorithm could be considered the best for all dosing ranges, it may be important to consider the characteristics or limitations of each dosing algorithm and the nature of a population in choosing the most appropriate pharmacogenetic dosing.

[Persistent left atrial thrombus in atrial fibrillation under oral anticoagulation]

The case of a 78-year-old female patient who suffered atrial fibrillation and persistent thrombus in the left atrial appendage despite sufficient anticoagulation is reported. The case is chosen to demonstrate the complexity inherent in prophylaxis as well as risk evaluation of thromboembolism on the basis of clinical and echocardiographic criteria. We also discuss transesophageal echocardiography as the standard diagnostic procedure for detection of intracardiac thrombi prior to cardioversion as well as cardiac computer tomography as an alternative.

Reasons for undertreatment with oral anticoagulants in frail geriatric outpatients with atrial fibrillation: a prospective, descriptive study

OBJECTIVES

The main aims of the study were to explore whether oral anticoagulation (OAC) for atrial fibrillation (AF) in geriatric outpatients is prescribed in accordance with international (American College of Cardiology/American Heart Association/European Society of Cardiology [ACC/AHA/ESC]) and Dutch national guidelines for the general practitioner (GP) and to identify whether age and selected co-morbid conditions are associated with undertreatment. As a secondary objective, we wanted to establish how many patients discontinue OAC because of major bleeding.

METHODS

In 2004, at the first visit of all patients to the geriatric day clinic of the Slotervaart Hospital in Amsterdam, the Netherlands, demographic data, Mini-Mental State Examination score, medical history, Charlson Comorbidity Index score, and data on medication use and changes were documented. The presence of AF was established by assessment of medical history information obtained by the GP, the history taken from patients and their caregivers, and the results of clinical evaluation, including ECG findings. Associations between the use of OAC, demographic data and co-morbid conditions registered in the Dutch NHG (Nederlands Huisartsen Genootschap [Dutch College of General Practitioners]) standard for GPs as risk factors for stroke or contraindications to the use of OAC were analysed. The reasons for discontinuing OAC were assessed after 4 years by requesting the information from the anticoagulation services or the GP.

RESULTS

At the time of the initial visit, 17.5% of the 807 outpatients had chronic AF (n = 135) or were known to have paroxysmal AF (n = 6). The mean age of the 141 patients in this cohort was 84.3 years (SD 6.2 years). Co-morbid conditions increasing the risk of stroke were present in 129 patients (91.5%). Contraindications to the use of OAC were observed in 118 patients (83.7%). Of the 116 patients with AF in their history before their visit, 57.8% were being treated with OAC at the time of their visit. After comprehensive geriatric assessment, 73 (51.8%) of the 141 patients with chronic or paroxysmal AF were continued on OAC. Of the 141 patients with chronic or paroxysmal AF, 110 (78.0%) had both extra stroke risk factors and contraindications to the use of OAC. Only increasing age was significantly and independently associated with not being prescribed anticoagulants (p < 0.001). At the 4-year follow-up, OAC had been discontinued in 5.5% of patients because of major bleeding; three patients (4.1%) taking OAC had died as a result of major bleeding, and one other patient had discontinued treatment because of a major, non-lethal bleeding episode.

CONCLUSION

Applying the NHG standard for appropriate prescription, and disregarding age as a risk factor or contraindication, in this population, 14 of 141 patients (9.9%) were inappropriately prescribed OAC, salicylates or no prophylaxis. Since only patient age was associated with not prescribing OAC in this study, higher age still seems to be considered the most important contraindication to anticoagulation therapy. Implementation of better models for stratifying bleeding risk in the frail elderly is needed. After 4 years, the cumulative rate of bleeding causing discontinuation of anticoagulation therapy in this usual-care study of frail older patients was not alarmingly higher than in other usual-care studies.

Thromboembolism in atrial fibrillation

Thromboembolism is a severe complication in atrial fibrillation. This overview presents thromboembolic disease as a single entity, ranging from stroke through mesenteric ischemia to acute limb ischemia. The PubMed, Embase, and Cochrane databases were systematically searched for the terms "atrial fibrillation" and "thromboembolism" in reports published from January 1986 to September 2009. The information of 10 evidence-based practice guideline documents and 61 further sources was systematically extracted. In atrial fibrillation, the average annual stroke risk is increased by 2.3% (lethality 30%). The annual incidence of acute mesenteric ischemia is 0.14% (lethality 70%), and that of acute limb ischemia is 0.4% (lethality 16%). In total, approximately 80% of embolism-related deaths are from stroke and 20% from other systemic thromboembolism. The ischemic symptoms generally have an acute onset but may mimic other diseases, particularly in mesenteric ischemia. Early diagnosis and treatment can limit or even prevent tissue infarction. Guideline-recommended therapy with aspirin or warfarin reduces the thromboembolic risk. Suitable patients may optimize their warfarin therapy by self-monitoring of the international normalized ratio (INR). New oral and parenteral anticoagulants with more stable pharmacokinetics are being developed. In conclusion, atrial fibrillation predisposes to thromboembolism. If ischemic stroke or systemic thromboembolism occurs, early diagnosis and treatment can improve outcomes. The thromboembolic risks are reduced by guideline-adherent antithrombotic therapy with warfarin or aspirin. Future directions may include self-monitoring of the international normalized ratio and novel anticoagulants.

Survival as a function of HbA(1c) in people with type 2 diabetes: a retrospective cohort study

BACKGROUND

Results of intervention studies in patients with type 2 diabetes have led to concerns about the safety of aiming for normal blood glucose concentrations. We assessed survival as a function of HbA(1c) in people with type 2 diabetes.

METHODS

Two cohorts of patients aged 50 years and older with type 2 diabetes were generated from the UK General Practice Research Database from November 1986 to November 2008. We identified 27 965 patients whose treatment had been intensified from oral monotherapy to combination therapy with oral blood-glucose lowering agents, and 20 005 who had changed to regimens that included insulin. Those with diabetes secondary to other causes were excluded. All-cause mortality was the primary outcome. Age, sex, smoking status, cholesterol, cardiovascular risk, and general morbidity were identified as important confounding factors, and Cox survival models were adjusted for these factors accordingly.

FINDINGS

For combined cohorts, compared with the glycated haemoglobin (HbA(1c)) decile with the lowest hazard (median HbA(1c) 7.5%, IQR 7.5-7.6%), the adjusted hazard ratio (HR) of all-cause mortality in the lowest HbA(1c) decile (6.4%, 6.1-6.6) was 1.52 (95% CI 1.32-1.76), and in the highest HbA(1c) decile (median 10.5%, IQR 10.1-11.2%) was 1.79 (95% CI 1.56-2.06). Results showed a general U-shaped association, with the lowest HR at an HbA(1c) of about 7.5%. HR for all-cause mortality in people given insulin-based regimens (2834 deaths) versus those given combination oral agents (2035) was 1.49 (95% CI 1.39-1.59).

INTERPRETATION

Low and high mean HbA(1c) values were associated with increased all-cause mortality and cardiac events. If confirmed, diabetes guidelines might need revision to include a minimum HbA(1c) value.

FUNDING

Eli Lilly and Company.

Pharmacology and management of the vitamin K antagonists: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines (8th Edition)

This article concerning the pharmacokinetics and pharmacodynamics of vitamin K antagonists (VKAs) is part of the American College of Chest Physicians Evidence-Based Clinical Practice Guidelines (8th Edition). It describes the antithrombotic effect of the VKAs, the monitoring of anticoagulation intensity, and the clinical applications of VKA therapy and provides specific management recommendations. Grade 1 recommendations are strong and indicate that the benefits do or do not outweigh the risks, burdens, and costs. Grade 2 recommendations suggest that the individual patient's values may lead to different choices. (For a full understanding of the grading, see the "Grades of Recommendation" chapter by Guyatt et al, CHEST 2008; 133:123S-131S.) Among the key recommendations in this article are the following: for dosing of VKAs, we recommend the initiation of oral anticoagulation therapy, with doses between 5 mg and 10 mg for the first 1 or 2 days for most individuals, with subsequent dosing based on the international normalized ratio (INR) response (Grade 1B); we suggest against pharmacogenetic-based dosing until randomized data indicate that it is beneficial (Grade 2C); and in elderly and other patient subgroups who are debilitated or malnourished, we recommend a starting dose of < or = 5 mg (Grade 1C). The article also includes several specific recommendations for the management of patients with nontherapeutic INRs, with INRs above the therapeutic range, and with bleeding whether the INR is therapeutic or elevated. For the use of vitamin K to reverse a mildly elevated INR, we recommend oral rather than subcutaneous administration (Grade 1A). For patients with life-threatening bleeding or intracranial hemorrhage, we recommend the use of prothrombin complex concentrates or recombinant factor VIIa to immediately reverse the INR (Grade 1C). For most patients who have a lupus inhibitor, we recommend a therapeutic target INR of 2.5 (range, 2.0 to 3.0) [Grade 1A]. We recommend that physicians who manage oral anticoagulation therapy do so in a systematic and coordinated fashion, incorporating patient education, systematic INR testing, tracking, follow-up, and good patient communication of results and dose adjustments [Grade 1B]. In patients who are suitably selected and trained, patient self-testing or patient self-management of dosing are effective alternative treatment models that result in improved quality of anticoagulation management, with greater time in the therapeutic range and fewer adverse events. Patient self-monitoring or self-management, however, is a choice made by patients and physicians that depends on many factors. We suggest that such therapeutic management be implemented where suitable (Grade 2B).

Improving outpatient warfarin use for hospitalized patients with atrial fibrillation

Atrial fibrillation affects an estimated 5 million Americans and accounts for approximately 15% of all strokes. Few studies have successfully addressed patient screening, assessment, and introduction of appropriate antithrombotic therapy in patients with atrial fibrillation.

An evaluation of the association between systemic inflammation--as measured by C-reactive protein--and hospital resource use

OBJECTIVE

To evaluate the association between inflammatory status, as measured by C-reactive protein (CRP), during inpatient admission and subsequent inpatient outcome and associated resource use.

METHODS

Probabilistic record linkage was used to match hospital episode data, laboratory reports and mortality statistics in a large urban population of 424,000 people in South Wales, UK. Inpatient mortality, length of stay, emergency readmissions and subsequent 1-year hospital bed day occupancy were assessed as a function of CRP status.

RESULTS

Between 2001 and 2005, in total there were 432,272 CRP observations from 98,505 people; 69,593 admissions had at least one CRP measurement, affecting 47,100 individual patients. Across all ICD-10 primary diagnoses, CRP was acutely high (> 10 mg/L) in three-quarters of admissions. Acutely high CRP was associated with an eight-fold increase in risk of hospital mortality (p < 0.001) and a doubling of length of stay (p < 0.001) compared to normal CRP levels, after standardising for age and gender. Across the range of observed maximum CRP values measured during admissions (1 mg/L to > 400 mg/L) the likelihood of emergency readmission within 28 days of discharge increased by 50% (p < 0.001), and the predicted number of subsequent bed days occupied in the year following discharge increased by 30-58% across the range of CRP measurement (p = 0.004).

CONCLUSIONS

CRP has been found to be clearly associated with hospital resource use. Furthermore, CRP also predicted in-hospital mortality. This may imply that better management of systemic inflammation would result in resource savings in inflammatory diseases such as rheumatoid arthritis.

Perioperative Management of Anticoagulant Therapy during Cutaneous Surgery: 2005 Survey of Mohs Surgeons

BACKGROUND

The perioperative management of anticoagulation and antiplatelet therapy is a controversial topic in the field of dermatologic surgery. Dermasurgeons must weigh the risk of bleeding against the risk of thrombotic complications when deciding how to manage perioperative anticoagulation.

OBJECTIVE

Our aim is to present a summary of current practice in anticoagulation management perioperatively during cutaneous surgery. We compare our results to those found in a similar survey in 2002.

METHODS AND MATERIALS

A questionnaire surveying current practice in perioperative management of anticoagulant therapy was mailed to 720 dermasurgeons.

RESULTS

Thirty-eight percent of dermasurgeons responded to the questionnaire. Of the responding physicians, 87% discontinue prophylactic aspirin therapy, 37% discontinue medically necessary aspirin, 44% discontinue warfarin, 77% discontinue nonsteroidal anti-inflammatory drugs (NSAIDs), and 77% discontinue vitamin E therapy perioperatively at least some of the time. Although clopidogrel was not surveyed, 78 physicians included comments about the management of this agent.

CONCLUSION

Dermasurgeons were more likely to continue medically necessary aspirin and warfarin in 2005 compared to 2002, with the most dramatic shift evident in the management of warfarin. They were more likely to discontinue prophylactic aspirin, NSAIDs, and vitamin E. Surgeons were concerned about bleeding with the antiplatelet agent clopidogrel. More evidence-based medicine is necessary to set guidelines for the management of anticoagulation and antiplatelet therapy perioperatively.

Primary Stroke Prevention

The best way to prevent a first-time stroke is to identify at-risk patients and control as many risk factors as possible. Some risk factors, such as smoking, can be eliminated; others, such as hypertension and carotid artery stenosis, can be controlled or treated to reduce the risk of stroke. Nurses are encouraged to work with patients to identify all risk factors in order to reduce the prevalence of this medical condition that costs billions of dollars annually and results in significant disability.

The cost effectiveness of anticoagulation management services for patients with atrial fibrillation and at high risk of stroke in the US

BACKGROUND

Anticoagulation therapy with warfarin is widely considered the standard of care for stoke prophylaxis in patients with atrial fibrillation who are at high risk of stroke. Community-based studies in the US have reported that the effectiveness of anticoagulation varies by management approach and that patients receiving warfarin have international normalised ratio (INR) values within the target therapeutic range less than half the time.

OBJECTIVE

To estimate the lifetime societal costs and health benefits of warfarin therapy to prevent strokes, specifically in elderly patients (mean age 70 years) with atrial fibrillation who are at high risk of stroke, when anticoagulation is managed through usual care versus anticoagulation management services, where dedicated anticoagulation professionals (e.g. physician or pharmacist) monitor and oversee patients.

METHODS

Semi-Markov decision model with a 30-day cycle length and 10-year time horizon (to reflect the mean life expectancy of the study population). Univariate sensitivity analyses and Bayesian second-order multivariate probabilistic sensitivity analysis using Monte Carlo simulation were performed. Outcomes measures were costs and QALYs. Most of the probability and outcome estimates included were derived from the recent SPORTIF (Stroke Prevention using ORal Thrombin Inhibitor in atrial Fibrillation) V trial. Utility values were derived from a large, nationally representative sample of individuals in the Medical Expenditure Panel Survey and were adjusted for age, sex, race, ethnicity, income, education and co-morbidity. Resource utilisation was based on experience at the University Medicine Group Practice Anticoagulation Clinic (University of Colorado, Denver, CO, USA) and costs ($US; 2004 values) included were for warfarin and aspirin (acetylsalicylic acid) use and those associated with major bleeding, treatment of primary events, routine INR and biochemistry monitoring, ECGs, and clinic visits. Costs and outcomes were discounted by 3% per annum.

RESULTS

The anticoagulation management service improved effectiveness by 0.057 (95% credible interval 0, 0.36) QALYs and reduced costs by $US2100 (95% credible interval -$US19,800, $US300) [2004 values] compared with usual care. Results were sensitive to the extent of the increase in risk of primary events (all strokes and systemic embolic events attributable to usual care, but were robust to variation in other input variables). The anticoagulation management service was the dominant strategy in 91% of Monte Carlo simulations.

CONCLUSION

The anticoagulation management service appears to cost less and provide greater effectiveness than usual care. To enhance stroke prophylaxis among high-risk patients with atrial fibrillation, physicians and Medicare plans may wish to consider augmenting 'usual care' by the addition of patient-monitoring technology strategies such as formally organised anticoagulation monitoring programmes.

[Asymptomatic atrial fibrillation with systematic screening using tele-ECG--relevance for anticoagulation in paroxysmal atrial fibrillation]

Event recorder monitoring plays an important role in the early detection and diagnosis of rhythm disorders such as atrial fibrillation (AF). In a recent study over 1000 patients with symptomatic paroxysmal AF were followed up by daily and symptom triggered ECG self monitoring. Independent of the presence of antiarrhythmic therapy, the incidence of AF was much higher than expected, since over 50% of AF episodes were asymptomatic. Therefore, patients symptoms are not a reliable surrogate parameter for the detection of AF. Moreover, antiarrhythmic therapy does not totally prevent atrial fibrillation, but raises the risk of silent AF episodes by reducing the mean heart rate. Based on these findings, effective anticoagulation should be taken into consideration in patients with paroxysmal AF independent of antiarrhythmic medication. The decision for anticoagulation with cumarine derivates or aspirin is dependent on the age, underlying diseases, and the individual thromboembolic risk in these patients.