Prevalence Of Non-valvular Atrial Fibrillation Research Articles

Fibrilación auricular no valvular en pacientes en diálisis peritoneal: prevalencia, tratamiento y profesionales implicados

Atrial fibrillation is the most frequent chronic arrhythmia in patients with chronic kidney disease. Oral anticoagulation with vitamin K antagonists and now direct oral anticoagulants have been and are the fundamental pillar for the prevention of thromboembolic events. However, there are no randomized clinical trials on the risk-benefit profile of oral anticoagulation in patients with chronic kidney disease stage 5 on peritoneal dialysis and there is little evidence in the literature in this population.The objective of our study was to know the prevalence, treatment and professionals involved in the management of atrial fibrillation in peritoneal dialysis patients. For this purpose, we performed a descriptive analysis through a survey sent to different peritoneal dialysis units in Spain. A total of 1403 patients on peritoneal dialysis were included in the study, of whom 186 (13.2%) had non-valvular atrial fibrillation. In addition, the assessment of the scores of thromboembolic and bleeding risks for the indication of oral anticoagulation was mainly carried out by the cardiologist (60% of the units), as well as its prescription (cardiologist 47% in consensus with the nephrologist 43%).In summary, patients on peritoneal dialysis have a remarkable prevalence of non-valvular atrial fibrillation. Patients frequently receive oral anticoagulation with vitamin K antagonists, as well as direct oral anticoagulants. The data obtained regarding the scales used for the assessment of thromboembolic and bleeding risk, treatment and involvement by Nephrology indicates that there is a need for training and involvement of the nephrologist in this pathology.

Oral Anticoagulation in Patients with Chronic Kidney Disease and Non-Valvular Atrial Fibrillation: The FAERC Study.

The FAERC study performed a retrospective multicentre analysis of historical cohorts in which data were collected from arrhythmia diagnosis onwards. We analysed a Spanish cohort of 4749 patients with CKD (mean eGFR 33.9 mL/min) followed up in the nephrology clinic, observing a 12.2% prevalence of non-valvular AF. In total, 98.6% of these patients were receiving anticoagulant treatment, mainly with coumarins (79.7%). Using direct-acting oral anticoagulants (DOACs) was associated with fewer cerebrovascular events than using acenocoumarol, but in contrast with other studies, we could not corroborate the association of risk of bleeding, coronary events, or death with a type of anticoagulant prescribed. Atrial fibrillation is highly prevalent in renal patients. Direct-acting anticoagulants seem to be associated with fewer ischemic-embolic complications, with no differences in bleeding, coronary events, or mortality rates.

MO717: Prevalence and Management of Non-Valvular Atrial Fibrillation in Peritoneal Dialysis. Results of a Multicentric Survey

Abstract BACKGROUND AND AIMS Among patients with chronic kidney disease, the incidence and prevalence of nonvalvular atrial fibrillation (NVAF) increases as renal function decreases, detecting a prevalence of up to 27% in hemodialysis patients. However, its prevalence among patients on peritoneal dialysis (PD) has been less studied. The aim of the study is to analyse the prevalence of NVAF and characteristics related to its management in PD patients older than 18 years. METHOD An observational, cross-sectional, multicenter and retrospective study was carried out through a survey and request for variables sent through a Google questionnaire to PD units in our country. A total of 1403 patients from 30 PD units were included. RESULTS The mean prevalence of NVAF in the study was 13.2%, median 11.7% (interquartile range: 6.1–19.4). A total of 60% of the centers had a prevalence >10%. A total of 57.6% (n = 17) used the CHADS2 or CHAS2-VASC score to calculate the risk of stroke/thromboembolism in their patients with NVAF. A total of 43.3% (n = 13) do not use it. In these cases, 15.3% (n = 2) do not calculate it because they treat all patients with NVAF and the remaining 84.6% (n = 11) do not use it because the cardiologist uses it and delegates it to them. Regarding the decision to start anticoagulant treatment in NVAF: in 60% of the centers (n = 18) the cardiologist indicates anticoagulation, in 36.7% (n = 11) the indication is made jointly (cardiologist and nephrologist) and only in 3.3% (n = 1) the indication is made by the nephrologist. A total of 72.5% of the patients with NVAF (135/186) received anticoagulant treatment. Of these, 28 (20.7%) received direct-acting anticoagulants and 107 (79.3%) received acenocoumarol. Among direct-acting anticoagulants, the most frequent regimens were: apixaban 2.5 mg/12 h (86%), and edoxaban 30 mg/24 h (7%). A total of 5.9% (11/186) of patients with NVAF did not receive anticoagulant or antiplatelet treatment. A total of 90% of the centers (n = 27) are familiar with the technique of percutaneous appendage closure for the treatment of NVAF, but it is not available in five of them. This technique has been performed in 17 of the patients with NVAF. CONCLUSION The prevalence of NVAF in PD patients is high. The management of these patients is carried out mainly by cardiologists with little participation of nephrologists. Most patients receive anticoagulant treatment with coumarin drugs. The data from this analysis, as well as the limited data from the literature, indicate that an adequate format, a consensus document, as well as more data from observational studies (and especially from randomized controlled trials) are needed to adequately address this common complication in patients with DP.

Association between renal function and clinical outcomes in elderly patients with nonvalvular atrial fibrillation: sub-analysis of the ANAFIE Registry

Abstract Background With the advance of age, the prevalence of non-valvular atrial fibrillation (NVAF) increases and renal function decreases. Decreased renal function is associated with a higher risk of both thrombotic and bleeding events. In clinical practice, warfarin (WF) is often administered to patients with decreased renal function rather than direct oral anticoagulants (DOAC) due to the lack of evidence for DOAC. Therefore, it is important to clarify the clinical features and optimal management of anticoagulants for elderly AF patients. Purpose The All Nippon Atrial Fibrillation In the Elderly (ANAFIE) Registry is a prospective, multicenter, observational study designed to collect real-world data on clinical status and prognosis for more than 30,000 Japanese patients (age ≥75 years) with NVAF. This sub-analysis of the ANAFIE Registry assessed 2-year outcomes and anticoagulant treatment in elderly NVAF patients, stratified by renal function. Methods A total of 32,275 patients from the ANAFIE registry were divided into 5 groups by creatinine clearance (CrCL), estimated using the Cockcroft–Gault equation modified for Japanese (CrCL: <15, 15 to <30, 30 to <50, 50 to <80, ≥80 mL/min). Kaplan-Meier analysis was used to evaluate the annualized incidence rates of clinical outcomes. Hazard ratios (HR) for clinical outcomes were analyzed using the Cox proportional-hazards model. Results In the total population, the mean age was 81.5 years; men accounted for 57.3%; the mean CHA2DS2-VASc score was 4.5; the mean HAS-BLED score was 1.9; the prevalence of paroxysmal AF was 42.1%; the mean follow-up period was 1.88 years; and oral anticoagulants were used by 92.4% of patients (WF, 25.5%; DOAC, 66.9%). The percentages of patients with CrCL <15, 15 to <30, 30 to <50, 50 to <80, and ≥80 mL/min were 1.3%, 10.7%, 33.4%, 32.4%, and 3.4%, respectively. As renal function decreased, the mean age was higher, the CHA2DS2-VASc and HAS-BLED scores were higher, the proportion of patients receiving anticoagulants was lower, the administration rate of WF was higher, and that of DOAC was lower. The overall incidence rates of clinical outcomes were 3.01% for stroke or systemic embolic events (SEE), 2.00% for major bleeding, 2.03% for CV death, and 6.95% for all-cause mortality. Compared with the reference group (CrCL ≥50 mL/min), the HRs for these clinical outcomes except major bleeding increased significantly as renal function decreased (p-value for trend <0.05 for all) (Table). In patients with CrCL15 to <30 mL/min, compared to patients receiving WF, those receiving DOAC had no significant difference in the HRs for stroke/SEE, major bleeding, CV death, and all-cause death. Conclusions Elderly NVAF patients with decreased CrCL were less likely to use oral anticoagulants and more likely to experience clinical events than those with normal renal function. Among patients with CrCL15 to <30 mL/min, the incidences of clinical events were similar between WF and DOAC. Funding Acknowledgement Type of funding sources: Private company. Main funding source(s): Daiichi Sankyo Co., Ltd.

Trends in Prevalence of Non-Valvular Atrial Fibrillation and Anticoagulation Therapy in a Japanese Region - Analysis Using the National Health Insurance Database.

Direct oral anticoagulants (DOACs) are effective in reducing thromboembolism events in patients with non-valvular atrial fibrillation (NVAF). However, little is known about trends in NVAF prevalence and DOAC prescriptions in daily clinical practice. This study investigated the current status and trends in NVAF prevalence and DOAC prescriptions in a region of Japan.Methods and Results:Annual data for the 4 years from May 2014 to May 2017 in the Tsugaru region of Aomori Prefecture, Japan, were obtained for analysis from the Japanese National Health Insurance database ("Kokuho" database [KDB]). The prevalence of NVAF in subjects aged 40-74 years increased gradually over the 4-year study period (1,094/57,452 [1.90%] in 2014, 1,055/56,018 [1.88%] in 2015, 1,072/54,256 [1.98%] in 2016, and 1,154/52,341 [2.20%] in 2017). The proportion of NVAF patients prescribed warfarin decreased (42%, 33%, 24%, and 21% in 2014, 2015, 2016, and 2017, respectively), the proportion of those prescribed DOACs increased (30%, 42%, 50%, and 57%, respectively), and the proportion not prescribed an oral anticoagulant (OAC) decreased (28%, 25%, 26%, and 22%, respectively). However, 17% of patients with a CHADS2score ≥2 were not prescribed an OAC in 2017. By using the KDB we found that the prevalence of NVAF has increased gradually from 2014 to 2017. In the Tsugaru region in Japan, DOACs prescriptions increased and warfarin prescriptions decreased over the 4-year period.

Burden of atrial fibrillation in Māori and Pacific people in New Zealand: a cohort study

Atrial fibrillation (AF) is a major risk factor for ischaemic stroke and cardiovascular events. In New Zealand (NZ), Māori (indigenous New Zealanders) and Pacific people experience higher rates of AF compared with non-Māori/non-Pacific people. To describe a primary care population with AF in NZ. Stroke risk and medication adherence according to ethnicity are also detailed. Electronic medical records for adults (≥20 years, n = 135 840, including 19 918 Māori and 43 634 Pacific people) enrolled at 37 NZ general practices were analysed for AF diagnosis and associated medication prescription information. The overall prevalence of non-valvular AF (NVAF) in this population was 1.3% (1769), and increased with age (4.4% in people ≥55 years). Māori aged ≥55 years were more likely to be diagnosed with NVAF (7.3%) than Pacific (4.0%) and non-Māori/non-Pacific people (4.1%, P < 0.001). Māori and Pacific NVAF patients were diagnosed with AF 10 years earlier than non-Māori/non-Pacific patients (median age of diagnosis: Māori = 60 years, Pacific = 61 years, non-Māori/non-Pacific = 71 years, P < 0.001). Overall, 67% of NVAF patients were at high risk for stroke (CHA2 DS2 -VASc ≥ 2) at the time of AF diagnosis. Almost half (48%) of Māori and Pacific NVAF patients aged <65 years were at high risk for stroke, compared with 22% of non-Māori/non-Pacific (P < 0.001). Irrespective of ethnic group, adherence to AF medication was suboptimal in those NVAF patients with a high risk of stroke or with stroke history. AF screening and stroke thromboprophylaxis in Māori and Pacific people could start below the age of 65 years in NZ.

Anticoagulation for atrial fibrillation after intracranial hemorrhage: A systematic review.

We summarize the existing evidence on the potential benefit of oral anticoagulation (OAC) in intracerebral hemorrhage (ICH) survivors with nonvalvular atrial fibrillation (NVAF). Systematic review of the literature to address the following issues: (1) prevalence of NVAF in ICH survivors, (2) current prescription of OAC, (3) factors associated with resumption of OAC, (4) risk of ischemic stroke (IS) and recurrent ICH, and (5) ideal timing for restarting OAC in ICH survivors with NVAF. After screening 547 articles, 26 were included in the review. Only 3 focused specifically on patients with ICH as primary event, NVAF as indication for OAC, and recurrent ICH and IS as primary endpoints. In addition, 19 letters to the editor/reviews/editorials/experts' surveys/experts' opinion were used for discussion purposes. NVAF is highly prevalent among ICH survivors. The risks of IS, recurrent ICH, and mortality are heightened in this group. Most published data show a net benefit in terms of IS prevention and mortality when anticoagulation is restarted. However, those studies are observational and mostly retrospective, therefore selection bias may play a major role in the results observed in these cohorts. Only randomized controlled trials, either pragmatic or explanatory, can provide more conclusive answers for this important clinical question.

Prevalence of Non-valvular Atrial Fibrillation Based on Geographical Distribution and Socioeconomic Status in the Entire Korean Population.

Background and ObjectivesPrevalence of atrial fibrillation (AF) varies based on geographical location and socioeconomic status. We aimed to evaluate the prevalence of AF and utilization of antithrombotic therapy based on geographical regions and income levels in the entire Korean population.MethodsWe performed a cross-sectional analysis of Korean adults (aged ≥20 years) using the 2015 National Health Insurance Service database (n=41,505,679). The study population was stratified into 17 geographical regions and 21 income levels.ResultsWe identified 276,842 patients diagnosed with AF. Overall prevalence of AF in suburban/rural regions was significantly higher than that observed in urban regions (0.72% vs. 0.61%, respectively, p<0.001). Elderly patients (age ≥75 years) showed a higher prevalence of AF and comorbidities related to AF development showed a higher prevalence among the population residing in suburban/rural regions. Among AF patients with a CHA2DS2-VASc score ≥2, oral anticoagulation (OAC) therapy utilization was lower in the suburban/rural regions than that observed in the urban regions (48.2% vs. 51.8%, respectively, p<0.001). The relationship between income levels and AF prevalence showed a J-shaped curve. The OAC prescription rate showed a positive correlation with income levels. Non-vitamin K antagonist oral anticoagulants tended to be more commonly prescribed among the higher income groups.ConclusionsGeographical location of residence and income levels were closely associated with the prevalence of AF and antithrombotic therapy utilization. This information may provide further insights for more effective surveillance of AF and stroke prevention for improved clinical outcomes.

Anticoagulation therapy in the elderly with non-valvular atrial fibrillation: a double-edged sword

Prevalence of non-valvular atrial fibrillation is increasing over time. Particularly in elderly population, treatment strategies to reduce the rate of stroke are challenging and still represent an unsolved cultural question. Indeed, the risk of thromboembolism increases in the elderly in parallel with the risk of bleeding. The frequent coexistence of several morbidities, frailty syndrome, polypharmacy, chronic kidney disease and dementia strengthens the perception that risk-benefit ratio of anticoagulant therapy could be unfavorable, and explains why such treatment is underused in the elderly. Recently, the introduction of non-vitamin K oral anticoagulants (NOACs) has allowed us to overcome the large number of limitations imposed by the use of vitamin K antagonists. In this manuscript, the benefits of individual NOACs in comparison with warfarin in elderly patients are reviewed. Targeted studies on complex elderly patients are needed to test usefulness of a geriatric comprehensive assessment, besides the scores addressing risk of thromboembolic and hemorrhagic events. In the meantime, it is mandatory that use of anticoagulant therapy in most elderly people, currently excluded from randomized controlled trials, is prudent and responsible.

Sex Differences in Outcomes among Stroke Survivors with Non-Valvular Atrial Fibrillation in China.

Atrial fibrillation (AF) significantly increases the risk of stroke and disease burden and is an established predictor of poor outcomes after stroke. However, data regarding sex differences in long-term outcomes following stroke in patients with AF are scarce. We thus aimed to assess these differences. We recruited 951 consecutive patients with acute ischemic stroke and non-valvular atrial fibrillation (NVAF) treated at three hospitals in Tianjin, China, from January 2006 to September 2014. Information regarding stroke subtype, severity, risk factors, and outcomes (mortality, dependency, and recurrence) at 3, 12, and 36 months after stroke was recorded. The prevalence of NVAF was 8.4% overall, with a higher frequency in women than in men (11.3 vs. 6.9%, P < 0.001). Among patients with NVAF, women were older than men. Women were more likely than men to have severe stroke (38.8 vs. 29.5%, P < 0.001), high levels of total cholesterol and high- and low-density lipoprotein cholesterol (all P < 0.001), hypertension (69.1 vs. 61.2%, P = 0.012), dyslipidemia (29.8 vs. 20.7%, P = 0.001), and obesity (18.5 vs. 11.6%, P = 0.003); they were less likely than men to be current smokers (12.2 vs. 33.6%, P < 0.001) and to consume alcohol (0.9 vs. 13.9%, P < 0.001). There were greater risks of dependency and recurrence at 36 months after stroke in women than in men [odds ratios (95% confidence intervals), 1.64 (1.02–2.64) for dependency, P = 0.043; and 2.03 (1.28–3.20) for recurrence, P = 0.002] after adjustment for stroke subtype, severity, and risk factors. These findings suggest that it is crucial to emphasize the need for individualized stroke prevention education and promotion of healthy lifestyles in order to improve NVAF-related stroke outcomes and reduce disease burden in women.

Antithrombotic treatment and characteristics of elderly patients with non-valvular atrial fibrillation hospitalized at Internal Medicine departments. NONAVASC registry

Background and objectivesThe prevalence of non-valvular atrial fibrillation (NVAF) increases with the patient's age and is associated with high morbi-mortality rates. The main goal of this study was to describe the characteristics of hospitalized elderly patients with NVAF and to identify the clinical and functional factors which determine the use of different antithrombotic strategies. Patients and methodsObservational, prospective, multicentre study carried out on patients with NVAF over the age of 75, who had been admitted for any medical condition to Internal Medicine departments. ResultsWe evaluated 804 patients with a mean age of 85 years (range 75–101), of which 53.9% were females. The prevalence of risk factors and cardiovascular disease was high: hypertension (87.6%), heart failure (65.4%), ischemic cardiomyopathy (24.4%), cerebrovascular disease (22.4%) and chronic kidney disease (45%). Among those cases with previous diagnoses of NVAF, antithrombotic treatment was prescribed in 86.2% of patients: anticoagulants (59.7%), antiplatelet medication (17.8%) and double therapy (8.7%). The factors associated with the use of antithrombotic treatment were history of acute coronary syndrome and atrial fibrillation progression longer than one year. Older age, atrial fibrillation for less than one year, higher HAS-BLED scores and severe cognitive impairment were associated with the use of anti-platelet drugs. Permanent atrial fibrillation favored the use of anticoagulants. ConclusionsHospitalized patients older than 75 years old with NVAF showed numerous comorbidities. The percentage of anticoagulation was small and 18% received only anti-platelet therapy. The patient's age, atrial fibrillation's progression time and the severity of the cognitive impairment influenced this therapy choice.

Características y tratamiento antitrombótico de los pacientes ancianos con fibrilación auricular no valvular hospitalizados en Medicina Interna. Registro NONAVASC

Background and objetivesThe prevalence of non-valvular atrial fibrillation (NVAF) increases with the patient's age and is associated with high morbi-mortality rates. The main goal of this study was to describe the characteristics of hospitalized elderly patients with NVAF and to identify the clinical and functional factors which determine the use of different antithrombotic strategies. Patients and methodsObservational, prospective, multicentre study carried out on patients with NVAF over the age of 75, who had been admitted for any medical condition to Internal Medicine departments. ResultsWe evaluated 804 patients with a mean age of 85 years (range 75-101), of which 53.9% were females. The prevalence of risk factors and cardiovascular disease was high: hypertension (87.6%), heart failure (65.4%), ischemic cardiomyopathy (24.4%), cerebrovascular disease (22.4%) and chronic kidney disease (45%). Among those cases with previous diagnoses of NVAF, antithrombotic treatment was prescribed in 86.2% of patients: anticoagulants (59.7%), antiplatelet medication (17.8%) and double therapy (8.7%). The factors associated with the use of antithrombotic treatment were history of acute coronary syndrome and atrial fibrillation progression longer than one year. Older age, atrial fibrillation for less than one year, higher HAS-BLED scores and severe cognitive impairment were associated with the use of anti-platelet drugs. Permanent atrial fibrillation favoured the use of anticoagulants. ConclusionsHospitalized patients older than 75 years old with NVAF showed numerous comorbidities. The percentage of anticoagulation was small and 18% received only anti-platelet therapy. The patient's age, atrial fibrillation's progression time and the severity of the cognitive impairment influenced this therapy choice.

The factor xa inhibitor edoxaban for the prevention of stroke and systemic embolism in patients with atrial fibrillation

ABSTRACTIntroduction: With the rising prevalence of nonvalvular atrial fibrillation (NVAF) in the general population, the development of new drugs for prevention of thromboembolic events is essential. Non-vitamin K antagonist oral anticoagulants (NOACs) have been shown to present a number of advantages over conventionally used agents, such as predictable pharmacokinetics and no requirement for continuous anticoagulant monitoring. The most recently approved NOAC for the NVAF indication is edoxaban. Several subgroup analyses from the edoxaban phase III ENGAGE AF-TIMI 48 trial have now been published, alongside meta-analysis data comparing the four currently approved NOACs. Consequently, an updated review of the literature is merited.Areas covered: A PubMed search using the terms ‘edoxaban’, ‘non-vitamin K antagonist oral anticoagulant’, ‘ENGAGE AF-TIMI 48’, and ‘atrial fibrillation’ was performed and results screened for the most relevant English language publications. The market position, pharmacological profile, clinical efficacy, safety and tolerability of edoxaban are presented and discussed.Expert commentary: Edoxaban has been shown to have an efficacy similar or superior to that of warfarin, with a potentially lower risk of major bleeding and predictable, dose-dependent pharmacology. In order to clarify its position within the NOAC market, head-to-head comparative studies are required.

Comorbidities against quality control of VKA therapy in non-valvular atrial fibrillation: a French national cross-sectional study.

BackgroundGiven the prevalence of non-valvular atrial fibrillation in the geriatric population, thromboembolic prevention by means of vitamin K antagonists (VKA) is one of the most frequent daily concerns of practitioners. The effectiveness and safety of treatment with VKA correlates directly with maximizing the time in therapeutic range, with an International Normalized Ratio (INR) of 2.0-3.0. The older population concentrates many of factors known to influence INR rate, particularly concomitant medications and concurrent medical conditions, also defined as comorbidities.ObjectiveDetermine whether a high burden on comorbidities, defined by a Charlson Comorbidity Index (CCI) of 3 or greater, is associated a lower quality of INR control.Study-DesignCross-sectional study.SettingsFrench geriatric care units nationwide.Participants2164 patients aged 80 and over and treated with vitamin K antagonists.MeasurementsComorbidities were assessed using the Charlson Comorbidity Index (CCI). The recorded data included age, sex, falls, kidney failure, hemorrhagic event, VKA treatment duration, and the number and type of concomitant medications. Quality of INR control, defined as time in therapeutic range (TTR), was assessed using the Rosendaal method.Results487 patients were identified the low-quality control of INR group. On multivariate logistic regression analysis, low-quality control of INR was independently associated with a CCI ≥3 (OR = 1.487; 95% CI [1.15; 1.91]). The other variables associated with low-quality control of INR were: hemorrhagic event (OR = 3.151; 95% CI [1.64; 6.07]), hospitalization (OR = 1.614, 95% CI [1.21; 2.14]).ConclusionAn elevated CCI score (≥3) was associated with low-quality control of INR in elderly patients treated with VKA. Further research is needed to corroborate this finding.

Prevalence and management of atrial fibrillation in primary care: a case study

Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia and a major predisposing risk factor for stroke. Current UK guidelines propose stroke-risk stratification of AF patients. Anticoagulation with warfarin is recommended for high risk patients, whereas treatment with aspirin alone is advised for those at low risk. The aim of this audit was to review practice at our institution and ascertain if guidelines on AF treatment were being followed. A retrospective review of all patients diagnosed with non-valvular AF in June 2010 was undertaken. Patient records were reviewed to collect demographic and co-morbidity data relevant to stroke risk stratification. This was subsequently used to stratify patients according to stroke-risk using the CHADS2 scoring system. The use of anticoagulation and anti-platelet medication as well as any documented reasons for the omission of anticoagulation in high risk patients was noted. The prevalence of non-valvular AF in our practice population was 1.5% (151/10,155); 70% (105/151) of AF patients were found to be at high risk of stroke; 36% (38/105) of high risk patients were not on anticoagulation and the majority (58%) of these patients had no clear reason documented for the omission of warfarin. Of the 15 patients at low risk of stroke, 12 (80%) were on warfarin. Seven (4.4%) of the 151 AF patients were on both warfarin and aspirin and six (4%) were on neither medication. The commonest documented reasons for omission of warfarin in the high risk group were dementia and a history of gastrointestinal bleeding. The lack of documentation on withholding a proven beneficial treatment in high risk patients could potentially leave physicians open to medico-legal scrutiny. Maintaining low risk patients on anticoagulation may expose them to unnecessary risk. We recommend the use of automated audit tools designed to improve compliance with national guidelines.

Use of oral anticoagulants in older patients.

Recently published American and British guidelines have comprehensively reviewed the indications for long term anticoagulation. The best evidence currently available supports the use of long term oral anticoagulants in patients with nonvalvular atrial fibrillation (NVAF), venous thromboembolic disease, ischaemic heart disease, mural thrombi, and mechanical heart valves. Selected patients with valvular heart disease, cerebral vascular disease, and peripheral arterial disease may also benefit from the use of these drugs. When no specific contraindications are present, elderly patients with either paroxysmal or persistent NVAF should be considered candidates for treatment with anticoagulants. Pooled analyses of the results from 9 randomised trials demonstrate that warfarin significantly reduces the risk of ischaemic stroke in patients with NVAF, particularly those in a 'high risk' category defined by the presence of additional clinical or echocardiographic risk factors. Long term anticoagulation does not appear to be justified in patients with NVAF considered to be at 'low risk' for stroke. Because the prevalence of NVAF and most other cardiovascular conditions increases with advancing age, many elderly patients will be candidates for thromboprophylaxis. The potential benefit of long term anticoagulation must be carefully weighed against the risk of serious haemorrhage in such patients. Bleeding complications with anticoagulant drugs appear to occur more frequently in older patients than in younger individuals. Advanced age (>75 years), intensity of anticoagulation [International Normalised Ratio (INR) >4.0], history of cerebral vascular disease (recent or remote), and concomitant use of drugs that interfere with haemostasis [aspirin (acetylsalicylic acid) or nonsteroidal anti-inflammatory drugs] are among the most important variables in determining an individual's risk for major bleeding with anticoagulants. Older patients often display increased sensitivity to the effects of warfarin, both in the early induction phase and during the long term maintenance phase of therapy. Conditions such as congestive heart failure, malignancy, malnutrition, diarrhoea and unsuspected vitamin K deficiency, enhance the prothrombin time response. The decision to interrupt anticoagulant therapy before elective surgery in elderly patients should evaluate the thrombotic risk of such a manoeuvre versus the risk of bleeding if anticoagulants are continued. In non-surgical patients, excessively elevated INRs without associated haemorrhage can usually be managed by simply witholding one or several doses of warfarin. If more rapid reversal is needed, small doses of phytomenadione (vitamin K1) can be administered safely without overcorrection or the development of vitamin K-induced warfarin resistance.