Hemostatic markers and platelet aggregation factors as predictive markers for type of stroke and neurological disability following cerebral infarction

Diagnostic performance of plasma D-dimer, fibrinogen, and D-dimer to fibrinogen ratio as potential biomarkers to predict hypertension-associated acute ischemic stroke

Background

Ischemic stroke is a common type of stroke that leads to death and functional disability in hypertensive patients. However, there are no well-studied non-invasive and less expensive fluid biomarkers routinely used to detect ischemic stroke in hypertensive patients. Hence, this study aimed to tease out the performance of D-dimer, fibrinogen, and the D-dimer to fibrinogen ratio (DDFR) in predicting hypertension-associated acute ischemic stroke.

Methods

A hospital-based cross-sectional study was done from October 2022 to January 2022 at Yikatit 12 Hospital Medical College, Ethiopia. We recruited 55 hypertensive patients who had an ischemic stroke and 110 who did not. A ROC curve was used to calculate the areas under the curves (AUCs) and determine the diagnostic power of the D-dimer, fibrinogen, and DDFR. The Youden index was used to find the best cut-off points for biomarkers in detecting acute ischemic stroke. A De Long test was employed to show whether there was a significant difference between the AUCs of biomarkers in diagnosing ischemic stroke.

Results

D-dimer yielded the highest diagnostic power (AUC = 0.776) in detecting acute ischemic stroke, followed by DDFR (AUC = 0.763) and fibrinogen (AUC = 0.694), but there was no significant difference between them. At 0.52 μg/ml cut-off point, D-dimer had 82.9% sensitivity, 66.7% specificity, 62.5% PPV, and 85.3% NPV to diagnose acute ischemic stroke. Fibrinogen could detect acute ischemic stroke at 405.85 mg/dl level, with 70.0% sensitivity, 57.1% specificity, 41.2% PPV and 81.6% NPV. At a 1.83 ratio, DDFR might also identify ischemic stroke with 80.0% sensitivity, 67.1% specificity, 51.1% PPV, and 88.7% NPV.

Conclusion

We showed D-dimer, fibrinogen, and DDFR as promising, affordable, and non-invasive biomarkers for the detection of ischemic stroke among subjects with hypertension. This will help clinicians make an early diagnosis and better guide patient therapy.

Comparison of circulating lipid profiles, D-dimer and fibrinogen levels between hypertensive patients with and without stroke

BACKGROUND

Stroke is one of the leading causes of global mortality and disability, particularly in hypertensive patients. This study aimed to compare lipid profile, fibrinogen, and D-dimer levels between hypertensive patient with and without stroke.

METHODS

This was a facility-based cross-sectional study conducted from November 2022 to January 2023 among 115 hypertensive patients (70 patients without stroke and 45 with stroke) who had follow-up at Yikatit 12 Hospital Medical College, Ethiopia. All data analyses were done using SPSS version 25.0 and comparisons of variables between groups were made using the Chi-square test, independent sample t-test, and Mann-Whitney U test. Multiple logistic regression analysis was done to identify predictors of stroke among hypertensive patients. A p-value <0.05 was assumed to be statistically significant for all statistical tests.

RESULTS

Significantly elevated levels of TC, LDL-C, D-DI, and fibrinogen were observed in the stroke group than in the non-stroke group (p-value<0.05). The mean values of TC, D-DI, and fibrinogen were significantly higher in patients with ischemic stroke compared to those with hemorrhagic stroke. Duration of hypertension (AOR: 1.21; CI: 1.10, 2.09), TC (AOR:1.07; CI: 1.01, 1.22), D-DI (AOR: 1.15; CI: 1.05, 1.69) and fibrinogen (AOR:1.19; CI: 1.10, 2.89) were identified to be independent predictors of stroke in hypertensive patients.

CONCLUSION

The circulating levels of TC, LDL-C, D-DI and fibrinogen in hypertensive patients with stroke were significantly higher than in those without stroke. But only TC, D-DI, and fibrinogen were found to be predictors of stroke in hypertensives. Considerably higher TC, D-DI, and fibrinogen levels were also seen in patients with ischemic stroke than in those with hemorrhagic stroke. This confirms the key roles of dyslipidemia (hypercholesterolemia) and aberrant hemostatic activation to stroke development, notably ischemic stroke.

Coagulation biomarkers for ischemic stroke

A State of the Art lecture titled "coagulation biomarkers for ischemic stroke" was presented at the International Society on Thrombosis and Haemostasis (ISTH) Congress in 2022. Ischemic stroke (IS) is a common disease with major morbidity and mortality. It is a challenge to determine which patients are at risk for IS or have poor clinical outcome after IS. An imbalance of coagulation markers may contribute to the progression and prognosis of IS. Therefore, we now discuss studies on the association of selected coagulation biomarkers from the hemostasis, inflammation, and immunothrombosis systems with the risk of IS, stroke severity at the acute phase, and clinical outcome after treatment. We report on coagulation biomarker-induced risk of IS, stroke severity, and outcomes following IS derived from prospective population studies, case-control studies, and acute-phase IS studies. We found indications that many coagulation and inflammation biomarkers are associated with IS, but it is early to conclude that any of these biomarkers can be applied in a therapeutic setting to predict patients at risk of IS, stroke severity at the acute phase, and clinical outcome after treatment. The strongest evidence for a role in IS was found for beta-thromboglobulin, von Willebrand factor, factor VIII, fibrinogen, thrombin-activatable fibrinolysis inhibitor, D-dimer, and neutrophil extracellular traps, and therefore, they are promising candidates. Further research and validation in large-size populations using well-defined study designs are warranted. Finally, we provide a selection of recent data relevant to this subject that was presented at the 2022 ISTH Congress.

Diagnostic and prognostic blood biomarkers in vascular dementia: From the viewpoint of ischemic stroke

Reliable quantitative blood biomarkers are important in vascular dementia (VaD) because early diagnosis and therapeutic intervention are effective in preventing progression of dementia. Although many blood biomarkers for acute ischemic stroke (AIS) or VaD have been reported, there are few reliable blood biomarkers. VaD and AIS have similar pathological conditions that are associated with small vessel disease (SVD) such as oxidative stress, inflammation, endothelial dysfunction, and neuronal injury. Therefore, it may be possible to find superior blood biomarkers of VaD among AIS blood biomarkers. Owing to recent developments, noncoding RNAs such as microRNA and long noncoding RNA, which can be analyzed using a single drop of blood, are also particularly reliable VaD markers because they stably reflect brain tissue damage. A multimarker combining several blood biomarkers or artificial intelligence technology may also be beneficial to compensate for insufficiencies of a single blood biomarker. This review describes the blood biomarkers of VaD and how they are related to blood biomarkers of AIS.

Association of platelet count and mean platelet volume (MPV) index with types of stroke

Background:

Stroke is known to be the third most prominent cause of death in the developing countries and the most common debilitating neurologic disease. This study aimed to investigate the association of platelet count (PC) and mean platelet volume (MPV) index with various stroke types.

Methods:

This cross-sectional study was carried out on patients over the age of 18 years who presented with signs and symptoms of the first acute stroke. Exclusion criteria were underlying chronic liver or renal disease and the time more than 6 hours from symptom initiation, hematological and infectious disorders in patients. After recording of demographic data, a complete blood cell count (CBC) test was performed.

Results:

From 150 patients, who enrolled in the study, 54.7% of patients were males. The initial brain CT scan was normal in 13 (8.7%) patients and showed evidence of brain infarction and intracranial hemorrhage in 84 (56%) and 53 (35.3%) patients respectively. Patients with intracranial hemorrhage had significantly higher mean of MPV index than the patients with normal brain-CT scan and patients with evidence of brain infarction (p<0.001).

Conclusion:

The MVP index can be a predictor of the type of hemorrhagic or ischemic finding in emergency CT scan in stroke patients. This relationship may help to better understand the physiopathologic role of platelets in the development of stroke (hemorrhagic or ischemic), but will not replace cerebral computed tomography to diagnose the type of stroke, or it may not initiate treatment for hemorrhagic stroke.

Hematological Abnormalities and Malnutrition Mediate Pathway between Cancer and Outcomes in Ischemic Stroke Patients

BACKGROUND

The present study aimed to examine whether variables including D-dimer, high-sensitivity C-reactive protein (hsCRP), hemoglobin, platelet count, and nutritional status mediate the pathway between cancer and ischemic stroke outcomes.

METHODS

We reviewed data from consecutive patients with ischemic stroke admitted to Osaka University Hospital between January 1, 2006, and December 31, 2016. Patients with ischemic stroke were grouped according to the presence of cancer. Nutritional status was assessed using Controlling Nutritional Status (CONUT) scores. Mediation analyses were utilized to address the study aims.

RESULTS

Among 1,570 patients with ischemic stroke, 185 (12%) had active cancer. Relative to patients with ischemic stroke in the non-cancer group, those in the cancer group exhibited higher National Institutes of Health Stroke Scale scores on admission, higher D-dimer and hsCRP levels, lower hemoglobin levels and platelet counts, higher CONUT scores, and poorer modified Rankin Scale scores at discharge. Mediation analysis revealed that D-dimer, hsCRP, hemoglobin, platelet count, and CONUT scores acted as mediators of poor prognosis in the cancer group. The association between the exposure and outcome variables was no longer significant in the models containing D-dimer and CONUT scores as mediator variables, suggesting that they were strong mediators. Regarding the association between the mediator and outcome variables, hemoglobin, platelet count, and CONUT exhibited non-linearity (p for non-linearity < 0.001).

CONCLUSIONS

D-dimer, hsCRP, hemoglobin, platelet count, and CONUT score act as mediators of poor prognosis in patients with ischemic stroke with comorbid cancer. Such abnormalities can help to predict ischemic stroke outcomes.

Prognostic Hemostasis Biomarkers in Acute Ischemic Stroke

Supplemental Digital Content is available in the text.

Objectives—

The prediction of patients at risk for poor clinical outcome after acute ischemic stroke remains challenging. An imbalance of coagulation factors may play an important role in progression and prognosis of these patients. In this systematic review, we assessed the current literature on hemostasis biomarkers and the association with poor clinical outcome in acute ischemic stroke.

Approach and Results—

A systematic search of Embase, Medline, Cochrane Library, Web of Science, and Google Scholar was performed on studies reporting on hemostasis biomarkers and clinical outcome after acute ischemic stroke. Studies were considered eligible if blood samples were collected within 72 hours after symptom onset. Additionally, clinical outcome should be assessed using a disability score (Barthel Index or modified Rankin scale). Methodological quality of included studies was assessed with an adapted version of the Quality Assessment of Diagnostic Accuracy Studies questionnaire. A total of 80 articles were read full text, and 41 studies were considered eligible for inclusion, reporting on 37 different hemostasis biomarkers. No single biomarker appeared to be effective in predicting poor clinical outcome in acute ischemic stroke patients.

Conclusions—

Based on current literature, no clear recommendations can be provided on which hemostasis biomarkers are a predictor of clinical outcome after acute ischemic stroke. However, some biomarkers show promising results and need to be further investigated and validated in large populations with clear defined study designs.

D-Dimer Concentrations and Thromboelastography in Five Dogs With Ischemic Stroke

Ischemic stroke is a condition increasingly recognized in dogs; however, the number of publications on dogs with ischemic stroke is still limited and hemostatic parameters are infrequently reported. D-dimer levels have been shown to be elevated in people with acute ischemic stroke compared to a healthy control population and it has been proposed that a normal D-dimer can be used to exclude thromboembolism in dogs. In this case series, we report hemostatic parameters, including D-dimer and thromboelastography (TEG) along with clinical and imaging findings for five dogs diagnosed with ischemic stroke. All dogs had a normal D-dimer concentration on presentation. A hypercoagulable state was identified in two dogs based on the results of the TEG, and was suspected in the remaining three cases based on a shortened TEG clot reaction time. Based on the findings in the present cases, a D-dimer within the normal reference range does not seem an appropriate negative predictor for canine ischemic stroke. The demonstration of a possible hypercoagulable state, as identified by the TEG, is an interesting finding which should be explored further to help reveal predisposing hypercoagulable conditions in dogs with ischemic stroke.

Predictive and prognostic role of mean platelet volume in patients with first-ever acute ischemic stroke

Objective:

To investigate any possible effects of mean platelet volume (MPV) on short-term stroke prognosis and functional outcome in patients with first-ever acute ischemic stroke (FEAIS).

Methods:

This retrospective cross-sectional study included 798 FEAIS patients admitted to the emergency department of a tertiary care hospital in Adiyaman, Turkey between January 2013 and June 2015. The data were evaluated according to whether alive or dead, MPV levels, modified Rankin scale (MRS) scores, National Institutes of Health Stroke Scale (NIHSS) scores. The patients were divided into 3 groups based on MPV level as 4.4-7.4 fL, 7.5-10.4 fL, higher than 10.4 fL.

Results:

A total of 250 patients with FEAIS were included in the study. In both those who survived and those who died, the area under the curve related to hospitalization days, time interval of venipuncture (TIV), and MPV measurements was not statistically significant (p>0.05). The 3 MPV groups showed no significant differences in terms of MRS score, median NIHSS score, hospitalization, and TIV. In subgroups based on MRS scores, there were no statistically significant differences according to median latency (p=0.087), median hospitalization (p=0.394), TIV (p=0.201), and MPV levels (p=0.847). Furthermore, there were no differences in MPV levels between the MRS based groups (p=0.527).

Conclusion:

The results showed that MPV was not a significantly associated and reliable marker for the prediction of prognosis or functional outcome of FEAIS attack.

Plasma D-Dimer Concentrations and Risk of Intracerebral Hemorrhage: A Systematic Review and Meta-Analysis

Background: The aim of our meta-analysis was to evaluate the association between plasma d-dimer and intracerebral hemorrhage (ICH).

Methods: Embase, Pubmed, and Web of Science were searched up to the date of March 19th, 2018, and manual searching was used to extract additional articles. Standard mean difference (SMD) with 95% confidence intervals (CI) was calculated to evaluate d-dimer levels.

Results: Thirteen studies including 891 ICH patients and 1,573 healthy controls were included. Our results revealed that higher levels of d-dimer were displayed in ICH patients than those in healthy controls (95% CI= 0.98–2.00, p< 0.001). Subgroup analysis based on continent of Asia and Europe, sample size, as well as age in relation to d-dimer levels between ICH patients and healthy controls did not change the initial observation; whereas no differences of d-dimer levels were found between ICH and controls in America.

Conclusions: This meta-analysis revealed that high level of d-dimer is associated with the risk of ICH. Plasma d-dimer is suggested to be a potential biomarker for patients with ICH in Asia and Europe rather than in America. There were no impact of sample size-related differences and age-related diversities on the risk of ICH with respect to d-dimer levels.

Prognostic Value of Serum D-Dimer in Noncardioembolic Ischemic Stroke

Background: Although D-dimer levels are significantly associated with cardioembolic infarction, the significance of D-dimer levels in relation to the severity and functional outcomes of other stroke subtypes, such as lacunar and large artery atherosclerosis infarction, remains unclear. The purpose of this study was to evaluate whether elevated initial D-dimer levels are significantly and cross-sectionally associated with poor functional outcomes at each time point during a 9-month follow-up period. We also investigated the significance of D-dimer levels in longitudinal temporal changes of functional outcomes in these patients. Methods: We recruited 146 patients with lacunar infarction and 161 patients with large artery atherosclerosis infarction who were consecutively admitted to our hospital after acute stroke. Serum D-dimer levels were evaluated initially and the modified Rankin scale were measured initially and at 1-, 3-, 6-, and 9-month follow-up visits. Results: Patients with higher D-dimer levels had significantly worse initial functional outcomes, and these worse outcomes were maintained throughout the 9-month follow-up period compared with the low D-dimer group. However, regardless of stroke subtype, D-dimer levels did not influence long-term changes in functional outcomes over the 9-month follow-up period. Conclusion: This study suggests that elevated D-dimer levels can be used as a surrogate marker for poor functional outcomes only during the acute stage. Further evaluation of serum D-dimer levels could provide a helpful predictive marker for stroke prognosis.

Plasma D-dimer Level, the Promising Prognostic Biomarker for the Acute Cerebral Infarction Patients

BACKGROUND

Despite being an important cause of death and functional disability, acute cerebral infarction (ACI) lacks accurate and easy tools to predict the outcome of patients beyond clinical variables such as age and stroke severity.

METHODS

To investigate if plasma D-dimer level can be used as such a prognostic biomarker for ACI, so as to better guide patients' management, we studied the association between plasma D-dimer and the functional recovery of 1173 ACI patients. The patients were divided into 2 groups according to modified Rankin Scale (mRS) scores or National Institutes of Health Stroke Scale (NIHSS) scores evaluated on the 30th day after onset.

RESULTS

We observed that plasma D-dimer level correlated significantly with the prognosis of ACI evaluated based on both mRS scores (389.68 ± 32.06 µg/L for poor prognosis versus 377.70 ± 32.68 µg/L for good prognosis, P < .001) and NIHSS scores (387.01 ± 30.60 µg/L for poor prognosis versus 375.23 ± 30.66  µg/L for good prognosis, P < .01). Logistic analysis confirmed that higher D-dimer level was a risk factor for poor prognosis (mRS: odds ratio [OR], 1.604; 95% confidence interval [CI], 1.360-1.892; P < .001; NIHSS: OR, 1.733; 95% CI, 1.461-2.056; P < .01), after adjusted for age, gender, hypertension, diabetes, smoking, and hyperlipidemia.

CONCLUSION

Our results show that plasma D-dimer level is a promising prognosis biomarker for ACI.

Assessment of Serum UCH-L1 and GFAP in Acute Stroke Patients

A rapid and reliable diagnostic test to distinguish ischemic from hemorrhagic stroke in patients presenting with stroke-like symptoms is essential to optimize management and triage for thrombolytic therapy. The present study measured serum concentrations of ubiquitin C-terminal hydrolase (UCH-L1) and glial fibrillary astrocytic protein (GFAP) in acute stroke patients and healthy controls and investigated their relation to stroke severity and patient characteristics. We also assessed the diagnostic performance of these markers for the differentiation of intracerebral hemorrhage (ICH) from ischemic stroke (IS). Both UCH-L1 and GFAP concentrations were significantly greater in ICH patients than in controls (p < 0.0001). However, exclusively GFAP differed in ICH compared with IS (p < 0.0001). GFAP yielded an AUC of 0.86 for differentiating between ICH and IS within 4.5hrs of symptom onset with a sensitivity of 61% and a specificity of 96% using a cut-off of 0.34ng/ml. Higher GFAP levels were associated with stroke severity and history of prior stroke. Our results demonstrate that blood UCH-L1 and GFAP are increased early after stroke and distinct biomarker-specific release profiles are associated with stroke characteristics and type. We also confirmed the potential of GFAP as a tool for early rule-in of ICH, while UCH-L1 was not clinically useful.

Blood biomarkers in the early stage of cerebral ischemia

In ischemic stroke patients, blood-based biomarkers may be applied for the diagnosis of ischemic origin and subtype, prediction of outcomes and targeted treatment in selected patients. Knowledge of the pathophysiology of cerebral ischemia has led to the evaluation of proteins, neurotransmitters, nucleic acids and lipids as potential biomarkers. The present report focuses on the role of blood-based biomarkers in the early stage of ischemic stroke-within 72h of its onset-as gleaned from studies published in English in such patients. Despite growing interest in their potential role in clinical practice, the application of biomarkers for the management of cerebral ischemia is not currently recommended by guidelines. However, there are some promising clinical biomarkers, as well as the N-methyl-d-aspartate (NMDA) peptide and NMDA-receptor (R) autoantibodies that appear to identify the ischemic nature of stroke, and the glial fibrillary acidic protein (GFAP) that might be able to discriminate between acute ischemic and hemorrhagic strokes. Moreover, genomics and proteomics allow the characterization of differences in gene expression, and protein and metabolite production, in ischemic stroke patients compared with controls and, thus, may help to identify novel markers with sufficient sensitivity and specificity. Additional studies to validate promising biomarkers and to identify novel biomarkers are needed.

Serum D-dimer Levels Are Proportionally Associated with Left Atrial Enlargement in Patients with an Acute Ischemic Stroke due to Non-valvular Atrial Fibrillation

Objective Left atrial enlargement (LAE) may predispose individuals to blood stasis in atrial fibrillation (AF), and thus play a crucial role in thrombogenesis. The D-dimer level is one of the surrogate markers for a hypercoagulable state and reflects thrombus formation in AF. Since the D-dimer level reflects hypercoagulability as well as thrombus and fibrin burdens, LAE could be associated with a D-dimer elevation. However, no studies have explored this association or which factors contribute to increases in the D-dimer levels in patients with AF. Therefore, we assessed whether the serum D-dimer levels are related to the left atrial volume index (LAVI) or other vascular risk factors and also evaluated the association between the D-dimer levels and the initial stroke severity. Methods Ninety-eight consecutive patients with an acute ischemic stroke and non-valvular AF (NVAF) who were anticoagulation-naïve were enrolled, and all patients were stratified into moderate-to-severe and mild neurologic deficit groups using the National Institutes of Health Stroke Scale on admission. The association between the initial serum D-dimer levels and the LAVI was evaluated in all enrolled patients, and the serum D-dimer levels were compared between the two groups. Results The patients were classified into two groups according to the severity of the neurologic deficit. In a partial correlation coefficient analysis adjusted for confounding factors, an increase in the initial serum D-dimer levels was significantly associated with LAVI (r=0.286; p=0.027). A linear regression analysis showed that a history of peripheral artery disease was the factor most strongly associated with the serum D-dimer level (t=3.90, p<0.001), followed by LAVI (t=2.37, p=0.021) and a history of congestive heart failure (t=2.16, p=0.035). The D-dimer levels were higher in the moderate-to-severe neurologic deficit group than in the mild deficit group, but this difference was not statistically significant (4.5±7.1 vs. 1.6±2.6 mg/L, p=0.068). Conclusion The serum D-dimer levels were significantly associated with LAE in anticoagulation-naïve patients with an acute ischemic stroke and NVAF.

Background rhythm frequency and theta power of quantitative EEG analysis: predictive biomarkers for cognitive impairment post-cerebral infarcts

In clinical settings, cerebral infarct is a common disease of older adults, which usually increases the risk of cognitive impairment. This study aims to assess the quantitative electroencephalography (qEEG) as a predictive biomarker for the development of cognitive impairment, post-cerebral infarcts, in subjects from the Department of Neurology. They underwent biennial EEG recording. Cerebral infarct subjects, with follow-up cognitive evaluation, were analyzed for qEEG measures of background rhythm frequency (BRF) and relative δ, θ, α, and β band power. The relationship between cognitive impairment and qEEG, and other possible predictors, was assessed by Cox regression. The results showed that the risk hazard of developing cognitive impairment was 14 times higher for those with low BRF than for those with high BRF (P < .001). Hazard ratio (HR) was also significant for more than median θ band power (HR = 5, P = .002) compared with less than median θ band power. The HRs for δ, α, and β bands were equal to the baseline demographic, and clinical characteristics were not significantly different. In conclusion, qEEG measures of BRF, and relative power in θ band, are potential predictive biomarkers for cognitive impairment in patients with cerebral infarcts. These biomarkers might be valuable in early prediction of cognitive impairment in patients with cerebral infarcts.

The role of hs-CRP, D-dimer and fibrinogen in differentiating etiological subtypes of ischemic stroke

The aim of this study was to evaluate the diagnostic value of the serum biochemical markers high-sensitivity C-reactive protein (hs-CRP), D-dimer (DD) and fibrinogen (Fg) in differentiating etiological subtypes of ischemic stroke. This study was a retrospective case-only study, consecutively including patients with acute ischemic stroke. All patients were classified into subtypes using the TOAST classification system. A total of 317 patients were evaluated. Hs-CRP and DD levels were significantly different among the subtypes and were the highest in CE, followed by LAA and SAA; no significant difference between the subtypes was found for Fg. Hs-CRP > 6.96 mg/L was classified as the CE subtype, with a sensitivity of 41% and a specificity of 74%; DD > 791.30 ng/mL was classified as CE, with a sensitivity of 58% and a specificity of 78%. The combination of hs-CRP and DD classification as CE yielded a sensitivity of 65% and a specificity of 91%. DD > 791.30 ng/mL was considered an independent predictive factor of CE. Hs-CRP and DD could be useful for identifying the etiological subtypes of acute ischemic stroke, especially for predicting CE. The diagnostic value of DD was higher than that of hs-CRP.

Post-thrombolysis haemostasis changes after rt-PA treatment in acute cerebral infarct. Correlations with cardioembolic aetiology and outcome

BACKGROUND

Little is known, in man, in the post-thrombolytic molecular dynamics of haemostasis, particularly the effect of rt-PA on antifibrinolytic components such as alpha2 anti-plasmin and Factor XIII.

AIMS AND HYPOTHESIS

The purpose of this study was to systematically determine changes in coagulation and fibrinolytic parameters after thrombolysis with rt-PA during 24h. We also aimed to correlate these parameters with different acute ischemic stroke subtypes and global outcome.

METHODS

Eighty consecutive patients with cerebral infarcts treated with rt-PA had their plasma levels of fibrinogen, plasminogen, alpha2-antiplasmin, Factor XIII, fibrin(ogen) degradation products (FDP) and D-Dimers measured at baseline (h0), 2 (h2) and 24h (h24) after initiation of thrombolysis. Correlations between the variations of these components were statistically studied, using the Spearman rank test or the Pearson test. These haemostatic parameters were also compared with cardioembolic and non cardioembolic patients, as well as between poor and favourable outcome patients.

RESULTS

Between h0 and h2, a decrease in fibrinogen, plasminogen, alpha2-antiplasmin, and factor XIII was observed, while an increase in FDP and D-Dimers took place. These values returned to the initial levels at h24. At 2h, the decrease in fibrinogen was significantly correlated with that of plasminogen (0.48, p=0.01), alpha2-antiplasmin (0.48, p=0.004), and factor XIII (0.44, p=0.01); the decrease in plasminogen was significantly correlated with those of antifibrinolytic components, factor XIII (0.47, p=0.02) and alpha2-antiplasmin (r=0.77, p<0.001). These variations were independent of NIHSS. Cardioembolic infarcts showed a statistically significant greater h0-h2 decrease in plasminogen (p=0.04) and an h0-h2 increase in FDP (p=0.02). Poor outcome was linked to low plasminogen values at 2 and 24h.

CONCLUSIONS

Supposed to be fibrin-specific, rt-PA induces a decrease in circulating fibrinogen, significantly linked to a decrease in plasminogen. A collateral increase in antifibrinolytic agents such as factor XIII and alpha2-antiplasmin is also observed. At 2h, a significant decrease in plasminogen and a significant increase in fibrin(ogen) degradation products (FDP) are observed in cardioembolic infarcts, and appear as early independent predictors of this aetiology. A low plasminogen value at 2h is potentially predictive of poor prognosis at 3months.

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.

Plasma D-dimer levels are associated with stroke subtypes and infarction volume in patients with acute ischemic stroke

BACKGROUND

It has been suggested that modestly elevated circulating D-dimer values may be associated with acute ischemic stroke (AIS). Thus, the purpose of this study was to investigate the association between plasma D-dimer level at admission and AIS in Chinese population.

METHODS

In a prospective observational study, plasma D-dimer levels were measured using a particle-enhanced, immunoturbidimetric assay on admission in 240 Chinese patients with AIS. The National Institutes of Health Stroke Scale (NIHSS) score was assessed on admission blinded to D-dimer levels.

RESULTS

Plasma median D-dimer levels were significantly (P = 0.000) higher in AIS patients as compared to healthy controls (0.88; interquartiler range [IQR], 0.28-2.11 mg/L and 0.31; IQR, 0.17-0.74 mg/L). D-dimer levels increased with increasing severity of stroke as defined by the NIHSS score(r = 0.179, p = 0.005) and infarct volume(r = 0.425, p = 0.000). Those positive trends still existed even after correcting for possible confounding factors (P = 0.012, 0.000; respectively). Based on the Receiver operating characteristic (ROC) curve, the optimal cut-off value of plasma D-dimer levels as an indicator for diagnosis of cardioembolic strokes was projected to be 0.91 mg/L, which yielded a sensitivity of 83.7% and a specificity of 81.5%, the area under the curve was 0.862(95% confidence interval [CI], 0.811-0.912).

CONCLUSION

We had shown that plasma D-dimer levels increased with increasing severity of stroke as defined by the NIHSS score and infarct volume. These associations were independent other possible variables. In addition, cardioembolic strokes can be distinguished from other stroke etiologies by measuring plasma D-dimer levels very early (0-48 hours from stroke symptom onset).

Ischemic stroke biomarkers in blood

Ischemic stroke is a leading cause of adult disability and mortality. With over 15 million strokes occurring every year in the world, methods to better identify patients at risk for stroke are needed, as are methods to improve patient diagnosis and prognosis when stroke occurs. Use of blood-based biomarkers is one method that has been evaluated to predict risk of stroke, diagnose stroke and its causes, predict stroke severity and outcome, and guide prevention therapy. Markers that have been identified include a variety of proteins, nucleic acids and lipids that relate to stroke pathophysiology. The role of blood biomarkers in ischemic stroke is still being defined, and further study is needed to develop blood biomarkers for clinical stroke use. In this review, the authors provide a summary of biomarkers that have been divided by their potential clinical application.

Stroke in sickle cell anemia patients: a need for multidisciplinary approaches

Sickle cell anemia (SCA) is an autosomal recessive disorder, with Mendelian inheritance pattern, caused by a missense mutation in the β-polypeptide chain of the hemoglobin B. SCA preferentially affects populations in countries where malaria was/is present (e.g. Africa, USA, Brazil). Thereby, in USA, the incidence of SCA is relatively high, around 1/500, and the prevalence is about 1/1000. In Brazil, SCA represents a major public health problem with an incidence ranging from 1/2000 to 1/600 depending on the regions. Homozygotic patients present more severe medical conditions and reduced life expectancy than heterozygous individuals who generally are asymptomatic. Eventually, this life-threatening disease displays a complex etiology owing to heterogeneous phenotypes and clinical outcomes, subsequently affecting the management of the patients. One of the most critical complications associated with SCA is stroke, a leading neurologic cause of death and disability. About 24% of SCA patients have a stroke by the age of 45 and 11% by the age of 20. From the general population, twin and familial aggregation studies as well as genome-wide association studies (GWAS), mostly in pediatric populations with ischemic stroke, showed that the risk of stroke has a substantial genetic component. Nevertheless, to fully characterize genomic contributors of stroke and permit reliable personalized medicine, multidisciplinary studies incorporating knowledge from clinical medicine, epidemiology, genetics, and molecular biology, are required. In this manuscript, stroke in SCA patients is extensively reviewed with emphasis to the US and Brazilian populations. Recent advances in genomics analysis of stroke in SCA patients are highlighted.

Relationship between plasma (D)-dimer level and cerebral infarction volume in patients with nonvalvular atrial fibrillation

BACKGROUND

Plasma D-dimer level may reflect the activity of thrombus formation in the left atrium of patients with nonvalvular atrial fibrillation (NVAF). Proper anticoagulation with warfarin dramatically decreases the rate of cerebral embolism, reduces stroke severity and subsequent risk of death, as well as the level of D-dimer in NVAF patients. However, the predictive value of D-dimer level on cerebral embolism severity has not been examined. Thus, the purpose of this study was to investigate the association between plasma D-dimer level at admission and infarct size in NVAF patients.

METHODS

We identified 124 patients with consecutive ischemic stroke and NVAF who were admitted within 48 h of symptom onset. We measured infarction volume from CT taken after 3 ± 1 days from the onset. Plasma D-dimer levels were measured at the time of admission. Relationships were analyzed between infarction volume and plasma D-dimer levels, cardiovascular risk factors, preadmission medications and admission conditions. We also assessed the influence of D-dimer level on functional outcome in patients with preadmission modified Rankin Scale (mRS) score of 0-1 and patients by tertile of D-dimer level (≤0.83, 0.83-2.16 and ≥2.16 µg/ml).

RESULTS

Infarction volume significantly correlated with D-dimer level (r = 0.309, p < 0.001), systolic blood pressure (r = 0.201, p = 0.026), diastolic blood pressure (r = 0.283, p = 0.002), National Institutes of Health Stroke Scale (NIHSS) score on admission (r = 0.546, p < 0.001) and mRS score at discharge (r = 0.557, p < 0.001). Multivariate regression analyses showed that the D-dimer level was significantly associated with infarction volume after adjusting for age, sex, current smoker or not, prothrombin time-international normalized ratio ≥1.6, diastolic blood pressure, CHADS(2) score and NIHSS score on admission. In patients with a preadmission mRS score of 0-1 (n = 108), D-dimer level was significantly associated with NIHSS score at admission (r = 0.318, p < 0.001) and mRS score at discharge (r = 0.310, p = 0.001). Patients in the highest D-dimer tertile group showed worse outcome than those in the middle (p = 0.041) and lowest (p < 0.001) tertiles.

CONCLUSIONS

Plasma D-dimer level on admission is significantly related to infarction volume and functional outcome, following cardioembolic stroke in NVAF patients.

Clinical presentation and ischemic zone on MRI in cancer patients with acute ischemic stroke

AIMS

This study was conducted to evaluate the clinical and MRI profiles in acute cancer strokes, and to demonstrate our experience with thrombolytic therapy in cancer stroke patients.

METHODS

We prospectively studied active cancer patients with acute ischemic stroke who underwent MRI within 48 h of the onset of symptoms. Patients were grouped based on the presence of conventional stroke mechanisms (CSM). Clinical characteristics and MRI profiles were evaluated.

RESULTS

A total of 70 patients were finally included in this study. Patients without CSM were more frequently presented with encephalopathy than those with CSM (29.4 vs. 2.8%, p = 0.002). The diffusion-perfusion mismatch pattern was more prevalent in patients with CSM (21 patients, 58.3%) than in patients without CSM (8 patients, 23.5%). Patients who had a higher tertiles of D-dimer level were significantly less likely to have the diffusion-perfusion mismatch pattern (p = 0.015). Among patients who presented within 6 h of the onset of stroke, revascularization therapy was performed in 4 of 16 (25%) patients with CSM, but none of the patients without CSM.

CONCLUSION

Based on the stroke mechanisms, the optimal strategy of thrombolytic therapy should be considered differently in cancer patients with acute ischemic stroke.

Proteomic analysis reveals platelet factor 4 and beta-thromboglobulin as prognostic markers in severe acute respiratory syndrome

Previously, we reported that proteomic fingerprints were present in sera of patients with severe acute respiratory syndrome (SARS), and could separate patients into subgroups with different prognoses. In the present study, we examined the prognostic values of the SARS‐associated proteomic features by biostatistical analysis, and deciphered the identities of those with prognostic values. Data of 20 SARS‐associated serum proteomic features and ten serological variables from 38 SARS adult patients before treatment were subjected to multivariate logistic regression. Proteomic features of m/z 6634, m/z 7769, m/z 8635, and m/z 8865 were identified as independent prognostic markers. After purification by cation‐exchange chromatography and gel electrophoresis, proteomic features of m/z 7769 and m/z 8865 were found to be platelet factor 4 (PF4) and beta‐thromboglobulin (beta‐TG) by tandem mass spectrometry, respectively. The associations of decreased serum PF4 and increased serum beta‐TG levels with poor prognosis were confirmed by Western blot. Previous studies suggest that PF4 and beta‐TG are involved in the pathogenesis of acute respiratory distress syndrome (ARDS) in a negative and positive way, respectively. Our results suggest that PF4 and beta‐TG may also play similar roles in the development of ARDS in SARS patients.

Biomarker level improves the diagnosis of embolic source in ischemic stroke of unknown origin

The risk of recurrent stroke is likely related to etiology. Therefore it is important to identify which patients are at highest early risk. We evaluated whether selected blood biomarkers may aid in the diagnosis of stroke etiology. We studied consecutive non-lacunar stroke patients between November 2006 and January 2007, and selected undetermined origin strokes. Blood samples were drawn at arrival to test brain natriuretic peptide (BNP), D-dimer, CK-MB, myoglobin, and troponin. Second harmonic transthoracic echocardiography (SHTTE) and ECG-24 h monitoring were also performed within the first 24 h. We evaluated 294 patients with ischemic stroke; 89 had an initial undetermined origin. After a cardiological work-up, 49 were diagnosed as embolic including atrial fibrillation (4), severe aortic arch atheromatosis (24), severe wall abnormalities (12), valve disease (3), dilated cardiomyopathy (1), and patent foramen (5). Higher levels of CK-MB, BNP, and myoglobin were found in patients with embolic source in SHTTE, but only CK-MB >1.5 ng/ml and BNP >64 pg/ml remained as independent predictors: BNP (OR 8.86; CI 95 % 2.79-28.09), CK-MB (OR 6.28; CI 95 % 1.66-23.69). BNP showed specificity of 75 %, sensitivity of 63.4 %, and positive predictive value (PPV) of 75.6 %. CK-MB had specificity of 85 %, sensitivity of 47.9 %, and PPV of 79.3 %. Measuring both biomarkers improves the finding of embolic source, increasing specificity to 95 % and PPV to 88.2 %. High-level CK-MB and BNP during the acute phase of ischemic stroke are associated with an embolic source. Measurement of both biomarkers may improve the diagnosis, guiding the need to perform a heart exploration.

Evolving role of biomarkers in acute cerebrovascular disease

The development of a clinically validated biomarker of acute cerebral ischemia would have the potential to facilitate the use of time-sensitive reperfusion strategies, allow for individualization of patient care by predicting relative risk of hemorrhage and volume of penumbral tissue, and add valuable prognostic information for patients presenting with acute stroke. Additionally, a stroke biomarker might benefit early stage clinical research by serving as a surrogate measure of ischemic injury. Although at present there are no clinically validated biomarkers of acute stroke, previous studies have focused on markers associated with different components of the ischemic cascade, including microglial activation, inflammation, oxidative stress, neuronal injury, hemostasis, and endothelial dysfunction. Evolving technologies have provided high throughput approaches to investigate potential gene and protein signatures, and methods to measure newly discovered markers of cell death and immune responses. Prior to defining the clinical utility of stroke biomarkers, it is critical to understand the inherent limitations of a biomarker-based approach and define its potential value for providing adjunctive diagnostic and prognostic information. The identification and validation of a clinically relevant biomarker, or panel of markers, of stroke will ultimately require incorporation of both stringent research design and assessment in the clinical context in which the marker will be used.

Predictors of poor outcome in patients with acute cerebral infarction

BACKGROUND AND PURPOSE

Plasma D-dimer levels are elevated during the acute phase of cerebral infarction (CI). We investigated whether the D-dimer level on admission and other clinical characteristics could be used to predict the poor outcome of patients with acute CI.

METHODS

The clinical characteristics and plasma D-dimer levels measured within 3 days of onset were compared according to outcome among patients with acute CI.

RESULTS

In total, 359 consecutive patients (mean age, 71.8 years) were examined, of which 174 had a poor outcome [score on the modified Rankin scale (mRS) ≥3] at 30 days after hospitalization. The mean mRS score was higher and a poor outcome was observed more frequently among women than among men (p<0.001 for each). The proportions of women, cardioembolism, atrial fibrillation, advanced age (≥75 years), prior history of CI or transient ischemic attack, and elevated D-dimer level (≥1.0 µg/mL) were significantly higher among patients with a poor outcome than among those with a good outcome. A multivariate analysis showed that elevated D-dimer level [≥1.0 µg/mL; odds ratio (OR), 2.45; 95% confidence interval (95% CI), 1.52-3.89; p<0.01], advanced age (OR, 1.93; 95% CI, 1.21-3.07; p<0.01), and female gender (OR, 1.75; 95% CI, 1.08-2.83; p=0.02) were independent predictors of a poor outcome.

CONCLUSIONS

Certain clinical characteristics (gender and advanced age) and an elevated D-dimer level upon admission can be used to predict the outcome of patients with acute CI at 30 days after hospitalization.

Correlation between Serum D-Dimer Level and Volume in Acute Ischemic Stroke

OBJECTIVE

D-dimer is a breakdown product of fibrin mesh after factor XIII stabilization. Previously, many authors have demonstrated a relationship between D-dimer level and stroke progression or type. This study aimed to investigate the relationship between D-dimer level and stroke volume.

METHODS

Between January 2008 and December 2009, we analyzed the D-dimer levels of 59 acute ischemic stroke patients in our neurosurgical department both upon admission and after seven days of initial treatment. Each patient's National Institute of Health Stroke Scale score, modified Rankin Scales score, Glasgow outcome score, and infarction volume were also evaluated.

RESULTS

Mean D-dimer level at admission was 626.6 µg/L (range, 77-4,752 µg/L) and the mean level measured after seven days of treatment was 238.3 µg/L (range, 50-924 µg/L). Mean D-dimer level at admission was 215.3 µg/L in patients with focal infarctions, 385.7 µg/L in patients with multiple embolic infarctions, 566.2 µg/L in those with 1-19 cc infarctions, 668.8 µg/L in 20-49 cc infarctions, 702.5 µg/L in 50-199 cc infarctions, and 844.0 µg/L in >200 cc infarctions (p=0.044). On the 7th day of treatment, the D-dimer levels had fallen to 201.0 µg/L, 293.2 µg/L, 272.0 µg/L, 232.8 µg/L, 336.6 µg/L, and 180.0 µg/L, respectively (p=0.530).

CONCLUSION

Our study shows that D-dimer level has the positive correlation with infarction volume and can be use to predict infarction-volume.

Blood biomarkers of ischemic stroke

This review provides a summary of the protein and RNA biomarkers that have been studied for the diagnosis and assessment of ischemic stroke. Many of the biomarkers identified relate to the pathophysiology of ischemic stroke, including ischemia of CNS tissue, acute thrombosis and inflammatory response. These biomarkers are summarized by their intended clinical application in ischemic stroke including diagnosis, prediction of stroke severity and outcome, and stratification of patients for stroke therapy. Among the biomarkers discussed are recent whole genome studies using RNA expression profiles to diagnose ischemic stroke and stroke etiology. Though many candidate blood based biomarkers for ischemic stroke have been identified, none are currently used in clinical practice. With further well designed study and careful validation, the development of blood biomarkers to improve the care of patients with ischemic stroke may be achieved.

D-dimer levels and stroke progression in patients with acute ischemic stroke and atrial fibrillation

BACKGROUND

Patients with acute ischemic stroke and atrial fibrillation are at increased risk of stroke progression and recurrence. We sought to assess whether D-dimer and other markers of hemostatic activation could predict these adverse events in such patients.

METHOD

Blood samples were obtained from patients included in the Heparin in Acute Embolic Stroke Trial. Stroke progression was defined as a ≥3-point worsening on the Scandinavian Stroke Scale during the first 48 h after randomization. Blood samples were analyzed for D-dimer, prothrombin fragment 1 + 2, soluble fibrin monomer, and C-reactive protein.

RESULTS

A total of 382 patients were included in the analyses. Levels of D-dimer and other markers of hemostatic activation were not significantly higher in patients with stroke progression than in other patients (D-dimer median values: 1025 ng/ml vs 970 ng/ml, P = 0.73). The same was true for recurrent stroke (D-dimer: 720 ng/ml vs 973 ng/ml, P = 0.96), and the combined endpoint of stroke progression, recurrent stroke, and death (D-dimer: 991 ng/ml vs 970 ng/ml, P = 0.91). Multivariable analyses did not alter the results.

CONCLUSION

D-dimer and other markers of hemostatic activation were not associated with stroke progression, recurrent stroke, or death in patients with acute ischemic stroke and atrial fibrillation.

Soluble glycoprotein VI is raised in the plasma of patients with acute ischemic stroke

BACKGROUND AND PURPOSE

Ischemic stroke induced by thrombosis may be triggered by atherosclerotic plaque rupture and collagen-induced platelet activation. Collagen induces glycoprotein VI shedding.

METHODS

We measured plasma-soluble glycoprotein VI (sGPVI) by enzyme-linked immunosorbent assay in 159 patients with acute (<7-day) ischemic stroke and age/sex-matched community-based control subjects.

RESULTS

sGPVI was elevated in stroke compared with controls (P=0.0168). ORs were higher in Quartile 4 for stroke cases (P=0.0121), and sGPVI was significantly elevated in stroke associated with large artery disease across Quartiles 2 to 4 and small artery disease in Quartile 4. sGPVI decreased 3 to 6 months after antiplatelet treatment, consistent with elevated sGPVI due to platelet activation during the thrombotic event. sGPVI correlated with P-selectin (P=0.0007) and was higher in individuals with the GPVIa haplotype (P=0.024).

CONCLUSIONS

Glycoprotein VI shedding is implicated in the pathology of acute ischemic stroke.

Clinical application of blood biomarkers in cerebrovascular disease

Identifying a biomarker or panel of biomarkers of cerebral ischemia would have a major impact on the care of stroke patients by facilitating early management decisions and individualization of care. Biochemical surrogates of cerebral ischemia might also play an important role by identifying relevant pathways for novel therapeutic strategies and by facilitating early clinical trials in cerebrovascular disease. Serum biomarkers related to pathways of hemostasis, oxidation and inflammation, or alterations in glial and neuronal proteins, have been identified but none have been recommended for routine clinical use. This review describes the most promising biomarkers of cerebrovascular disease and the context and limitations in which they have been studied.

Prognostic values of lesion volume and biochemical markers in ischemic and hemorrhagic stroke: a stereological and clinical study

PURPOSE

Our aim was to evaluate the relationship between lesion volume, serum level of biochemical markers, and clinical situation in ischemic and hemorrhagic stroke.

METHODS

MRI was obtained on 33 ischemic and 28 hemorrhagic strokes. The Cavalieri method was used to measure the volume. To evaluate neurological situation of the patients, we used the National Institutes of Health Stroke Scale (NIHSS) and Rankin Disability Scores at the first, third, seventh, and thirtieth days. We measured the level of leptin, high sensitivity C-reactive protein (hs-CRP), insulin, cortisol, fibrinogen, protein C, protein S, von Willebrand factor, D-dimer, Antitrombin III, and Factor VIII (F VIII) at the same time intervals.

RESULTS

In ischemic events, cortisol level at third and seventh days, and fibrinogen level at the first day were correlated with lesion volumes (r = 0.5, p = .02; r = 0.4, p = .02; r = 0.5, p = .005, respectively). In hemorrhagic events, only fibrinogen level was correlated with lesion volumes at third day (r = 0.6, p = .04). No significant differences were found among all these biochemical parameters, neurological situation (p > .05), and lesion volumes at all times.

CONCLUSION

In the prediction of stroke prognosis, lesion volume and all of the evaluated biochemical parameters are not deterministic factors.

Lupus anticoagulants and anti-phospholipid antibodies as risk factors for a first episode of ischemic stroke

BACKGROUND

Antiphospholipid antibodies (aPLA) and lupus anticoagulant (LAC) were shown to precipitate thromboembolic events. Their association with ischemic stroke remains to be seen.

OBJECTIVES

We investigated the contribution of LAC, and antibodies directed against the phospholipids cardiolipin (aCL), phosphatidylserine (aPS), and the phospholipid-dependent cofactors beta2-glycoprotein I and annexin V, to the risk for ischemic stroke.

PATIENTS/METHODS

LAC and antibody levels were measured in 208 stroke patients and 203 age- and gender-matched control subjects.

RESULTS

Positive LAC resulted in an increased risk for stroke [OR (95% CI) = 8.1 (2.4-27.5)]. Significant elevation in aPS IgG, aCL IgM and aCL IgG titers, and increased prevalence of elevated aPS IgG, aCL IgM and aCL IgG (based on P95 cutoff values of healthy individuals) were seen in patients. aPS IgG was associated with cardioembolic, whereas aCL IgG and IgM were elevated in lacunar, atherosclerotic and cardioembolic, and LAC positivity was documented only in lacunar stroke subtypes. The co-presence of LAC with a positive aCL IgM/IgG or aPS IgG did not affect the overall risk for stroke. Multivariate analysis confirmed the association of positive LAC with stroke [aOR (95% CI) = 9.7 (1.8-52.5)], and demonstrated a clear gradation of increasing risk of stroke associated with the four categories of aCL IgG and aPS IgG, and identified aCL IgM P95 as independent predictors of stroke after adjusting for potentially confounding covariates.

CONCLUSIONS

Our study demonstrates that the presence of LAC, and elevated aCL IgG and aPS IgG antibodies are risk factors for stroke.

Is D-dimer helpful in evaluating stroke patients? A systematic review

D-dimer (DD) is a fibrin degradation product present in negligible amounts in healthy individuals, but in thrombotic/fibrinolytic conditions substantially increases in plasma. Over the last two decades numerous studies have explored whether DD measurements would help stroke clinicians. An easy, reliable, and inexpensive test for stroke diagnosis, determination of stroke subtype, severity, prognosis, and recurrence risk is being sought. We searched the database, of studies indexed in English on MEDLINE, using the keywords 'cerebral venous thrombosis, D-dimer, deep vein thrombosis, intracerebral hemorrhage, ischemic stroke, outcome, prognosis, and subarachnoid hemorrhage' for relevant studies. Here, we systematically review current evidence on plasma DD levels in patients with ischemic and hemorrhagic strokes, transient ischemic attacks, and cerebral venous thrombosis. Numerous studies showed that patients with various strokes and stroke-related diseases had acutely increased plasma DD levels. Plasma DD levels, however, are neither sensitive nor specific enough to be utilized in stroke diagnostics and cannot replace either clinical or radiological evaluation. Regarding prediction of patient outcome, good clinical evaluation is clearly superior to DD testing.

Gene expression in peripheral blood differs after cardioembolic compared with large-vessel atherosclerotic stroke: biomarkers for the etiology of ischemic stroke

There are no biomarkers that differentiate cardioembolic from large-vessel atherosclerotic stroke, although the treatments differ for each and approximately 30% of strokes and transient ischemic attacks have undetermined etiologies using current clinical criteria. We aimed to define gene expression profiles in blood that differentiate cardioembolic from large-vessel atherosclerotic stroke. Peripheral blood samples were obtained from healthy controls and acute ischemic stroke patients (<3, 5, and 24 h). RNA was purified, labeled, and applied to Affymetrix Human U133 Plus 2.0 Arrays. Expression profiles in the blood of cardioembolic stroke patients are distinctive from those of large-vessel atherosclerotic stroke patients. Seventy-seven genes differ at least 1.5-fold between them, and a minimum number of 23 genes differentiate the two types of stroke with at least 95.2% specificity and 95.2% sensitivity for each. Genes regulated in large-vessel atherosclerotic stroke are expressed in platelets and monocytes and modulate hemostasis. Genes regulated in cardioembolic stroke are expressed in neutrophils and modulate immune responses to infectious stimuli. This new method can be used to predict whether a stroke of unknown etiology was because of cardioembolism or large-vessel atherosclerosis that would lead to different therapy. These results have wide ranging implications for similar disorders.

Etiologic diagnosis of ischemic stroke subtypes with plasma biomarkers

BACKGROUND AND PURPOSE

Because there is no biologic marker offering precise information about stroke etiology, many patients receive a diagnosis of undetermined stroke even after all available diagnostic tests are done, precluding correct treatment.

METHODS

To examine the diagnostic value of a panel of biochemical markers to differentiate stroke etiologies, consecutive acute stroke patients were prospectively evaluated. Brain computed tomography, ultrasonography, cardiac evaluations, and other tests were done to identify an etiologic diagnosis according to TOAST classification. Blood samples were drawn on Emergency Department arrival (<24 hours) to test selected biomarkers: C-reactive protein, D-dimer, soluble receptor for advanced glycation end products, matrix metalloproteinase-9, S-100b, brain natriuretic peptide (BNP), neurotrophin-3, caspase-3, chimerin, and secretagogin (assayed by ELISA).

RESULTS

Of 707 ischemic stroke patients included, 36.6% were cardioembolic, 21.4% atherothrombotic, 18.1% lacunar, and 23.9% of undetermined origin. High levels of BNP, soluble receptor for advanced glycation end products, and D-dimer (P<0.0001) were observed in patients with cardioembolic stroke. Independent predictors (odds ratios with CIs are given) of cardioembolic stroke were as follows: atrial fibrillation 15.3 (8.4-27.7, P<0.001); other embolic cardiopathies 14.7 (4.7-46, P<0.001); total anterior circulation infarction 4 (2.3-6.8, P<0.001); BNP >76 pg/mL 2.3 (1.4-3.7, P=0.001); and D-dimer >0.96 microg/mL 2.2 (1.4-3.7, P=0.001). Even among patients with transient symptoms (n=155), a high BNP level identified cardioembolic etiology (6.7, 2.4-18.9; P<0.001). A model combining clinical and biochemical data had a sensitivity of 66.5% and a specificity of 91.3% for predicting cardioembolism.

CONCLUSIONS

Using a combination of biomarkers may be a feasible strategy to improve the diagnosis of cardioembolic stroke in the acute phase, thus rapidly guiding other diagnostic tests and accelerating the start of optimal secondary prevention.

Hypercoagulable states and strokes

Several hematologic disorders and hemostatic defects increase risk of ischemic stroke. A common feature of these disorders is the creation of a prothrombotic state, now commonly referred to as "hypercoagulable state." Hematologic diseases such as essential thrombocythemia, polycythemia vera, and thrombotic thrombocytopenic purpura clearly cause stroke. Effective treatment is now available for these disorders. Association of hemostatic defects with stroke risk is still at the investigational stage. Although a number of factors such as soluble thrombomodulin, fibrinogen, factor VIII, von Willebrand factor, and plasminogen activator inhibitor-1 are associated with stroke risk, their predictive values remain unknown. Furthermore, causal relationship has not been established.

Prostaglandin A1 inhibits increases in intracellular calcium concentration, TXA(2) production and platelet activation

AIM

In our previous studies we found that cyclopentenane prostaglandin A1 (PGA1) had neuroprotective effects in a rodent ischemic model. In the present study we aimed to investigate the inhibitory effect of PGA1 on platelet function.

METHOD

The rate of aggregation of human platelets was measured by using turbidimetry. The rate of adhesion of platelets to cultured endothelial cells was determined by using [(3)H]-adenine labeled platelets. 5-Hydroxytryptamine release from platelets was measured with O-phthaldialdehyde fluorospectrophotometry. The levels of TXB(2), a stable metabolite of TXA(2), were determined by radioimmuno-assay. Alternations in platelet morphology were observed using an electron microscope, and the intraplatelet free calcium concentrations were measured with Fluo-3/AM FCM assay.

RESULTS

PGA1 significantly inhibited thrombin-, collagen- and ADP-induced aggregation and adhesion of platelets. The morphological changes of platelets induced by thrombin were blocked by PGA1. PGA1 inhibited the release of 5-hydroxytyptamine from dense granules and the synthesis of TXA(2).

CONCLUSION

PGA1 inhibits the activation of platelets probably through blocking increases in intracellular calcium concentration and TXA(2) synthesis.