Hemostatic markers of recanalization in patients with ischemic stroke treated with rt-PA

The Joint Effect of Renal Function Status and Coagulation Biomarkers on In-Hospital Outcomes in Acute Ischemic Stroke Patients With Intravenous Thrombolysis

OBJECTIVE

To demonstrate whether combining renal function status [estimating glomerular filtration rate (eGFR)] with coagulation biomarkers [fibrinogen (Fg) and d-dimer] is more beneficial in predicting in-hospital outcomes following intravenous thrombolysis (IVT) in acute ischemic stroke (AIS) patients.

METHODS

We studied 417 AIS patients with IVT. According to the cut-offs of coagulation biomarkers (Fg and d-dimer) and eGFR determined by receiver operating characteristic (ROC) curves, the patients were divided into four groups: LFLG (low Fg and low eGFR), LFHG (low Fg and high eGFR), HFLG (high Fg and low eGFR), and HFHG (high Fg and high eGFR); or LDLG (low d-dimer and low eGFR), LDHG (low d-dimer and high eGFR), HDLG (high d-dimer and low eGFR), and HDHG (high d-dimer and high eGFR). Logistic regression models were used to calculate odds ratios (ORs) and 95% confidence intervals (CIs) for poor outcomes at discharge and post-stroke pneumonia across the four groups.

RESULTS

The patients in the HFLG and HDLG groups had the poorest prognosis at discharge and the highest risk of in-hospital pneumonia. They experienced 3.00 or 4.59 times higher risk of in-hospital pneumonia than those in the LFHG and LDHG groups (95%CI: 1.07-8.44, p < 0.05; 95%CI: 1.58-13.32, p = 0.005). Similarly, the risk of adverse outcome at discharge was 3.02 and 1.52 times higher in HFLG and HDLG groups (95%CI: 1.63-9.91, p < 0.005; 95%CI: 1.11-5.74, p < 0.05) compared to that in LFHG and LDHG groups. Adding eGFR and Fg or d-dimer to the risk model improved the risk reclassification for in-hospital pneumonia and functional outcomes at discharge.

CONCLUSION

Combining renal function status and coagulation biomarkers within 4.5 h after onset could better predict in-hospital outcomes of AIS patients with IVT.

Nonlinear association of fibrinogen levels with functional prognosis in patients with acute ischemic stroke: a prospective cohort study

OBJECTIVE

Fibrinogen, essential in primary hemostasis, platelet aggregation, and leukocyte-endothelial interactions, is also associated with a heightened risk of acute ischemic stroke (AIS). However, its influence on AIS patient outcomes is unclear. This study examines the correlation between fibrinogen levels and the risk of unfavorable outcomes three months post-AIS.

METHODS

This is a secondary analysis of a prospective cohort study conducted in Korea. The sample consisted of 1851 AIS patients who received treatment at a Korean hospital between January 2010 and December 2016. Statistical models were established to understand the relationship between fibrinogen levels(mg/dL) and unfavorable outcomes(mRs ≥ 3), including logistic regression models, Generalized Additive Models (GAM), and smooth curve fitting (penalized splines). The log-likelihood ratio test has been utilized to evaluate the best fit. To ensure the robustness of the results, sensitivity analyses were conducted by reanalyzing the relationship after excluding participants with TG > 200 mg/dl and BMI > 25 kg/m2. Subgroup analyses were also performed to assess whether influencing factors modify the association between fibrinogen levels and unfavorable outcomes.

RESULTS

After adjusting for multiple covariates including age, BMI, sex, LDL-c, TG, HGB, HDL-c, BUN, FPG, ALB, PLT, AF, hypertension, smoking, DM, mRs score at admission, the binary logistic regression model demonstrated revealed a significant positive association between fibrinogen levels and the risk of unfavorable outcomes in AIS patients (OR = 1.215, 95% CI: 1.032-1.429, p = 0.019). Sensitivity analyses supported these findings, with similar ORs observed in subsets of patients with TG < 200 mg/dL (OR = 1.221, 95% CI: 1.036-1.440) and BMI < 25 kg/m2 (OR = 1.259, 95% CI: 1.051-1.509). Additionally, the relationship between fibrinogen levels and outcomes was nonlinear, with a critical threshold of 2.74 g/L. Below the inflection point, the OR for unfavorable outcomes was 0.666 ((95% CI: 0.360, 1.233, p = 0.196), whereas above it, the OR increased to 1.374 (95% CI: 1.138, 1.659).

CONCLUSIONS

This study has provided evidence of a positive and nonlinear correlation between fibrinogen levels and 3-month poor functional outcomes in patients with AIS. When fibrinogen levels exceeded 2.74 g/L, a significant and positive association was observed with the risk of poor outcomes. This study provides a further reference for optimizing rehabilitation exercises and facilitating clinical counseling in patients with acute ischemic stroke.

Role of factor XIII in ischemic stroke: a key molecule promoting thrombus stabilization and resistance to lysis

BACKGROUND

Active coagulation factor XIII (FXIII) catalyzing crosslinking of fibrin and other hemostatic factors plays a key role in clot stability and lysis.

OBJECTIVES

To evaluate the effect of FXIII inhibition in a mouse model of ischemic stroke (IS) and the role of activated FXIII (FXIIIa) in clot formation and lysis in patients with IS.

METHODS

A ferric chloride IS murine model was performed before and after administration of a FXIIIa inhibitor (FXIIIinh). Thromboelastometry in human and mice blood was used to evaluate thrombus stiffness and lysis with FXIIIinh. FXIIIa-dependent fibrin crosslinking and lysis with fibrinolytic drugs (tissue plasminogen activator and tenecteplase) were studied on fibrin plates and on thrombi and clotted plasma of patients with IS. Finally, circulating and thrombus FXIIIa were measured in 85 patients with IS.

RESULTS

FXIIIinh administration before stroke induction reduced infarct size, α2-antiplasmin (α2AP) crosslinking, and local microthrombosis, improving motor coordination and fibrinolysis without intracranial bleeds (24 hours). Interestingly, FXIII blockade after stroke also reduced brain damage and neurologic deficit. Thromboelastometry in human/mice blood with FXIIIinh showed delayed clot formation, reduced clot firmness, and shortened tissue plasminogen activator lysis time. FXIIIa fibrin crosslinking increased fibrin density and lysis resistance, which increased further after α2AP addition. FXIIIinh enhanced ex vivo lysis in stroke thrombi and fibrin plates. In patients with IS, thrombus FXIII and α2AP were associated with inflammatory and hemostatic components, and plasma FXIIIa correlated with thrombus α2AP and fibrin.

CONCLUSION

Our results suggest a key role of FXIIIa in thrombus stabilization, α2AP crosslinking, and lysis resistance, with a protective effect of FXIIIinh in an IS experimental model.

The Change in Fibrinogen is Associated with Outcome in Patients with Acute Ischemic Stroke Treated with Endovascular Thrombectomy

BACKGROUND

Fibrinogen has been identified as a modulator of the coagulation and inflammatory process. There is uncertainty about the relationship between the dynamic profile of fibrinogen levels and its impact on clinical outcomes in patients with acute ischemic stroke treated with endovascular thrombectomy.

METHODS

We consecutively enrolled patients with acute ischemic stroke who underwent endovascular thrombectomy. Fibrinogen was measured on admission and during hospitalization. The change in fibrinogen (Δfibrinogen) was calculated as the highest follow-up fibrinogen minus admission fibrinogen, with a positive Δfibrinogen indicating an increase in fibrinogen level. Functional outcome was assessed by the modified Rankin Scale at 3 months. Poor outcome was defined as modified Rankin Scale > 2.

RESULTS

A total of 346 patients were included (mean age 67.4 ± 13.6 years, 52.31% men). The median fibrinogen on admission was 2.77 g/L (interquartile range 2.30-3.39 g/L). The median Δfibrinogen was 1.38 g/L (interquartile range 0.27-2.79 g/L). Hyperfibrinogenemia (> 4.5 g/L) on admission was associated with an increased risk of poor outcome [odds ratio (OR) 5.93, 95% confidence interval (CI) 1.44-24.41, p = 0.014]. There was a possible U-shaped association of Δfibrinogen with outcomes, with an inflection point of - 0.43 g/L (p = 0.04). When Δfibrinogen was <  - 0.43 g/L, a higher decrease in fibrinogen (lower Δfibrinogen value) was associated with a higher risk of poor outcome (OR 0.22, 95% CI 0.02-2.48, p = 0.219). When Δfibrinogen was >  - 0.43 g/L, the risk of poor outcome increased with increasing fibrinogen (OR 1.27, 95% CI 1.04-1.54, p = 0.016).

CONCLUSIONS

In patients with endovascular thrombectomy, hyperfibrinogenemia on admission was associated with poor functional outcomes at 3 months, whereas Δfibrinogen was associated with poor 3-month outcomes in a possible U-shaped manner.

Low α2-Plasmin Inhibitor Antigen Levels on Admission Are Associated With More Severe Stroke and Unfavorable Outcomes in Acute Ischemic Stroke Patients Treated With Intravenous Thrombolysis

Background

Intravenous administration of recombinant tissue plasminogen activator (rt-PA) fails to succeed in a subset of acute ischemic stroke (AIS) patients, while in approximately 6–8% of cases intracerebral hemorrhage (ICH) occurs as side effect.

Objective

Here, we aimed to investigate α2-plasmin inhibitor (α2-PI) levels during thrombolysis and to find out whether they predict therapy outcomes in AIS patients.

Patients/Methods

In this prospective, observational study, blood samples of 421 AIS patients, all undergoing i.v. thrombolysis by rt-PA within 4.5 h of their symptom onset, were taken before and 24 h after thrombolysis. In a subset of patients (n = 131), blood was also obtained immediately post-lysis. α2-PI activity and antigen levels were measured by chromogenic assay and an in-house ELISA detecting all forms of α2-PI. α2-PI Arg6Trp polymorphism was identified in all patients. Stroke severity was determined by NIHSS on admission and day 7. Therapy-associated ICH was classified according to ECASSII. Long-term outcomes were defined at 3 months post-event by the modified Rankin Scale (mRS).

Results

Median α2-PI activity and antigen levels showed a significant drop immediately post-lysis and increased to subnormal levels at 24 h post-event. Admission α2-PI levels showed a significant negative stepwise association with stroke severity. Patients with favorable long-term outcomes (mRS 0–1) had significantly higher admission α2-PI antigen levels (median:61.6 [IQR:55.9–70.5] mg/L) as compared to patients with poor outcomes (mRS 2–5: median:59.7 [IQR:54.5–69.1] and mRS 6: median:56.0 [IQR:48.5–61.0] mg/L, p < 0.001). In a Kaplan–Meier survival analysis, patients with an α2-PI antigen in the highest quartile on admission showed significantly better long-term survival as compared to those with α2-PI antigen in the lowest quartile (HR: 4.54; 95%CI:1.92–10.8, p < 0.001); however, in a multivariate analysis, a low admission α2-PI antigen did not prove to be an independent risk factor of poor long-term outcomes. In patients with therapy-related ICH (n = 34), admission α2-PI antigen levels were significantly, but only marginally, lower as compared to those without hemorrhage.

Conclusions

Low α2-PI antigen levels on admission were associated with more severe strokes and poor long-term outcomes in this cohort. Our results suggest that in case of more severe strokes, α2-PI may be involved in the limited efficacy of rt-PA thrombolysis.

Repurposing new drug candidates and identifying crucial molecules underlying PCOS Pathogenesis Based On Bioinformatics Analysis

BACKGROUNDS

Polycystic ovary syndrome affects 7% of women of reproductive ages. Poor-quality oocytes, along with lower cleavage and implantation rates, reduce fertilization.

OBJECTIVE

This study aimed to determine crucial molecular mechanisms behind PCOS pathogenesis and repurpose new drug candidates interacting with them. To predict a more in-depth insight, we applied a novel bioinformatics approach to analyze interactions between the drug-related and PCOS proteins in PCOS patients.

METHODS

The newest proteomics data was retrieved from 16 proteomics datasets and was used to construct the PCOS PPI network using Cytoscape. The topological network analysis determined hubs and bottlenecks. The MCODE Plugin was used to identify highly connected regions, and the associations between PCOS clusters and drug-related proteins were evaluated using the Chi-squared/Fisher's exact test. The crucial PPI hub-bottlenecks and the shared molecules (between the PCOS clusters and drug-related proteins) were then investigated for their drug-protein interactions with previously US FDA-approved drugs to predict new drug candidates.

RESULTS

The PI3K/AKT pathway was significantly related to one PCOS subnetwork and most drugs (metformin, letrozole, pioglitazone, and spironolactone); moreover, VEGF, EGF, TGFB1, AGT, AMBP, and RBP4 were identified as the shared proteins between the PCOS subnetwork and the drugs. The shared top biochemical pathways between another PCOS subnetwork and rosiglitazone included metabolic pathways, carbon metabolism, and citrate cycle, while the shared proteins included HSPB1, HSPD1, ACO2, TALDO1, VDAC1, and MDH2. We proposed some new candidate medicines for further PCOS treatment investigations, such as copper and zinc compounds, reteplase, alteplase, gliclazide, Etc.

CONCLUSION

Some of the crucial molecules suggested by our model have already been experimentally reported as critical molecules in PCOS pathogenesis. Moreover, some repurposed medications have already shown beneficial effects on infertility treatment. These previous experimental reports confirm our suggestion for investigating our other repurposed drugs (in vitro and in vivo).

The Role of Biomarkers in Atherothrombotic Stroke-A Systematic Review

Stroke represents the primary debilitating disease in adults and is the second-highest cause of death worldwide. Atherosclerosis, the most prevalent etiology for vascular conditions, is a continuous process that gradually creates and develops endothelial lesions known as atherosclerotic plaques. These lesions lead to the appearance of atherothrombotic stroke. In the last decades, the role of biological biomarkers has emerged as either diagnostic, prognostic, or therapeutic targets. This article aims to create a list of potential biomarkers related to atherothrombotic stroke by reviewing the currently available literature. We identified 23 biomarkers and assessed their roles as risk factors, detection markers, prognostic predictors, and therapeutic targets. The central aspect of these biomarkers is related to risk stratification, especially for patients who have not yet suffered a stroke. Other valuable data are focused on the predictive capabilities for stroke patients regarding short-term and long-term prognosis, including their influence over the acute phase treatment, such as rt-PA thrombolysis. Although the role of biomarkers is anticipated to be of extreme value in the future, they cannot yet compete with traditional stroke neuroimaging markers but could be used as additional tools for etiological diagnosis.

Timely and Blood-Based Multiplex Molecular Profiling of Acute Stroke

Stroke is a leading cause of death and disability in the world. To address such a problem, early diagnosis and tailored acute treatment represent one of the major priorities in acute stroke care. Since the efficacy of reperfusion treatments is highly time-dependent, there is a critical need to optimize procedures for faster and more precise diagnosis. We provide a concise review of the most relevant and well-documented blood-protein biomarkers that exhibit greater potential for translational to clinical practice in stroke differential diagnosis and to differentiate ischemic stroke from hemorrhagic stroke, followed by an overview of the most recent point-of-care technological approaches to address this problem. The integration of fluid-based biomarker profiling, using point-of-care biosensors with demographic, clinical, and neuroimaging parameters in multi-dimensional clinical decision-making algorithms, will be the next step in personalized stroke care.

Alpha2-Antiplasmin: The Devil You Don't Know in Cerebrovascular and Cardiovascular Disease

Alpha2-antiplasmin (α2AP), the fast-reacting, serine protease inhibitor (serpin) of plasmin, was originally thought to play a key role in protection against uncontrolled, plasmin-mediated proteolysis of coagulation factors and other molecules. However, studies of humans and mice with genetic deficiency of α2AP have expanded our understanding of this serpin, particularly in disease states. Epidemiology studies have shown an association between high α2AP levels and increased risk or poor outcome in cardiovascular diseases. Mechanistic studies in disease models indicate that α2AP stops the body's own fibrinolytic system from dissolving pathologic thrombi that cause venous thrombosis, pulmonary embolism, arterial thrombosis, and ischemic stroke. In addition, α2AP fosters the development of microvascular thrombosis and enhances matrix metalloproteinase-9 expression. Through these mechanisms and others, α2AP contributes to brain injury, hemorrhage and swelling in experimental ischemic stroke. Recent studies also show that α2AP is required for the development of stasis thrombosis by inhibiting the early activation of effective fibrinolysis. In this review, we will discuss the key role played by α2AP in controlling thrombosis and fibrinolysis and, we will consider its potential value as a therapeutic target in cardiovascular diseases and ischemic stroke.

Plasmin Generation Potential and Recanalization in Acute Ischaemic Stroke; an Observational Cohort Study of Stroke Biobank Samples

Rationale: More than half of patients who receive thrombolysis for acute ischaemic stroke fail to recanalize. Elucidating biological factors which predict recanalization could identify therapeutic targets for increasing thrombolysis success.

Hypothesis: We hypothesize that individual patient plasmin potential, as measured by in vitro response to recombinant tissue-type plasminogen activator (rt-PA), is a biomarker of rt-PA response, and that patients with greater plasmin response are more likely to recanalize early.

Methods: This study will use historical samples from the Barcelona Stroke Thrombolysis Biobank, comprised of 350 pre-thrombolysis plasma samples from ischaemic stroke patients who received serial transcranial-Doppler (TCD) measurements before and after thrombolysis. The plasmin potential of each patient will be measured using the level of plasmin-antiplasmin complex (PAP) generated after in-vitro addition of rt-PA. Levels of antiplasmin, plasminogen, t-PA activity, and PAI-1 activity will also be determined. Association between plasmin potential variables and time to recanalization [assessed on serial TCD using the thrombolysis in brain ischemia (TIBI) score] will be assessed using Cox proportional hazards models, adjusted for potential confounders.

Outcomes: The primary outcome will be time to recanalization detected by TCD (defined as TIBI ≥4). Secondary outcomes will be recanalization within 6-h and recanalization and/or haemorrhagic transformation at 24-h. This analysis will utilize an expanded cohort including ~120 patients from the Targeting Optimal Thrombolysis Outcomes (TOTO) study.

Discussion: If association between proteolytic response to rt-PA and recanalization is confirmed, future clinical treatment may customize thrombolytic therapy to maximize outcomes and minimize adverse effects for individual patients.

Elevated plasma fibrinogen indicates short-term poor outcome in patients with acute ischemic stroke after intravenous thrombolysis

BACKGROUND

Fibrinogen is a central protein of hemostasis and a major determinant of plasma viscosity and key factor for platelet activation. The aim of this study is to investigate the relationship between fibrinogen level and short-term outcome in acute ischemic stroke patients receiving intravenous thrombolysis.

METHODS

This retrospective study included 176 acute ischemic stroke patients who received intravenous thrombolysis with recombinant tissue plasminogen activator and provided plasma fibrinogen level within 24 h after stroke onset. Patients were categorized by plasma fibrinogen level: Quartile 1 (≤ 1.74 g/L), Quartile 2 (1.75-2.08 g/L), Quartile 3 (2.09-2.69 g/L), and Quartile 4 (> 2.69 g/L). The medical record of each patient was reviewed, and demographic, clinical and laboratory information was abstracted. Functional outcome at 14 days was assessed with the modified Rankin Scale.

RESULTS

Poor outcome was present in 75 (42.6%) of the 176 patients that were included in the study (mean age, 72 years; male, 53.4%). After adjustment for potential confounding variables, higher plasma fibrinogen level on admission was associated with poor outcome (adjusted odds ratio 10.45, 95% confidence interval 1.49-73.15 for Q4:Q1; P = 0.02). According to receiver operating characteristic analysis, the best discriminating factor for poor outcome was a plasma fibrinogen level ≥ 2.585 g/L (area under the curve 0.672; sensitivity 50.7%; specificity 86.1%).

CONCLUSION

Elevated plasma fibrinogen levels on admission are significantly associated with poor outcome after admission for acute ischemic stroke, suggesting the potential role of plasma fibrinogen level as a predictive marker for short-term poor outcome in acute ischemic stroke patients receiving thrombolytic therapy.

Predictors of Postthrombolysis Outcome and Symptomatic Postthrombolysis Hemorrhage following Intravenous Thrombolysis with Alteplase for Acute Ischemic Stroke

Background  Thrombolysis improves the outcome in acute ischemic stroke (AIS), albeit with an increased risk of symptomatic intracranial hemorrhage (sICH). Biomarkers to find patients at risk of sICH, and guide treatment and prognosis would be valuable. Methods  Consecutive patients of AIS thrombolysed between February 2017 and September 2019 at Calcutta National Medical College were studied prospectively for sICH and outcome at 6-month follow-up. We identified the independent risk factors for unfavorable outcomes, mortality, and sICH using multivariate analysis. Prethrombolysis and 24-hour postthrombolysis fibrinogen levels were estimated to evaluate its biomarker role. Results  Out of 180 AIS patients admitted during the study period, 60 patients were thrombolysed. Door to needle time was <3 hours among 24 patients and 3 to 4.5 hours among 36 patients. Favorable outcomes occurred among 76.67% and sICH occurred among 13.33% patients. Upper tertile of National Institute of Health Stroke Scale (NIHSS) had the highest adjusted odds for sICH (17.5 [95% confidence intervals=1.7-178.44]). Total anterior circulation stroke had the highest adjusted odds for unfavorable outcome (19.11 [3.9-92.6]). Following thrombolysis, the mean (standard deviation) fibrinogen level of 449.27 (32.87) decreased 7% to postthrombolysis level of 420 (20.5; p< 0.0001). Higher tertiles of fibrinogen levels had progressively increasing odds for morbidity and sICH. Conclusion  Congestive heart failure, hypertension, age ≥75 years, diabetes mellitus, stroke (double weight), i.e., CHADS2 score >2, low ejection fraction, the occurrence of total anterior circulation stroke and higher mean arterial blood pressure, blood glucose level, NIHSS score, and fibrinogen at admission were the common risk factors significantly predicting postthrombolysis sICH and morbidity. Antiplatelet and anticoagulant therapy, lower ASPECT (Alberta Stroke Program Early CT Score), and higher SEDAN scores also predicted sICH . Fibrinogen levels were significantly higher among those developing sICH and having unfavorable outcome. The performance of thrombolysis within 3 hours or between 3 and 4.5 hours after symptom onset did not affect morbidity, mortality, or the occurrence of sICH.

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.

Blood Biomarkers of Parenchymal Damage in Ischemic Stroke Patients Treated With Revascularization Therapies

Purpose

Postischemic reperfusion injury may exacerbate cerebral damage and capillary dysfunction, leading to brain edema (BE), hemorrhagic transformation (HT), necrosis, and injury from free radicals with subsequent infarct growth (IG). Several plasmatic biomarkers involved in the ischemic cascade have been studied in relation to radiological and clinical outcomes of reperfusion injury in ischemic stroke with heterogeneous results. This article provides a brief overview of the contribution of circulating biomarkers to the pathophysiology of parenchymal damage in ischemic stroke patients treated with revascularization therapies.

Methods

We included full reports with measurements of plasma markers in patients with acute ischemic stroke treated with revascularization therapies.

Findings

Our research included a large number of observational studies investigating a possible role of circulating biomarkers in the development of parenchymal damage after acute stroke treatments. To make the results clearer, we divided the review in 4 sections, exploring the relation of different biomarkers with each of the indicators of parenchymal damage (HT, BE, IG, recanalization).

Discussion and conclusion

Definite conclusions are difficult to draw because of heterogeneity across studies. However, our review seems to confirm an association between some circulating biomarkers (particularly matrix metalloproteinase-9) and occurrence of parenchymal damage in ischemic stroke patients treated with revascularization therapies.

Blood Biomarkers for Stroke Diagnosis and Management

Biomarkers are objective indicators used to assess normal or pathological processes, evaluate responses to treatment and predict outcomes. Many blood biomarkers already guide decision-making in clinical practice. In stroke, the number of candidate biomarkers is constantly increasing. These biomarkers include proteins, ribonucleic acids, lipids or metabolites. Although biomarkers have the potential to improve the diagnosis and the management of patients with stroke, there is currently no marker that has demonstrated sufficient sensitivity, specificity, rapidity, precision, and cost-effectiveness to be used in the routine management of stroke, thus highlighting the need for additional work. A better standardization of clinical, laboratory and statistical procedures between centers is indispensable to optimize biomarker performance. This review focuses on blood biomarkers that have shown promise for translation into clinical practice and describes some newly reported markers that could add to routine stroke care. Avenues for the discovery of new stroke biomarkers and future research are discussed. The description of the biomarkers is organized according to their expected application in clinical practice: diagnosis, treatment decision, and outcome prediction.

PAI-1 5G/5G genotype is an independent risk of intracranial hemorrhage in post-lysis stroke patients

Objective

Thrombolysis by recombinant tissue plasminogen activator (rt‐PA) is the main pharmacological therapy in acute ischemic stroke (IS); however, it is only effective in a subset of patients. Here we aimed to investigate the role of plasminogen activator inhibitor‐1 (PAI‐1), an effective inhibitor of t‐PA, and its major polymorphism (PAI‐1 4G/5G) in therapy outcome.

Methods

Study population included 131 consecutive IS patients who all underwent thrombolysis. Blood samples were taken on admission, 1 and 24 h after rt‐PA infusion. PAI‐1 activity and antigen levels were measured from all blood samples and the PAI‐1 4G/5G polymorphism was determined. Clinical data including NIHSS were registered on admission and day 1. ASPECTS was assessed using CT images taken before and 24 h after thrombolysis. Intracranial hemorrhage (ICH) was classified according to ECASS II. Long‐term outcome was defined 90 days post‐event by the modified Rankin Scale (mRS).

Results

PAI‐1 activity levels dropped transiently after thrombolysis, while PAI‐1 antigen levels remained unchanged. PAI‐1 4G/5G polymorphism had no effect on PAI‐1 levels and did not influence stroke severity. PAI‐1 activity/antigen levels as measured on admission were significantly elevated in patients with worse 24 h ASPECTS (<7). Logistic regression analysis including age, sex, NIHSS on admission, BMI, history of arterial hypertension, and hyperlipidemia conferred a significant, independent risk for developing ICH in the presence of 5G/5G genotype (OR:4.75, 95%CI:1.18–19.06). PAI‐1 levels and PAI‐1 4G/5G polymorphism had no influence on long‐term outcomes.

Interpretation

PAI‐1 5G/5G genotype is associated with a significant risk for developing ICH in post‐lysis stroke patients.

Fibrinolysis in patients with chemotherapy-induced thrombocytopenia and the effect of platelet transfusion

Essentials Bleeding in chemotherapy induced thrombocytopenia (CIT) might be influenced by hyperfibrinolysis. t-PA-thromboelastography is a fast and reliable assay for hyperfibrinolysis in CIT patients. Clots of CIT patients are more susceptible to t-PA induced lysis compared to healthy individuals. Besides platelets, other factors are likely to influence clot lysis in CIT patients.

BACKGROUND

Bleeding events in chemotherapy-induced thrombocytopenic (CIT) patients with similar platelet counts might be influenced by changes in clot lysis potential.

OBJECTIVES

To investigate, in an observational study, thromboelastographic lysis parameters, alterations in clot strength and susceptibility to clot lysis in CIT patients. To identify factors associated with fibrinolytic profiles, and to evaluate the effects of platelet transfusions.

METHODS

Independent determinants of tissue-type plasminogen activator (t-PA)-ROTEM lysis parameters were identified with multivariable linear regression. Clot formation, strength and lysis parameters were compared with the results of healthy individuals. Characteristics of CIT patients with and without hyperfibrinolytic profiles were compared. t-PA-ROTEM results before, 1 hour after and 24 hours after platelet transfusion were compared.

RESULTS

A total of 72 consecutive CIT patients were included. t-PA-ROTEM lysis parameters correlated with changes in fibrinolytic proteins. Clot formation time was longer, maximum clot firmness was weaker and lysis times were shorter than in healthy individuals. CIT patients had low plasminogen activator inhibitor-1 and thrombin-activatable fibrinolysis inhibitor levels, and 40% showed hyperfibrinolytic profiles. Platelet transfusions resulted in less hyperfibrinolytic profiles in many, but not all CIT patients. Patients without hyperfibrinolytic profiles had higher fibrinogen, factor VIII and α2 -antiplasmin levels.

CONCLUSIONS

t-PA-ROTEM can be used as a fast and reliable assay to detect hyperfibrinolytic profiles in CIT patients. CIT patients have weaker clots, which are more susceptible to clot lysis, than healthy individuals. Besides platelets, other factors are likely to influence clot susceptibility to fibrinolysis in CIT patients. The impact of a hyperfibrinolytic t-PA-ROTEM profile on bleeding remains to be investigated.

Markers of Coagulation and Fibrinolysis Predicting the Outcome of Acute Ischemic Stroke Thrombolysis Treatment: A Review of the Literature

Intravenous administration of recombinant tissue plasminogen activator (rt-PA) has been proven to be safe and effective in the treatment of acute ischemic stroke. Little is known, however, why this treatment is less effective in some patients while in others life-threatening side-effects, e.g., symptomatic intracerebral hemorrhage might occur. Clinical failure of thrombolysis related to absent or partial recanalization or reocclusion as well as hemorrhagic complications of thrombolysis are possibly related to hemostatic events. Data on markers of coagulation and/or fibrinolysis in acute stroke patients are numerous and may provide indications regarding therapy outcomes. Better understanding of the hemostatic and fibrinolytic system during rt-PA therapy might be clinically useful and ultimately might lead to an improvement in the efficacy or safety of this treatment. Studies on thrombus composition retrieved from cerebral arteries may also advance our knowledge and provide a key to improve acute stroke therapy. Here we provide a comprehensive review on a wide range of factors and markers of coagulation and fibrinolysis that have been studied in the context of thrombolysis outcome in ischemic stroke patients. Moreover, a brief summary is given on the most recent research on thrombus composition having a potential influence on outcomes.

Low factor XIII levels after intravenous thrombolysis predict short-term mortality in ischemic stroke patients

In this observational study we investigated whether levels of factor XIII (FXIII) and its major polymorphisms affect the outcome of thrombolysis by recombinant tissue plasminogen activator (rtPA) in acute ischemic stroke (AIS) patients. Study cohort included 132 consecutive AIS patients undergoing i.v. thrombolysis within 4.5 h of symptom onset. Blood samples taken on admission, immediately after and 24 h after therapy were analyzed for FXIII activity and antigen levels. FXIII-A p.Val34Leu, p.Tyr204Phe, FXIII-B p.His95Arg and intron K(IVS11 + 144) polymorphisms were genotyped. Neurological deficit was assessed using the National Institutes of Health Stroke Scale. Intracranial hemorrhage was classified according to ECASSII criteria. Long-term functional outcome was defined at 3 months post-event by the modified Rankin scale. FXIII levels showed a gradual decrease immediately after thrombolysis and 24 h later, which was not related to therapy-associated bleeding. In a multiple logistic regression model, a FXIII level in the lowest quartile 24 h post-lysis proved to be an independent predictor of mortality by 14 days post-event (OR:4.95, 95% CI:1.31-18.68, p < 0.05). No association was found between the investigated FXIII polymorphisms and therapeutic outcomes. In conclusion, our findings indicate that FXIII levels 24 h after thrombolysis might help to identify patients at increased risk for short-term mortality.

Early changes in fibrinogen after administration of alteplase are associated with the short-term efficacy of thrombolysis

The authors aimed to determine whether early changes in fibrinogen were associated with the efficacy of intravenous thrombolysis at 24 hours after alteplase infusion. The authors retrospectively reviewed a consecutive series of 56 patients with acute ischemic stroke treated with alteplase in the clinical database. The fibrinogen levels were monitored at the first and fourth hours after alteplase infusion. Additionally, the National Institutes of Health Stroke Scale (NIHSS) scores were recorded to define the short-term efficacy of intravenous thrombolysis before and 24 hours after alteplase infusion. The patients were distributed into amelioration, deterioration, and inefficiency groups according the short-term efficacy of intravenous thrombolysis. One-way ANOVA and post hoc analysis were used to compare the differences in the clinical characteristics among these groups. The relationships among changes in the fibrinogen levels, other potential risk factors, and NIHSS scores were examined using logistic regression analysis. Fifty-two patients (mean age, 65.71 ± 11.04 years; male, 57.7%) were finally enrolled in the study. The median NIHSS of these patients was 11 (range, 2-23), and the mean time from symptom onset to thrombolysis was 187.17 ± 67.53 minutes. The frequency of hypertension in the deterioration group was significantly higher than that in the inefficiency group (P = .01). Changes in the fibrinogen level were more significant in the amelioration group than in the other groups (P < .05). Logistic regression analysis revealed that changes in the fibrinogen levels between the first and fourth hours were positively associated with the short-term efficacy of alteplase infusion (odds ratio, 3.98; 95% confidence interval, 1.56-10.16; P = .004). Early changes in fibrinogen levels may be a potential predictor for the short-term efficacy of alteplase treatment in acute ischemic stroke. Additionally, these changes may be helpful for determining the short-term efficacy of alteplase treatment and early therapeutic strategies in clinical practice.

Matrix Metalloproteinase-9 Mediates the Deleterious Effects of α2-Antiplasmin on Blood-Brain Barrier Breakdown and Ischemic Brain Injury in Experimental Stroke

During acute brain ischemia, α2-antiplasmin markedly enhances brain injury, blood-brain barrier breakdown and matrix metalloproteinase-9 (MMP-9) expression. Although α2-antiplasmin inhibits fibrin thrombus-degradation, and MMP-9 is a collagen-degrading enzyme altering blood-brain barrier, both have similar deleterious effects on the ischemic brain. We examined the hypothesis that MMP-9 is an essential downstream mediator of α2-antiplasmin's deleterious effects during brain ischemia. Middle cerebral artery thromboembolic stroke was induced in a randomized, blinded fashion in mice with increased blood levels of α2-antiplasmin. There was a robust increase in MMP-9 expression (immunofluorescence) in the ischemic vs. the non-ischemic hemisphere of MMP-9^+/+ but not MMP-9^-/- mice, 24 h after stroke. Brain swelling and hemorrhage were significantly increased in the ischemic vs. the non-ischemic hemisphere of MMP-9^+/+ mice. By comparison to MMP-9^+/+ mice, the ischemic hemispheres of MMP-9^-/- mice showed a ∼6-fold reduction in brain swelling (p < 0.001) and a ∼9-fold reduction in brain hemorrhage. Brain infarction (p < 0.0001) and TUNEL-positive cell death (p < 0.001) were significantly diminished in the ischemic hemisphere of MMP-9^-/- mice vs. MMP-9^+/+ mice. Ischemic breakdown of the blood-brain barrier and fibrin deposition were also significantly reduced in MMP-9^-/- mice vs. MMP-9^+/+ mice (p < 0.05), as measured by quantitative immunofluorescence. We conclude that MMP-9 deficiency ablates many of the deleterious effects of high α2-antiplasmin levels, significantly reducing blood-brain barrier breakdown, TUNEL-positive cell death, brain hemorrhage, swelling and infarction. This suggests that the two molecules may be in a shared pathway in which MMP-9 is essential downstream for the deleterious effects of α2-antiplasmin in ischemic stroke.

Thrombelastography does not predict clinical response to rtPA for acute ischemic stroke

Thrombelastography (TEG) measures coagulation in venous blood. We hypothesized that TEG, by reflecting clot subtype and ex vivo fibrinolysis, might predict fibrinolytic response to tPA as reflected by rapid clinical improvement or hemorrhagic transformation of the infarct. 171 acute ischemic stroke patients treated with tPA were prospectively enrolled. Venous blood for TEG was drawn before and 10 min after tPA bolus. We measured rapid clinical improvement (RCI = 8 point improvement on NIHSS or total NIHSS of 0, 1 at 36 h), Hemorrhagic transformation (HT = any blood on imaging within 36 h), and hyperdense middle cerebral artery sign (HDMCA = biomarker for erythrocyte-rich clot). Multivariable regression models compared TEG parameters after adjusting for potential confounders. No differences in pre- or post-tPA TEG were found between patients with or without RCI. Also, there was no correlation between TEG and HDMCA. Clotting was slightly prolonged in patients with HT (p = 0.046). We failed to find a robust association between TEG and clinical response to tPA. It is likely that arterial clot lysis is determined by factors unrelated to coagulation status as measured by TEG in the venous circulation. It is unlikely that TEG will be useful to predict clinical response to tPA, but may help predict bleeding.

α2-Antiplasmin: New Insights and Opportunities for Ischemic Stroke

Thrombotic vascular occlusion is the leading cause of ischemic stroke. High blood levels of α₂-antiplasmin (a2AP), an ultrafast, covalent inhibitor of plasmin, have been linked in humans to increased risk of ischemic stroke and failure of tissue plasminogen activator (tPA) therapy. Consistent with these observations, a2AP neutralizes the therapeutic benefit of tPA therapy in experimental stroke. In addition, a2AP has deleterious, dose-related effects on ischemic brain injury in the absence of therapy. Experimental therapeutic inactivation of a2AP markedly reduces microvascular thrombosis, ischemic brain injury, brain swelling, brain hemorrhage, and death after thromboembolic stroke. These data provide new insights into the critical importance of a2AP in the pathogenesis of ischemic brain injury and suggest that transiently inactivating a2AP may have therapeutic value in ischemic stroke.

Factor seven activating protease (FSAP) predicts response to intravenous thrombolysis in acute ischemic stroke

BACKGROUND

Prediction of recanalization after intravenous thrombolysis could be important to direct secondary reperfusion techniques. Factor seven activating protease (FSAP) has been described to have a relevant pathophysiological role in stroke.

AIM

The aim is to determine whether plasma FSAP levels are associated with recanalization after tissue plasminogen activator in acute stroke.

METHODS

FSAP antigen, activity, and FSAP-inhibitor complexes were measured in 120 acute stroke patients admitted to Hospital Vall d'Hebron with arterial occlusions, before intravenous thrombolysis. Recanalization was assessed by transcranial Doppler 2 h after thrombolysis. Predictors of recanalization were determined by logistic regression analysis and the additional predictive value of FSAP over them was determined by integrated discrimination improvement index.

RESULTS

Complete recanalization was achieved in 31 patients. FSAP antigen levels were lower in patients achieving recanalization (8.2 (6.3-11.7) µg/mL vs. 9.8 (7.6-12.8) µg/mL; p = 0.046). After adjustment by age, sex, and National Institutes of Health Stroke Scale, Oxfordshire Community Stroke Project (odds ratio = 0.33 (0.13-0.82), p = 0.017) and FSAP antigen (odds ratio = 3.22 (1.22-8.47), p = 0.018) were independently associated with recanalization, and the addition of FSAP improved the model discrimination (integrated discrimination improvement = 5.5% (1.4-9.7), p = 0.009).

CONCLUSIONS

Our study showed that lower FSAP antigen plasma levels were associated with a higher chance of arterial recanalization after tissue plasminogen activator treatment, suggesting an involvement of FSAP in tissue plasminogen activator-induced clot lysis. FSAP antigen determination might be useful in predicting tissue plasminogen activator response in stroke patients.

Ischemic stroke outcome: A review of the influence of post-stroke complications within the different scenarios of stroke care

Stroke remains one of the main causes of death and disability worldwide. The challenge of predicting stroke outcome has been traditionally assessed from a general point of view, where baseline non-modifiable factors such as age or stroke severity are considered the most relevant factors. However, after stroke occurrence, some specific complications such as hemorrhagic transformations or post stroke infections, which lead to a poor outcome, could be developed. An early prediction or identification of these circumstances, based on predictive models including clinical information, could be useful for physicians to individualize and improve stroke care. Furthermore, the addition of biological information such as blood biomarkers or genetic polymorphisms over these predictive models could improve their prognostic value. In this review, we focus on describing the different post-stroke complications that have an impact in short and long-term outcome across different time points in its natural history and on the clinical-biological information that might be useful in their prediction.

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.

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.

Microvascular thrombosis, fibrinolysis, ischemic injury, and death after cerebral thromboembolism are affected by levels of circulating α2-antiplasmin

OBJECTIVE

Ischemic stroke is primarily attributable to thrombotic vascular occlusion. Elevated α2-antiplasmin (a2AP) levels correlate with increased stroke risk, but whether a2AP contributes to the pathogenesis of stroke is unknown. We examined how a2AP affects thrombosis, ischemic brain injury, and survival after experimental cerebral thromboembolism.

APPROACH AND RESULTS

We evaluated the effects of a2AP on stroke outcomes in mice with increased, normal, or no circulating a2AP, as well as in mice given an a2AP-inactivating antibody. Higher a2AP levels were correlated with greater ischemic brain injury (rs=0.88, P<0.001), brain swelling (rs=0.82, P<0.001), and reduced middle cerebral artery thrombus dissolution (rs=-0.93, P<0.001). In contrast, a2AP deficiency enhanced thrombus dissolution, increased cerebral blood flow, reduced brain infarction, and decreased brain swelling. By comparison to tissue plasminogen activator (TPA), a2AP inactivation hours after thromboembolism still reduced brain infarction (P<0.001) and hemorrhage (P<0.05). Microvascular thrombosis, a process that enhances brain ischemia, was markedly reduced in a2AP-deficient or a2AP-inactivated mice compared with TPA-treated mice or mice with increased a2AP levels (all P<0.001). Matrix metalloproteinase-9 expression, which contributes to acute brain injury, was profoundly decreased in a2AP-deficient or a2AP-inactivated mice versus TPA-treated mice or mice with increased a2AP levels (all P<0.001). a2AP inactivation markedly reduced stroke mortality versus TPA (P<0.0001).

CONCLUSIONS

a2AP has profound, dose-related effects on ischemic brain injury, swelling, hemorrhage, and survival after cerebral thromboembolism. By comparison to TPA, the protective effects of a2AP deficiency or inactivation seem to be mediated through reductions in microvascular thrombosis and matrix metalloproteinase-9 expression.

Reversing the deleterious effects of α2-antiplasmin on tissue plasminogen activator therapy improves outcomes in experimental ischemic stroke

High blood levels of α2-antiplasmin have been associated with failed tissue plasminogen activator (TPA) therapy for ischemic stroke. Yet, other data suggests that α2-antiplasmin may be protective in stroke, because it defends against bleeding and excitotoxicity. To address this paradox, we examined the effects of high α2-antiplasmin levels and α2-antiplasmin inactivation in mice treated with TPA 0.5-2.5h after middle cerebral artery (MCA) thromboembolism. Brain infarction, swelling, hemorrhage, blood brain barrier breakdown and neuronal apoptosis were measured by a blinded observer. Thrombus dissolution was determined by gamma counting. During TPA treatment, high α2-antiplasmin blood levels increased brain infarction (2.2-fold) and swelling (3.7-fold), but decreased MCA thrombus dissolution. Conversely, α2-antiplasmin inactivation during TPA treatment reduced brain infarction, hemorrhage and swelling, but increased MCA thrombus dissolution. Inactivation of α2-antiplasmin during TPA treatment reduced neuronal apoptosis and blood brain barrier breakdown. Inactivation of α2-antiplasmin also reduced short-term mortality. Taken together these data show that α2-antiplasmin opposes the effects of TPA therapy and contributes to enhanced brain injury after experimental thromboembolic stroke. Conversely, α2-antiplasmin inactivation during TPA treatment improves thrombus dissolution and reduces brain infarction, swelling and hemorrhage. Consistent with clinical observations, these data suggest that α2-antiplasmin exerts deleterious effects that reduce the efficacy and safety of TPA therapy for ischemic stroke.

Endothelial markers are associated with thrombolysis resistance in acute stroke patients

BACKGROUND AND PURPOSE

The endothelium is crucial in maintaining the haemostatic balance between pro- and anti-thrombotic factors. In this pilot study, the association of endothelial biomarkers with arterial recanalization and clinical outcome in the setting of acute ischaemic stroke (AIS) was evaluated amongst patients treated with recombinant tissue plasminogen activator (rt-PA).

METHODS

Sixty-four AIS patients treated with rt-PA were prospectively recruited. Blood was collected before thrombolysis and analysed for von Willebrand factor (vWF), soluble thrombomodulin (sTM) and soluble endothelial protein C receptor (sEPCR). Complete recanalization was defined by a Thrombolysis in Myocardial Infarction Score of 3. Favourable clinical outcome was defined by a modified Rankin Score of 0-2 at 90 days.

RESULTS

Amongst the 64 patients, 31 had no documented occlusion, 19 had persistent occlusion and 14 had complete recanalization. After adjustment for confounding factors, these patients presented lower sTM and sEPCR levels than patients with persistent occlusion (median sTM, 21 vs. 48 ng/ml, P = 0.008; median sEPCR, 78 vs. 114 ng/ml, P = 0.018), but similar levels compared with patients without occlusion. vWF levels did not differ between groups. None of these biomarkers was significantly associated with favourable outcome.

CONCLUSIONS

Recanalization after thrombolytic therapy is associated with low sTM and sEPCR levels but not with vWF levels. If corroborated in further larger studies, these findings could be helpful in the identification of patients resistant to rt-PA thrombolysis who could benefit from a modified recanalization therapy.

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.

Biomarkers for stroke

Background

Major stroke clinical trials have failed during the past decades. The failures suggest the presence of heterogeneity among stroke patients. Biomarkers refer to indicators found in the blood, other body fluids or tissues that predicts physiologic or disease states, increased disease risk, or pharmacologic responses to a therapeutic intervention. Stroke biomarkers could be used as a guiding tool for more effective personalized therapy.

Main Contents

Three aspects of stroke biomarkers are explored in detail. First, the possible role of biomarkers in patients with stroke is discussed. Second, the limitations of conventional biomarkers (especially protein biomarkers) in the area of stroke research are presented with the reasons. Lastly, various types of biomarkers including traditional and novel genetic, microvesicle, and metabolomics-associated biomarkers are introduced with their advantages and disadvantages. We especially focus on the importance of comprehensive approaches using a variety of stroke biomarkers.

Conclusion

Although biomarkers are not recommended in practice guidelines for use in the diagnosis or treatment of stroke, many efforts have been made to overcome the limitations of biomarkers. The studies reviewed herein suggest that comprehensive analysis of different types of stroke biomarkers will improve the understanding of individual pathophysiologies and further promote the development of screening tools for of high-risk patients, and predicting models of stroke outcome and rational stroke therapy tailored to the characteristics of each case.

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.

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.

Update on the Serum Biomarkers and Genetic Factors Associated with Safety and Efficacy of rt-PA Treatment in Acute Stroke Patients

An accurate understanding of the mechanisms underlying an individual's response to rt-PA treatment is critical to improve stroke patients' management. We thus reviewed the literature in order to identify biochemical and genetic factors that have been associated with safety and efficacy of rt-PA administration after stroke.

Blood markers for the prognosis of ischemic stroke: a systematic review

BACKGROUND AND PURPOSE

The performance of validated prognostic clinical models in acute ischemic stroke might be improved by addition of data on blood biomarkers.

METHODS

We searched Medline and EMBASE from 1966 to January 2007 for studies of blood markers in patients with ischemic stroke and an assessment of outcome (death, disability, or handicap). We adopted several strategies to reduce bias.

RESULTS

Studies were generally small (median number of subjects, 85; interquartile range, 49 to 184). Few had evidence of a sample size calculation (7 of 82 [9%]) or reported blinding to whether patients had stroke (21 of 82 [26%]). Of the 66 studies reporting a measure of association, 10 did not adjust for age or stroke severity, 14 adjusted for age, 7 adjusted for severity, and 35 adjusted for both; 30% (20 of 66) used a data-dependent threshold to predict good or bad outcome. There was evidence of within-study reporting bias and publication bias. Cardiac markers showed the most consistent association with poor outcome.

CONCLUSIONS

Blood biomarkers might provide useful information to improve the prediction of outcome after acute ischemic stroke. However, this review showed that many studies were subject to bias. Although some markers had some predictive ability, none of the studies was able to demonstrate that the biomarker added predictive power to a validated clinical model. The clinical usefulness of blood biomarkers for predicting prognosis in the setting of ischemic stroke has yet to be established.

Change in hemostatic markers after recombinant tissue-type plasminogen activator is not associated with the chance of recanalization

BACKGROUND AND PURPOSE

We evaluated the association between recombinant tissue-type plasminogen activator recanalization and change in hemostatic markers.

METHODS

We studied 40 patients. Recanalization was measured with transcranial Doppler. We evaluated the change in markers of coagulation (fibrinogen) and fibrinolysis (thrombin activatable fibrinolysis inhibitor and alpha(2)-antiplasmin) in patients with ischemic stroke treated with recombinant tissue-type plasminogen activator. Samples were obtained before and 90 minutes after recombinant tissue-type plasminogen activator infusion.

RESULTS

The analyses (2-way analysis of variance) showed that the change in the value of each marker did not depend on the vascular patency status.

CONCLUSIONS

From a practical point of view, the measurement of these hemostatic markers is probably not useful for predicting recanalization.

Applicability of biomarkers in ischemic stroke

Cerebral ischemia results in the activation of a cascade of molecular events as a result of which several substances with the potential characteristics of biomarkers are released into the peripheral blood. Although still in the research phase, the analysis of these biomarkers in the serum has proved to be useful for stroke diagnosis, as well as for the prediction of the evolution of the ischemic lesion and the clinical prognosis. In fact, the feasibility and applicability of a panel of biomarkers for the diagnosis of stroke has recently been tested. Biomarkers of excitotoxicity, inflammation and oxidative stress have been demonstrated as being useful in the prediction of ischemic lesion enlargement and secondary neurological deterioration. On the other hand, biomarkers of endothelial damage have been shown to be especially helpful in the prediction of hemorrhagic transformation of the ischemic lesion, both spontaneously and after the administration of thrombolytic therapy, as well as in the prediction of brain edema with the secondary development of malignant middle-cerebral-artery infarction. Moreover, coagulation and fibrinolytic-cascade markers have been reported as being correlated with the recanalization rate after the administration of thrombolysis, and they might therefore be useful in estimating the effectiveness of thrombolytic therapy. However, for these biomarkers to become applicable to routine clinical practice, faster tests to perform the analyses are required and further studies must be undertaken to validate and generalize the results.

Vasculite cutânea de pequenos vasos: etiologia, patogênese, classificação e critérios diagnósticos - Parte I

Vasculite é a inflamação da parede dos vasos. Pode variar em gravidade desde doença autolimitada de um único órgão até doença grave com risco de morte por falência de múltiplos órgãos. Existem várias causas, embora só se apresente por poucos padrões histológicos de inflamação vascular. Vasos de qualquer tipo e em qualquer órgão podem ser afetados, resultando em ampla variedade de sinais e sintomas. Diferentes vasculites com apresentações clínicas indistinguíveis têm evolução e tratamento muito diferentes. Essa condição representa desafio para o médico, incluindo classificação, diagnóstico, exames laboratoriais pertinentes, tratamento e seguimento adequado. Neste artigo são revistos a classificação, a etiologia, a patogênese e os critérios diagnósticos das vasculites cutâneas.

Influence of thrombin-activatable fibrinolysis inhibitor and plasminogen activator inhibitor-1 gene polymorphisms on tissue-type plasminogen activator-induced recanalization in ischemic stroke patients

OBJECTIVE

Endogenous resistance to tissue-type plasminogen activator (t-PA) might decrease the benefit of thrombolysis-induced recanalization. Thrombin-activatable fibrinolysis inhibitor (TAFI) and plasminogen activator inhibitor-1 (PAI-1) are fibrinolysis inhibitors. TAFI removes residues from partially degraded fibrin that in turn eliminates plasminogen binding sites; PAI-1 directly inhibits the activity of t-PA. We aimed to study whether the presence of two common functional polymorphisms of the TAFI and PAI-1 genes influence rates of recanalization of the middle cerebral artery (MCA) among t-PA-treated stroke patients.

METHODS AND RESULTS

TAFI and PAI-1 polymorphism determinations were performed by restriction fragment length polymorphism mapping and conventional sequencing in 139 patients with strokes involving the MCA and who received t-PA within 3 h. Recanalization was diagnosed by means of transcranial Doppler. No association was found between PAI-1 4 G/5 G polymorphism and recanalization rate. Dyslipidemia and TAFI Thr325Ile polymorphism were the main variables associated with recanalization resistance by the end of t-PA infusion: odds ratio (OR) 4.1 [95% confidence interval (95% CI) 1.6-10.8, P = 0.003] and OR 5.6 (95% CI 1.2-20, P = 0.031), respectively. The combination of the two polymorphisms doubled the risk of absence of recanalization: OR 11.1 (95% CI 1.4-89.8, P = 0.025).

CONCLUSIONS

Polymorphic fibrinolysis inhibitor genes influence t-PA-induced recanalization resistance in ischemic stroke patients, especially when coexisting in the same patient. Efforts to individualize thrombolytic treatments are required.

Biochemical and bioimaging markers for risk assessment and diagnosis in major cardiovascular diseases: a road to integration of complementary diagnostic tools

This report from the first International Course on Integrated Biomarkers, Biochemical and Bioimaging Endpoints in Cardiovascular Diagnosis, Prevention, Therapy and Drug Development provides the basis for optimizing diagnostic, prognostic and therapeutic information in four areas of cardiovascular medicine: primary prevention of cardiovascular diseases, acute coronary syndromes, heart failure and stroke. Risk stratification and treatment strategies can be refined and enhanced through integration of bioimaging and biochemical markers to characterize sub-clinical and clinical atherosclerosis. For the integrative approach to be useful, each of the biomarkers must be validated and cost-effective. Clinical decision is the primary level of integration and is based on clinical evaluation and the use of a combination of bioimaging and biochemical markers. The decision to initiate preventive or therapeutic intervention must take into account the factors affecting the levels of expression of the biomarker and the potential input the biomarker has on metabolic processes or modulation of other biomarkers. The optimal approach to intervention must take into consideration the risk-benefit and cost-effectiveness ratios.

Hemostatic Activation and Outcome After Recombinant Tissue Plasminogen Activator Therapy for Acute Ischemic Stroke

BACKGROUND AND PURPOSE

Early thrombolytic therapy with intravenous recombinant tissue plasminogen activator (rtPA) improves clinical outcome in acute ischemic stroke (AIS), but impaired endogenous fibrinolysis, thrombin generation, and vascular injury may hamper the efficacy of thrombolysis. We investigated in an exploratory, post hoc analysis the relationship between hemostatic markers and clinical outcomes among patients included in the National Institute of Neurological Disorders and Stroke (NINDS) rtPA Stroke Study.

METHODS

Tissue plasminogen activator (tPA) antigen, thrombin-antithrombin complex (TAT), soluble thrombomodulin, and fibrinogen levels were measured in patients with AIS included in the NINDS rtPA Stroke Study from plasma samples collected at baseline, at 2 hours after treatment, and after 24 hours.

RESULTS

TAT and tPA antigen levels peaked at 2 hours selectively in the rtPA treatment group, whereas fibrinogen levels dropped at 2 hours and remained low after 24 hours (P<0.0001 for interaction effects between time and treatment). At 24 hours, higher levels of tPA antigen were associated with a lower chance of favorable outcome (odds ratio [OR]=0.34; 95% CI, 0.14 to 0.82) selectively in the rtPA group, and higher levels of TAT (OR=1.72; 95% CI, 1.26 to 2.34) in the entire cohort and of thrombomodulin selectively in the rtPA group (OR=4.45; 95% CI, 1.26 to 15.67) were associated with higher 3-month mortality.

CONCLUSIONS

Hemostatic activation after AIS appears to be independently associated with clinical outcome in patients treated with rtPA. However, because we have tested for multiple associations, some may have been identified by chance alone and require further confirmatory studies. On the basis of this exploratory analysis, there is a rationale to investigate the safety and efficacy of protocols in which rtPA is complemented by agents that are antithrombotic and enhance fibrinolysis.