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1.  Anticoagulant prophylaxis against stroke in atrial fibrillation: effectiveness in actual practice 
BACKGROUND: Randomized trials have shown a beneficial effect of anticoagulation with warfarin to prevent stroke in atrial fibrillation. It is not known whether the same effect will be obtained in actual practice. The authors conducted a prospective observational study to evaluate the effect of preventive anticoagulation in patients with atrial fibrillation in 2 practice settings in Montreal. METHODS: Of the 1725 outpatients screened between October 1990 and September 1993 at a community hospital and a university-affiliated hospital, 221 with documented atrial fibrillation were enrolled and followed up for a mean of 27 months. Most (75%) of the patients excluded did not meet the inclusion criteria (because of, for example, an artificial heart valve, mitral stenosis, cardiac transplantation or transient atrial fibrillation); the remainder had not completed enrollment before the end of the study. Following the baseline visit, patients were interviewed by telephone every 6 months, and reported events were confirmed through review of the patients' charts. Hazards for stroke and for stroke and transient ischemic attack (TIA) combined were calculated for each of 4 treatment groups: ASA, warfarin, blended treatment and no treatment, based on the type of anticoagulation therapy patients received during the entire observation period. The blended-treatment group consisted of patients who started on one active therapy and switched to the other or who switched treatments more than once. Corresponding rate ratios (RRs) and 95% confidence intervals (CIs) were calculated with reference to the no-treatment group. Cox proportional hazards analysis was used to adjust for differences in patient characteristics. The rates of bleeding episodes were also analysed. RESULTS: On average, the study patients were older (71.6 [standard deviation 9.3] years) and had a higher prevalence of underlying heart disease (52.0%) than those in the randomized trials. Nineteen patients had a first stroke: 4 in the ASA group, 4 in the warfarin group, 4 in the blended-treatment group and 7 in the no-treatment group, for rates of 5.2, 1.8, 5.3 and 5.9 per 100 person-years, respectively. Only warfarin was associated with a significantly lower risk of stroke compared with no anticoagulant therapy (RR 0.31, 95% CI 0.09-1.00). A similar protective effect of warfarin was found for stroke and TIA combined (2.3 v. 6.7 per 100 person-years; RR 0.34, 95% CI 0.12-0.99); the effect of ASA and blended treatment was not significantly different from no treatment. The rate per 100 person-years of any bleeding was not significantly higher for any treatment group (ASA 2.5, warfarin 3.4 and blended treatment 3.5) compared with the no-treatment group (1.9). Patients receiving warfarin had a significantly greater risk of any bleeding event than patients not receiving anticoagulant therapy (RR 1.79, 95% CI 1.07-3.00). INTERPRETATION: The relative effect of anticoagulant therapy with warfarin in preventing stroke in these practice settings was equivalent to that in the randomized trials, although these patients were older and sicker. This preventive treatment is likely to confer additional benefit as it is more widely prescribed.
PMCID: PMC1230577  PMID: 10497604
2.  Utilization of Anticoagulation Therapy in Medicare Patients with Nonvalvular Atrial Fibrillation 
American Health & Drug Benefits  2012;5(3):157-168.
Clinical guidelines recommend oral anticoagulation for stroke prevention in patients with atrial fibrillation (AF) at moderate or high risk for stroke but not at high risk for bleeding; however, studies consistently report suboptimal use of such therapy. This study used Medicare Part D claims data to assess the use of warfarin in the Medicare population.
To compare real-world warfarin utilization with current treatment guideline recommendations, and to assess the effect of warfarin exposure level on patient outcomes in Medicare beneficiaries with nonvalvular AF (NVAF).
Patients who were recently diagnosed with NVAF were identified using a random 5% sample of Research Identifiable Files of Medicare beneficiaries in 2006 or 2007. Individuals with moderate-to-high stroke risk per CHADS2 but not at high bleeding risk per ATRIA (Anticoagulation and Risk Factors in Atrial Fibrillation) bleeding risk score were evaluated for warfarin use, as identified by the presence of ≥1 warfarin prescription claims within 12 months after the index diagnosis. Warfarin exposure level was assessed by the proportion of days covered during the 12-month follow-up period. The effect of warfarin exposure on ischemic stroke and major bleeding event rates during the 12-month follow-up period were assessed using multivariate logistic regression.
Data from 14,149 newly diagnosed patients with NVAF (mean age, 79 years; 58.7% female) were analyzed, and of these, 7524 (53.2%) patients were identified as having moderate-to-high stroke risk and not being at high bleeding risk. Of these patients, 3110 (41.3%) did not receive warfarin within 12 months of the index diagnosis. The risk for ischemic stroke was significantly lower in those with warfarin exposure versus no warfarin exposure (adjusted odds ratio [OR], 0.51; confidence interval [CI], 0.43–0.61; P <.001) and in patients with warfarin proportion of days covered ≥80% versus those with proportion of days covered <80% (adjusted OR, 0.59; 95% CI, 0.48–0.72; P<.001). Warfarin exposure was associated with a significantly higher major bleeding rate (adjusted OR, 1.19; 95% CI, 1.04–1.36; P = .013), with this significant difference being driven by patients aged >65 years.
Based on a risk-stratification scheme composed of previously published tools, such as CHADS2 and the ATRIA bleeding risk index, a significant proportion of Medicare beneficiaries with AF are not receiving guideline-recommended anticoagulation therapy, which leads to an excess rate of ischemic stroke in this patient population. These findings highlight quality-of-care issues for patients with AF and the need to improve compliance with anticoagulation guidelines in the Medicare population.
PMCID: PMC4046469  PMID: 24991318
3.  Associations between Stroke Mortality and Weekend Working by Stroke Specialist Physicians and Registered Nurses: Prospective Multicentre Cohort Study 
PLoS Medicine  2014;11(8):e1001705.
In a multicenter observational study, Benjamin Bray and colleagues evaluate whether weekend rounds by stroke specialist physicians, or the ratio of registered nurses to beds on weekends, is associated with patient mortality after stroke.
Please see later in the article for the Editors' Summary
Observational studies have reported higher mortality for patients admitted on weekends. It is not known whether this “weekend effect” is modified by clinical staffing levels on weekends. We aimed to test the hypotheses that rounds by stroke specialist physicians 7 d per week and the ratio of registered nurses to beds on weekends are associated with mortality after stroke.
Methods and Findings
We conducted a prospective cohort study of 103 stroke units (SUs) in England. Data of 56,666 patients with stroke admitted between 1 June 2011 and 1 December 2012 were extracted from a national register of stroke care in England. SU characteristics and staffing levels were derived from cross-sectional survey. Cox proportional hazards models were used to estimate hazard ratios (HRs) of 30-d post-admission mortality, adjusting for case mix, organisational, staffing, and care quality variables. After adjusting for confounders, there was no significant difference in mortality risk for patients admitted to a stroke service with stroke specialist physician rounds fewer than 7 d per week (adjusted HR [aHR] 1.04, 95% CI 0.91–1.18) compared to patients admitted to a service with rounds 7 d per week. There was a dose–response relationship between weekend nurse/bed ratios and mortality risk, with the highest risk of death observed in stroke services with the lowest nurse/bed ratios. In multivariable analysis, patients admitted on a weekend to a SU with 1.5 nurses/ten beds had an estimated adjusted 30-d mortality risk of 15.2% (aHR 1.18, 95% CI 1.07–1.29) compared to 11.2% for patients admitted to a unit with 3.0 nurses/ten beds (aHR 0.85, 95% CI 0.77–0.93), equivalent to one excess death per 25 admissions. The main limitation is the risk of confounding from unmeasured characteristics of stroke services.
Mortality outcomes after stroke are associated with the intensity of weekend staffing by registered nurses but not 7-d/wk ward rounds by stroke specialist physicians. The findings have implications for quality improvement and resource allocation in stroke care.
Please see later in the article for the Editors' Summary
Editors' Summary
In a perfect world, a patient admitted to hospital on a weekend or during the night should have as good an outcome as a patient admitted during regular working hours. But several observational studies (investigations that record patient outcomes without intervening in any way; clinical trials, by contrast, test potential healthcare interventions by comparing the outcomes of patients who are deliberately given different treatments) have reported that admission on weekends is associated with a higher mortality (death) rate than admission on weekdays. This “weekend effect” has led to calls for increased medical and nursing staff to be available in hospitals during the weekend and overnight to ensure that the healthcare provided at these times is of equal quality to that provided during regular working hours. In the UK, for example, “seven-day working” has been identified as a policy and service improvement priority for the National Health Service.
Why Was This Study Done?
Few studies have actually tested the relationship between patient outcomes and weekend physician or nurse staffing levels. It could be that patients who are admitted to hospital on the weekend have poor outcomes because they are generally more ill than those admitted on weekdays. Before any health system introduces potentially expensive increases in weekend staffing levels, better evidence that this intervention will improve patient outcomes is needed. In this prospective cohort study (a study that compares the outcomes of groups of people with different baseline characteristics), the researchers ask whether mortality after stroke is associated with weekend working by stroke specialist physicians and registered nurses. Stroke occurs when the brain's blood supply is interrupted by a blood vessel in the brain bursting (hemorrhagic stroke) or being blocked by a blood clot (ischemic stroke). Swift treatment can limit the damage to the brain caused by stroke, but of the 15 million people who have a stroke every year, about 6 million die within a few hours and another 5 million are left disabled.
What Did the Researchers Do and Find?
The researchers extracted clinical data on 56,666 patients who were admitted to stroke units in England over an 18-month period from a national stroke register. They obtained information on the characteristics and staffing levels of the stroke units from a biennial survey of hospitals admitting patients with stroke, and information on deaths among patients with stroke from the national register of deaths. A quarter of the patients were admitted on a weekend, almost half the stroke units provided stroke specialist physician rounds seven days per week, and the remainder provided rounds five days per week. After adjustment for factors that might have affected outcomes (“confounders”) such as stroke severity and the level of acute stroke care available in each stroke unit, there was no significant difference in mortality risk between patients admitted to a stroke unit with rounds seven days/week and patients admitted to a unit with rounds fewer than seven days/week. However, patients admitted on a weekend to a stroke unit with 1.5 nurses/ten beds had a 30-day mortality risk of 15.2%, whereas patients admitted to a unit with 3.0 nurses/ten beds had a mortality risk of 11.2%, a mortality risk difference equivalent to one excess death per 25 admissions.
What Do These Findings Mean?
These findings show that the provision of stroke specialist physician rounds seven days/week in stroke units in England did not influence the (weak) association between weekend admission for stroke and death recorded in this study, but mortality outcomes after stroke were associated with the intensity of weekend staffing by registered nurses. The accuracy of these findings may be affected by the measure used to judge the level of acute care available in each stroke unit and by residual confounding. For example, patients admitted to units with lower nursing levels may have shared other unknown characteristics that increased their risk of dying after stroke. Moreover, this study considered the impact of staffing levels on mortality only and did not consider other relevant outcomes such as long-term disability. Despite these limitations, these findings support the provision of higher weekend ratios of registered nurses to beds in stroke units, but given the high costs of increasing weekend staffing levels, it is important that controlled trials of different models of physician and nursing staffing are undertaken as soon as possible.
Additional Information
Please access these websites via the online version of this summary at
This study is further discussed in a PLOS Medicine Perspective by Meeta Kerlin
Information about plans to introduce seven-day working into the National Health Service in England is available; the 2013 publication “NHS Services—Open Seven Days a Week: Every Day Counts” provides examples of how hospitals across England are working together to provide routine healthcare services seven days a week; a “Behind the Headlines” article on the UK National Health Service Choices website describes a recent observational study that investigated the association between admission to hospital on the weekend and death, and newspaper coverage of the study's results; the Choices website also provides information about stroke for patients and their families, including personal stories
A US nurses' site includes information on the association of nurse staffing with patient safety
The US National Institute of Neurological Disorders and Stroke provides information about all aspects of stroke (in English and Spanish); its Know Stroke site provides educational materials about stroke prevention, treatment, and rehabilitation, including personal stories (in English and Spanish); the US National Institute of Health SeniorHealth website has additional information about stroke
The Internet Stroke Center provides detailed information about stroke for patients, families, and health professionals (in English and Spanish)
PMCID: PMC4138029  PMID: 25137386
4.  Outcomes of Temporary Interruption of Rivaroxaban Compared With Warfarin in Patients With Nonvalvular Atrial Fibrillation 
Circulation  2014;129(18):1850-1859.
During long-term anticoagulation in atrial fibrillation, temporary interruptions (TIs) of therapy are common, but the relationship between patient outcomes and TIs has not been well studied. We sought to determine reasons for TI, the characteristics of patients undergoing TI, and the relationship between anticoagulant and outcomes among patients with TI.
Methods and Results
In the Rivaroxaban Once Daily, Oral, Direct Factor Xa Inhibition Compared With Vitamin K Antagonism for Prevention of Stroke and Embolism Trial in Atrial Fibrillation (ROCKET AF), a randomized, double-blind, double-dummy study of rivaroxaban and warfarin in nonvalvular atrial fibrillation, baseline characteristics, management, and outcomes, including stroke, non–central nervous system systemic embolism, death, myocardial infarction, and bleeding, were reported in participants who experienced TI (3–30 days) for any reason. The at-risk period for outcomes associated with TI was from TI start to 30 days after resumption of study drug. In 14 236 participants who received at least 1 dose of study drug, 4692 (33%) experienced TI. Participants with TI were similar to the overall ROCKET AF population in regard to baseline clinical characteristics. Only 6% (n=483) of TI incidences involved bridging therapy. Stroke/systemic embolism rates during the at-risk period were similar in rivaroxaban-treated and warfarin-treated participants (0.30% versus 0.41% per 30 days; hazard ratio [confidence interval]=0.74 [0.36–1.50]; P=0.40). Risk of major bleeding during the at-risk period was also similar in rivaroxaban-treated and warfarin-treated participants (0.99% versus 0.79% per 30 days; hazard ratio [confidence interval]=1.26 [0.80–2.00]; P=0.32).
TI of oral anticoagulation is common and is associated with substantial stroke risks and bleeding risks that were similar among patients treated with rivaroxaban or warfarin. Further investigation is needed to determine the optimal management strategy in patients with atrial fibrillation requiring TI of anticoagulation.
Clinical Trial Registration
URL: Unique identifier: NCT00403767.
PMCID: PMC4206548  PMID: 24552831
anticoagulation; atrial fibrillation; stroke
5.  Analysis of Antithrombotic Therapy After Cardioembolic Stroke Due to Atrial Fibrillation or Flutter 
Hospital Pharmacy  2013;48(2):127-133.
Guidelines recommend that all patients with atrial fibrillation and a history of ischemic stroke should receive an anticoagulant. Prior analyses show that warfarin is underutilized in most populations.
To examine the use of antithrombotic and anticoagulant therapy in patients with atrial fibrillation or flutter during the index hospitalization for acute, ischemic stroke.
Retrospective electronic medical record review of 200 patients treated at a tertiary care hospital with a primary ICD-9 code for ischemic stroke and a secondary ICD-9 code for atrial fibrillation or flutter. Exclusion criteria were active bleeding, pregnancy, age less than 18, pre-existing warfarin allergy, or dabigatran use.
Fifty-two percent of patients received at least one dose of warfarin during the index hospitalization. There was no relationship between CHADS2 score and likelihood of receiving warfarin (P > .05). There was no significant difference in adverse event rate in patients receiving warfarin compared to those receiving aspirin (3.8% vs 9.1%; P = .14), but the rate of hemorrhagic transformation was lower in patients receiving warfarin (1% vs 7%; P = .03). The composite of hemorrhagic stroke or hemorrhagic transformation was significantly lower in patients receiving bridging therapy (0% vs 11%; P = .03). Sixteen patients were readmitted for stroke within 3 months of discharge. Ten were readmitted for ischemic stroke, 3 for hemorrhagic stroke or hemorrhagic transformation, and 3 for systemic bleeding. Ten patients (62.5%) were receiving warfarin at readmission, but only one of these patients had a therapeutic INR.
Warfarin was underutilized as secondary stroke prophylaxis in these high-risk patients. Bridging therapy appeared to be safe and was not associated with an increase in adverse events.
PMCID: PMC3839477  PMID: 24421450
anticoagulant; atrial fibrillation; atrial flutter; stroke; warfarin
6.  Differential Use of Warfarin for Secondary Stroke Prevention in Patients With Various Types of Atrial Fibrillation 
The American journal of cardiology  2008;103(2):227-231.
Anticoagulation therapy significantly reduces the incidence of thromboembolic events in patients with atrial fibrillation (AF), and warfarin therapy at discharge is a class I–indicated drug in patients with ischemic stroke with persistent or paroxysmal AF without contraindications. The aim was to determine whether participation in the Get With The Guidelines-Stroke (GWTG-S) quality improvement program would be associated with improved adherence to anticoagulation guidelines for patients with all types of AF. Adherence to warfarin treatment at hospital discharge was assessed in eligible patients with AF who presented with stroke or transient ischemic attack, based on type of AF. Of patients with stroke, 10.5% presented with some form of AF. When AF was documented using electrocardiography or telemetry (ECG) during the present admission, eligible patients were more likely to receive warfarin compared with patients for whom AF was reported using medical history only (78.8% vs 49.4%; p <0.0001). Improvement after GWTG-S participation in warfarin use was observed in patients with ECG-documented AF (73.8% at baseline vs 88.5% after the intervention; p <0.0001), but not patients using history only. Women and elderly patients were less likely to receive warfarin, and these gaps in treatment did not narrow during the quality improvement program for patients with ECG-documented AF and those with history only. In conclusion, anticoagulation for stroke prevention was underused in general for patients with AF, even in such high-risk groups as patients with stroke. GWTG-S was associated with improved adherence for patients with ECG-documented AF, but patients with a history of AF alone were largely untreated.
PMCID: PMC3086549  PMID: 19121441
7.  Care Transitions in Anticoagulation Management for Patients With Atrial Fibrillation: An Emphasis on Safety 
The Ochsner Journal  2013;13(3):419-427.
Thromboprophylaxis with oral anticoagulants is an important but underused element of atrial fibrillation (AF) treatment. Reduction of stroke risk by anticoagulants comes at the price of bleeding risk. Patients with AF receiving anticoagulants require heightened attention with transition from one care setting to another.
This review of the literature focuses on issues specific to the anticoagulation treatment of patients with AF.
Patients presenting for emergency care of anticoagulant-related bleeding should be triaged for the severity and source of the bleeding using appropriate measures, such as discontinuing the oral anticoagulant, administering vitamin K when appropriate to reverse warfarin-induced bleeding, or administering clotting factors for emergent bleeding. Reversal of oral anticoagulants in patients admitted to the hospital for surgery can be managed similarly to patients with bleeding, depending on the urgency of the surgical procedure. Patients with AF who are admitted for conditions unrelated to AF should be assessed for adequacy of stroke risk prophylaxis and bleeding risk. Newly diagnosed AF should be treated in nearly all patients with either warfarin or a newer anticoagulant.
Patient education is critically important with all anticoagulants. Close adherence to the prescribed regimen, regular international normalized ratio testing for warfarin, and understanding the stroke risk conferred by AF and aging are goals for all patients receiving oral anticoagulants. Detailed handoff from the hospitalist to the patient's primary care physician is required for good continuity of care. Monitoring by an anticoagulation clinic is the best arrangement for most patients. The elderly, particularly frail or debilitated patients who are transferring to long-term care, need a detailed transfer of information between settings, education for the patient and family, and medication reconciliation. Communication and coordination of care among outpatient, emergency, inpatient, subacute, and long-term care settings are vital in patients with AF who are receiving anticoagulants to balance stroke prevention and bleeding risk.
PMCID: PMC3776521  PMID: 24052775
Anticoagulant drugs; atrial fibrillation; hemorrhage; stroke
8.  Patterns of warfarin use and subsequent outcomes in atrial fibrillation in primary care practices 
Warfarin is recommended for stroke prevention in high-risk patients with atrial fibrillation. However, it is often underutilized and inadequately managed in actual clinical practice.
To examine the patterns of warfarin use and their relationship with stroke and bleeding in atrial fibrillation patients in community-based primary care practices.
Retrospective longitudinal cohort study.
A total of 1141 atrial fibrillation patients were selected from 17 primary care practices with a shared electronic medical record and characterized by stroke risk, potential barriers to anticoagulation, and comorbid conditions.
Main measures
Duration and number of warfarin exposures, interruptions in warfarin exposure > 45 days, stroke, and bleeding events.
Among 1141 patients with a mean age of 70 years (standard deviation 13.3) and mean follow-up of 3.4 years (standard deviation 3.0), 764 (67%) were treated with warfarin. Warfarin was discontinued within 1 year in 194 (25.4%), and 349 (45.7%) remained on warfarin at the end of follow-up. Interruptions in warfarin use were common, occurring in 32.6% (249 of 764) of patients. Those with two or more interruptions were younger and at lower baseline stroke risk when compared to those with no interruptions. There were 76 first strokes and 73 first-bleeding events in the follow-up period. When adjusted for baseline stroke risk, time to warfarin start, and total exposure time, two or more interruptions in warfarin use was associated with an increased risk of stroke (relative risk, 2.29; 95% confidence interval: 1.29–4.07). There was no significant association between warfarin interruptions and bleeding events.
Warfarin was underutilized in a substantial portion of eligible atrial fibrillation patients in these community-based practices. In addition, prolonged interruptions in anticoagulation were common in this population, and multiple interruptions were associated with over twice the risk of stroke when compared to those treated continuously.
PMCID: PMC3480279  PMID: 23112579
cardiovascular disease; primary care; quality assessment; outcomes
9.  Utilization of Parenteral Anticoagulants and Warfarin: Impact on the Risk of Venous Thromboembolism Recurrence in the Outpatient Setting 
American Health & Drug Benefits  2014;7(8):444-451.
Clinical guidelines recommend parenteral anticoagulation therapy with an early initiation of warfarin therapy for the treatment of patients with acute venous thromboembolism (VTE) and the prevention of recurrence.
To evaluate the outpatient utilization of parenteral anticoagulant therapy and warfarin among patients with VTE, and to examine the effects of parenteral anticoagulant use and the time to warfarin initiation from VTE diagnosis on the risk for VTE recurrence.
The Truven Health MarketScan Commercial Claims Database was used to identify patients aged 18 to 64 years who had an outpatient claim for deep-vein thrombosis or pulmonary embolism between January 2010 and December 2011 (ie, index date) and had no VTE diagnosis or treatment during the 12 months before the index date, had no hospital or emergency department VTE claim within 7 days after the index outpatient VTE claim, and had received warfarin <30 days after the index date. A recurrent VTE event was defined as a VTE-related emergency department visit or hospitalization within 8 to 365 days after the index date. A Cox proportional hazards model was used to estimate the adjusted hazard ratio (HR) associated with VTE recurrence risk related to parenteral anticoagulant use and warfarin initiation timing.
A total of 5820 patients were included in the study (mean age, 50.5 years); of these, 45% were female. A total of 75.7% (4403) of the patients receiving warfarin also received a parenteral anticoagulant, and the median time from VTE diagnosis to warfarin initiation was 5 days for parenteral anticoagulant users compared with 11 days for nonusers. Parenteral anticoagulant use was associated with a 49% recurrent VTE risk reduction (HR, 0.51; 95% confidence interval [CI], 0.43–0.60; P <.001). Each day of delayed warfarin initiation from the diagnosis of acute VTE was associated with a 1% increase in the risk for VTE recurrence (HR, 1.01; 95% CI, 1.01–1.02; P = .003).
Overall, 1 in 4 patients with VTE who had received warfarin in the outpatient setting did not receive parenteral anticoagulation therapy. Among those who received warfarin, its initiation was not always timely, despite its positive effects on reducing VTE recurrence. These findings highlight the potential quality-of-care concerns associated with the failure to use or the delayed implementation of guideline-recommended VTE treatment, and the need to improve compliance with clinical guidelines in the treatment of patients with VTE.
PMCID: PMC4280521  PMID: 25558306
10.  Risk of First and Recurrent Stroke in Childhood Cancer Survivors treated with Cranial and Cervical Radiation Therapy 
Radiation therapy increases stroke risk in pediatric cancer patients, but risk of stroke recurrence in this population remains unknown. In a retrospective cohort study, we assessed rates and predictors of first and recurrent stroke in patients treated with cranial irradiation (CRT) and/or cervical irradiation ≤ 18 years of age.
We performed chart abstraction (n=383) and phone interviews (n=104) to measure first and recurrent stroke in 383 patients who received CRT and/or cervical radiation at a single institution between1980–2009. Stroke was defined as a physician diagnosis and symptoms consistent with stroke. Incidence of first-stroke was number of first-strokes per person-years of observation after radiation. We used survival analysis techniques to determine cumulative incidence of first and recurrent stroke.
Among 325 subjects with sufficient follow-up data, we identified 19 first-strokes (13 ischemic, 4 hemorrhagic, 2 unknown sub-type) occurring at a median age of 24 years (Interquartile range (IQR) 17–33 years) in patients treated with CRT. Imaging was reviewed when available (n=13) and the stroke was confirmed in 12. Overall rate of first-stroke was 625 (95% CI 378–977) per 100,000 person-years. The cumulative incidence of first stroke was 2% (95% CI 0.01–5.3%) at 5 years and 4% (95% C.I. 2.0–8.4%) at 10 years post irradiation. With each 100cGy increase in the radiation dose, the stroke hazard increased by 5% (Hazard ratio = 1.05; 95% CI 1.01–1.09; p=0.02). We identified 6 recurrent strokes; 5 had available imaging that confirmed the stroke. Median time to recurrence was 15 months (IQR 6 months–3.2 years) after first-stroke. The cumulative incidence of recurrent stroke was 38% (95% CI 17–69%) at 5 years and 59% (95% CI 27–92%) at 10 years post first-stroke.
CRT puts childhood cancer survivors at high risk of both first and recurrent stroke. Stroke prevention strategies for these survivors are needed.
PMCID: PMC3696632  PMID: 23623405
11.  Warfarin Discontinuation after Starting Warfarin for Atrial Fibrillation 
Although warfarin is widely recommended to prevent atrial fibrillation-related thromboembolism, many eligible patients do not take warfarin. The objective of this study was to describe factors associated with warfarin discontinuation in people newly starting warfarin for atrial fibrillation.
Methods and Results
We identified 4,188 subjects newly starting warfarin in the ATRIA Study and tracked longitudinal warfarin use using pharmacy and laboratory databases. Data on patient characteristics, international normalized ratio (INR) tests, and incident hospitalizations for hemorrhage were obtained from clinical and laboratory databases. Multivariable Cox regression analysis was used to identify independent predictors of prolonged warfarin discontinuation, defined as ≥ 180 consecutive days off warfarin.
Within one year after warfarin initiation, 26.3% of subjects discontinued therapy despite few hospitalizations for hemorrhage (2.3% of patients). The risk of discontinuation was higher in patients aged < 65 years (adjusted hazard ratio and 95%CI [HR] 1.33 [1.03-1.72] compared to age ≥ 85 years), patients with poorer anticoagulation control (HR 1.46 [1.42-1.49] for every 10% decrease in time in therapeutic INR range) and lower stroke risk (HR 2.54 [1.86-3.47] for CHADS2 stroke risk index of 0 compared to 4-6).
More than one in four individuals newly starting warfarin for atrial fibrillation discontinued therapy in the first year despite a low overall hemorrhage rate. Individuals deriving potentially less benefit from warfarin, including those with younger age, fewer stroke risk factors, and poorer INR control, were less likely to remain on warfarin. Maximizing the benefits of anticoagulation for atrial fibrillation depends upon determining which patients are most appropriately initiated and maintained on therapy.
PMCID: PMC3063305  PMID: 20959565
anticoagulation; atrial fibrillation; discontinuation; stroke prevention; warfarin
12.  Assessment of female sex as a risk factor in atrial fibrillation in Sweden: nationwide retrospective cohort study  
Objective To determine whether women with atrial fibrillation have a higher risk of stroke than men.
Design Nationwide retrospective cohort study.
Setting Patients with a diagnosis of atrial fibrillation in the Swedish hospital discharge register between 1 July 2005 and 31 December 2008. Information about drug treatment taken from the Swedish drug register.
Participants 100 802 patients with atrial fibrillation at any Swedish hospital or hospital affiliated outpatient clinic with a total follow-up of 139 504 years at risk (median 1.2 years). We excluded patients with warfarin at baseline, mitral stenosis, previous valvular surgery, or who died within 14 days from baseline.
Main outcome measure Incidence of ischaemic stroke.
Results Ischaemic strokes were more common in women than in men (6.2% v 4.2% per year, P<0.0001). The univariable hazard ratio for women compared with men was 1.47 (95% confidence 1.40 to 1.54), indicating a 47% higher incidence of ischaemic stroke in women than in men. Stratification according to the CHADS2 scheme showed increased stroke rates for women in all strata. After multivariable adjustment for 35 cofactors for stroke, an increased risk of stroke in women remained (1.18, 1.12 to 1.24). Among patients with “lone atrial fibrillation” (age <65 years and no vascular disease), the annual stroke rate tended to be higher in women than in men, although this difference was not significant (0.7% v 0.5%, P=0.09). When low risk patients with CHADS2 scores of 0-1 were stratified according to their CHA2DS2-VASc scores, women did not have higher stroke incidence than men at CHA2DS2-VASc scores of 2 or less.
Conclusion Women with atrial fibrillation have a moderately increased risk of stroke compared with men, and thus, female sex should be considered when making decisions about anticoagulation treatment. However, women younger than 65 years and without other risk factors have a low risk for stroke, and do not need anticoagulant treatment.
PMCID: PMC3365143  PMID: 22653980
13.  Withdrawal of Antithrombotic Agents and Its Impact on Ischemic Stroke Occurrence 
Antithrombotic medications (anticoagulants and antiplatelets) are often withheld in the periprocedural period and after bleeding complications to limit the risk of new or recurrent bleeding. These medications are also stopped by patients for various reasons such as cost, side effects, or unwillingness to take medication.
Methods and Results
Patient records from the population-based Greater Cincinnati / Northern Kentucky Stroke Study were reviewed to identify cases of ischemic stroke in 2005 and determine the temporal association of strokes with withdrawal of antithrombotic medication. Ischemic strokes and reasons for medication withdrawal were identified by study nurses for subsequent physician review.
In 2005, 2,197 cases of ischemic stroke among residents of the region were identified via hospital discharge records. Of the 2,197 ischemic strokes, 114 (5.2%) occurred within 60 days of an antithrombotic medication withdrawal: 61 (53.5%) of these after stoppage of warfarin and the remainder after stoppage of an antiplatelet medication. Of the strokes following withdrawal, 71 (62.3%) were first-ever, and 43 (37.7%) were recurrent; 54 (47.4%) occurred after withdrawal of medication by a physician in the periprocedural period.
The withdrawal of antiplatelet and antithrombotic medications in the 60 days preceding an acute ischemic stroke was associated with 5.2% of ischemic strokes in our study population. This finding emphasizes the need for thoughtful decision making concerning antithrombotic medication use in the periprocedural period and efforts to improve patient compliance.
PMCID: PMC3166233  PMID: 21719769
Ischemic stroke; antiplatelet therapy; anticoagulant therapy
14.  Language, Literacy, and Characterization of Stroke Among Patients Taking Warfarin for Stroke Prevention: Implications for Health Communication 
Patient education and counseling  2009;75(3):403-410.
Warfarin is a medication commonly prescribed to prevent strokes associated with certain medical conditions such as atrial fibrillation; however, little is known about how people taking warfarin perceive the goal of therapy and how they describe strokes. We assessed the stroke-related health literacy of anticoagulated patients to inform ways in which to improve health communication among people taking warfarin.
We conducted a mixed-methods study of an ethnically and linguistically diverse sample of people taking warfarin to prevent stroke (N=183) and measured literacy using the short-form Test of Functional Health Literacy in Adults. We asked participants to (1) describe their indication for warfarin, and (2) describe a stroke. Transcribed answers were coded as concordant or discordant with established indications for warfarin and definitions of stroke.
Forty-three percent of participants provided a discordant response when describing their indication for warfarin. Only 9.3% reported that the purpose of taking warfarin was to prevent stroke. Not speaking English [OR = 2.4 (1.1–5.6)] and less than a college education [OR = 3.3 (1.4–7.3)] were independently associated with discordant answers about warfarin. Nearly 40% of subjects had inaccurate perceptions of stroke, and only one-third of subjects described a symptom or sign of stroke. Among English and Spanish-speaking participants, inadequate literacy was strongly associated with discordant responses about stroke [OR = 5.8 (2.1–15.6)].
Among high risk people taking warfarin to prevent stroke, significant gaps in stroke-related health literacy exist. These gaps likely represent mismatches in the ways clinicians teach and patients learn.
Practice implications
Since stroke risk awareness and early recognition of the signs and symptoms of stroke are critical aspects of stroke prevention and treatment, clinicians should more strongly link warfarin therapy to stroke prevention and ensure that patients know the presenting symptoms and signs of stroke. Public health communication strategies regarding stroke prevention need to target individuals with limited literacy and limited English proficiency.
PMCID: PMC2740646  PMID: 19171448
health literacy; language barriers; disparities; anticoagulation; knowledge; stroke; communication
15.  5-year survival and rehospitalization due to stroke recurrence among patients with hemorrhagic or ischemic strokes in Singapore 
BMC Neurology  2013;13:133.
Stroke is the 4th leading cause of death and 1st leading cause of disability in Singapore. However the information on long-term post stroke outcomes for Singaporean patients was limited. This study aimed to investigate the post stroke outcomes of 5-year survival and rehospitalization due to stroke recurrence for hemorrhagic and ischemic stroke patients in Singapore. The outcomes were stratified by age, ethnic group, gender and stroke types. The causes of death and stroke recurrence were also explored in the study.
A multi-site retrospective cohort study. Patients admitted for stroke at any of the three hospitals in the National Healthcare Group of Singapore were included in the study. All study patients were followed up to 5 years. Kaplan-Meier was applied to study the time to first event, death or rehospitalization due to stroke recurrence. Cox proportional hazard model was applied to study the time to death with adjustment for stroke type, age, sex, ethnic group, and admission year. Cumulative incidence model with competing risk was applied for comparing the risks of rehospitalization due to stroke recurrence with death as the competing risk.
Totally 12,559 stroke patients were included in the study. Among them, 59.3% survived for 5 years; 18.4% were rehospitalized due to stroke recurrence in 5 years. The risk of stroke recurrence and mortality increased with age in all stroke types. Gender, ethnic group and admitting year were not significantly associated with the risk of mortality or stroke recurrence in hemorrhagic stroke. Male or Malay patient had higher risk of stroke recurrence and mortality in ischemic stroke. Hemorrhagic stroke had higher early mortality while ischemic stroke had higher recurrence and late mortality. The top cause of death among died stroke patients was cerebrovascular diseases, followed by pneumonia and ischemic heart diseases. The recurrent stroke was most likely to be the same type as the initial stroke among rehospitalized stroke patients.
Five year post-stroke survival and rehospitalization due to stroke recurrence as well as their associations with patient demographics were studied for different stroke types in Singapore. Specific preventive strategies are needed to target the high risk groups to improve their long-term outcomes after acute stroke.
PMCID: PMC3850698  PMID: 24088308
Stroke; Outcomes; Recurrence; Rehospitalization; Mortality; Singapore
16.  Outcomes Associated With Warfarin Use in Older Patients With Heart Failure and Atrial Fibrillation and a Cardiovascular Implantable Electronic Device: Findings From the ADHERE Registry Linked to Medicare Claims 
Clinical cardiology  2012;35(11):649-657.
Warfarin use and associated outcomes in patients with heart failure and atrial fibrillation and a cardiovascular implantable electronic device have not been described previously.
We hypothesized that warfarin is underused and is associated with lower risks of mortality, thromboembolic events, and myocardial infarction.
Using data from a clinical registry linked with Medicare claims, we examined warfarin use at discharge and 30-day and 1-year Kaplan-Meier estimates of all-cause mortality and cumulative incidence rates of mortality, thromboembolic events, myocardial infarction, and bleeding events in patients 65 years or older with a history of atrial fibrillation and a cardiovascular implantable electronic device admitted with heart failure between 2001 and 2006 who were naïve to anticoagulation therapy at admission. We compared outcomes between patients who were or were not prescribed warfarin at discharge and tested associations between treatment and outcomes.
Of 2586 eligible patients in 252 hospitals, 2049 were discharged without a prescription for warfarin. At 1 year, the group discharged without warfarin had a higher mortality rate after discharge (37.4% vs 28.8%; P < .001) but similar rates of thromboembolism, myocardial infarction, and bleeding events. After adjustment, treatment with warfarin was associated with lower risk of all-cause death 1 year after discharge (hazard ratio, 0.76; 95% confidence interval, 0.63–0.92).
Among older patients with heart failure and atrial fibrillation and a cardiovascular implantable electronic device, 4 of 5 were discharged without a prescription for warfarin. Warfarin nonuse was associated with a higher risk of death 1 year after discharge.
PMCID: PMC4076954  PMID: 23070696
Atrial Fibrillation; Cardiac Resynchronization Therapy Devices; Defibrillators; Implantable; Heart Failure; Pacemaker; Artificial; Warfarin
17.  Uncovering Treatment Burden as a Key Concept for Stroke Care: A Systematic Review of Qualitative Research 
PLoS Medicine  2013;10(6):e1001473.
In a systematic review of qualitative research, Katie Gallacher and colleagues examine the evidence related to treatment burden after stroke from the patient perspective.
Please see later in the article for the Editors' Summary
Patients with chronic disease may experience complicated management plans requiring significant personal investment. This has been termed ‘treatment burden’ and has been associated with unfavourable outcomes. The aim of this systematic review is to examine the qualitative literature on treatment burden in stroke from the patient perspective.
Methods and Findings
The search strategy centred on: stroke, treatment burden, patient experience, and qualitative methods. We searched: Scopus, CINAHL, Embase, Medline, and PsycINFO. We tracked references, footnotes, and citations. Restrictions included: English language, date of publication January 2000 until February 2013. Two reviewers independently carried out the following: paper screening, data extraction, and data analysis. Data were analysed using framework synthesis, as informed by Normalization Process Theory. Sixty-nine papers were included. Treatment burden includes: (1) making sense of stroke management and planning care, (2) interacting with others, (3) enacting management strategies, and (4) reflecting on management. Health care is fragmented, with poor communication between patient and health care providers. Patients report inadequate information provision. Inpatient care is unsatisfactory, with a perceived lack of empathy from professionals and a shortage of stimulating activities on the ward. Discharge services are poorly coordinated, and accessing health and social care in the community is difficult. The study has potential limitations because it was restricted to studies published in English only and data from low-income countries were scarce.
Stroke management is extremely demanding for patients, and treatment burden is influenced by micro and macro organisation of health services. Knowledge deficits mean patients are ill equipped to organise their care and develop coping strategies, making adherence less likely. There is a need to transform the approach to care provision so that services are configured to prioritise patient needs rather than those of health care systems.
Systematic Review Registration
International Prospective Register of Systematic Reviews CRD42011001123
Please see later in the article for the Editors' Summary
Editors' Summary
Every year, 15 million people have a stroke. About 5 million of these people die within a few days, and another 5 million are left disabled. Stroke occurs when the blood supply of the brain is suddenly interrupted by a blood vessel in the brain being blocked by a blood clot (ischemic stroke) or bursting (hemorrhagic stroke). Deprived of the oxygen normally carried to them by the blood, the brain cells near the blockage die. The symptoms of stroke depend on which part of the brain is damaged but include sudden weakness or paralysis along one side of the body, vision loss in one or both eyes, and confusion or trouble speaking or understanding speech. Anyone experiencing these symptoms should seek immediate medical attention because prompt treatment can limit the damage to the brain. In the longer term, post-stroke rehabilitation can help individuals overcome the physical disabilities caused by stroke, and drugs that thin the blood, reduce blood pressure and reduce cholesterol (major risk factors for stroke) alongside behavioral counseling can reduce the risk of a second stroke.
Why Was This Study Done?
Treatment for, and rehabilitation from, stroke is a lengthy process that requires considerable personal investment from the patient. The term “treatment burden” describes the self-care practices that patients with stroke and other chronic diseases must perform to follow the complicated management strategies that have been developed for these conditions. Unfortunately, treatment burden can overwhelm patients. They may be unable to cope with the multiple demands placed on them by health-care providers and systems for their self-care, a situation that leads to poor adherence to therapies and poor outcomes. For example, patients may find it hard to complete all the exercises designed to help them regain full movement of their limbs after a stroke. Treatment burden has been poorly examined in relation to stroke. Here, the researchers identify and describe the treatment burden in stroke by undertaking a systematic review (a study that uses predefined criteria to identify all the literature on a given topic) of qualitative studies on the patient experience of stroke management. Qualitative studies collect non-quantitative data so, for example, a qualitative study on stroke treatment might ask people how the treatment made them feel whereas a quantitative study might compare clinical outcomes between those receiving and not receiving the treatment.
What Did the Researchers Do and Find?
The researchers identified 69 qualitative studies dealing with the experiences of stroke management of adult patients and analyzed the data in these papers using framework synthesis—an approach that divides data into thematic categories. Specifically, the researchers used a coding framework informed by normalization process theory, a sociological theory of the implementation, embedding and integration of tasks and practices; embedding is the process of making tasks and practices a routine part of everyday life and integration refers to sustaining these embedded practices. The researchers identified four main areas of treatment burden for stroke: making sense of stroke management and planning care; interacting with others, including health care professionals, family and other patients with stroke; enacting management strategies (including enduring institutional admissions, managing stroke in the community, reintegrating into society and adjusting to life after stroke); and reflecting on management to make decisions about self-care. Moreover, they identified problems in all these areas, including inadequate provision of information, poor communication with health-care providers, and unsatisfactory inpatient care.
What Do These Findings Mean?
These findings show that stroke management is extremely demanding for patients and is influenced by both the micro and macro organization of health services. At the micro organizational level, fragmented care and poor communication between patients and clinicians and between health-care providers can mean patients are ill equipped to organize their care and develop coping strategies, which makes adherence to management strategies less likely. At the macro organizational level, it can be hard for patients to obtain the practical and financial help they need to manage their stroke in the community. Overall, these findings suggest that care provision for stroke needs to be transformed so that the needs of patients rather than the needs of health-care systems are prioritized. Further work is required, however, to understand how the patient experience of treatment burden is affected by the clinical characteristics of stroke, by disability level, and by other co-existing diseases. By undertaking such work, it should be possible to generate a patient-reported outcome measure of treatment burden that, if used by policy makers and health-care providers, has the potential to improve the quality of stroke care.
Additional Information
Please access these Web sites via the online version of this summary at
The US National Institute of Neurological Disorders and Stroke provides information about all aspects of stroke (in English and Spanish); its Know Stroke site provides educational materials about stroke prevention, treatment, and rehabilitation including personal stories (in English and Spanish); the US National Institutes of Health SeniorHealth website has additional information about stroke
The Internet Stroke Center provides detailed information about stroke for patients, families, and health professionals (in English and Spanish)
The UK National Health Service Choices website also provides information about stroke for patients and their families, including personal stories
MedlinePlus has links to additional resources about stroke (in English and Spanish)
The UK not-for-profit website Healthtalkonline provides personal stories about stroke
Wikipedia provides information on the burden of treatment and on the normalization process theory (note: Wikipedia is a free online encyclopedia that anyone can edit; available in several languages)
PMCID: PMC3692487  PMID: 23824703
18.  Treatments for reversing warfarin anticoagulation in patients with acute intracranial hemorrhage: a structured literature review 
Study objective
The acute management of patients on warfarin with spontaneous or traumatic intracranial hemorrhage continues to be debated in the medical literature. The objective of this paper was to conduct a structured review of the medical literature and summarize the advantages and risks of the available treatment options for reversing warfarin anticoagulation in patients who present to the emergency department with acute intracranial hemorrhage.
A structured literature search and review of articles relevant to intracranial hemorrhage and warfarin and treatment in the emergency department was performed. Databases for PubMed, CINAHL, and Cochrane EBM Reviews were electronically searched using keywords covering the concepts of anticoagulation drugs, intracranial hemorrhage (ICH), and treatment. The results generated by the search were limited to English- language articles and reviewed for relevance to our topic. The multiple database searches revealed 586 papers for review for possible inclusion. The final consensus of our comprehensive search strategy was a total of 23 original studies for inclusion in our review.
Warfarin not only increases the risk of but also the severity of ICH by causing hematoma expansion. Prothrombin complex concentrate is statistically significantly faster at correcting the INR compared to fresh frozen plasma transfusions. Recombinant factor VIIa appears to rapidly reverse warfarin's effect on INR; however, this treatment is not FDA-approved and is associated with a 5% thromboembolic event rate. Slow intravenous dosing of vitamin K is recommended in patients with ICH. The 30-day risk for ischemic stroke after discontinuation of warfarin therapy was 3-5%. The risks of not reversing the anticoagulation in ICH generally outweigh the risk of thrombosis in the acute setting.
Increasing numbers of patients are on anticoagulation including warfarin. There is no uniform standard for reversing warfarin in intracranial hemorrhage. Intravenous vitamin K in addition to fresh frozen plasma or prothrombin complex concentrate is recommended be used to reverse warfarin-associated intracranial hemorrhage. No mortality benefit for one treatment regimen over another has been shown. Emergency physicians should know their hospital's available warfarin reversal options and be comfortable administering these treatments to critically ill patients.
PMCID: PMC3141388  PMID: 21740550
19.  Atrial fibrillation anticoagulation care in a large urban family medicine practice 
Canadian Family Physician  2014;60(3):e173-e179.
To determine the proportion of patients with atrial fibrillation (AF) in primary care achieving guideline-concordant stroke prevention treatment based on both the previous (2010) and the updated (2012) Canadian guideline recommendations.
Retrospective chart review.
Primary care patients (N = 204) with AF. The mean age was 71.3 years and 53.4% were women.
Large urban community family practice in Toronto, Ont.
Main outcome measures
Patient demographic characteristics such as sex and age; a list of current cardiac medications including anticoagulants and antiplatelets; the total number of medications; relevant current and past medical history including presence of diabetes, stroke or transient ischemic attack, hypertension, and vascular disease; number of visits to the family physician and cardiologist in the past year and past 5 years, and how many of these were for AF; the number of visits to the emergency department or hospitalizations for AF, congestive heart failure, or stroke; if patients were taking warfarin, how often their international normalized ratios were recorded, and how many times they were in the reference range; CHADS2 (congestive heart failure, hypertension, age ≥ 75, diabetes mellitus, and stroke or transient ischemic attack) score, if recorded; and reason for not taking oral anticoagulants when they should have been, if recorded.
Among those who had CHADS2 scores of 0, 64 patients (97.0%) were receiving appropriate stroke prevention in AF (SPAF) treatment according to the 2010 guidelines. When the 2012 guidelines were applied, 39 patients (59.1%) were receiving appropriate SPAF treatment (P < .001). For those with CHADS2 scores of 1, 88.4% of patients had appropriate SPAF treatment according to the 2010 guidelines, but only 55.1% were adequately treated according to the 2012 guidelines (P < .001). Of the patients at the highest risk (CHADS2 score > 1), 68.1% were adequately treated with anticoagulation and an additional 8.7% (6 of 69) had documented reasons why they were not taking anticoagulants.
When assessed using the 2012 Canadian Cardiovascular Society AF guidelines, the proportion of patients receiving appropriate SPAF therapy in this primary care setting decreased substantially. All patients with CHADS2 scores of 0 or 1 should be reassessed to ensure that they are receiving optimal stroke prevention treatment.
PMCID: PMC3952782  PMID: 24627401
20.  Antithrombotic therapy and outcomes of patients with atrial fibrillation following primary percutaneous coronary intervention: results from the APEX-AMI trial 
European Heart Journal  2009;30(16):2019-2028.
To assess the incidence and timing of atrial fibrillation (AF), describe antithrombotic therapy use, and evaluate the association of AF with 90 day mortality and other secondary clinical outcomes.
Methods and results
We studied 5745 ST-segment elevation myocardial infarction patients treated with primary percutaneous coronary intervention (PCI) in APEX-AMI. Approximately 11% had AF during hospitalization. Atrial fibrillation prevalence at baseline and at discharge was 4.8% [confidence interval (CI) 4.3–5.4%] and 2.5% (CI 2.1–2.9%), respectively. The proportion of 5466 patients without AF at baseline who developed new onset AF was 6.3% (CI 5.6–6.9%). This corresponded to 9.3 cases of new onset AF/1000 patient days at risk. New onset AF was independently associated with 90 day mortality [adjusted hazard ratio (HR) 1.81; 95% CI 1.06–3.09; P = 0.029] after accounting for baseline covariates and in-hospital procedures and complications. New onset AF was associated with shock (adjusted HR 3.81; 95% CI 1.88–7.70; P = 0.0002), congestive heart failure (adjusted HR 2.66; 95% CI 1.74–4.06; P < 0.0001), and stroke (adjusted HR 2.98; 95% CI 1.47–6.04; P = 0.0024) in models accounting for baseline covariates. Of AF patients, 55% did not receive oral anticoagulation therapy at discharge. Among patients with coronary stents, 5.1% were discharged on triple therapy. Patients at highest risk of stroke (CHADS2 score ≥2) were least likely to receive oral anticoagulation at discharge (39%). Warfarin use in patients with AF at discharge (43.4%) was associated with lower rates of 90 day mortality and stroke.
Atrial fibrillation prevalence at baseline and at discharge was 4.8 and 2.5%, respectively. The proportion of patients who developed new onset AF was 6.3%. New onset AF was independently associated with 90 day mortality and was a marker of adverse outcomes in patients undergoing primary PCI.
PMCID: PMC2764954  PMID: 19502623
Atrial fibrillation; Myocardial infarction; Antithrombotic therapy; Outcomes
There is some evidence to suggest that the standard of acute medical care provided to patients with cerebrovascular disease is a major determinant of the eventual outcome. Consequently, the Royal College of Physicians (RCP) of London issues periodic guidelines to assist healthcare providers in the management of patients presenting with stroke.
An audit of the acute management of stroke in two hospitals belonging to the same health care trust in the UK.
Retrospective review of 98 randomly selected case-notes of patients managed for cerebrovascular disease in two acute hospitals in the UK between April and June 2004. The pertinent guidelines of RCP (London) are highlighted while audit targets were set at 70%.
84% of patients presenting with cerebrovascular disease had a stroke rather than a TIA, anterior circulation strokes were commonest. All patients with stroke were admitted while those with TIAs were discharged on the same day but most patients with TIA were not followed up by Stroke specialists. Most CT-imaging of the head was done after 24 hours delaying the commencement of anti-platelets for patients with ischaemic stroke or neurosurgical referral for haemorrhagic stroke. Furthermore, there was a low rate of referral for carotid ultrasound in patients with anterior circulation strokes. Anti-platelets and statins were commenced for most patients with ischaemic stroke while diabetes was well controlled in most of them. However, ACE-inhibitors and diuretics such as indapamide were under-utilized for secondary prevention in such patients. Warfarin anti-coagulation was underutilized in patients with ischaemic stroke who had underlying chronic atrial fibrillation. While there was significant multi-disciplinary team input, dysphagia and physiotherapy assessments were delayed. Similarly, occupational therapy input and psychological assesment were omitted from the care of most patients.
Hospital service provision for the management of cerebrovascular disease needs to provide appropriate specialist follow up for patients with TIA, prompt radiological imaging and multi-disciplinary team input for patients with stroke. Furthermore, physicians need to utilize appropriate antihypertensives and anti-coagulation more frequently in the secondary prevention of stroke.
PMCID: PMC4111017  PMID: 25161444
Stroke; anti-platelets; anti-coagulation; carotid stenosis; secondary prevention.
22.  Bleeding complications associated with warfarin treatment in ischemic stroke patients with atrial fibrillation: a population-based cohort study 
Bleeding events are the major obstacle to the widespread use of warfarin for secondary stroke prevention. Previous studies have not examined the use of risk stratification scores to estimate lifetime bleeding risk associated with warfarin treatment in a population-based setting. The purpose of this study is to determine the lifetime risk of bleeding events in ischemic stroke patients with atrial fibrillation (AF) undergoing warfarin treatment in a population-based cohort and to evaluate the use of bleeding risk scores to identify patients at high-risk for lifetime bleeding events.
The resources of the Rochester Epidemiology Project Medical Linkage System were used to identify acute ischemic stroke patients with atrial fibrillation undergoing warfarin treatment for secondary stroke prevention from 1980 to 1994. Medical information for patients seen at Mayo Clinic and at Olmsted Medical Center were used to retrospectively risk-stratify stroke patients according to bleeding risk scores (including the HAS-BLED and HEMORR2HAGES scores) prior to warfarin initiation. These scores were reassessed one and five years later, and compared with lifetime bleeding events.
One hundred patients (mean age, 79.3 years; 68% women) were studied. Ninety-nine patients were followed to death. Major bleeding events occurred in 41 patients at a median of 19 months following warfarin initiation. Patients with a history of hemorrhage before warfarin treatment were more likely to develop major hemorrhage (15% vs 3%, p=0.04). Patients with baseline HAS-BLED scores ≥2 had a higher lifetime risk of major bleeding events compared with those with scores ≤1 (53% vs 7%, p<0.01), while those with HEMORR2HAGES score ≥2 had a higher life-time risk of major bleeding events compared with those with scores ≤1 (52% vs 16%, p=0.03). Patients with an increase in the HAS-BLED and HEMORR2HAGES scores during follow-up had a higher remaining lifetime risk of major bleeding events compared to those with no change.
Our findings indicate high lifetime bleeding risk associated with warfarin treatment for patients with ischemic stroke. Risk stratification scores are useful to identify patients at high-risk of developing bleeding complications and should be recalculated at regular intervals to evaluate the bleeding risk in anticoagulated patients with ischemic stroke.
PMCID: PMC4080718  PMID: 23499334
stroke; atrial fibrillation; warfarin; bleeding complications
23.  Characteristics affecting oral anticoagulant therapy choice among patients with non-valvular atrial fibrillation: a retrospective claims analysis 
Dabigatran is one of the three newer oral anticoagulants (OACs) recently approved in the United States for stroke prevention in non-valvular atrial fibrillation (NVAF) patients. The objective of this study was to identify patient, healthcare provider, and health plan factors associated with dabigatran versus warfarin use among NVAF patients.
Administrative claims data from patients with ≥2 NVAF medical claims in the HealthCore Integrated Research Database between 10/1/2009 and 10/31/2011 were analyzed. During the study intake period (10/1/2010 - 10/31/2011), dabigatran patients had ≥2 dabigatran prescriptions, warfarin patients had ≥2 warfarin and no dabigatran prescriptions, and the first oral anticoagulant (OAC) prescription date was the index date. Continuous enrollment for 12 months preceding (“pre-index”) and ≥ 6 months following the index date was required. Patients without pre-index warfarin use were assigned to the ‘OAC-naïve’ subgroup. Separate analyses were performed for ‘all-patient’ and ‘OAC-naïve’ cohorts. Multivariable logistic regression (LR) identified factors associated with dabigatran versus warfarin use.
Of 20,320 patients (3,019 dabigatran and 17,301 warfarin) who met study criteria, 27% of dabigatran and 13% of warfarin patients were OAC-naïve. Among all-patients, dabigatran patients were younger (mean 67 versus 73 years, p < 0.001), predominantly male (71% versus 61%, p < 0.001), and more frequently had a cardiologist prescriber (51% versus 30%, p < 0.001) than warfarin patients. Warfarin patients had higher pre-index Elixhauser Comorbidity Index (mean: 4.3 versus 4.0, p < 0.001) and higher ATRIA bleeding risk score (mean: 3.0 versus 2.3, p < 0.001). LR results were generally consistent between all- and OAC-naïve patients. Among OAC-naïve patients, strongest factors associated with dabigatran use were prescriber specialty (OR = 3.59, 95% CI 2.68-4.81 for cardiologist; OR = 2.22, 95% CI 1.65-2.97 for other specialist), health plan type (OR = 1.47 95% CI 1.10-1.96 for preferred provider organization), and prior ischemic stroke (OR = 1.42, 95% CI 1.06-1.90). Older age decreased the probability of dabigatran use.
Beside patient characteristics, cardiology specialty of the prescribing physician and health plan type were the strongest factors associated with dabigatran use.
PMCID: PMC4112613  PMID: 25034699
Non-valvular atrial fibrillation; Dabigatran; Warfarin; Oral anticoagulation; Healthcare
24.  Stroke in Heart Failure in Sinus Rhythm: The Warfarin versus Aspirin in Reduced Cardiac Ejection Fraction Trial 
The Warfarin versus Aspirin in Reduced Cardiac Ejection Fraction trial found no difference between warfarin and aspirin in patients with low ejection fraction in sinus rhythm for the primary outcome: first to occur of 84 incident ischemic strokes (IIS), 7 intracerebral hemorrhages or 531 deaths. Prespecified secondary analysis showed a 48% hazard ratio reduction (p = 0.005) for warfarin in IIS. Cardioembolism is likely the main pathogenesis of stroke in heart failure. We examined the IIS benefit for warfarin in more detail in post hoc secondary analyses.
We subtyped IIS into definite, possible and noncardioembolic using the Stroke Prevention in Atrial Fibrillation method. Statistical tests, stratified by prior ischemic stroke or transient ischemic attack, were the conditional binomial for independent Poisson variables for rates, the Cochran-Mantel-Haenszel test for stroke subtype and the van Elteren test for modified Rankin Score (mRS) and National Institute of Health Stroke Scale (NIHSS) distributions, and an exact test for proportions.
Twenty-nine of 1,142 warfarin and 55 of 1,163 aspirin patients had IIS. The warfarin IIS rate (0.727/100 patient-years, PY) was lower than for aspirin (1.36/100 PY, p = 0.003). Definite cardioembolic IIS was less frequent on warfarin than aspirin (0.22 vs. 0.55/100 PY, p = 0.012). Possible cardioembolic IIS tended to be less frequent on warfarin than aspirin (0.37 vs. 0.67/100 PY, p = 0.063) but noncardioembolic IIS showed no difference: 5 (0.12/100 PY) versus 6 (0.15/100 PY, p = 0.768). Among patients experiencing IIS, there were no differences by treatment arm in fatal IIS, baseline mRS, mRS 90 days after IIS, and change from baseline to post-IIS mRS. The warfarin arm showed a trend to a lower proportion of severe nonfatal IIS [mRS 3–5; 3/23 (13.0%) vs. 16/48 (33.3%), p = 0.086]. There was no difference in NIHSS at the time of stroke (p = 0.825) or in post-IIS mRS (p = 0.948) between cardioembolic, possible cardioembolic and noncardioembolic stroke including both warfarin and aspirin groups.
The observed benefits in the reduction of IIS for warfarin compared to aspirin are most significant for cardioembolic IIS among patients with low ejection fraction in sinus rhythm. This is supported by trends to lower frequencies of severe IIS and possible cardioembolic IIS in patients on warfarin compared to aspirin.
PMCID: PMC4256381  PMID: 23921215
Aspirin; Cardiac embolism; Heart failure; Stroke prevention
25.  Management of gastrointestinal bleeding in patients anticoagulated with dabigatran compared with warfarin: a retrospective, comparative case review 
Dabigatran etexilate, was found to be effective for stroke prevention in patients with non-valvular atrial fibrillation. Given its predictable pharmacodynamics, laboratory monitoring is not required. Moreover, the risks of overall bleeding, intracranial bleeding, and life-threatening hemorrhage from dabigatran were found to be lower than warfarin. However, a higher risk of gastrointestinal (GI) bleeding caused by dabigatran from the randomized evaluation of long-term anticoagulant therapy (RE-LY) trial has raised the concern regarding clinical outcomes of patients with GI bleeding caused by dabigatran compared with warfarin.
We retrospectively studied patients who were hospitalized for GI bleeding from dabigatran compared with warfarin with therapeutic anticoagulation monitoring during 2009 to 2012. Initial laboratory findings at presentation, number of transfused packed red blood cells (PRBCs), acute kidney injury, clinical outcomes (e.g., hypotension, tachycardia), length of stay, and death were compared.
Thirteen patients taking dabigatran and 26 patients who were on warfarin with therapeutic international normalized ratio (INR) were hospitalized during the study period. Demographic data and baseline parameters between the two groups were not significantly different except for concurrent aspirin use (84.6% vs. 50%, P=0.036). Fifty-four percent of patients taking dabigatran did not have activated partial thromboplastin time (aPTT) level performed at presentation (7/13). The patients with GI bleeding from warfarin received significantly more PRBC transfusions compared with the dabigatran group (1.92±2.2 vs. 0.69±1.1 units, P=0.024). After controlling for initial hemoglobin and history of chronic kidney disease by using multivariate analysis, the patients in the warfarin group were likely to receive more PRBC. Hypotension at presentation was more common in GI bleeding caused by warfarin than dabigatran but the P value was insignificant (30.8% vs. 7.7%, P=0.11). Nevertheless, no differences in clinical outcomes or length of stay were found between the two groups.
From our data, the patients with GI bleeding from dabigatran were likely to receive fewer PRBC transfusions; however, clinical outcomes and length of stay were comparable to GI bleeding caused by warfarin. Our sample generalizes to an elderly population (mean age of 77.9±10 years old) with creatinine clearance (CrCl) >30 mL/min who experience GI bleeding during chronic anticoagulation.
PMCID: PMC4069982  PMID: 25009791
Dabigatran; direct thrombin inhibitor; gastrointestinal bleeding (GI bleeding); warfarin

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