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

Ischemia preconditioning induces an adaptive response that defines a circulating metabolomic signature in ischemic stroke patients

Transient ischemic attacks (TIAs) before an acute ischemic stroke (AIS) could induce ischemic tolerance (IT) phenomena. with an endogenous neuroprotective role (Ischemic preconditioning. IPC). A consecutive prospective cohort of patients with AIS were recruited from 8 different hospitals. Participants were classified by those with non-previous recent TIA vs. previous TIA (within seven days. TIA ≤7d). A total of 541 AIS patients were recruited. 40 (7.4%). of them had previous TIA ≤7d. In line with IPC. patients with TIA ≤7d showed: 1) a significantly less severe stroke at admission by NIHSS score. 2) a better outcome at 7-90 days follow-up and reduced infarct volumes. 3) a specific upregulated metabolomics/lipidomic profile composed of diverse lipid categories. Effectively. IPC activates an additional adaptive response on increasing circulation levels of structural and bioactive lipids to facilitate functional recovery after AIS which may support biochemical machinery for neuronal survival. Furthermore. previous TIA before AIS seems to facilitate the production of anti-inflammatory mediators that contribute to a better immune response. Thus. the IT phenomena contributes to a better adaptation of further ischemia. Our study provides first-time evidence of a metabolomics/lipidomic signature related to the development of stroke tolerance in AIS patients induced by recent TIA.

Risk of New-Diagnosed Atrial Fibrillation After Transient Ischemic Attack

Background

Transient ischemic attack (TIA) provides a unique opportunity to optimize secondary preventive treatments to avoid subsequent ischemic stroke (SIS). Although atrial fibrillation (AF) is the leading cause of cardioembolism in IS and anticoagulation prevents stroke recurrence (SR), limited data exists about the risk of new-diagnosed AF (NDAF) after TIA and the consequences of the diagnostic delay. The aim of our study was to determine this risk in a cohort of TIA patients with long-term follow-up.

Methods

We carried out a prospective cohort study of 723 consecutive TIA patients from January 2006 to June 2010. Median follow-up was 6.5 (5.0–9.6) years. In a subgroup of 204 (28.2%) consecutive patients, a panel of biomarkers was assessed during the first 24 h of the onset of symptoms. Multivariate analyses were performed to find out the associated factors of NDAF. Kaplan-Meier analysis was also performed to analyzed risk of SIS.

Results

NDAF was indentified in 116 (16.0%) patients: 42 (36.2%) during admission, 18 (15.5%) within first year, 29 (25%) between one and five years and 27 (23.3%) beyond 5 years. NDAF was associated with sex (female) [hazard ratio (HR) 1.61 (95% CI, 1.07- 2.41)], age [[HR 1.05 (95% CI, 1.03–1.07)], previous ischemic heart disease (IHD) [HR 1.84, (95% CI 1.15–2.97)] and cortical DWI pattern [HR 2.81 (95% CI, 1.87–4.21)]. In the Kaplan-Meier analysis, NT-proBNP ≥ 218.2 pg/ml (log-rank test P < 0.001) was associated with significant risk of NDAF during the first 5 years of follow-up. Patients with NDAF after admission and before 5 years of follow-up had the highest risk of SIS (P = 0.002).

Conclusion

The risk of NDAF after TIA is clinically relevant. We identified clinical and neuroimaging factors of NDAF. In addition, NT-proBNP was related to NDAF. Our results can be used to evaluate the benefit of long-term cardiac monitoring in selected patients.

European Stroke Organisation (ESO) guideline on screening for subclinical atrial fibrillation after stroke or transient ischaemic attack of undetermined origin

We aimed to provide practical recommendations for the screening of subclinical atrial fibrillation (AF) in patients with ischaemic stroke or transient ischaemic attack (TIA) of undetermined origin. These guidelines are based on the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) methodology. Five relevant Population, Intervention, Comparator, Outcome questions were defined by a multidisciplinary module working group (MWG).

Longer duration of cardiac rhythm monitoring increases the detection of subclinical AF, but the optimal monitoring length is yet to be defined. We advise longer monitoring to increase the rate of anticoagulation, but whether longer monitoring improves clinical outcomes needs to be addressed. AF detection does not differ from in- or out-patient ECG-monitoring with similar monitoring duration, so we consider it reasonable to initiate in-hospital monitoring as soon as possible and continue with outpatient monitoring for more than 48h. Although insertable loop recorders (ILR) increase AF detection based on their longer monitoring duration, comparison with non-implantable ECG devices for similar monitoring time is lacking. We suggest the use of implantable devices, if feasible, for AF detection instead of non- implantable devices to increase the detection of subclinical AF. There is weak evidence of a useful role for blood, ECG, and brain imaging biomarkers for the identification of patients at high risk of AF. In patients with patent foramen ovale, we found insufficient evidence from RCT, but prolonged cardiac monitoring in patients >55 years is advisable for subclinical AF detection. To conclude, in adult patients with ischaemic stroke or TIA of undetermined origin, we recommend longer duration of cardiac rhythm monitoring of more than 48h and if feasible with IRL to increase the detection of subclinical AF.

Basal IL-6 and S100b levels are associated with infarct volume

OBJECTIVES

The study of biomarkers related to the infarct volume of acute ischaemic stroke (AIS) is a valuable clinical strategy. We conducted a prospective study to evaluate the relationship between a wide panel of biomarkers involved in different biochemical pathways and lesion volume.

MATERIALS & METHODS

We studied 332 patients with AIS. Infarct volume was calculated from diffusion weighted imaging (DWI). Blood samples were drawn within 24 h of symptom onset to test a panel of biomarkers that included high-sensitivity C-reactive protein (hs-CRP), IL-6, neuron-specific enolase (NSE), N-terminal pro-B-type natriuretic peptide (NT-ProBNP), S100b, troponin and IL-10.

RESULTS

The median lesion volume was 2.5 cc (IQR: 0.6-15.3). Patients with previous atrial fibrillation, cardioembolic aetiology and total anterior circulation infarct TACI classification had higher lesion volumes than those without them. Patients with previous recent TIA had smaller ischaemic lesions than those without it. Age and NIHSS were significantly correlated with lesion volume. In a linear regression analysis adjusted by aetiology, S100b and IL-6 emerged as the only biomarkers independently associated with infarct volume. In contrast, previous recent TIA and small-vessel disease were inversely related to infarct volume.

CONCLUSIONS

The correlation between the two blood marker levels and ischaemic lesion volume would support the use of these biomarkers as a surrogate endpoint in AIS, especially in centres without DWI 24/7 but these could not substitute basic neuroimaging. Our findings should be further explored in larger, preferably multicentre studies.

Promising Biomarker Candidates for Cardioembolic Stroke Etiology. A Brief Narrative Review and Current Opinion

Determining the cause of stroke is considered one of the main objectives in evaluating a stroke patient in clinical practice. However, ischemic stroke is a heterogeneous disorder and numerous underlying disorders are implicated in its pathogenesis. Although progress has been made in identifying individual stroke etiology, in many cases underlying mechanisms still remain elusive. Since secondary prevention strategies are tailored toward individual stroke mechanisms, patients whose stroke etiology is unknown may not receive optimal preventive treatment. Cardioembolic stroke is commonly defined as cerebral vessel occlusion by distant embolization arising from thrombus formation in the heart. It accounts for the main proportion of ischemic strokes, and its share to stroke etiology is likely to rise even further in future decades. However, it can be challenging to distinguish cardioembolism from other possible etiologies. As personalized medicine advances, stroke researchers' focus is increasingly drawn to etiology-associated biomarkers. They can provide deeper insight regarding specific stroke mechanisms and can help to unravel previously undetected pathologies. Furthermore, etiology-associated biomarkers could play an important role in guiding future stroke prevention strategies. To achieve this, broad validation of promising candidate biomarkers as well as their implementation in well-designed randomized clinical trials is necessary. This review focuses on the most-promising candidates for diagnosis of cardioembolic stroke. It discusses existing evidence for possible clinical applications of these biomarkers, addresses current challenges, and outlines future perspectives.

Inflammatory Response of Ischemic Tolerance in Circulating Plasma: Preconditioning-Induced by Transient Ischemic Attack (TIA) Phenomena in Acute Ischemia Patients (AIS)

Introduction: Ischemic tolerance (IT) refers to a state where cells are resistant to the damaging effects caused by periods of ischemia. In a clinical scenario, the IT phenomenon would be activated by a recent transient ischemic attack (TIA) before an ischemic stroke (IS). The characterization of inflammatory protein expression patterns will contribute to improved understanding of IT.

Methods: A total of 477 IS patients from nine hospitals, recruited between January 2011 and January 2016, were included in the current study and divided in three groups: 438 (91.9%) patients without previous TIA (group 1), 22 (4.6%) patients who suffered TIA 24 h before IS (group 2), and 17 (3.5%) patients who suffered TIA between 24 h and 7 days prior to IS (group 3). An inflammatory biomarker panel (IL-6, NT-proBNP, hsCRP, hs-Troponin, NSE, and S-100b) on plasma and a cytokine antibody array was performed to achieve the preconditioning signature potentially induced by TIA phenomena. Primary outcome was modified rankin scale (mRs) score at 90 days.

Results: Recent previous TIA was associated with better clinical outcome at 90 days (median mRS of group 1: 2.0 [1.0–4.0]; group 2: 2.0 [0.0–3.0]; group 3: 1.0 [0–2.5]; p = 0.086) and smaller brain lesion (group 1: 3.7 [0.7–18.3]; group 2: 0.8 [0.3–8.9]; group 3: 0.6 [0.1–5.5] mL; p = 0.006). All inflammation biomarkers were down regulated in the groups of recent TIA prior to IS compared to those who did not suffer a TIA events. Moreover, a cytokine antibody array revealed 30 differentially expressed proteins between the three groups. Among them, HRG1-alpha (Fold change 74.4 between group 1 and 2; 74.2 between group 1 and 3) and MAC-1 (Fold change 0.05 between group 1 and 2; 0.06 between group 1 and 3) expression levels would better stratify patients with TIA 7 days before IS. These two proteins showed an earlier inflammation profile that was not detectable by the biomarker panel.

Conclusion: Inflammatory pathways were activated by transient ischemic attack, however the period of time between this event and a further ischemic stroke could be determined by a protein signature that would contribute to define the role of ischemic tolerance induced by TIA.

Blood markers of inflammation and endothelial dysfunction in cardioembolic stroke: systematic review and meta-analysis

CONTEXT

Various processes including inflammation and endothelial dysfunction have been implicated in the pathogenesis of cardioembolic (CE) strokes.

OBJECTIVE

To review the evidence and investigate the association between immune-inflammatory biomarkers and CE strokes versus other stroke subtypes.

METHODS

We systematically reviewed the literature (sources: MEDLINE, web-based register http://stroke-biomarkers.com , reference lists) with quality assessment and meta-analysis of selected articles.

RESULTS

The most consistent association was found between C-reactive protein (CRP) and CE strokes when compared to other stroke subtypes (standardized mean difference 0.223 (0.116, 0.343); p < 0.001) Conclusions: Our findings confirm a possible association between selected inflammatory biomarkers and CE stroke.

The determination of copeptin levels helps management decisions among transient ischaemic attack patients

BACKGROUND

Most approaches to transient ischaemic attack (TIA) triage use clinical scores and vascular imaging; however, some biomarkers have been suggested to improve the prognosis of TIA patients.

METHODS

Serum levels of copeptin, adiponectin, neopterin, neuron-specific enolase, high-sensitivity C-reactive protein, IL-6, N-terminal pro-B-type natriuretic peptide, S100β, tumour necrosis factor-alpha and IL-1α as well as clinical characteristics were assessed on consecutive TIA patients during the first 24 h of the onset of symptoms.

RESULTS

Among 237 consecutive TIA patients, 12 patients (5%) had a stroke within 7 days and 15 (6%) within 90 days. Among all candidate biomarkers analysed, only copeptin was significantly increased in patients with stroke recurrence (SR) within 7 days (P = 0.026) but not within 90 days. A cut-off point of 13.8 pmol/l was established with a great predictive negative value (97.4%). Large artery atherosclerosis (LAA) [hazard ratio (HR) 12.7, 95% CI 3.2-50.1, P < 0.001] and copeptin levels ≥13.8 pmol/l (HR 3.9, 95% CI 1.01-14.4, P = 0.039) were independent predictors of SR at the 7-day follow-up. LAA was the only predictor of 90-day SR (HR 7.4, 95% CI 2.5-21.6, P < 0.001). ABCD3I was associated with 7- and 90-day SRs (P = 0.025 and P = 0.034, respectively). The association between copeptin levels and LAA had a diagnostic accuracy of 90.3%.

CONCLUSIONS

Serum copeptin could be an important prognostic biomarker to guide management decisions among TIA patients. Therefore, TIA patients with copeptin levels below 13.8 pmol/l and without LAA have an insignificant risk of 7-day SR and could be managed on an outpatient basis.

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.

Metabolomics predicts stroke recurrence after transient ischemic attack

OBJECTIVE

To discover, by using metabolomics, novel candidate biomarkers for stroke recurrence (SR) with a higher prediction power than present ones.

METHODS

Metabolomic analysis was performed by liquid chromatography coupled to mass spectrometry in plasma samples from an initial cohort of 131 TIA patients recruited <24 hours after the onset of symptoms. Pattern analysis and metabolomic profiling, performed by multivariate statistics, disclosed specific SR and large-artery atherosclerosis (LAA) biomarkers. The use of these methods in an independent cohort (162 subjects) confirmed the results obtained in the first cohort.

RESULTS

Metabolomics analyses could predict SR using pattern recognition methods. Low concentrations of a specific lysophosphatidylcholine (LysoPC[16:0]) were significantly associated with SR. Moreover, LysoPC(20:4) also arose as a potential SR biomarker, increasing the prediction power of age, blood pressure, clinical features, duration of symptoms, and diabetes scale (ABCD2) and LAA. Individuals who present early (<3 months) recurrence have a specific metabolomic pattern, differing from non-SR and late SR subjects. Finally, a potential LAA biomarker, LysoPC(22:6), was also described.

CONCLUSIONS

The use of metabolomics in SR biomarker research improves the predictive power of conventional predictors such as ABCD2 and LAA. Moreover, pattern recognition methods allow us to discriminate not only SR patients but also early and late SR cases.