Incidence of new thromboembolic stroke in persons 62 years and older with chronic atrial fibrillation treated with warfarin versus aspirin

Prevalence of atrial fibrillation and outcomes in older long-term care residents: a systematic review

BACKGROUND

anticoagulation is integral to stroke prevention for atrial fibrillation (AF), but there is evidence of under-treatment in older people in long-term care (LTC).

OBJECTIVE

to synthesise evidence on the prevalence and outcomes (stroke, mortality or bleeding) of AF in LTC and the factors associated with the prescription of anticoagulation.

METHODS

studies were identified from Medline, CINAHL, PsycINFO, Scopus and Web of Science from inception to 31 October 2019. Two reviewers independently applied the selection criteria and assessed the quality of studies using the Newcastle Ottawa Scale.

RESULTS

twenty-nine studies were included. Prevalence of AF was reported in 21 studies, ranging from 7 to 38%. Two studies reported on outcomes based on the prescription of anticoagulation or not; one reported a reduction in the ischaemic stroke event rate associated with anticoagulant (AC) prescription (2.84 per 100 person years, 95% confidence interval [CI]: 1.98-7.25 versus 3.95, 95% CI: 2.85-10.08) and a non-significant increase in intracranial haemorrhage rate (0.71 per 100 person years, 95% CI: 0.29-2.15 versus 0.65, 95% CI: 0.29-1.93). The second study reported a 76% lower chance of ischaemic stroke with AC prescription and a low incidence of bleeding (n = 4 events). Older age, dementia/cognitive impairment and falls/falls risk were independently associated with the non-prescription of anticoagulation. Conversely, previous stroke/transient ischaemic attack and thromboembolism were independently associated with an increased prescription of anticoagulation.

CONCLUSION

estimates of AF prevalence and factors associated with AC prescription varied extensively. Limited data on outcomes prevent the drawing of definitive conclusions. We recommend panel data collection and systems for linkage to create longitudinal cohorts to provide more robust evidence.

The impact of atrial fibrillation type on the risks of thromboembolic recurrence, mortality and major haemorrhage in patients with previous stroke: A systematic review and meta-analysis of observational studies

Introduction

There is conflicting evidence on the impact of atrial fibrillation (AF) type, i.e. non-paroxysmal AF or paroxysmal AF, on thromboembolic recurrence. The consensus of risk equivalence is greatly based on historical evidence, focussing on initial stroke risks. We conducted a systematic review and meta-analysis to describe the impact of AF type on the risk of thromboembolic recurrence, mortality and major haemorrhage in patients with previous stroke.

Methods

We systematically searched four multidisciplinary databases from inception to December 2018. We selected observational studies investigating clinical outcomes in patients with ischaemic stroke and AF, stratified by AF type. We assessed all included studies for risk of bias using the 'Risk of Bias In Non-randomised Studies - of Exposures' tool. The Comprehensive Meta-Analysis Software was used to calculate odds ratios from crude event rates.

Results

After reviewing 14,127 citations, we selected 108 studies for full-text screening. We extracted data from a total of 26 studies, reporting outcomes on 23,054 patients. Overall, risk of bias was moderate. The annual incidence rates of thromboembolism in patients with non-paroxysmal AF and paroxysmal AF were 7.1% (95% confidence interval: 4.2-11.7) and 5.2% (95% confidence interval: 3.2-8.2), respectively. The odds ratio for thromboembolism in patients with non-paroxysmal AF versus paroxysmal AF was 1.47 (95% confidence interval: 1.08-1.99, p = 0.013). The annual mortality rates in patients with non-paroxysmal AF and paroxysmal AF were 20.0% (95% confidence interval: 13.2-28.0) and 10.1% (95% confidence interval: 5.4-17.3), respectively, and odds ratio was 1.90 (95% confidence interval: 1.43-2.52, p < 0.001). There was no difference in rates of major haemorrhage, odds ratio  = 1.01 (95% confidence interval: 0.61-1.69, p = 0.966).

Conclusion

In patients with prior stroke, non-paroxysmal AF is associated with significantly higher risk of thromboembolic recurrence and mortality than paroxysmal AF. Although current guidelines make no distinction between non-paroxysmal AF and paroxysmal AF for secondary stroke prevention, future guidance and risk stratification tools may need to consider this differential risk (PROSPERO ID: CRD42019118531).

Meta-Analysis of Efficacy and Safety of Apixaban in Patients Undergoing Catheter Ablation for Atrial Fibrillation

BACKGROUND

The efficacy and safety of apixaban in patients undergoing catheter ablation (CA) for atrial fibrillation (AF) are little investigated.

METHODS

The Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, and EMBASE were searched up to September 2015. Four literatures comparing apixaban with vitamin K antagonists (VKAs) were included. Data were pooled in Review Manager Software, using Mantel-Haenszel methods with a fixed-effects model. The funnel plots and Egger's test were used to examine publication bias. Heterogeneity was assessed using the I(2) test. Risk ratios (RR) and 95% confidence intervals (CI) of each study were calculated and pooled.

RESULTS

No significant differences were observed in rates of total bleeding (RR = 0.91, 95% CI [0.57, 1.46], I(2) = 0.0%), thromboembolic complications (RR = 0.75, 95% CI [0.03, 18.22], I(2) = 0.0%), or total events (RR = 0.90, 95% CI [0.56, 1.44], I(2) = 0.0%) between apixaban and VKAs group. The frequency of major bleeding was similar between apixaban and VKAs group (RR = 1.34, 95% CI [0.34, 5.30], I(2) = 0.0%).

CONCLUSION

Apixaban was as effective and safe as VKAs in the periprocedural period of CA.

Quality of vitamin K antagonist control and outcomes in atrial fibrillation patients: a meta-analysis and meta-regression

BACKGROUND

Atrial fibrillation (AF) patients frequently require anticoagulation with vitamin K antagonists (VKAs) to prevent thromboembolic events, but their use increases the risk of hemorrhage. We evaluated time spent in therapeutic range (TTR), proportion of international normalized ratio (INR) measurements in range (PINRR), adverse events in relation to INR, and predictors of INR control in AF patients using VKAs.

METHODS

We searched MEDLINE, CENTRAL and EMBASE (1990-June 2013) for studies of AF patients receiving adjusted-dose VKAs that reported INR control measures (TTR and PINRR) and/or reported an INR measurement coinciding with thromboembolic or hemorrhagic events. Random-effects meta-analyses and meta-regression were performed.

RESULTS

Ninety-five articles were included. Sixty-eight VKA-treated study groups reported measures of INR control, while 43 studies reported an INR around the time of the adverse event. Patients spent 61% (95% CI, 59-62%), 25% (95% CI, 23-27%) and 14% (95% CI, 13-15%) of their time within, below or above the therapeutic range. PINRR assessments were within, below, and above range 56% (95% CI, 53-59%), 26% (95% CI, 23-29%) and 13% (95% CI, 11-17%) of the time. Patients receiving VKA management in the community spent less TTR than those managed by anticoagulation clinics or in randomized trials. Patients newly receiving VKAs spent less TTR than those with prior VKA use. Patients in Europe/United Kingdom spent more TTR than patients in North America. Fifty-seven percent (95% CI, 50-64%) of thromboembolic events and 42% (95% CI, 35 - 51%) of hemorrhagic events occurred at an INR <2.0 and >3.0, respectively; while 56% (95% CI, 48-64%) of ischemic strokes and 45% of intracranial hemorrhages (95% CI, 29-63%) occurred at INRs <2.0 and >3.0, respectively.

CONCLUSIONS

Patients on VKAs for AF frequently have INRs outside the therapeutic range. While, thromboembolic and hemorrhagic events do occur patients with a therapeutic INR; patients with an INR <2.0 make up many of the cases of thromboembolism, while those >3.0 make up many of the cases of hemorrhage. Managing anticoagulation outside of a clinical trial or anticoagulation clinic is associated with poorer INR control, as is, the initiation of therapy in the VKA-naïve. Patients in Europe/UK have better INR control than those in North America.

Monitoring anticoagulation in atrial fibrillation

BACKGROUND

Randomized control trials and observational studies show high-quality warfarin therapy leads to safe and effective stroke prophylaxis. In usual community practice, patient, physician and health care system factors are barriers to optimal anticoagulation. We examined the predictive relationship between inpatient and outpatient INR values in chronic non-valvular atrial fibrillation (AF) patients hospitalized for ischemic stroke (S), bleed (B) and control events (C) in usual community practice.

METHODS

This nested case-control analysis identified AF patients hospitalized for S, B and C using medical and pharmacy claims spanning 4.5 years ('98-'03) and validating diagnosis with chart abstraction. AF was defined as 2 medical claims for AF >or= 42 days apart with a related prescription claim for warfarin. INRs from both outpatient and inpatient settings were used to yield a continuous history of coagulation status. Time-in-therapeutic-range (TTR) was calculated by Rosendaal's linear interpolation method. Correlation of inpatient and prognostic utility of last outpatient INRs was tested with S or B hospitalizations using univariate and multivariate logistic regression.

RESULTS

Overall, 614 hospitalizations (means: age 73.9, CHADS(2) = 3.24; 52% male) included S (n = 98), B (n = 101) and C (n = 415) events. Average TTR was 28.6% (49.4% at INR <2.0, 21.9% at INR >3.0). First INR on admission (INR <2.0 or >3.0) was associated with S and B hospitalizations (OR-adjusted [95%CI], 1.68 [1.04-2.73] and 1.72 [1.02-2.90]), respectively. Last outpatient INR <2.0 was not associated with S (OR-adjusted [95%CI], 1.12 [0.77-1.81]), and INR >3.0 was not associated with B (OR-adjusted [95%CI], 1.25 [0.67-2.32]). Last outpatient INR measurement occurred at 28, 22 and 24 days (median; S, B & C, respectively) before hospitalization.

CONCLUSION

Patients were observed within therapeutic range less than 30% of their time on warfarin. While inpatient INRs were clearly associated with both ischemic stroke and bleed events, last outpatient INR before event was not predictive.

Role of video-assisted thoracoscopy in the management of stroke

OBJECTIVE

To evaluate the role of surgery (anterior thoracotomy versus video-assisted thoracoscopy) in avoidance of stroke by obliteration of the left atrial appendage in patients with chronic nonrheumatic atrial fibrillation.

METHODS

In a prospective study, 58 patients (35 men and 23 women, aged 62 ± 13.2 years) with chronic nonrheumatic atrial fibrillation were divided into 2 groups: group A was 29 patients who underwent an anterior thoracotomy, and group B was 29 patients who had video-assisted thoracoscopic obliteration of the left atrial appendage. All patients were followed up for at least 2 years.

RESULTS

The 2 groups were well matched for age, sex, and comorbidities. No stroke was observed in either group. Operative time was significantly longer in group B. There was no intraoperative or postoperative complication, except for 2 cases of superficial wound infection in group A.

CONCLUSIONS

In chronic atrial fibrillation, prophylactic left atrial appendage exclusion is suggested to prevent occurrence of stroke, which can be achieved by a surgical or thoracoscopic approach, but a video-assisted thoracoscopic approach is effective, less invasive, and avoids the complications of a surgical approach.

Cardioembolic stroke in atrial fibrillation-rationale for preventive closure of the left atrial appendage

Atrial fibrillation is the most common cardiac arrhythmias, and a major cause of morbidity and mortality due to cardioembolic stroke. The left atrial appendage is the major site of thrombus formation in non-valvular atrial fibrillation. Loss of atrial systole in atrial fibrillation and increased relative risk of associated stroke point strongly toward a role for stasis of blood in left atrial thrombosis, although thrombus formation is multifactorial, and much more than blood flow irregularities are implicated. Oral anticoagulation with vitamin-K-antagonists is currently the most effective prophylaxis for stroke in atrial fibrillation. Unfortunately, this treatment is often contraindicated, particularly in the elderly, in whom risk of stroke is high. Moreover, given the risk of major bleeding, there is reason to be skeptical of the net benefit when warfarin is used in those patients. This work reviews the pathophysiology of cardioembolic stroke and critically spotlights the current status of preventive anticoagulation therapy. Various techniques to exclude the left atrial appendage from circulation were discussed as a considerable alternative for stroke prophylaxis.

Incidence of thromboembolic stroke and of major bleeding in patients with atrial fibrillation and chronic kidney disease treated with and without warfarin

The objective was to investigate the incidence of thromboembolic stroke in patients with chronic kidney disease (CKD) and atrial fibrillation (AF) treated with and without warfarin. We investigated the incidence of thromboembolic stroke and of major bleeding in 399 unselected patients with CKD and AF treated with warfarin to maintain an international normalized ratio (INR) between 2.0 and 3.0 (N = 232) and without warfarin (N = 167). Of the 399 patients, 93 (23%) were receiving hemodialysis, and 132 (33%) had an estimated glomerular filtration rate (GFR) of <15 mL/min/1.73 m² At the 31-month follow-up of patients treated with warfarin and 23-month follow-up of patients not treated with warfarin, thromboembolic stroke developed in 21 of 232 patients (9%) treated with warfarin and in 43 of 167 patients (26%) not treated with warfarin (P < 0.001). Major bleeding occurred in 32 of 232 patients (14%) treated with warfarin and in 15 of 167 patients (9%) not treated with warfarin (P not significant). Stepwise Cox regression analysis showed that significant independent predictors of thromboembolic stroke were use of warfarin (odds ratio, 0.28; P < 0.0001) and prior stroke or transient ischemic attack (odds ratio, 2.9; P < 0.05). In conclusion, this observational study showed that CKD patients with AF treated with warfarin to maintain an INR between 2.0 and 3.0 had a significant reduction in thromboembolic stroke and an insignificant increase in major bleeding.

Atrial Fibrillation: The New Epidemic of the Ageing World

The prevalence of atrial fibrillation (AF) increases with age. As the population ages, the burden of AF increases. AF is associated with an increased incidence of mortality, stroke, and coronary events compared to sinus rhythm. AF with a rapid ventricular rate may cause a tachycardia-related cardiomyopathy. Immediate direct-current (DC) cardioversion should be performed in patients with AF and acute myocardial infarction, chest pain due to myocardial ischemia, hypotension, severe heart failure, or syncope. Intravenous beta blockers, diltiazem, or verapamil may be administered to reduce immediately a very rapid ventricular rate in AF. An oral beta blocker, verapamil, or diltiazem should be used in persons with AF if a fast ventricular rate occurs at rest or during exercise despite digoxin. Amiodarone may be used in selected patients with symptomatic life-threatening AF refractory to other drugs. Digoxin should not be used to treat patients with paroxysmal AF. Nondrug therapies should be performed in patients with symptomatic AF in whom a rapid ventricular rate cannot be slowed by drugs. Paroxysmal AF associated with the tachycardia-bradycardia syndrome should be treated with a permanent pacemaker in combination with drugs. A permanent pacemaker should be implanted in patients with AF and symptoms such as dizziness or syncope associated with ventricular pauses greater than 3 seconds which are not drug-induced. Elective DC cardioversion has a higher success rate and a lower incidence of cardiac adverse effects than does medical cardioversion in converting AF to sinus rhythm. Unless transesophageal echocardiography has shown no thrombus in the left atrial appendage before cardioversion, oral warfarin should be given for 3 weeks before elective DC or drug cardioversion of AF and continued for at least 4 weeks after maintenance of sinus rhythm. Many cardiologists prefer, especially in elderly patients , ventricular rate control plus warfarin rather than maintaining sinus rhythm with antiarrhythmic drugs. Patients with chronic or paroxysmal AF at high risk for stroke should be treated with long-term warfarin to achieve an International Normalized Ratio of 2.0 to 3.0. Patients with AF at low risk for stroke or with contraindications to warfarin should be treated with aspirin 325 mg daily.

Anticoagulation for Atrial Fibrillation in the Elderly

Atrial fibrillation is a risk factor for stroke, particularly among elderly patients. Multiple trials have established that antithrombotic therapy decreases stroke risk. Aspirin is associated with a relative risk reduction of about 21% and adjusted-dose warfarin (international normalized ratio 2.0-3.0) is associated with a relative risk reduction of about 68%. Warfarin is more effective than aspirin but is used less often than indicated because of hemorrhagic risk and the inconvenience of coagulation monitoring. The oral direct thrombin ximelagatran has been investigated for stroke prevention in patients with atrial fibrillation in two large clinical trials. The results suggest efficacy in a fixed dose compared with well controlled warfarin. Although anticoagulation intensity was not monitored or regulated during treatment with ximelagatran, it was associated with less bleeding than warfarin. Other antithrombotic agents are under development as alternatives to warfarin, but sufficient data are not yet available to justify their clinical use in patients with atrial fibrillation.

[Age, an independent risk factor for thrombosis. Epidemiologic data]

The incidence of thrombosis--arterial and venous--increases with age. This is the case for atheromatous diseases, atrial fibrillation and even venous thromboembolic disease. Ischemic heart disease is the most common cause of death in the elderly. Atrial fibrillation, an independent risk factor for cerebral vascular accidents, affects around 10% of persons older than 80 years. The incidence of venous thromboembolic disease increases with age, reaching 12.5 per 1000 people older than 75 years, compared with 5 per 1000 aged 60-75 and 2.5 per 1000 aged 40-59. Elderly persons often have two or more cardiovascular or venous thromboembolic risk factors and thus a still higher risk of thrombotic events. Their risk of thrombosis justifies the systematic search for acquired risk factors to assess the level of risk and take appropriate prevention measures.

Management patterns and outcomes of patients with venous thromboembolism in the usual community practice setting

OBJECTIVE

The objectives of this study were to observe a commercially insured sample diagnosed with a venous thromboembolism (VTE) event and treated postevent with warfarin and to detail the thromboembolic and bleeding outcomes in the time periods during warfarin therapy and after discontinuation of such therapy.

METHODS

This retrospective, observational cohort study used medical, pharmacy, and eligibility data from 2 US health plans. Study inclusion required an inpatient diagnosis of deep venous thrombosis (DVT) or pulmonary embolism (PE) between January 1, 1998, and December 31, 2000; warfarin, heparin, or low-molecular-weight heparin within 30 days after diagnosis; no VTE diagnosis; and no anticoagulant use for 3 months preceding diagnosis. A random sample of medical charts was abstracted to validate VTE events and collect prothrombin time/international normalized ratio (INR) result data. Recurrent VTE events, bleeding events, and proportion of time within INR range were captured in the postindex VTE event time period. Univariate and multivariate statistical techniques were used to assess outcomes.

RESULTS

A total of 2,090 patients were identified with a newly diagnosed VTE event (DVT only, 1450; PE with or without DVT, 640). Mean (SD) age was 61.7 (16) years; mean (SD) follow-up time after the index diagnosis was 21.3 (10) months. Overall mean (SD) length of warfarin therapy was 6.6 (6) months. During the follow-up period, 224 patients (10.7%) experienced a recurrent VTE event and 122 patients (5.8%) experienced a bleeding event requiring hospitalization. The cumulative incidence of recurrent VTE events over 3 and 6 months was 9.0% and 10.9%, respectively. Using the chart abstraction subset, patients were within the appropriate INR range 37.7% of the time while receiving warfarin.

CONCLUSIONS

Negative outcomes associated with warfarin therapy-recurrent VTE events and bleeding requiring hospitalization-were experienced by 10.7% and 5.8% of patients, respectively. These data suggest that negative outcomes may be more prevalent in usual community medical practice compared with rates observed in the controlled environment of the clinical trial or specialized anticoagulation clinic.

Antithrombotic Therapy in Atrial Fibrillation

This chapter about antithrombotic therapy in atrial fibrillation (AF) is part of the Seventh ACCP Conference on Antithrombotic and Thrombolytic Therapy: Evidence Based Guidelines. Grade 1 recommendations are strong and indicate that the benefits do, or do not, outweigh risks, burden, and costs. Grade 2 suggests that individual patients' values may lead to different choices (for a full understanding of the grading see Guyatt et al, CHEST 2004; 126:179S-187S). Among the key recommendations in this chapter are the following (all vitamin K antagonist [VKA] recommendations have a target international normalized ratio [INR] of 2.5; range, 2.0 to 3.0): In patients with persistent or paroxysmal AF (PAF) [intermittent AF] at high risk of stroke (ie, having any of the following features: prior ischemic stroke, transient ischemic attack, or systemic embolism, age > 75 years, moderately or severely impaired left ventricular systolic function and/or congestive heart failure, history of hypertension, or diabetes mellitus), we recommend anticoagulation with an oral VKA, such as warfarin (Grade 1A). In patients with persistent AF or PAF, age 65 to 75 years, in the absence of other risk factors, we recommend antithrombotic therapy with either an oral VKA or aspirin, 325 mg/d, in this group of patients who are at intermediate risk of stroke (Grade 1A). In patients with persistent AF or PAF < 65 years old and with no other risk factors, we recommend aspirin, 325 mg/d (Grade 1B). For patients with AF and mitral stenosis, we recommend anticoagulation with an oral VKA (Grade 1C+). For patients with AF and prosthetic heart valves, we recommend anticoagulation with an oral VKA (Grade 1C+); the target INR may be increased and aspirin added depending on valve type and position, and on patient factors. For patients with AF of > or = 48 h or of unknown duration for whom pharmacologic or electrical cardioversion is planned, we recommend anticoagulation with an oral VKA for 3 weeks before and for at least 4 weeks after successful cardioversion (Grade 1C+). For patients with AF of > or = 48 h or of unknown duration undergoing pharmacologic or electrical cardioversion, an alternative strategy is anticoagulation and screening multiplane transesophageal echocardiography (Grade 1B). If no thrombus is seen and cardioversion is successful, we recommend anticoagulation for at least 4 weeks (Grade 1B). For patients with AF of known duration < 48 h, we suggest cardioversion without anticoagulation (Grade 2C). However, in patients without contraindications to anticoagulation, we suggest beginning IV heparin or low molecular weight heparin at presentation (Grade 2C).

Thoracoscopic extracardiac obliteration of the left atrial appendage for stroke risk reduction in atrial fibrillation

OBJECTIVES

We evaluated left atrial appendage obliteration in high-risk patients with atrial fibrillation (AF).

BACKGROUND

Left atrial appendage thrombosis and embolization is the principal mechanism of stroke in AF. Anticoagulation is underutilized and often contraindicated.

METHODS

Thoracoscopic Left Appendage, Total Obliteration, No cardiac Invasion (LAPTONI) was undertaken with a loop snare in eight patients and a stapler in seven patients, median age 71 years, with clinical risk factors for stroke and with an absolute contraindication to or failure of prior thrombosis prevention with warfarin. Eleven patients had a history of prior thromboembolism. One patient took sustained warfarin during follow-up.

RESULTS

The LAPTONI procedure was completed in 14 of 15 patients, and 1 patient required urgent conversion to open thoracotomy because of bleeding. Patients have been followed up for 8 to 60 months, mean 42 +/- 14 months. One fatal stroke occurred 55 months after surgery, and one non-disabling stroke three months after surgery. Two other deaths occurred, one after coronary bypass surgery and the other from hepatic failure. The subgroup of 11 patients with prior thromboembolism had an annualized rate of stroke of 5.2% per year (95% confidence interval [CI] 1.3 to 21) after LAPTONI, which compares to a rate of 13% per year (95% CI 9.0 to 19) for similar aspirin-treated patients from the Stroke Prevention in Atrial Fibrillation trials (p = 0.15).

CONCLUSIONS

The LAPTONI procedure appears technically feasible without immediate disabling neurologic morbidity or mortality, and it demonstrates low post-operative event rates and a statistical trend toward thromboembolic risk reduction in high-risk AF patients.

Atrial fibrillation or flutter and stroke: a Danish population-based study of the effectiveness of oral anticoagulation in clinical practice

OBJECTIVES

A pooled analysis of randomized trials has shown that oral anticoagulation therapy reduces the risk of ischaemic stroke with 68% in patients with atrial fibrillation. We examined the effectiveness of oral anticoagulation on risk of stroke of any nature (fatal and nonfatal ischaemic and/or haemorrhagic stroke) in patients with nonvalvular atrial fibrillation or flutter living in the County of North Jutland, Denmark.

DESIGN

Cohort study.

SUBJECTS AND METHODS

We used the Hospital Discharge Registry covering the county (490 000 inhabitants) from 1991 to 1998 to identify 2699 men and 2425 women with atrial fibrillation or flutter, aged 60-89 years. Data on prescriptions of anticoagulation were obtained from the National Health Service. We defined use of oral anticoagulation as date of prescription or reiteration plus 90 days. Patients were followed in the County Hospital Discharge Registry until a diagnosis of stroke (fatal and nonfatal ischaemic and/or haemorrhagic stroke), emigration, death or the end of 1998. We used Cox regression analyses to estimate the relative risk of stroke associated with use of oral anticoagulation compared with no use, adjusted for age, diabetes and underlying cardiovascular diseases.

RESULTS

Eight hundred and thirty-eight of 2699 men (31%) and 552 of 2425 women (23%) with atrial fibrillation had one or more recorded prescriptions of oral anticoagulation. The incidence rates of stroke were 31 per 1000 person-years of follow-up in men, and 30 per 1000 person-years of follow-up in women. The adjusted relative risks of stroke during anticoagulation were 0.6 [95% confidence interval (CI) 0.4-1.0] in men, and 1.0 (95% CI 0.7-1.6) in women compared with nonuse periods.

CONCLUSIONS

The effectiveness of oral anticoagulation in clinical practice may be lesser than the efficacy of oral anticoagulation reported from randomized trials.

Management of the older person with atrial fibrillation

Atrial fibrillation (AF) is associated with a higher incidence of mortality, stroke, and coronary events than is sinus rhythm. AF with a rapid ventricular rate may cause a tachycardia-related cardiomyopathy. Immediate direct-current (DC) cardioversion should be performed in patients with AF and acute myocardial infarction, chest pain due to myocardial ischemia, hypotension, severe heart failure, or syncope. Intravenous beta blockers, verapamil, or diltiazem may be given to slow immediately a very rapid ventricular rate in AF. An oral beta blocker, verapamil, or diltiazem should be used in persons with AF if a fast ventricular rate occurs at rest or during exercise despite digoxin. Amiodarone may be used in selected patients with symptomatic life-threatening AF refractory to other drugs. Nondrug therapies should be performed in patients with symptomatic AF in whom a rapid ventricular rate cannot be slowed by drugs. Paroxysmal AF associated with the tachycardia-bradycardia syndrome should be treated with a permanent pacemaker in combination with drugs. A permanent pacemaker should be implanted in patients with AF and with symptoms such as dizziness or syncope associated with ventricular pauses greater than 3 seconds that are not drug-induced. Elective DC cardioversion has a higher success rate and a lower incidence of cardiac adverse effects than does medical cardioversion in converting AF to sinus rhythm. Unless transesophageal echocardiography has shown no thrombus in the left atrial appendage before cardioversion, oral warfarin should be given for 3 weeks before elective DC or drug cardioversion of AF and should be continued for at least 4 weeks after maintenance of sinus rhythm. Many cardiologists prefer, especially in older persons, ventricular rate control plus warfarin rather than maintaining sinus rhythm with antiarrhythmic drugs. Digoxin should not be used to treat patients with paroxysmal AF. Patients with chronic or paroxysmal AF at high risk for stroke should be treated with long-term warfarin to achieve an International Normalized Ratio of 2.0 to 3.0. Patients with AF at low risk for stroke or with contraindications to warfarin should receive 325 mg of aspirin daily.

Atrial fibrillation

The prevalence and incidence of atrial fibrillation increase with age. Atrial fibrillation is associated with a higher incidence of coronary events, stroke, and mortality than sinus rhythm. A fast ventricular rate associated with atrial fibrillation may cause tachycardia-related cardiomyopathy. Management of atrial fibrillation includes treatment of underlying causes and precipitating factors. Immediate direct-current cardioversion should be performed in persons with atrial fibrillation associated with acute myocardial infarction, chest pain due to myocardial ischemia, hypotension, severe heart failure, or syncope. Intravenous beta-blockers, verapamil, or diltiazem may be used to immediately slow a fast ventricular rate associated with atrial fibrillation. An oral beta-blocker, verapamil, or diltiazem should be given to persons with atrial fibrillation if a rapid ventricular rate occurs a rest or during exercise despite digoxin. Amiodarone may be used in selected persons with symptomatic life-threatening atrial fibrillation refractory to other drug therapy. Nondrug therapies should be performed in persons with symptomatic atrial fibrillation in whom a rapid ventricular rate cannot be slowed by drug therapy. Paroxysmal atrial fibrillation associated with the tachycardia-bradycardia syndrome should be managed with a permanent pacemaker in combination with drugs. A permanent pacemaker should be implanted in persons with atrial fibrillation in whom symptoms such as dizziness or syncope associated with non-drug-induced ventricular pauses longer than 3 seconds develop. Elective direct-current cardioversion has a higher success rate and a lower incidence of cardiac adverse effects than medical cardioversion in converting atrial fibrillation to sinus rhythm. Unless transesophageal echocardiography shows no thrombus in the left atrial appendage before cardioversion, oral warfarin should be given for 3 weeks before elective direct-current or drug cardioversion of atrial fibrillation and continued for at least 4 weeks after maintenance of sinus rhythm. Many cardiologists prefer the treatment strategy of ventricular rate control plus warfarin rather than to maintain sinus rhythm with antiarrhythmic drugs, especially in older patients. Digoxin should not be used in persons with paroxysmal atrial fibrillation. Patients with chronic or paroxysmal atrial fibrillation who are at high risk for stroke should be treated with long-term warfarin to achieve an International Normalized Ratio (INR) of 2.0 to 3.0. Persons with atrial fibrillation who are at low risk for stroke or who have contraindications to warfarin should receive 325 mg aspirin daily.

A review of anticoagulation with warfarin in patients with nonvalvular atrial fibrillation

BACKGROUND

Warfarin therapy has proved safe and effective in a number of randomized controlled trials of stroke prophylaxis in patients with nonvalvular atrial fibrillation (NVAF), reducing the risk of stroke in these patients by two thirds. However, participants in the clinical trials were carefully selected and younger than patients in actual clinical practice.

OBJECTIVE

This analysis sought to determine whether the results of clinical trials in patients with NV can be extrapolated to the general population seen in clinical practice.

METHODS

A MEDLINE search from 1966 to the present was used to identify observational trials of anticoagulation in patients with NVAF that addressed warfarin use, anticoagulation control, efficacy, and complications. The search terms used were atrial fibrillation and anticoagulation.

RESULTS

Although warfarin prophylaxis against stroke in patients with NVAF appeared to be as well tolerated and effective in clinical practice as in clinical trials, it was generally underused, particularly in the elderly. Anticoagulation control was not as good in clinical practice as in clinical trials, although the rates of stroke and major bleeding were comparable.

CONCLUSIONS

Judicious use of warfarin, tailored to individual stroke risk, seems to be a reasonable policy. Warfarin therapy increases quality-adjusted survival in patients at high risk for stroke, and it is recommended for medium-risk patients unless their risk of bleeding is high or their quality of life while taking warfarin would be poor. Patients at a low risk for stroke will have equivalent health outcomes and incur lower costs if treated with aspirin. Despite the increased risk of hemorrhage in elderly patients, the net benefit of warfarin therapy is greater in this age group because of the higher risk of stroke. Active involvement of patients and their caregivers in an anticoagulation service setting may improve outcomes of anticoagulation therapy.

Use of antihypertensive and antithrombotic medications after stroke in community-based care

BACKGROUND

Secondary stroke prevention strategies include pharmacologic approaches to control hypertension and reduce thromboembolic risk.

OBJECTIVE

To describe antithrombotic and antihypertensive medication use, and rates of blood pressure control in the Kansas City Stroke Study, a prospective stroke cohort receiving community-based care after primarily mild and moderate stroke.

METHODS

Participants from 12 area hospitals provided information about medication use prior to stroke. Study personnel measured blood pressures at enrollment and at one, three, and six months, and collected medication data at six months during in-home assessment.

RESULTS

Complete data at six months were available for 355 subjects with ischemic stroke, among whom 13% had atrial fibrillation and 67% had prior hypertension. Prior to stroke, only 45% of the patients were receiving any antithrombotic (anticoagulant and/or antiplatelet) therapy; this figure rose to 77% at six months. Antithrombotic treatment rates among those with atrial fibrillation were 59% before stroke and 83% at six months, including warfarin in 64%. Approximately 70% of subjects had controlled blood pressures one, three, and six months after stroke, defined as systolic blood pressure < or = 140 mm Hg and diastolic blood pressure < or = 90 mm Hg. Use of multiple antihypertensive agents was common; calcium-channel blockers and angiotensin-converting enzyme inhibitors were used most frequently. However, 19% of subjects with uncontrolled blood pressure were untreated at six months.

CONCLUSIONS

Although room for improvement remains, these data suggest improved rates of antithrombotic and antihypertensive medication use after stroke in community-based care in a midwestern metropolitan community, compared with previous reports.

Prospective cohort study to determine if trial efficacy of anticoagulation for stroke prevention in atrial fibrillation translates into clinical effectiveness

OBJECTIVE

To determine whether trial efficacy of prophylaxis with warfarin for patients with atrial fibrillation at high risk of stroke translates into effectiveness in clinical practice.

DESIGN

Two year prospective cohort study.

SETTING

District general hospital.

PARTICIPANTS

167 patients with atrial fibrillation and at high stroke risk who were eligible for anticoagulation.

INTERVENTIONS

Long term anticoagulation with warfarin at adjusted doses to maintain an international normalised ratio of 2.0-3.0.

MAIN OUTCOME MEASURES

Comparison of patient characteristics, comorbidity, anticoagulation control, stroke rate, and haemorrhagic complications with pooled data from five randomised controlled trials.

RESULTS

Patients in the study group were seven years older (95% confidence interval 4 to 10) and comprised 33% more women than patients in the pooled trials. The international normalised ratio was in the target range for 61% of the time (range 37%-85%), below for 26% of the time (range 8%-32%), and above for 13% of the time (range 6%-26%). The time that patients in the study group spent in the target range was significantly less than in the pooled analysis. The incidence of stroke in the study group (2.0% per year, 0.7% to 4. 4%) was comparable to that of patients receiving warfarin in pooled studies (1.4%, 0.8% to 2.3%). Per year the incidence of major (1.7% v 1.6%) and minor (5.4% v 9.2%) bleeding complications was also similar.

CONCLUSION

Rates of stroke and major haemorrhage after anticoagulation in clinical practice were comparable to those obtained from pooled data from randomised controlled studies for patients with atrial fibrillation at high risk of stroke.

Warfarin therapy: a review of the literature since the Fifth American College of Chest Physicians' Consensus Conference on Antithrombotic Therapy

Evidence-based medicine is currently a fashionable term. The evidence that warfarin is safe, effective, and cost beneficial in preventing stroke in AF, DVT treatment, and DVT prophylaxis is mounting. However, the evidence that warfarin remains underutilized in these conditions is also mounting. There is new evidence that supports conservative management of overanticoagulation without bleeding. The amount of time, if any, that patients are off warfarin for various procedures is being reduced. Warfarin interactions with other agents continue to be reported so that practitioners can avoid or treat them. Even the contraindication of warfarin in pregnancy is being reexamined. Those with expertise in anticoagulation therapy have an imperative to inform colleagues about the evidence in favor of warfarin.

Association of left ventricular hypertrophy and chronic atrial fibrillation with the incidence of new thromboembolic stroke in 2,384 older persons

In a prospective study of 2,384 persons, mean age 81 years, at 44-month follow-up, new thromboembolic stroke developed in 510 of 2,384 persons (21%). The Cox regression model showed that significant independent risk factors for new thromboembolic stroke were atrial fibrillation (risk ratio 3.2), left ventricular hypertrophy (risk ratio 2.8), prior stroke (risk ratio 2.2), and male gender (risk ratio 1.2).

Management of the older person with atrial fibrillation

OBJECTIVE

To review the management of the older person with atrial fibrillation (AF).

DATA SOURCES

A computer-assisted search of the English language literature (MEDLINE) database followed by a manual search of the bibliographies of pertinent articles.

STUDY SELECTION

Studies on the management of persons with AF were screened for review. Studies of persons older than age 60 and recent studies were emphasized.

DATA EXTRACTION

Pertinent data were extracted from the reviewed articles. Emphasis was placed on studies involving older persons. Relevant articles were reviewed in depth.

DATA SYNTHESIS

Available data about the management of persons with paroxysmal or chronic AF were summarized

CONCLUSIONS

Management of AF includes treatment of the underlying disease and precipitating factors. Immediate direct-current cardioversion should be performed in persons with AF associated with an acute myocardial infarction, chest pain caused by myocardial ischemia, hypotension, severe heart failure, or syncope. Intravenous verapamil, diltiazem, or beta-blockers should be used to slow a very rapid ventricular rate associated with AF immediately. Oral verapamil, diltiazem, or a beta-blocker should be given if a rapid ventricular rate occurs at rest or during exercise despite digoxin. Amiodarone may be used in selected persons with symptomatic life-threatening AF refractory to other drug therapy. Nondrug therapies should be performed in persons with symptomatic AF in whom a rapid ventricular rate cannot be slowed by drug therapy. Paroxysmal AF associated with the tachycardia-bradycardia syndrome should be treated with a permanent pacemaker in combination with drugs. A permanent pacemaker should be implanted in persons with AF who develop cerebral symptoms such as dizziness or syncope associated with ventricular pauses greater than 3 seconds that are not drug-induced. Elective cardioversion of AF should not be performed in asymptomatic older persons with chronic AF. Unless transesophageal echocardiography has shown no thrombus in the left atrial appendage before cardioversion, oral warfarin should be given for 3 weeks before elective direct-current or drug cardioversion of AF and continued for at least 4 weeks after maintenance of sinus rhythm. Many cardiologists prefer the treatment strategy, especially in older persons, of ventricular rate control plus warfarin rather than maintaining sinus rhythm with antiarrhythmic drugs. Digoxin should be avoided in persons with sinus rhythm who have a history of paroxysmal AF. Older persons with chronic or paroxysmal AF who are at high risk for stroke or who have a history of hypertension and no contraindications to warfarin should receive long-term warfarin to achieve an International Normalized Ratio of 2.0 to 3.0. Older persons with AF who are at low risk for stroke or who have contraindications to warfarin should receive 325 mg of aspirin daily.