Secondary Prevention of Stroke in Patients with Atrial Fibrillation: Factors Influencing the Prescription of Oral Anticoagulation at Discharge

Nucleic Acid Therapies for Ischemic Stroke

Stroke remains a leading cause of disability and death worldwide despite significant scientific and therapeutic advances. Therefore, there is a critical need to improve stroke prevention and treatment. In this review, we describe several examples that leverage nucleic acid therapeutics to improve stroke care through prevention, acute treatment, and recovery. Aptamer systems are under development to increase the safety and efficacy of antithrombotic and thrombolytic treatment, which represent the mainstay of medical stroke therapy. Antisense oligonucleotide therapy has shown some promise in treating stroke causes that are genetically determined and resistant to classic prevention approaches such as elevated lipoprotein (a) and cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL). Targeting microRNAs may be attractive because they regulate factors involved in neuronal cell death and reperfusion-associated injury, as well as neurorestorative pathways. Lastly, microRNAs may aid reliable etiologic classification of stroke subtypes, which is important for effective secondary stroke prevention.

Two-dimensional versus three-dimensional transesophageal echocardiography in percutaneous left atrial appendage occlusion

BACKGROUND

Real-time three-dimensional transesophageal echocardiography (RT3D TEE) enables better visualization of the left atrial appendage (LAA) and may be superior to real-time two-dimensional transesophageal echocardiography (RT2D TEE) for LAA occlusion (LAAO). The aim of this study was to assess inter- and intra-observer variability of RT2D TEE and RT3D TEE measurements of LAA, and to assess the accordance of RT2D TEE and RT3D TEE with appropriate occluder selection.

METHODS

Transesophageal echocardiography was performed in 40 patients during LAAO. RT2D TEE and RT3D TEE measurements of the ostium and landing zone were performed independently by two echocardiographers. The appropriate choice of occluder was confirmed with fluoroscopic criteria. After the procedures, RT2D TEE and RT3D TEE evaluation were repeated separately by the same echocardiographers.

RESULTS

The mean ostium diameters by RT2D TEE obtained by the two observers were 23.6 ± 4.2 vs. 24.8 ± 5.2 (p = 0.04), and the mean landing zone diameters were 17.7 ± 4.4 vs. 19.4 ± 3.9 (p < 0.01). In the case of RT3D TEE, the ostium diameters were 29.6 ± 5.3 vs. 29.4 ± 6.4 (p = not significant [NS]) and the landing zone diameters were 21.4 ± 3.8 vs. 21.6 ± 3.9 (p = NS). Intra-observer differences were absent in the case of RT3D TEE. The comparison of RT2D TEE vs. RT3D TEE analyses performed by the same echocardiographer revealed significant differences in the ostium and landing zone measurements (both p < 0.01). Agreement between the suggested device size was better for RT3D TEE (weighted kappa was 0.62 vs. 0.28, respectively).

CONCLUSIONS

The results obtained with RT3D TEE showed significantly larger dimensions of the ostium and the landing zone. RT3D TEE showed lesser inter- and intra-observer variability and better agreement with the implanted device.

Low Use of Oral Anticoagulant Prescribing for Secondary Stroke Prevention: Results From the Ontario Stroke Registry

BACKGROUND

Oral anticoagulation reduces the risk of stroke in atrial fibrillation but is often underused.

OBJECTIVES

To identify factors associated with oral anticoagulant prescribing and adherence after stroke or transient ischemic attack (TIA).

RESEARCH DESIGN

Retrospective cohort study using linked Ontario Stroke Registry and prescription claims data.

SUBJECTS

Consecutive patients with atrial fibrillation and ischemic stroke/TIA admitted to 11 stroke centers in Ontario, Canada between 2003 and 2011.

MEASURES

We used modified Poisson regression models to determine predictors of anticoagulant prescribing and multiple logistic regression to determine predictors of 1-year adherence.

RESULTS

Of the 5781 patients in the study cohort, 4235 (73%) were prescribed oral anticoagulants at discharge. Older patients were less likely to receive anticoagulation [adjusted relative risk (aRR) for each additional year=0.997; 95% confidence interval (CI), 0.995-0.998], as were those with TIA compared with ischemic stroke (aRR=0.904; 95% CI, 0.865-0.945), prior gastrointestinal bleed (aRR=0.778; 95% CI, 0.693-0.873), dementia (aRR=0.912; 95% CI, 0.856-0.973), and those from a long-term care facility (aRR=0.810; 95% CI, 0.737-0.891). After limiting the sample to those without obvious contraindications to anticoagulation, age, dementia, and long-term care residence continued to be associated with lower prescription of oral anticoagulants. One-year adherence to therapy was similar across most patient groups.

CONCLUSIONS

Age, dementia, and long-term care residence are predictors of lower oral anticoagulant use for secondary stroke prevention and represent key target areas for quality improvement initiatives.

Safely Addressing Patients with Atrial Fibrillation to Early Anticoagulation after Acute Stroke

BACKGROUND

It has been widely reported that anticoagulants (ACs) are underused for primary and secondary prevention of ischemic stroke in patients with atrial fibrillation (AFib). Furthermore, precise evidence-based guidelines about the best timing for AC initiation after acute stroke are currently lacking.

METHODS AND RESULTS

In this retrospective, observational study, we analyzed prescription trends in AFib patients with acute ischemic stroke who were hospitalized in four neurologic stroke units of our region (Lombardia, Italy). In-hospital antithrombotic prescription was performed in highly heterogeneous patterns. A prestroke treatment with AC was the leading factor enhancing AC prescription during hospitalization. The other factors promoting AC were male gender, younger age, lower prestroke disability and stroke severity, and smaller stroke volumes. AFib subtype influenced AC prescription only in AC-naïve patients. Interestingly, Congestive heart failure, Hypertension, Age higher than 75 years, Diabetes, previous Stroke or TIA or thromboembolism, Vascular disease, Age 64-75 years, female Sex (CHA₂DS₂-VASc) and Hypertension, Abnormal renal and liver function, Stroke, Bleeding, Labile INRs, Elderly, Drugs and alcohol (HAS-BLED) scores were not associated with AC prescription. However, patients who were treated with AC, including early treatment (<48 hours), showed a low rate of bleeding.

CONCLUSIONS

Our findings potentially suggest that, although apparently neglecting the common risk stratification tools, our neurologists were able to select the more suitable candidates for prompt AC treatment. Further studies are needed to develop new scoring systems to aid ischemic and hemorrhagic risk estimation in the secondary prevention of stroke.

Real life anticoagulation treatment of patients with atrial fibrillation in Germany: extent and causes of anticoagulant under-use

Oral anticoagulation (OAC) with either new oral anticoagulants (NOACs) or Vitamin-K antagonists (VKAs) is recommended by guidelines for patients with atrial fibrillation (AF) and a moderate to high risk of stroke. Based on a claims-based data set the aim of this study was to quantify the stroke-risk dependent OAC utilization profile of German AF patients and possible causes of OAC under-use. Our claims-based data set was derived from two German statutory health insurance funds for the years 2007-2010. All prevalent AF-patients in the period 2007-2009 were included. The OAC-need in 2010 was assumed whenever a CHADS2- or CHA2DS2-VASC-score was >1 and no factor that disfavored OAC use existed. Causes of OAC under-use were analyzed using multivariate logistic regression. 108,632 AF-prevalent patients met the inclusion criteria. Average age was 75.43 years, average CHA2DS2-VASc-score was 4.38. OAC should have been recommended for 56.1/62.9 % of the patients (regarding factors disfavouring VKA/NOAC use). For 38.88/39.20 % of the patient-days in 2010 we could not observe any coverage by anticoagulants. Dementia of patients (OR 2.656) and general prescription patterns of the treating physician (OR 1.633) were the most important factors increasing the risk of OAC under-use. Patients who had consulted a cardiologist had a lower risk of being under-treated with OAC (OR 0.459). OAC under-use still seems to be one of the major challenges in the real-life treatment of AF patients. Our study confirms that both patient/disease characteristics and treatment environment/general prescribing behaviour of physicians may explain the OAC under-use in AF patients.

Adherence to Guidelines for Antithrombotic Therapy in Patients with Atrial Fibrillation According to CHADS2 Score before and after Stroke: A Multicenter Observational Study from Korea

Background and Purpose

A substantial proportion of patients with atrial fibrillation (AF) are not treated optimally; however, the inappropriateness of drug therapy has never been evaluated before or after a stroke event. We investigated the adherence to guidelines for therapy in AF patients hospitalized with acute ischemic stroke (AIS) before stroke onset and at discharge, with the aim of identifying the factors associated with inappropriate therapy.

Methods

AIS patients with AF hospitalized within 7 days of onset were identified from a prospective nine-center stroke registry database. Two cohorts were defined: patients diagnosed with AF prior to the stroke event (admission cohort) and patients diagnosed with AF at discharge from hospital (discharge cohort). Any of the following conditions were regarded as nonadherence to guidelines in this study: use of anticoagulant or nonuse of antithrombotics with CHADS2 score=0, nonuse of antithrombotics with CHADS2 score=1, or nonuse of anticoagulant with CHADS2 score ≥2.

Results

Overall, 406 patients were enrolled in the admission cohort and 518 in the discharge cohort. The rates of nonadherence before a stroke event and at discharge were 77.8% and 33.3%, respectively. These rates varied widely for both cohorts, with interhospital differences being statistically significant. Multivariable analysis revealed that old age, stroke history, and congestive heart failure were associated with nonadherence before stroke. At discharge, males, coronary heart disease, inappropriate antithrombotic use before stroke, and functional disability at discharge were associated with nonadherence.

Conclusions

This study shows that antithrombotic use in AIS patients with AF might be not optimal before and after stroke in Korea.

Non-vitamin K antagonist oral anticoagulants and atrial fibrillation guidelines in practice: barriers to and strategies for optimal implementation

Stroke is a leading cause of morbidity and mortality worldwide. Atrial fibrillation (AF) is an independent risk factor for stroke, increasing the risk five-fold. Strokes in patients with AF are more likely than other embolic strokes to be fatal or cause severe disability and are associated with higher healthcare costs, but they are also preventable. Current guidelines recommend that all patients with AF who are at risk of stroke should receive anticoagulation. However, despite this guidance, registry data indicate that anticoagulation is still widely underused. With a focus on the 2012 update of the European Society of Cardiology (ESC) guidelines for the management of AF, the Action for Stroke Prevention alliance writing group have identified key reasons for the suboptimal implementation of the guidelines at a global, regional, and local level, with an emphasis on access restrictions to guideline-recommended therapies. Following identification of these barriers, the group has developed an expert consensus on strategies to augment the implementation of current guidelines, including practical, educational, and access-related measures. The potential impact of healthcare quality measures for stroke prevention on guideline implementation is also explored. By providing practical guidance on how to improve implementation of the ESC guidelines, or region-specific modifications of these guidelines, the aim is to reduce the potentially devastating impact that stroke can have on patients, their families and their carers.

Anticoagulant therapy in practice

Atrial fibrillation is a risk factor for ischemic stroke. To prevent stroke oral anticoagulants can be administered. Old and new types of anticoagulants are available. Nowadays, old type, acenocumarol based anticoagulants are used preferentially in Hungary. Aim: The advantages and the disadvantages of anticoagulants are well known, but anticoagulants are underused in many cases. Method: The authors retrospectively examined how frequent atrial fibrillation was and whether the usage of anticoagulants in practice was in accordance with current guidelines among acute stroke cases admitted to the Department of Neurology, Medical and Health Science Centre of Debrecen University in 2009. Results: Of the 461 acute stroke cases, 96 patients had known and 22 patients had newly discovered atrial fibrillation. Half of the patients did not receive proper anticoagulation. Only 8.4% of them had their INR levels within the therapeutic range. Conclusions: The findings are similar to those reported in other studies. Many factors may contribute to the high proportion of improper use of anticoagulants, and further investigations are needed to determine these factors. In any case, elimination of these factors leading to a failure of anticoagulation may decrease the incidence of stroke. Orv. Hetil., 2012, 153, 732–736.

Influence of lipid profiles on the risk of hemorrhagic transformation after ischemic stroke: systematic review

Background

It has been suggested that low cholesterol levels might be associated with an increased risk of hemorrhagic transformation (HT) in patients with acute cerebral ischemia. We systematically reviewed the literature to determine the influence of lipid profiles on the HT risk.

Methods

We searched PubMed from 1966 and EMBASE from 1980 for studies that investigated the association between lipid profiles and HT. We performed a meta-analysis (weighted mean difference method) for the comparison between presence and absence of HT (all or symptomatic) for total, low-density-lipoprotein (LDL) and high-density-lipoprotein (HDL) cholesterol, and triglycerides.

Results

Eight studies investigating 1,763 patients were eligible, but none was designed specifically to address this question. All studies recruited acute stroke patients selected on the presumed cause of cerebral ischemia or treatment received. The meta-analysis showed that: (i) patients with all HT had lower LDL cholesterol levels (p = 0.008) but no difference in HDL cholesterol levels (p = 0.066), total cholesterol (p = 0.129) and triglycerides (p = 0.900); (ii) patients with symptomatic HT had lower total cholesterol levels (p = 0.035) but did not differ in LDL (p = 0.056) and HDL cholesterol (p = 0.138) and triglyceride (p = 0.851) levels.

Conclusion

HT is associated with baseline total and LDL cholesterol levels, but the mechanism of this association needs to be explored to identify preventive strategies.

Underuse of oral anticoagulants in atrial fibrillation: a systematic review

BACKGROUND

Atrial fibrillation is associated with substantial mortality and morbidity from stroke and thromboembolism. Despite an efficacious oral anticoagulation therapy (warfarin), atrial fibrillation patients at high risk for stroke are often under-treated. This systematic review compares current treatment practices for stroke prevention in atrial fibrillation with published guidelines.

METHODS

Literature searches (1997-2008) identified 98 studies concerning current treatment practices for stroke prevention in atrial fibrillation. The percentage of patients eligible for oral anticoagulation due to elevated stroke risk was compared with the percentage treated. Under-treatment was defined as treatment of <70% of high-risk patients.

RESULTS

Of 54 studies that reported stroke risk levels and the percentage of patients treated, most showed underuse of oral anticoagulants for high-risk patients. From 29 studies of patients with prior stroke/transient ischemic attack who should all receive oral anticoagulation according to published guidelines, 25 studies reported under-treatment, with 21 of 29 studies reporting oral anticoagulation treatment levels below 60% (range 19%-81.3%). Subjects with a CHADS(2) (congestive heart failure, hypertension, age >75 years, diabetes mellitus, and prior stroke or transient ischemic attack) score >or=2 also were suboptimally treated, with 7 of 9 studies reporting treatment levels below 70% (range 39%-92.3%). Studies (21 of 54) using other stroke risk stratification schemes differ in the criteria they use to designate patients as "high risk," such that direct comparison is not possible.

CONCLUSIONS

This systematic review demonstrates the underuse of oral anticoagulation therapy for real-world atrial fibrillation patients with an elevated risk of stroke, highlighting the need for improved therapies for stroke prevention in atrial fibrillation.

Stroke prevention: modifying risk factors

Risk factor modification remains as the principal aspect of care for stroke prevention. Understanding of risk factors has advanced and several options are now available to treat modifiable risk factors. However, effective treatment remains a challenging task in clinical practice. Prevention begins with awareness of risk factors by patients and clinicians. Risk factor assessment along with overall stroke risk estimation should be part of evaluation of patients with stroke, and used with careful clinical judgment. In this review, we discuss the impact of modifiable traditional vascular risk factors on ischemic stroke, interventions for stroke prevention, and evidence for early treatment of risk factors where available, as well as areas of research progress. Emphasis should be put on the education of patients, the community, and medical personnel. Future research in the field of genetic determinants of vascular risk factors and stroke will increase our understanding of the underlying mechanisms of cerebrovascular disease and likely result in development of new therapies and individualized programs for stroke prevention.

Short-term outcome of patients with cardiac- and thrombo-embolic cerebral infarcts

OBJECTIVES

It has already been demonstrated by previous studies that patients suffering from a cardiac-embolic stroke (CES) have a worse outcome than those with a thrombo-embolic stroke (TES). Many factors, such as age, initial stroke severity, stroke recurrence and vascular risk factors have been quoted as a possible explanation. The present retrospective study re-investigates more in detail which variables are the most important to explain the difference in disability between patients with CES and with TES on hospital discharge.

PATIENTS AND METHODS

Seven hundred forty-two consecutive patients with a territorial infarct were admitted to the Stroke Unit of the Ghent University Hospital between October 2002 and June 2007. The groups of CES and TES consisted, respectively of 283 and of 459 patients. Age, gender, vascular risk factors including previous strokes and pacemaker implantation, initial stroke severity and outcome, determined by the mean modified Rankin (mR) scale on hospital discharge, were compared between both groups.

RESULTS

Although the hospital stay of the patients with CES and TES was quite similar, the former group was much older with more females, more vascular risk factors, worse neurological deficit on admission and more disability on discharge. On logistic regression analysis coronary artery disease, isolated atrial fibrillation and cardiac valve disorder appear as independent predictors of stroke outcome.

CONCLUSION

The worse outcome in the CES patients is mainly due to the cardiac status of the patients.

Functional outcome 3 months after stroke predicts long-term survival

BACKGROUND

When reporting stroke survival and prognostic factors with a possible effect on outcome, the starting point for the observation of a clinical cohort usually is the onset of stroke or the acute admission of a patient. Thus, acute and early mortality inflict prognosis on long-term outcome. In order to give a more robust analysis of long-term survival after the acute period we chose to start our observation with 3-month survivors.

METHODS

We used data from Riks-Stroke, the Swedish quality register for stroke care, together with survival information from the Swedish population register to explore the influence of disability level 3 months after stroke on long-term survival. The main analysis included 15,959 stroke patients, registered during 2001-2002, who had been independent in primary activities of daily living before stroke, had suffered an ischaemic or a haemorrhagic stroke and reported no previous stroke.

RESULTS

Impaired functional outcome after stroke was an independent predictor of poor survival. Patients with modified Rankin scale (mRS) grades 3, 4 and 5 had hazard ratios of 1.7, 2.5 and 3.8, respectively, as compared with patients with lower mRS grades. In addition to high mRS, male sex, high age, diabetes, smoking, hypertension therapy at stroke onset, atrial fibrillation and depressed mood were also recognized as significant predictors of poor survival using a multiple Cox regression model.

CONCLUSION

The influence of disability on survival is stronger than that of several other well-known prognostic factors. This finding indicates that any intervention in the acute phase that may improve functional status at 3 months will also have favourable secondary effects on survival in the long term.