Plasma brain natriuretic peptide as a surrogate marker for cardioembolic stroke

Serum NT-proBNP level for predicting functional outcomes after acute ischemic stroke

N-terminus pro-brain natriuretic peptide (NT-proBNP) has been studied and recognized as a biomarker of cardiac thrombogenicity and stroke risk. However, the association between NT-proBNP and functional outcomes following acute ischemic stroke is still debated. This study aimed to investigate whether serum NT-proBNP level is associated with functional outcomes in acute ischemic stroke individuals. This prospective cohort study included patients diagnosed with acute ischemic stroke, and serum NT-proBNP levels were measured within 72 h. At 3 months, all patients were followed up for a modified Rankin Scale (mRS), and logistic regression models were used to evaluate the association of NT-proBNP on the primary outcome, in which a score of 3-6 was classified as an unfavorable functional outcome. Sixty-seven patients were enrolled in the study, and 23 (34.3%) patients were identified with an unfavorable functional outcome. Elevated serum NT-proBNP levels (> 100 pg/mL) were observed in 57 (85.1%) patients, and the Youden index demonstrated a cutpoint estimation of poor outcomes at 476 pg/mL with 74% sensitivity and 63% specificity. Multivariate regression analysis showed an elevation of NT-proBNP above the cutpoint level was an independent predictor for unfavorable functional outcomes, odds ratio 3.77, 95% confidence interval (1.04-13.62), P = 0.04. The present study demonstrated that elevated serum NT-proBNP levels were expected among acute ischemic stroke patients and represented the risk of unfavorable functional outcomes, suggesting that NT-proBNP might be a useful biomarker for predicting prognosis after ischemic stroke.

Atrial Fibrillation, thromboembolic risk, and the potential role of the natriuretic peptides, a focus on BNP and NT-proBNP - A narrative review

Atrial fibrillation (AF) is one of the most commonly encountered arrythmia in clinical practice. AF itself can be driven by genetic predisposition, ectopic electrical activity, and abnormal atrial tissue substrates. Often there is no single etiological mechanism, but rather a combination of factors that feed back to remodel and worsen tissue substrate, "AF begets AF". The clinical consequences of AF can often include emboli, heart failure, and early mortality. The classical AF cardioembolic (CE) concept requires thrombus formation in the left atrial appendage, with subsequent embolization. The temporal dissociation between AF occurrence and CE events has thrown doubt on AF as the driver of this mechanism. Instead, there has been a resurgence of the "atrial cardiomyopathy" (ACM) concept. An ACM is proposed as a potential mechanism of embolic disease through promotion of prothrombotic mechanisms, with AF instead reflecting atrial disease severity. Regardless, AF has been implicated in 25% to 30% of cryptogenic strokes. Natriuretic peptide(NP)s have been shown to be elevated in AF, with higher levels of both NT-proBNP and BNP being predictive of incidental AF. NPs potentially reflect the atrial environment and could be used to identify an underlying ACM. Therefore, this narrative review examines this evidence and mechanisms that may underpin the role of NPs in identifying atrial dysfunction, with focus on both, BNP and NTproBNP. We explore their potential role in the prediction and screening for both, ACM and AF. Moreover, we compare both NPs directly to ascertain a superior biomarker.

Biomarkers Associated with Stroke Risk in Atrial Fibrillation

Background:

Atrial fibrillation (AF) is associated with an increased risk of cardioembolic stroke. The risk of cardioembolism is not adequately reduced with the administration of oral anticoagulants, since a number of patients continue to experience thromboembolic events despite receiving treatment. Therefore, identification of a circulating biomarker to identify these high-risk patients would be clinically beneficial.

Objective:

In the present article, we aim to review the available data regarding use of biomarkers to predict cardioembolic stroke in patients with AF.

Methods:

We performed a thorough search of the literature in order to analyze the biomarkers identified thus far and critically evaluate their clinical significance.

Results:

A number of biomarkers have been proposed to predict cardioembolic stroke in patients with AF. Some of them are already used in the clinical practice, such as d-dimers, troponins and brain natriuretic peptide. Novel biomarkers, such as the inflammatory growth differentiation factor-15, appear to be promising, while the role of micro-RNAs and genetics appear to be useful as well. Even though these biomarkers are associated with an increased risk for thromboembolism, they cannot accurately predict future events. In light of this, the use of a scoring system, that would incorporate both circulating biomarkers and clinical factors, might be more useful.

Conclusions:

Recent research has disclosed several biomarkers as potential predictors of cardioembolic stroke in patients with AF. However, further research is required to establish a multifactorial scoring system that will identify patients at high-risk of thromboembolism, who would benefit from more intensive treatment and monitoring.

Blood Biomarkers for the Differentiation of Cardiac Ischemic Stroke Subtypes: A Systematic Review

BACKGROUND

Blood biomarkers are a cost-effective and valid method to diagnose ischemic stroke and differentiate its subtypes in countries with poor resources.

OBJECTIVE

To perform a systematic review of published literature evaluating the diagnostic utility of blood-based biomarkers to diagnose and differentiate the etiology of ischemic stroke.

METHODS

A comprehensive literature search was carried out till December 2017 in major scientific and medical databases including PubMed, Cochrane, OVID and Google Scholar. Modified Quality Assessment of Diagnostic Accuracy Studies questionnaire was used to assess the methodological quality of each study.

RESULTS

Twenty-six studies were identified relevant to our systematic review. Various biomarkers have been studied, though only a few biomarkers such as a B-type natriuretic peptide (BNP) and Ddimer have proved their clinical utility. None of the other tested biomarkers appeared to have consistent results to diagnose ischemic stroke subtypes. Most of the studies had limitations in the classification of ischemic stroke, sample size, sample collection time, methods, biomarker selection and data analysis.

CONCLUSION

Our systematic review does not recommend the use of any blood biomarker for clinical purposes based on the studies conducted to date. BNP and D-dimer may present optimal biomarker for diagnosis and differentiation of ischemic stroke. However, large well-designed clinical studies are required to validate utility of these biomarkers to differentiate subtypes of ischemic stroke.

STAF score is a new simple approach for diagnosing cardioembolic stroke

BACKGROUND AND PURPOSE

Detecting cardioembolic stroke soon after acute cerebral ischemia has a major impact on secondary stroke prevention. Recently, the Score for the Targeting of Atrial Fibrillation (STAF) was introduced to identify stroke patients at risk of atrial fibrillation. However, whether the STAF score could be a useful approach to differentiate cardioembolic stroke from other stroke subtypes is unclear.

METHODS

Consecutive patients with acute ischemic stroke that were admitted to our stroke center were enrolled. Each patient was assessed (age, baseline National Institutes of Health Stroke Scale, left atrial dilatation and absence of vascular etiology) to calculate the STAF score. A follow-up visit was conducted for each patient during hospitalization to determine the diagnosed stroke etiology according to the Trial of Org 10172 in Acute Stroke Treatment criteria.

RESULTS

The median and interquartile range of the STAF score was significantly higher in the cardioembolic than in the non-cardioembolic group [6 (2) vs. 2 (3), p < 0.001]. The discriminating ability of the STAF score model was good as demonstrated by the receiver operating characteristic curve. The area under the curve (AUC) of STAF score (AUC = 0.98; 95% CI, 0.96-0.99) was significantly greater than B-type natriuretic peptide (AUC = 0.87; 95% CI, 0.83-0.91) (p < 0.05). The optimal STAF cut-off value was ≥ 5, which diagnosed cardioembolic stroke with a sensitivity of 90% and specificity of 95%.

CONCLUSIONS

The STAF score is a simple and accurate tool that can discriminate the cardioembolic stroke from other types during hospitalization for acute ischemic stroke.

Brain Natriuretic Peptide and Particular Left Ventricle Segment Asynergy Associated with Cardioembolic Stroke from Old Myocardial Infarction

BACKGROUND

It is important to determine the usage of anticoagulants by defining the actual risk of cardioembolic stroke in patients with old myocardial infarction. In the present study, we aimed to more precisely evaluate the risks of each segment associated with cardioembolic stroke using a 16-segment model. The usage of the plasma brain natriuretic peptide (BNP) associated with cardioembolic stroke was also evaluated in comparison with a left ventricle ejection fraction less than 40%.

METHODS

There were a total of 190 ischemic stroke patients who had premorbid myocardial infarction. The study included a total of 143 ischemic stroke patients with old myocardial infarction who were available for evaluation and excluded patients with atrial fibrillation or acute myocardial infarction. Their left ventricle wall motion abnormality and the level of plasma BNP at their admission were analyzed.

RESULTS

Hypertension and a plasma BNP level of 206.9 pg/mL or higher, determined from the receiver operating characteristic curve, were independently associated with cardioembolic stroke (χ(2) = 35.6, R(2) = .30, P < .001). Adjusting for these factors, statistically independent high risk was observed at the basal-inferior, basal-inferolateral, mid-anterior, mid-anteroseptal, apical-anterior, and apical-septal left ventricles.

CONCLUSION

High plasma BNP levels and left ventricular wall motion abnormalities in the segments perfused with left anterior descending coronary artery or right coronary artery show a high risk for cardioembolic stroke in patients with old myocardial infarction. Considering these factors, it could be possible to more precisely define the risk of cardioembolic stroke and to perform appropriate antithrombotic treatments in old myocardial infarction patients.

B-Type Natriuretic Peptides Help in Cardioembolic Stroke Diagnosis

Background and Purpose—

Determining the underlying cause of stroke is important to optimize secondary prevention treatment. Increased blood levels of natriuretic peptides (B-type natriuretic peptide/N-terminal pro-BNP [BNP/NT-proBNP]) have been repeatedly associated with cardioembolic stroke. Here, we evaluate their clinical value as pathogenic biomarkers for stroke through a literature systematic review and individual participants’ data meta-analysis.

Methods—

We searched publications in PubMed database until November 2013 that compared BNP and NT-proBNP circulating levels among stroke causes. Standardized individual participants’ data were collected to estimate predictive values of BNP/NT-proBNP for cardioembolic stroke. Dichotomized BNP/NT-proBNP levels were included in logistic regression models together with clinical variables to assess the sensitivity and specificity to identify cardioembolic strokes and the additional value of biomarkers using area under the curve and integrated discrimination improvement index.

Results—

From 23 selected articles, we collected information of 2834 patients with a defined cause. BNP/NT-proBNP levels were significantly elevated in cardioembolic stroke until 72 hours from symptoms onset. Predictive models showed a sensitivity >90% and specificity >80% when BNP/NT-proBNP were added considering the lowest and the highest quartile, respectively. Both peptides also increased significantly the area under the curve and integrated discrimination improvement index compared with clinical models. Sensitivity, specificity, and precision of the models were validated in 197 patients with initially undetermined stroke with final pathogenic diagnosis after ancillary follow-up.

Conclusions—

Natriuretic peptides are strongly increased in cardioembolic strokes. Future multicentre prospective studies comparing BNP and NT-proBNP might aid in finding the optimal biomarker, the best time point, and the optimal cutoff points for cardioembolic stroke identification.

Cardioembolic stroke diagnosis using blood biomarkers

Stroke is one of the main causes of death and disability in the world. Cardioembolic etiology accounts for approximately one fifth of all ischemic strokes whereas 25-30% remains undetermined even after an advanced diagnostic workup. Despite there is not any biomarker currently approved to distinguish cardioembolic stroke among other etiologies in clinical practice the use of biomarkers represents a promising valuable complement to determine stroke etiology reducing the number of cryptogenic strokes and aiding in the prescription of the most appropriated primary and secondary treatments in order to minimize therapeutic risks and to avoid recurrences. In this review we present an update about specific cardioembolic stroke-related biomarkers at a protein, transcriptomic and genetic level. Finally, we also focused on reported biomarkers associated with atrial fibrillation (a cardiac illness strongly related with cardioembolic stroke subtype) thus with a potential to become biomarkers to detect cardioembolic stroke in the future.

A bioclinical pattern for the early diagnosis of cardioembolic stroke

Background and Scope. Early etiologic diagnosis of ischemic stroke subtype guides acute management and treatment. We aim to evaluate if plasma biomarkers can predict stroke subtypes in the early phase from stroke onset. Methods. Plasma N-terminal prohormone of brain natriuretic peptide (NT-proBNP), D-dimer, C-reactive protein, serum albumin, and globulin levels have been investigated in 114 consecutive patients presenting at the emergency room within 6 hours of the ischemic stroke onset. Plasma levels of biomarkers have been correlated with stroke aetiology (based on TOAST criteria) by multivariable logistic regression analysis, adjusted for several covariates. Results. Of the 114 patients, 34 (30%) had cardioembolic stroke, 27 (23%) atherothrombotic stroke, 19 (17%) lacunar stroke, and 34 (30%) stroke of undetermined origin. Patients with cardioembolic stroke had significantly higher levels of NT-proBNP and lower globulin/albumin (G/A) ratio compared with the other subgroups. At multiple logistic regression NT-proBNP > 200 pg/mL, G/A ratio > 0.70, and NIHSS score were independent predictors of cardioembolic stroke with high accuracy of the model, either including (AUC, 0.91) or excluding (AUC, 0.84) atrial fibrillation. Conclusions. A prediction model that includes NT-proBNP, G/A ratio, and NIHSS score can be useful for the early etiologic diagnosis of ischemic stroke.

N-terminal pro-brain natriuretic peptide level determined at different times identifies transient ischaemic attack patients with atrial fibrillation

BACKGROUND AND PURPOSE

The etiological classification of patients with transient ischaemic attack (TIA) is a difficult endeavor and the use of serum biomarkers could improve the diagnostic accuracy. The aim of this study was to correlate atrial fibrillation, the main cardioembolic etiology (CE), with different serum biomarkers measured in consecutive TIA patients.

METHODS

The concentrations of interleukin-6 (IL-6), tumor necrosis factor-alpha, neuron-specific enolase, high-sensitivity C-reactive protein, IL-1-α and the N-terminal pro-B type natriuretic peptide (NT-proBNP) were quantified in the serum of 140 patients with TIA and 44 non-stroke subjects. Measurements were performed at different times throughout evolution: within 24 h of symptoms onset and at days 7 and 90.

RESULTS

With the exception of IL-6, all biomarkers were higher in TIA patients than in controls. NT-proBNP was significantly related to the presence or new diagnosis of AF at all time points analyzed. Furthermore, the baseline NT-proBNP level was significantly higher than values at the 7-day and 90-day follow-up. For this reason, different cut-off values were obtained at different times: 313 pg/ml at baseline [odds ratio (OR) = 18.99, P < 0.001], 181 pg/ml at 7 days (OR = 11.4, P = 0.001) and 174 pg/ml (OR = 8.46, P < 0.001) at 90 days.

CONCLUSION

High levels of NT-proBNP determined during the first 3 months after a TIA were associated with AF. Consequently, this biomarker may be useful to reclassify undetermined TIA patients as having disease of CE.

Aortic Stiffness and Plasma Brain Natriuretic Peptide Predicts Mortality in Acute Ischemic Stroke

Background

The study aimed to evaluate the prognostic role and discriminative power of aortic stiffness and plasma brain natriuretic peptide levels in a cohort of patients hospitalized for acute ischemic stroke.

Methods and Results

Three hundred and ten consecutive patients aged 50 years and older with a first episode of acute ischemic stroke were prospectively evaluated. All patients were admitted to the hospital within 24 h of the onset of stroke symptoms. The type of acute ischemic stroke was classified according to the Trial of Org 10172 in Acute Stroke Treatment classification. Blood samples were taken for measurement of brain natriuretic peptide levels at admission. Aortic stiffness indices, aortic strain and distensibility, were calculated from the aortic diameters measured by transthoracic echocardiography. The patients were followed for one-year or until death, whichever came first. Death occurred in 51 (16·5%) patients. On multivariate logistic regression analysis, National Institutes of Health Stroke Scale score >13, diabetes, brain natriuretic peptide >235 pg/mL, aortic distensibility, and aortic strain were associated with all-cause mortality. The optimal cutoff level of brain natriuretic peptide to distinguish the deceased group from the survival group was 235 pg/mL (sensitivity 71·0% and specificity 63·0%) and to distinguish cardioembolic stroke from noncardioembolic stroke was 155 pg/mL (sensitivity 81% and specificity 63%).

Conclusions

Aortic stiffness and brain natriuretic peptide predict mortality in patients with first-ever acute ischemic stroke. Brain natriuretic peptide also differentiates cardioembolic stroke from noncardioembolic stroke.

Amino terminal pro-B-type natriuretic peptide, secondary stroke prevention, and choice of antithrombotic therapy

BACKGROUND AND PURPOSE

Because of its association with atrial fibrillation and heart failure, we hypothesized that amino terminal pro-B-type natriuretic peptide (NT-proBNP) would identify a subgroup of patients from the Warfarin-Aspirin Recurrent Stroke Study, diagnosed with inferred noncardioembolic ischemic strokes, where anticoagulation would be more effective than antiplatelet agents in reducing risk of subsequent events.

METHODS

NT-proBNP was measured in stored serum collected at baseline from participants enrolled in Warfarin-Aspirin Recurrent Stroke Study, a previously reported randomized trial. Relative effectiveness of warfarin and aspirin in preventing recurrent ischemic stroke or death over 2 years was compared based on NT-proBNP concentrations.

RESULTS

About 95% of 1028 patients with assays had NT-proBNP below 750 pg/mL, and among them, no evidence for treatment effect modification was evident. For 49 patients with NT-proBNP >750 pg/mL, the 2-year rate of events per 100 person-years was 45.9 for the aspirin group and 16.6 for the warfarin group, whereas for 979 patients with NT-proBNP ≤750 pg/mL, rates were similar for both treatments. For those with NT-proBNP >750 pg/mL, the hazard ratio was 0.30 (95% confidence interval: 0.12-0.84; P=0.021) significantly favoring warfarin over aspirin. A formal test for interaction of NT-proBNP with treatment was significant (P=0.01).

CONCLUSIONS

For secondary stroke prevention, elevated NT-proBNP concentrations may identify a subgroup of ischemic stroke patients without known atrial fibrillation, about 5% based on the current study, who may benefit more from anticoagulants than antiplatelet agents. Clinical Trial Registration- This trial was not registered because enrollment began before 2005.

Elevated plasma brain natriuretic peptide levels predict left atrial appendage dysfunction in patients with acute ischemic stroke

BACKGROUND

It is well known that left atrial appendage (LAA) dysfunction plays an important role in the occurrence of cardioembolic stroke. The atrium is the main source of brain natriuretic peptide (BNP) in patients with atrial fibrillation (AF). We hypothesized that the plasma BNP level would be a sensitive predictor of LAA dysfunction in patients with acute ischemic stroke.

METHODS AND RESULTS

Transesophageal echocardiography was performed and plasma BNP levels were measured in 223 patients (145 males, age 69 ± 14 years), within 7 days after the onset of acute ischemic stroke. None of the patients had a history of congestive heart failure. LAA thrombus was detected in 23 of 77 (30%) patients with AF. Plasma BNP levels were markedly higher in patients with cardioembolic stroke compared to those without (144 pg/ml vs. 35 pg/ml, p<0.05). Plasma BNP levels were significantly correlated with LAA emptying flow velocity regardless of sinus rhythm (R=-0.352) or AF (R=-0.436). Furthermore, among patients with cardioembolic stroke, plasma BNP levels were markedly higher in patients with cardiogenic stroke, as diagnosed by transesophageal echocardiography, than in those with cryptogenic stroke (193 pg/ml vs. 14 pg/ml, p<0.05). Multivariate logistic regression analysis showed that a BNP concentration >90 pg/ml was an independent predictor of cardiogenic stroke (odds ratio 41.39, 95% confidence interval 1.28-138; p=0.0358).

CONCLUSION

Elevated plasma BNP concentrations may be a reliable surrogate marker for the prediction of LAA dysfunction and cardiogenic stroke in patients with acute ischemic stroke.

Blood biomarkers in cardioembolic stroke

One promising field in neurovascular diseases investigation is the use of biomarkers to guide stroke etiology diagnosis and classification. Since treatment differs among etiologic subtypes and nowadays many patients receive a diagnosis of undetermined stroke, biomarkers might become an important additional diagnostic tool. In this review we update current knowledge about biomarkers related with cardioembolic stroke etiology (such as BNP and D-dimer proteins, or PITX2 and ZFHX3 genes), that in the future, might allow rapidly guiding other diagnostic tests and accelerating the onset of an optimal secondary prevention.

Inflammatory and neuroendocrine biomarkers of prognosis after ischemic stroke

Stroke is the third leading cause of mortality in the USA and one of the leading causes of severe morbidity. It is important to provide stroke patients and physicians with the most accurate prognostic information to optimize care and allocation of healthcare resources. Reliable prognostic markers available during the initial phase after acute stroke may aid clinical decision-making. Several interesting candidate biomarkers have been studied to address prognostic questions; this article will focus on selected inflammatory and neuroendocrine markers. The utility of a biomarker is defined by its ability to improve clinical decision-making and add timely information beyond that readily available from clinical examination and routine imaging. This aim has not been completely achieved yet for any biomarkers, but promising data are available and further studies are ongoing.

Association between N-terminal pro-brain natriuretic peptide and acute ischemic stroke in patients on chronic hemodialysis

BACKGROUND

Plasma N-terminal pro-brain natriuretic peptide (NT-proBNP) has been reported as a predictor for ischemic stroke in general population. However, predictive value of plasma NT-proBNP for acute ischemic stroke in patients on chronic hemodialysis has not been well established. The aim of this study was to determine whether NT-proBNP could predict acute ischemic stroke in patients on chronic hemodialysis.

METHODS

This study was designed prospectively. Clinical, laboratory, and echocardiographic variables were assessed in 72 patients on chronic hemodialysis. The plasma levels of NT-proBNP were measured by immunoassay.

RESULTS

During the follow-up period of 45 months, 11 patients had an acute ischemic stroke. The Kaplan-Meier plot showed an increased frequency of acute ischemic stroke in patients with plasma levels of NT-proBNP above the median values compared to patients with lower concentrations (P = 0.028). The multivariate Cox proportional hazard models showed that the NT-proBNP was a significant independent predictor of acute ischemic stroke after adjustment for age, sex, mean blood pressure, diabetes, serum cholesterol levels, left ventricular mass index, and left ventricular fractional shortening (HR 6.66, 95% CI, 1.22-36.48, P = 0.029).

CONCLUSIONS

Our data suggest that plasma NT-proBNP levels predict the risk of acute ischemic stroke in patients on chronic hemodialysis.