Oral anticoagulants for preventing stroke in patients with non-valvular atrial fibrillation and no previous history of stroke or transient ischemic attacks

Preceding direct oral anticoagulant administration reduces the severity of stroke in patients with atrial fibrillation - K-PLUS registry

BACKGROUND

Stroke severity can be mitigated by preceding anticoagulant administration in acute ischemic stroke patients with atrial fibrillation (AF). We investigated if such mitigative effects are different between warfarin and direct oral anticoagulants (DOACs).

MATERIAL AND METHODS

We collected data from a regional multicenter stroke registry. Ischemic stroke or transient ischemic attack patients with AF were included. Background characteristics, National Institutes of Health Stroke Scale (NIHSS) score on admission, lesion characteristics, and in-hospital death were analyzed according to preceding antithrombotic agents at onset.

RESULTS

A total of 2173 patients had AF; 628 were prescribed warfarin, 272 DOACs, 429 antiplatelets alone, and 844 no antithrombotics. The NIHSS score on admission was lowest in the DOACs group compared to the other groups. In neuroimaging analysis, small ischemic lesions were observed more frequently in the DOACs group, while large ischemic lesions were less frequent in this group. When the no antithrombotics group was used as a reference, the adjusted odds ratio for moderate to severe stroke was 0.56 (95% confidence interval, 0.40-0.78) in the DOACs group, while it was 0.98 (0.77-1.24) in the warfarin group and 0.94 (0.72-1.22) in the antiplatelets group. In-hospital mortality was lowest in the DOACs group compared to the other groups.

CONCLUSION

Preceding DOAC administration might mitigate the severity of stroke in AF patients more strongly than other antithrombotics, possibly leading to a better outcome in patients with stroke.

WITHDRAWN: Pharmacological cardioversion for atrial fibrillation and flutter

BACKGROUND

Atrial fibrillation is the commonest cardiac dysrhythmia. It is associated with significant morbidity and mortality. There are two approaches to the management of atrial fibrillation: controlling the ventricular rate or converting to sinus rhythm in the expectation that this would abolish its adverse effects.

OBJECTIVES

To assess the effects of pharmacological cardioversion of atrial fibrillation in adults on the annual risk of stroke, peripheral embolism, and mortality.

SEARCH METHODS

We searched the Cochrane Controlled Trials Register (Issue 3, 2002), MEDLINE (2000 to 2002), EMBASE (1998 to 2002), CINAHL (1982 to 2002), Web of Science (1981 to 2002). We hand searched the following journals: Circulation (1997 to 2002), Heart (1997 to 2002), European Heart Journal (1997-2002), Journal of the American College of Cardiology (1997-2002) and selected abstracts published on the web site of the North American Society of Pacing and Electrophysiology (2001, 2002).

SELECTION CRITERIA

Randomised controlled trials or controlled clinical trials of pharmacological cardioversion versus rate control in adults (>18 years) with acute, paroxysmal or sustained atrial fibrillation or atrial flutter, of any duration and of any aetiology.

DATA COLLECTION AND ANALYSIS

One reviewer applied the inclusion criteria and extracted the data. Trial quality was assessed and the data were entered into RevMan.

MAIN RESULTS

We identified two completed studies AFFIRM (n=4060) and PIAF (n=252). We found no difference in mortality between rhythm control and rate control relative risk 1.14 (95% confidence interval 1.00 to 1.31).Both studies show significantly higher rates of hospitalisation and adverse events in the rhythm control group and no difference in quality of life between the two treatment groups.In AFFIRM there was a similar incidence of ischaemic stroke, bleeding and systemic embolism in the two groups. Certain malignant dysrhythmias were significantly more likely to occur in the rhythm control group. There were similar scores of cognitive assessment.In PIAF, cardioverted patients enjoyed an improved exercise tolerance but there was no overall benefit in terms of symptom control or quality of life.

AUTHORS' CONCLUSIONS

There is no evidence that pharmacological cardioversion of atrial fibrillation to sinus rhythm is superior to rate control. Rhythm control is associated with more adverse effects and increased hospitalisation. It does not reduce the risk of stroke. The conclusions cannot be generalised to all people with atrial fibrillation. Most of the patients included in these studies were relatively older (>60 years) with significant cardiovascular risk factors.

Substantial differences in initiation of oral anticoagulant therapy and clinical outcome among non-valvular atrial fibrillation patients treated in inpatient and outpatient settings

AIMS

Patients with atrial fibrillation (AF) are encountered and treated in different healthcare settings, which may affect the quality of care. We investigated the use of oral anticoagulant (OAC) therapy and the risk of thrombo-embolism (TE) and bleeding, according to the healthcare setting.

METHODS AND RESULTS

Using national Danish registers, we categorized non-valvular AF patients (2002-11) according to the setting of their first-time AF contact: hospitalization (inpatients), ambulatory (outpatients), or emergency department (ED). Event rates and hazard ratios (HRs), calculated using Cox regression analysis, were estimated for outcomes of TE and bleeding. We included 116 051 non-valvular AF patients [mean age 71.9 years (standard deviation 14.1), 51.3% males], of whom 55.2% were inpatients, 41.9% outpatients, and 2.9% ED patients. OAC therapy 180 days after AF diagnosis among patients with a CHADS2 ≥ 2 was 42.1, 63.0, and 32.4%, respectively. Initiation of OAC therapy was only modestly influenced by CHADS2 and HAS-BLED scores, regardless of the healthcare setting. The rate of TE was 4.30 [95% confidence interval (CI) 4.21-4.40] per 100 person-years for inpatients, 2.28 (95% CI 2.22-2.36) for outpatients, and 2.30 (95% CI 2.05-2.59) for ED patients. The adjusted HR of TE, with inpatients as reference, was 0.74 (95% CI 0.71-0.77) for outpatients and 0.89 (95% CI 0.79-1.01) for ED patients.

CONCLUSION

In a nationwide cohort of non-valvular AF patients, outpatients were much more likely to receive OAC therapy and had a significantly lower risk of stroke/TE compared with inpatients and ED patients. However, across all settings investigated, OAC therapy was far from optimal.

Anticoagulation treatment for the reduction of stroke in atrial fibrillation: a cohort study to examine the gap between guidelines and routine medical practice

BACKGROUND

Atrial fibrillation (AF) is the most common heart arrhythmia, affecting 6% of people over 65 years, and carries a 4.5% average annual stroke risk, which can be reduced by appropriate anticoagulation. A multi-centre observational study, Management and Outcomes in the Care of Atrial fibrillation in Germany (MOCA) was conducted to evaluate the current anticoagulation treatment pattern in patients with AF in Germany.

METHODS

Patients with AF were recruited from December 2003 to June 2004 in physician practices. Clinical data including International Normalised Ratio (INR) values and anticoagulation strategy were obtained from the physician chart and the patient follow-up, documenting hospitalisations, medications, and complications, was conducted at three and six months. Main outcome measures included anticoagulation methods, practice guidelines adherence and time within recommended anticoagulation range.

RESULTS

361 patients with AF (mean age 71+/-9, 61% male) were recruited in 45 physician practices. 90% of all patients had been treated with Vitamin K-Antagonists (VKA) at some time since AF-diagnosis, 88% were still treated. 10% of patients received aspirin as their anticoagulation therapy. Monitoring occurred at least once a month in over 70% of patients. Monitored INR values were 56% of the time within, 14% below and 30% over the recommended target range. A gap of 40% existed between the guideline recommendations and actual practice. Younger patients (<60 years of age) with no documented risk factors for stroke were over-treated with VKAs and patients older than 75 years without contraindications for anticoagulation were under-treated.

CONCLUSIONS

This study presents 'real-life' data in treating patients with AF in Germany and identifies the potential to advance the quality of care with respect to anticoagulation.

The Belgian Improvement Study on Oral Anticoagulation Therapy: a randomized clinical trial

AIMS

In Belgium, general practitioners (GPs) mainly manage oral anticoagulation therapy. To improve the quality of oral anticoagulation management by GPs and to compare different models and interventions, a randomized clinical trial was performed.

METHODS AND RESULTS

Stratified randomization divided 66 GP-practices into four groups. A 6-month retrospective analysis assessed the baseline quality. In the prospective study, each group received education on oral anticoagulation, anticoagulation files, and patient information booklets (groups A, B, C, and D). Group B additionally received feedback every 2 months on their anticoagulation performance; group C determined the international normalized ratio (INR) with a CoaguChek device in the doctor's office or at the patient's home; and group D received Dawn AC computer assisted advice for adapting oral anticoagulation. For the different groups, the time spent in target INR range (Rosendaal's method) and adverse events related to anticoagulation were determined and compared with the same quality indicators at baseline. There was a significant increase in per cent of time within 0.5 INR from target, from 49.5% at baseline to 60% after implementing the different interventions. However, neither the per cent in target range nor the event rates differed among the four groups.

CONCLUSION

The interventions significantly improved the quality of management of oral anticoagulation by Belgian GPs, mainly as a result of an education and support programme.

A Bayesian approach to evaluating net clinical benefit allowed for parameter uncertainty

BACKGROUND AND OBJECTIVE

Although randomized controlled trials (RCTs) are conducted to establish whether novel interventions work on average in the patient population, there is a growing desire to move to a more individualized approach to evaluation. The potential benefits and harms of a treatment policy may differ between individuals. If these benefits and harms are not evaluated distinctly, and in a quantitative framework, transparency can be lost in the decision-making process.

METHODS

Glasziou and Irwig have outlined the concept of net clinical treatment benefit for identifying the patients for whom the potential benefits of treatment outweigh the possible side effects. This study revisits the decision whether to use warfarin to treat atrial fibrillation. In this analysis, RCT and various sorts of observational data are synthesized.

RESULTS

This reanalysis brings into question the conclusions of the original analysis on who would benefit from warfarin; however, caution is advised, due to limitations in the quality of life data available.

CONCLUSION

A fully realized Bayesian implementation of the model is presented. This provides a framework for including uncertainty related to the estimation of all model parameters, and permits both direct probability statements and credible intervals for specific patient groups to be expressed.

[Level of understanding of patients on anticoagulants at a health centre: relationship of this and monitoring of therapy]

OBJECTIVES

To ascertain the level of understanding that patients taking oral anti-coagulants (OAC) and monitored at a primary care centre have of their treatment and to relate this to the monitoring of the therapy.

DESIGN

Descriptive study lasting one year.

SETTING

Pintores Health Centre, Parla. Area 10.

PARTICIPANTS

Adult patients in treatment for at least 6 months with OAC treatment and monitored in PC. Method. Patients took a 9-question test. The replies were evaluated, with points from 0 to 3 awarded for the understanding the patient possessed. The highest score possible was 15. To assess the degree of therapy monitoring, the crossover analysis of the determinations of the international normalized ratio (INR) over the previous year was used, taking at random 6 determinations per patient. An association between patients' level of understanding (<10 points and >10 points) and the degree of therapy monitoring (<66% or >66% of determinations of INR in rank) was looked for, using the Chi-squared as a statistical test.

RESULTS

50 patients were assessed with a mean score of 7.14 points. In addition, 294 INR determinations were analysed, with 56.12% at satisfactory levels. No significant relationship was found between patients' level of understanding and the degree of therapy monitoring.

CONCLUSIONS

The level of understanding of patients on OAC about their illness and treatment is very low, and basically depends on age. Even so, monitoring by health professionals and patients' high degree of compliance with their therapy despite their scant understanding lead to excellent levels at monitoring, with a very low index of appearance of greater complications.

Atrial fibrillation in a primary care practice: prevalence and management

BACKGROUND

Atrial fibrillation is a common serious cardiac arrhythmia. Knowing the prevalence of atrial fibrillation and documentation of medical management are important in the provision of primary care. This study sought to determine the prevalence of atrial fibrillation in a primary care population and to identify and quantify the treatments being used for stroke prevention in this group of patients.

METHODS

A prevalence study through chart audit was conducted in the family medicine practice at the Sunnybrook campus of the Sunnybrook and Women's College Health Sciences Centre. The main outcome measures were the prevalence of atrial fibrillation in our primary care practice and the use of warfarin for stroke prevention in this population.

RESULTS

261 patients in our practice have atrial fibrillation. The overall prevalence in our family practice unit is 3.9%. When considering patients aged 60 and over, the prevalence rises to 12.2%. 204 of our patients with atrial fibrillation (78.2%) are currently being treated with warfarin. Another 21 patients were previously treated and discontinued for a number of reasons. Of the 57 patients not currently treated with warfarin, 44 are treated with ASA, 2 with ticlopidine, and 11 are receiving no preventative treatment.

CONCLUSIONS

The prevalence of atrial fibrillation in our practice is higher than the range of prevalence reported in the general literature. However, our coverage with warfarin treatment exceeds previous reports in the literature.

Risk of early death and recurrent stroke and effect of heparin in 3169 patients with acute ischemic stroke and atrial fibrillation in the International Stroke Trial

BACKGROUND AND PURPOSE

We sought to investigate the apparently high risk of early death after an ischemic stroke among patients with atrial fibrillation (AF), identify the main factors associated with early death, and assess the effect of treatment with different doses of subcutaneous unfractionated heparin (UFH) given within 48 hours.

METHODS

We studied the occurrence of major clinical events within 14 days among 18 451 patients from the International Stroke Trial, first for all treatment groups combined. Then, among patients with AF, we examined the effects of treatment with subcutaneous UFH started within 48 hours and continued until 14 days after stroke onset.

RESULTS

A total of 3169 patients (17%) had AF. Seven hundred eighty-four patients were allocated to UFH 12 500 IU SC BID, 773 to UFH 5000 IU SC BID, and 1612 to no heparin. Within each of these groups, half of the patients were randomly assigned to aspirin 300 mg once daily. Compared with patients without AF, patients with AF were more likely to be female (56% versus 45%), to be old (mean age, 78 versus 71 years), to have an infarct on prerandomization CT (57% versus 47%), and to have impaired consciousness (37% versus 20%). The initial ischemic stroke type was more often a large-artery infarct (36% versus 21%). A lacunar stroke syndrome was less common (13% versus 26%). Death within 14 days was more common in patients with AF (17% versus 8%) and more often attributed to neurological damage from the initial stroke (10% versus 4%). The frequency of recurrent ischemic or undefined stroke was not significantly different (3.9% versus 3.3%). The proportion of AF patients with further events within 14 days allocated to UFH 12 500 IU (n=784), UFH 5000 IU (n=773), and to no-heparin (n=1612) groups were as follows: ischemic stroke, 2.3%, 3.4%, 4.9% (P=0.001); hemorrhagic stroke, 2.8%, 1.3%, 0.4% (P<0.0001); and any stroke or death, 18.8%, 19.4% and 20.7% (P=0.3), respectively. No effect of heparin on the proportion of patients dead or dependent at 6 months was apparent.

CONCLUSIONS

Acute ischemic stroke patients with AF have a higher risk of early death, which can be explained by older age and larger infarcts but not by a higher risk of early recurrent ischemic stroke, although slightly more patients with AF died from a fatal recurrent stroke of ischemic or unknown type (1.3% versus 0.9%). In patients with AF the absolute risk of early recurrent stroke is low, and there is no net advantage to treatment with heparin. These data do not support the widespread use of intensive heparin regimens in the acute phase of ischemic stroke associated with AF.

Antithrombotic therapy to prevent stroke in patients with atrial fibrillation: a meta-analysis

PURPOSE

To characterize the efficacy and safety of anticoagulants and antiplatelet agents for prevention of stroke in patients with atrial fibrillation.

DATA SOURCES

Randomized trials identified by using the search strategy developed by the Cochrane Collaboration Stroke Review Group.

STUDY SELECTION

All published randomized trials testing antithrombotic agents to prevent stroke in patients with atrial fibrillation.

DATA EXTRACTION

Data on interventions, number of participants, duration of exposure and occurrence of all stroke (ischemic and hemorrhagic), major extracranial bleeding, and death were extracted independently by two investigators.

DATA SYNTHESIS

Sixteen trials included a total of 9874 participants (mean follow-up, 1.7 years). Adjusted-dose warfarin (six trials, 2900 participants) reduced stroke by 62% (95% CI, 48% to 72%); absolute risk reductions were 2.7% per year for primary prevention and 8.4% per year for secondary prevention. Major extracranial bleeding was increased by warfarin therapy (absolute risk increase, 0.3% per year). Aspirin (six trials, 3119 participants) reduced stroke by 22% (CI, 2% to 38%); absolute risk reductions were 1.5% per year for primary prevention and 2.5% per year for secondary prevention. Adjusted-dose warfarin (five trials, 2837 participants) was more efficacious than aspirin (relative risk reduction, 36% [CI, 14% to 52%]). Other randomized comparisons yielded inconclusive results.

CONCLUSIONS

Adjusted-dose warfarin and aspirin reduce stroke in patients with atrial fibrillation, and warfarin is substantially more efficacious than aspirin. The benefit of antithrombotic therapy was not offset by the occurrence of major hemorrhage among participants in randomized trials. Judicious use of antithrombotic therapy, tailored according to the inherent risk for stroke, importantly reduces stroke in patients with atrial fibrillation.