Ischemic Stroke and Heart Failure: Facts and Numbers. An Update

Heart failure (HF) is a severe clinical syndrome accompanied by a number of comorbidities. Ischemic stroke occurs frequently in patients with HF as a complication of the disease. In the present review, we aimed to summarize the current state of research on the role of cardio–cerebral interactions in the prevalence, etiology, and prognosis of both diseases. The main pathophysiological mechanisms underlying the development of stroke in HF and vice versa are discussed. In addition, we reviewed the results of recent clinical trials investigating the prevalence and prevention of stroke in patients with HF.

Long-term morbidity and mortality in patients without early complications after stroke or transient ischemic attack

BACKGROUND

Secondary prevention after stroke and transient ischemic attack (TIA) has focused on high early risk of recurrence, but survivors of stroke can have substantial long-term morbidity and mortality. We quantified long-term morbidity and mortality for patients who had no early complications after stroke or TIA and community-based controls.

METHODS

This longitudinal case-control study included all ambulatory or hospitalized patients with stroke or TIA (discharged from regional stroke centres in Ontario from 2003 to 2013) who survived for 90 days without recurrent stroke, myocardial infarction, all-cause admission to hospital, admission to an institution or death. Cases and controls were matched on age, sex and geographic location. The primary composite outcome was death, stroke, myocardial infarction, or admission to long-term or continuing care. We calculated 1-, 3- and 5-year rates of composite and individual outcomes and used cause-specific Cox regression to estimate long-term hazards for cases versus controls and for patients with stroke versus those with TIA.

RESULTS

Among patients who were initially stable after stroke or TIA (n = 26 366), the hazard of the primary outcome was more than double at 1 year (hazard ratio [HR] 2.4, 95% confidence interval [CI] 2.3-2.5), 3 years (HR 2.2, 95% CI 2.1-2.3) and 5 years (HR 2.1, 95% CI 2.1-2.2). Hazard was highest for recurrent stroke at 1 year (HR 6.8, 95% CI 6.1-7.5), continuing to 5 years (HR 5.1, 95% CI 4.8-5.5), and for admission to an institution (HR 2.1, 95% CI 1.9-2.2). Survivors of stroke had higher mortality and morbidity, but 31.5% (1789/5677) of patients with TIA experienced an adverse event within 5 years.

INTERPRETATION

Patients who survive stroke or TIA without early complications are typically discharged from secondary stroke prevention services. However, these patients remain at substantial long-term risk, particularly for recurrent stroke and admission to an institution. Novel approaches to prevention, potentially embedded in community or primary care, are required for long-term management of these initially stable but high-risk patients.

Cost effectiveness of rivaroxaban for stroke prevention in German patients with atrial fibrillation

OBJECTIVE

The aim of this study was to assess the cost effectiveness of the novel fixed-dose anticoagulant rivaroxaban compared with the current standard of care, warfarin, for the prevention of stroke in patients with atrial fibrillation (AF).

METHODS

A Markov model was constructed to model the costs and health outcomes of both treatments, potential adverse events, and resulting health states over 35 years. Analyses were based on a hypothetical cohort of 65-year-old patients with non-valvular AF at moderate to high risk of stroke. The main outcome measure was cost per quality-adjusted life-year (QALY) gained over the lifetime, and was assessed from the German Statutory Health Insurance (SHI) perspective. Costs and utility data were drawn from public data and the literature, while event probabilities were derived from both the literature and rivaroxaban's pivotal ROCKET AF trial.

RESULTS

Stroke prophylaxis with rivaroxaban offers health improvements over warfarin treatment at additional cost. From the SHI perspective, at baseline the incremental cost-effectiveness ratio of rivaroxaban was <euro>15,207 per QALY gained in 2014. The results were robust to changes in the majority of variables; however, they were sensitive to the price of rivaroxaban, the hazard ratios for stroke and intracranial hemorrhage, the time horizon, and the discount rate.

CONCLUSIONS

Our results showed that the substantially higher medication costs of rivaroxaban were offset by mitigating the shortcomings of warfarin, most notably frequent dose regulation and bleeding risk. Future health economic studies on novel oral anticoagulants should evaluate the cost effectiveness for secondary stroke prevention and, as clinical data from direct head-to-head comparisons become available, new anticoagulation therapies should be compared against each other.

An assessment of the cost-effectiveness of magnetic resonance, including diffusion-weighted imaging, in patients with transient ischaemic attack and minor stroke: a systematic review, meta-analysis and economic evaluation

BACKGROUND

Patients with transient ischaemic attack (TIA) or minor stroke need rapid treatment of risk factors to prevent recurrent stroke. ABCD2 score or magnetic resonance diffusion-weighted brain imaging (MR DWI) may help assessment and treatment.

OBJECTIVES

Is MR with DWI cost-effective in stroke prevention compared with computed tomography (CT) brain scanning in all patients, in specific subgroups or as 'one-stop' brain-carotid imaging? What is the current UK availability of services for stroke prevention?

DATA SOURCES

Published literature; stroke registries, audit and randomised clinical trials; national databases; survey of UK clinical and imaging services for stroke; expert opinion.

REVIEW METHODS

Systematic reviews and meta-analyses of published/unpublished data. Decision-analytic model of stroke prevention including on a 20-year time horizon including nine representative imaging scenarios.

RESULTS

The pooled recurrent stroke rate after TIA (53 studies, 30,558 patients) is 5.2% [95% confidence interval (CI) 3.9% to 5.9%] by 7 days, and 6.7% (5.2% to 8.7%) at 90 days. ABCD2 score does not identify patients with key stroke causes or identify mimics: 66% of specialist-diagnosed true TIAs and 35-41% of mimics had an ABCD2 score of ≥ 4; 20% of true TIAs with ABCD2 score of < 4 had key risk factors. MR DWI (45 studies, 9078 patients) showed an acute ischaemic lesion in 34.3% (95% CI 30.5% to 38.4%) of TIA, 69% of minor stroke patients, i.e. two-thirds of TIA patients are DWI negative. TIA mimics (16 studies, 14,542 patients) make up 40-45% of patients attending clinics. UK survey (45% response) showed most secondary prevention started prior to clinic, 85% of primary brain imaging was same-day CT; 51-54% of patients had MR, mostly additional to CT, on average 1 week later; 55% omitted blood-sensitive MR sequences. Compared with 'CT scan all patients' MR was more expensive and no more cost-effective, except for patients presenting at > 1 week after symptoms to diagnose haemorrhage; strategies that triaged patients with low ABCD2 scores for slow investigation or treated DWI-negative patients as non-TIA/minor stroke prevented fewer strokes and increased costs. 'One-stop' CT/MR angiographic-plus-brain imaging was not cost-effective.

LIMITATIONS

Data on sensitivity/specificity of MR in TIA/minor stroke, stroke costs, prognosis of TIA mimics and accuracy of ABCD2 score by non-specialists are sparse or absent; all analysis had substantial heterogeneity.

CONCLUSIONS

Magnetic resonance with DWI is not cost-effective for secondary stroke prevention. MR was most helpful in patients presenting at > 1 week after symptoms if blood-sensitive sequences were used. ABCD2 score is unlikely to facilitate patient triage by non-stroke specialists. Rapid specialist assessment, CT brain scanning and identification of serious underlying stroke causes is the most cost-effective stroke prevention strategy.

FUNDING

The National Institute for Health Research Health Technology Assessment programme.

Secondary prevention after ischemic stroke or transient ischemic attack

BACKGROUND

Patients with stroke or transient ischemic attack are at increased risk of recurrent stroke. Transient ischemic attack is a harbinger for stroke merely hours to days after the initial transient ischemic attack. There is thus a narrow window of opportunity to initiate evidence-based therapies for secondary prevention of stroke. Our objective was to assess hospital adherence at discharge to secondary prevention measures after transient ischemic attack or ischemic stroke.

METHODS

Observational study of patients in the Get With The Guidelines-Stroke registry from 2007 to 2011. Patients were divided into 2 cohorts based on presentation: transient ischemic attack versus ischemic stroke. Adherence to evidence-based secondary prevention and other quality measures were assessed.

RESULTS

Among the 858,835 patients with transient ischemic attack or ischemic stroke, 259,319 (30%) patients presented with a transient ischemic attack and 599,516 (70%) patients presented with an ischemic stroke. After adjusting for patient and hospital characteristics, adherence to secondary prevention measures was consistently lower for the transient ischemic attack cohort (vs ischemic stroke cohort), who had lower odds of being discharged on antithrombotics (odds ratio [OR] 0.63; 95% confidence interval [CI], 0.59-0.66; P <.0001), anticoagulants for atrial fibrillation (OR 0.65; 95% CI, 0.61-0.68; P <.0001), lipid-lowering medication for LDL >100 mg/dL (OR 0.52; 95% CI, 0.50-0.54; P <.0001), intensive statin therapy (OR 0.74; 95% CI, 0.72-0.76; P <.0001), LDL cholesterol measurement (OR 0.66; 95% CI, 0.64-0.68; P <.0001), smoking cessation counseling (OR 0.83; 95% CI, 0.78-0.89; P <.0001), stroke education (OR 0.71; 95% CI, 0.69-0.73; P <.0001), or weight loss recommendations (OR 0.88; 95% CI, 0.85-0.90; P <.0001). The adherence to evidence-based therapies increased significantly (P <.0001) over time (2007-2011) for both the cohorts, but the increasing trend was consistently lower for patients who presented with transient ischemic attack.

CONCLUSIONS

In patients surviving an ischemic stroke or transient ischemic attack, adherence to evidence-based secondary prevention discharge measures were consistently less for patients with transient ischemic attack, thus representing a missed opportunity at instituting preventive measures to reduce the risk of recurrent stroke.

How predictors and patterns of stroke recurrence after a TIA differ during the first year of follow-up

The highest risk of subsequent stroke after a TIA occurs within the first week after the index event. However, the risk of stroke recurrence (SR) remains high during the first year of follow-up. We studied the temporal pattern and predictors of SR (at 7 days and from 7 days to 1-year follow-up). Between April 2008 and December 2009, we included 1,255 consecutive TIA patients from 30 Spanish stroke centers (PROMAPA study). We determined the short-term (at 7 days) and long-term (from 8 days to 1 year) risk of SR. Patients who underwent short-term recurrence and long-term recurrence were compared with regard to clinical findings, vascular territories, and etiology. Enough information (clinical variables and extracranial vascular imaging) was assessed in 1,137 (90.6 %) patients. The 7-day stroke risk was 2.6 %. 32 (3.0 %) patients had an SR after 7-day follow-up. Multiple TIA (HR 3.50, 1.67-7.35, p = 0.001) and large artery atherosclerosis (HR 2.51, 1.17-5.37, p = 0.018) were independent predictors of early SR, whereas previous stroke (HR 1.40, 1.03-1.92, p = 0.034) and coronary heart disease (2.65, 1.28-5.50, p = 0.009) were independent predictors of late SR. Notoriously, 80 % of SR happened in the same territory of the index TIA at 7-day follow-up, whereas only 38 % during the long-term follow-up (p < 0.001). Different predictors of SR were identified throughout the follow-up period. Moreover, the ischemic mechanism differed in early and late stroke recurrences.

Long-term risk of stroke after transient ischaemic attack: a hospital-based validation of the ABCD² rule

BACKGROUND

The ABCD2 clinical prediction rule is a seven point summation of clinical factors independently predictive of stroke risk. The purpose of this cohort study is to validate the ABCD2 rule in a Bulgarian hospital up to three years after TIA.

METHODS

All consecutive admissions to an emergency department with symptoms of a first TIA were included. Baseline data and clinical examinations including the ABCD2 scores were documented by neurologists. Discrimination and calibration performance was examined using ABCD2 cut-off scores of ≥3, ≥4 and ≥5 points, consistent with the international guidelines. The Hosmer-Lemeshow test was used to examine calibration between the observed and expected outcomes as predicted by ABCD2 score within the logistic regression analysis.

RESULTS

Eighty-nine patients were enrolled to the study with a mean age of 63 years (+/- 12 years). Fifty-nine percent (n = 53) of the study population was male. Seven strokes (7.8%) occurred within the first year and six further strokes within the three-year follow-up period. There was no incident of stroke within the first 90 days after TIA. The rule demonstrated good predictive (OR = 1.58, 95% CI 1.09-2.29) and discriminative performance (AUCROC = 0.72, 95% CI 0.58-0.86), as well as a moderate calibration performance at three years.

CONCLUSION

This validation of the ABCD2 rule in a Bulgarian hospital demonstrates that the rule has good predictive and discriminative performance at three years. The ABCD2 is quick to administer and may serve as a useful tool to assist clinicians in the long-term management of individuals with TIA.

Etiologic subtype predicts outcome in mild stroke: prospective data from a hospital stroke registry

Background

Few studies on whether etiologic subtype can predict outcome in mild stroke are available. The study aim to explore the effect of different etiologic subtype on prognosis of these patients.

Methods

We prospectively registered consecutive cases of acute ischemic stroke from September. 01, 2009 to August. 31, 2011. Patients with National Institute of Health Stroke Scale (NIHSS) ≦3 and within 30 days of symptom onset were included. All cause death or disability (defined as modified Rankin Scale >2) were followed up at 3 months. The multivariate logistical regression model was used to analyse relationship between etiologic subtype and clinical outcomes.

Results

We included 680 cases, which accounted for 41.1% (680/1655) of the total registered cases. Mean age were 62.54 ± 13.51 years, and males were 65.4%. The median time of symptoms onset to admission was 72 hours. 3.8% (26/680) of cases admitted within 3 hours and 4.7% (32/680) admitted within 4.5 hours. However, no patient received intravenous thrombolysis. Of included patients, 21.5% large-artery atherosclerosis, 40.6% small-vessel disease, 7.5% cardioembolisms, 2.2% other causes and 28.2% undetermined causes. The rate of case fatality and death/disability was 2.2% and 10.1% respectively at 3 months. After adjustment of potential confounders, such as age, sex, NIHSS on admission and vascular risk factors et al., cardioembolism (RR = 3.395;95%CI 1.257 ~ 9.170) was the predictor of death or disability at 3 months and small vessel occlusion (RR = 0.412;95%CI 0.202 ~ 0.842) was the protective factor of death or disability at 3 months.

Conclusion

Different etiologic subtype can predict the outcome in patients with mild stroke and it can help to stratify these patients for individual decision-making.

Changes in Hypothalamus–Pituitary–Adrenal Axis Following Transient Ischemic Attack

Acute brain ischemia caused by transient ischemic attack initiates a complex sequence of events in the central nervous system and hypothalamic–pituitary–adrenal (HPA) axis which may ultimately culminate in neuronal and cell damage. The brain is highly susceptible to ischemia and in response to stress shows changes in morphology and chemistry that are largely reversible. These responses are known to modify the function of the HPA axis, but their mechanisms are not yet clear. Duration and size of the HPA axis activation are regulated by corticotropin-releasing hormone, vasopressin (AVP), and glucocorticoids, including cortisol. Numerous studies suggest that activation of these hormones following brain ischemia can result in neurohormonal dysfunction that can exacerbate long-term prognosis following stroke. These studies represent evidence that changes in the HPA axis play an important role in brain ischemia.

Impaired nocturnal melatonin in acute phase of ischaemic stroke: cross-sectional matched case-control analysis

Quantitative data on melatonin in stroke patients are scarce. A gender- and age-matched cross-sectional case-control study in 33 patients with ischaemic stroke was performed and associations between nocturnal melatonin and other factors (e.g. cortisol) were evaluated. Clinical and laboratory (e.g. melatonin and cortisol) measurements (03.00 h and 08.00 h) with statistical techniques [e.g. multifactorial regressions, receiver operating characteristic (ROC) curve and curvilinear estimations] were used. We identified mean value and 95% confidence interval (CI) (69.70 pg/ml; 95% CI = 53.86-85.54) for control levels of nocturnal melatonin in healthy subjects. The patients with stroke had lower melatonin (48.1 +/- 35.9 pg/ml) and higher cortisol (297.3 +/- 157.8 nmol/l) at 03.00 h (P < 0.05) but not at 08.00 h (P > 0.05). Stroke was the strongest factor of disturbed nocturnal cortisol (P < 0.001), whereas decreased melatonin depended on stroke (P = 0.010) and gender (P = 0.018). At the same time, vice versa, only nocturnal measures were associated with an increased probability of the presence of stroke (accuracy > 75%, Pmodel < 0.001). Thus, a hypothesis that a decrease of melatonin with 1.0 pg/ml might be associated with > 2% increase in the probability of the presence of stroke [adjusted odds ratio (OR) = 1.020; 95% CI = 1.002-1.037] was also suggested. The ROC curve (0.67, P = 0.0119) and optimisation techniques indicated that a novel best cut-off < 51.5 pg/ml for decreased nocturnal melatonin in the view of the presence of stroke (OR = 3.12, P = 0.0463) might exist. The classification performance of such a cut-off might be confirmed by existing nocturnal melatonin and cortisol differences between the sub-groups; potential differences in diurnal melatonin were also suggested. In conclusion, a novel melatonin cut-off of 51.5 pg/ml may be associated with the presence of ischaemic stroke. As a single marker (84% sensitivity, 74% specificity), it is hypothesised that modelling performance was independent of age, gender and cortisol. These new results, including the suggested hypothesis, might be further tested in follow-up (cohort), longitudinal studies and be applied to explore melatonin disturbances as targets in high-risk pre-stroke and post-stroke patients.

Diastolic blood pressure cut-off predicts major cerebrovascular events after minor ischaemic stroke: a post-hoc modelling study

Only few follow-up studies have studied in detail the role of most important risk factors, but no reports were found on critical values (cut-offs) for such factors in prospectively predicting cerebrovascular events (CVE) in patients with minor ischaemic stroke (MIS). Estimates of predictive importance of such cut-offs may better inform and contribute to optimize treatment. This was a post-hoc modelling study with unique data from Bulgaria on 54 consecutive patients with MIS, aged ł 40, followed for 12 months for nonfatal or fatal CV events. A set of routine clinical demographic and known risk factors (SBP, DBP, HDL cholesterol, etc.) were explored using univariate statistics and multivariate regression models to identify the most important independent predictors of secondary CVE. An artificial neural network (ANN) model, irrespective of usual statistical constraints, also confirmed the specific role and importance of identified predictors. A receiver operating characteristics (ROC) curve and stratified survival analyses were used to define the best cut-off of most important predictors and validate the final model. During follow-up period of 11.1±2.4 months, 8 secondary CV events (14.8%) were observed only in males with MIS at the 5.8±2.7 months mark. No difference in age of patients with CV event (61.1±12.6 years) vs. those without (62.1±9.6 years) was found (p>0.05). The one-year risk for CVE was.15% (95%CI 7.1, 27.7%). The two most important risk factors in patients with versus without CV events were acute MIS onset (62.5 vs. 13.0%) and mean DBP at day 30 post-MIS (101.3±9.9 vs. 92.3±10.8 mmHg), with a relative importance by ANN of 20.92 versus 15.9 points, respectively. At multivariate logistic analysis only MIS onset and DBP were independently associated with the risk for secondary CVE (79.6% model accuracy, p model=0.0015). An increase of DBP with 1 mmHg was associated with 8% higher risk of CVE [adjusted OR=1.08 (95%Cl 1.004, 1.158)]. With this method, a novel cut-off predictive DBP value of 95 mmHg (ROCAUC=0.79, 95%Cl 0.60, 0.99, p=0.009) for CV events in patients with MIS has been found. In conclusions the new DBP cut-off (sensitivity >87%, specificity >69%) clearly discriminated between absence and presence of secondary CVE as also confirmed by stratified survival analysis (7 vs. 1 events, plog-rank =0.0103). This cut-off may be applied to better precisely evaluate and define, as earlier as possible, MIS patients at increased risk of secondary CV events.