A prospective study of plasma fibrinogen levels and the risk of stroke among participants in the bezafibrate infarction prevention study

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.

Adeno-Associated Virus-Mediated Gain-of-Function mPCSK9 Expression in the Mouse Induces Hypercholesterolemia, Monocytosis, Neutrophilia, and a Hypercoagulative State

Hypercholesterolemia has previously been induced in the mouse by a single intravenous injection of adeno-associated virus (AAV)-based vector harboring gain-of-function pro-protein convertase subtilisin/kexin type 9. Despite the recent emergence of the PCSK9-AAV model, the profile of hematological and coagulation parameters associated with it has yet to be characterized. We injected 1.0 × 10¹¹ viral particles of mPCSK9-AAV or control AAV into juvenile male C57BL/6N mice and fed them with either a Western-type high-fat diet (HFD) or standard diet over the course of 3 weeks. mPCSK9-AAV mice on HFD exhibited greater plasma PCSK9 concentration and lower low-density lipoprotein levels, concomitant with increased total cholesterol and non-high-density lipoprotein (non-HDL)-cholesterol concentrations, and lower HDL-cholesterol concentrations than control mice. Furthermore, mPCSK9-AAV-injected mice on HFD exhibited no signs of atherosclerosis at 3 weeks after the AAV injection. Hypercholesterolemia was associated with a thromboinflammatory phenotype, as neutrophil levels, monocyte levels, and neutrophil-to-lymphocyte ratios were higher and activated partial thromboplastin times (aPTTs) was lower in HFD-fed mPCSK9-AAV mice. Therefore, the mPCSK9-AAV is a suitable model of hypercholesterolemia to examine the role of thromboinflammatory processes in the pathogenesis of cardiovascular and cerebrovascular diseases.

Fibrinogen is an Independent Risk Factor for White Matter Hyperintensities in CADASIL but not in Sporadic Cerebral Small Vessel Disease Patients

The relationship between fibrinogen and white matter hyperintensities (WMHs) are inconsistent. Whether there are different relationships between WMHs and fibrinogen in disparate subtypes of cerebral small vessel disease (CSVD) remains unknown. Here, we investigated the roles of plasma fibrinogen in sporadic CSVD (sCSVD) and Cerebral Autosomal Dominant Arteriopathy with Subcortical Infarcts and Leukoencephalopathy (CADASIL) patients. We performed a cross-sectional study that included 74 CSVD patients (19 CADASIL and 55 sporadic) and 74 age- and gender-matched healthy controls (HCs). Plasma fibrinogen was determined, and the severity of WMHs in CSVD patients was rated according to Fazekas scales. Univariate analysis and ordinal logistic regression were performed to evaluate the relationship between fibrinogen and the severity of WMHs in CSVD. Both CADASIL and sCSVD patients showed significantly higher plasma fibrinogen levels than HCs. No significant difference in the plasma fibrinogen level was observed between CADASIL and sCSVD. Univariate analysis and ordinal logistic regression indicated that fibrinogen is an independent risk factor for the severity of WMHs in CADASIL patients (odds ratio [OR] =1.064; 95% Confidence interval (CI, 1.004-1.127); p =0.037). However, age (odds ratio [OR] =1.093; 95% CI (1.033-1.156); P = 0.002), but not fibrinogen (odds ratio [OR] =1.004; 95% CI (0.997-1.011); P=0.262), is an independent risk factor for the severity of WMHs in sCSVD patients. Our results suggest that high levels of plasma fibrinogen are associated with the severity of WMHs in CADASIL but not in sCSVD patients, indicating that the role of fibrinogen may be different in disparate subtypes of CSVD. A better understanding of fibrinogen may yield insights into the pathogenesis of CSVD.

FM Combined With NIHSS Score Contributes to Early AIS Diagnosis and Differential Diagnosis of Cardiogenic and Non-Cardiogenic AIS

A growing researchers have suggested that fibrin monomer (FM) plays an important role in early diagnosis of thrombotic diseases. We explored the application of FM in the diagnosis and classification of acute ischemic stroke (AIS). The differences in FM, D-dimer, and NIHSS scores between different TOAST (Trial of ORG 10172 in Acute Stroke Treatment) types were analyzed with one-way ANOVA; the correlation between FM, D-dimer and NIHSS score in patients with different TOAST classification was analyzed by Pearson linear correlation. The ROC curve was utilized to analyze the diagnostic performance. 1. FM was more effective in diagnosing patients with AIS than D-dimer. 2. The FM level in cardiogenic AIS was significantly different from that in non-cardiogenic patients (P < 0.05); the NIHSS score in cardiogenic stroke was significantly higher than in atherosclerotic and unexplained stroke group. Whereas, no statistical difference was observed in the D-dimer level between these groups (P > 0.05). 3. The correlation between FM and NIHSS scores in the cardiogenic (r = 0.3832) and atherosclerotic (r = 0.3144) groups was statistically significant. 4. FM exhibited the highest diagnostic efficacy for cardiogenic AIS; furthermore, FM combined with the NIHSS score was more conducive to the differential diagnosis of cardiogenic and non-cardiogenic AIS. FM detection contributes to the early diagnosis of AIS, and is important for the differential diagnosis of different TOAST types of AIS. Moreover, FM combined with the NIHSS score is valuable in the differential diagnosis of cardiogenic and non-cardiogenic AIS.

Fibrinogen and risk of dementia: A systematic review and meta-analysis

BACKGROUND

The aim of this meta-analysis is to evaluate the association of fibrinogen with risk of dementia and its subtypes.

METHODS

Embase, Pubmed and Web of Science were retrieved systematically up to February 2019. Standard mean difference (SMD) with 95 % confidence intervals was estimated using random-effects models.

RESULTS

Sixteen studies involving 3,649 participants were summarized. Patients with all-cause dementia exhibited higher fibrinogen levels than those in non-dementia controls (SMD = 0.90 [0.43;1.36] p < 0.01). Further subgroup analysis revealed a positive association of fibrinogen with vascular dementia (VaD) (SMD = 1.11 [0.45;1.78] p < 0.01) rather than Alzheimer's disease (AD) (SMD = 0.01 [-0.17;0.19]) p = 0.92) and Parkinson's disease dementia (PDD) (SMD = 0.35 [-0.23;0.93] p = 0.24). This correlation was significant in Europeans (SMD = 0.92 [0.34;1.49] p < 0.01), but probably not in Asian based populations (SMD = 1.04 [-0.09;2.17] p = 0.07), and gradually declined with advancing age (60 ≤ age < 70: SMD = 1.22 [0.38;2.06] p < 0.01; 70 ≤ age < 80: SMD = 0.29 [0.04;0.53] p = 0.02; age ≥ 80: SMD = 0.01 [-0.12;0.15] p = 0.84).

CONCLUSIONS

Plasma fibrinogen is a potential risk factor for all-cause dementia and VaD under the age of 80, and is more obvious in cohorts with people of European descent.

Secondary Prevention of Ischemic Cerebrovascular Disease. What Is the Evidence?

Patients who had a transient ischemic attack or stroke are at increased risk of experiencing recurrent cerebrovascular events. For this reason, secondary prevention of ischemic cerebrovascular disease is essential. Several modifiable, lifestyle-associated risk factors have been implicated, such as physical activity, smoking, and alcohol consumption. Established and emerging vascular risk factors are associated with an increased risk of stroke. Pharmacologic treatment, including the use of antiplatelet, antihypertensive, and lipid-lowering agents, has also been shown to reduce the risk of secondary cerebrovascular events. Surgical intervention, either open or endovascular, may be the preferred therapeutic option in well-defined subsets of patients. It is important to establish specific measures for the early detection and prevention of recurrent cerebrovascular disease. Therefore, further research and greater awareness in this field are needed.

The Relationship Between Circulating Fibrinogen and Lipoprotein (a) Levels in Patients With Primary Dyslipidemia

The correlation between 2 predictors of vascular events, plasma fibrinogen and serum lipoprotein (a), was evaluated in patients referred to a specialist clinic because of primary hyperlipidemia. A significant correlation existed between fibrinogen and lipoprotein (a) in nonsmokers but not in smokers. Plasma fibrinogen concentration correlated positively and significantly with serum lipoprotein (a) levels in men nonsmokers without cardiovascular disease and in women nonsmokers with cardiovascular disease. Nonsmoker women without cardiovascular disease had significantly higher plasma fibrinogen (3.63 g/L versus 3.07 g/L, P < .0001) than the corresponding men. Nonsmoker women with and without cardiovascular disease had significantly higher lipoprotein (a) levels than the corresponding groups of men (0.36 versus 0.18 g/L; P = .0015 and 0.40 versus 0.26 g/L; P = .008), respectively. The relationship between fibrinogen and lipoprotein (a) levels alters markedly depending on the population selected. This relationship is influenced by gender, the presence of cardiovascular disease and smoking status.

Circulating biomarkers for predicting cardiovascular disease risk; a systematic review and comprehensive overview of meta-analyses

BACKGROUND

Cardiovascular disease is one of the major causes of death worldwide. Assessing the risk for cardiovascular disease is an important aspect in clinical decision making and setting a therapeutic strategy, and the use of serological biomarkers may improve this. Despite an overwhelming number of studies and meta-analyses on biomarkers and cardiovascular disease, there are no comprehensive studies comparing the relevance of each biomarker. We performed a systematic review of meta-analyses on levels of serological biomarkers for atherothrombosis to compare the relevance of the most commonly studied biomarkers.

METHODS AND FINDINGS

Medline and Embase were screened on search terms that were related to "arterial ischemic events" and "meta-analyses". The meta-analyses were sorted by patient groups without pre-existing cardiovascular disease, with cardiovascular disease and heterogeneous groups concerning general populations, groups with and without cardiovascular disease, or miscellaneous. These were subsequently sorted by end-point for cardiovascular disease or stroke and summarized in tables. We have identified 85 relevant full text articles, with 214 meta-analyses. Markers for primary cardiovascular events include, from high to low result: C-reactive protein, fibrinogen, cholesterol, apolipoprotein B, the apolipoprotein A/apolipoprotein B ratio, high density lipoprotein, and vitamin D. Markers for secondary cardiovascular events include, from high to low result: cardiac troponins I and T, C-reactive protein, serum creatinine, and cystatin C. For primary stroke, fibrinogen and serum uric acid are strong risk markers. Limitations reside in that there is no acknowledged search strategy for prognostic studies or meta-analyses.

CONCLUSIONS

For primary cardiovascular events, markers with strong predictive potential are mainly associated with lipids. For secondary cardiovascular events, markers are more associated with ischemia. Fibrinogen is a strong predictor for primary stroke.

Circulating biomarkers for predicting cardiovascular disease risk; a systematic review and comprehensive overview of meta-analyses

BACKGROUND

Cardiovascular disease is one of the major causes of death worldwide. Assessing the risk for cardiovascular disease is an important aspect in clinical decision making and setting a therapeutic strategy, and the use of serological biomarkers may improve this. Despite an overwhelming number of studies and meta-analyses on biomarkers and cardiovascular disease, there are no comprehensive studies comparing the relevance of each biomarker. We performed a systematic review of meta-analyses on levels of serological biomarkers for atherothrombosis to compare the relevance of the most commonly studied biomarkers.

METHODS AND FINDINGS

Medline and Embase were screened on search terms that were related to "arterial ischemic events" and "meta-analyses". The meta-analyses were sorted by patient groups without pre-existing cardiovascular disease, with cardiovascular disease and heterogeneous groups concerning general populations, groups with and without cardiovascular disease, or miscellaneous. These were subsequently sorted by end-point for cardiovascular disease or stroke and summarized in tables. We have identified 85 relevant full text articles, with 214 meta-analyses. Markers for primary cardiovascular events include, from high to low result: C-reactive protein, fibrinogen, cholesterol, apolipoprotein B, the apolipoprotein A/apolipoprotein B ratio, high density lipoprotein, and vitamin D. Markers for secondary cardiovascular events include, from high to low result: cardiac troponins I and T, C-reactive protein, serum creatinine, and cystatin C. For primary stroke, fibrinogen and serum uric acid are strong risk markers. Limitations reside in that there is no acknowledged search strategy for prognostic studies or meta-analyses.

CONCLUSIONS

For primary cardiovascular events, markers with strong predictive potential are mainly associated with lipids. For secondary cardiovascular events, markers are more associated with ischemia. Fibrinogen is a strong predictor for primary stroke.

Antithrombotic effect of a novel protein from Fusarium sp. CPCC 480097 in a rat model of artery-vein bypass thrombosis

CONTEXT

The incidence and mortality of thrombotic disorders are rapidly increasing throughout the world. Therefore, attempts have been made to develop new anticoagulant and antithrombotic drugs. Our previous studies showed that a novel protein, named Fu-P, had fibrinogenolytic activity and much higher fibrinolytic activity on the fibrin plate than urokinase in vitro.

OBJECTIVE

The antithrombotic activities of Fu-P in vivo are investigated here for the first time.

MATERIALS AND METHODS

Antithrombotic activity of Fu-P was studied in a rat model of artery-vein bypass thrombosis. The anticoagulant activity of Fu-P was measured by clotting assay of activated partial thrombinplastin time and prothrombin time (PT). The effects of Fu-P on the factor Xa and thrombin were assayed using the chromogenic substrate S-2765 and S-2238.

RESULTS

Intravenous injection of Fu-P produced a 58.4% inhibition ratio of thrombus formation at 0.1 mg/kg body weight, while heparin produced 42.5% inhibition ratio of thrombus formation at 0.6 mg/kg body weight. Fu-P significantly prolonged fibrinogen clotting time, activated partial thrombinplastin time and thrombin time, which also prolonged PT. The inhibition assay of the coagulant factors using chromogenic substrates S-2238 and S-2765 showed that Fu-P was not the inhibitor of the thrombin and Xa.

DISCUSSION AND CONCLUSION

These findings demonstrated that the novel fibrinolytic enzyme (Fu-P) might also be used as a natural agent for thrombolytic therapy or thrombosis prevention.

Study of hemostatic biomarkers in acute ischemic stroke by clinical subtype

BACKGROUND

We studied the usefulness of hemostatic biomarkers in assessing the pathology of thrombus formation, subtype diagnosis, prognosis in the acute phase of cerebral infarction, and differences between various hemostatic biomarkers.

METHODS

Our study included 69 patients with acute cerebral infarction who had been hospitalized within 2 days of stroke onset. Fibrin monomer complex (FMC), soluble fibrin (SF), D-dimer, thrombin-antithrombin III complex, fibrinogen, antithrombin III, and fibrin/fibrinogen degradation products (FDPs) were assayed as hemostatic biomarkers on days 1, 2, 3, and 7 of hospitalization.

RESULTS

In the cardioembolic (CE) stroke group, FMC and SF levels were significantly higher on days 1 and 2 of hospitalization, and D-dimer levels were significantly higher on day 1 of hospitalization, compared to the noncardioembolic (non-CE) stroke group. FDP levels were significantly higher at all times in the CE group compared to the non-CE group. Neither the National Institute of Health Stroke Scale (NIHSS) used during hospitalization nor the modified Rankin Scale (mRS) used at discharge found any significant correlations to hemostatic biomarkers, but the NIHSS score during hospitalization was significantly higher in the CE group than in the non-CE group.

CONCLUSIONS

Measurements of hemostatic biomarkers, such as FMC, SF, and D-dimer on the early stage of cerebral infarction are useful for distinguishing between CE and non-CE stroke.

Fibrinogen gene variation and ischemic stroke

BACKGROUND

Plasma fibrinogen level and fibrin clot structure are heritable traits that may be of importance in the pathogenesis of ischemic stroke.

OBJECTIVES

To investigate associations between variation in the fibrinogen gamma (FGG), alpha (FGA) and beta (FGB) genes, fibrinogen level, and ischemic stroke.

METHODS

The Sahlgrenska Academy Study on Ischemic Stroke comprises 600 cases and 600 matched population controls. Stroke subtypes were defined according to TOAST criteria. Plasma fibrinogen level was measured by an automated clot-rate assay. Eight tagging single nucleotide polymorphisms (SNPs) were selected to capture genetic variation in the FGA, FGG, and FGB genes.

RESULTS

Plasma fibrinogen was independently associated with overall ischemic stroke and all subtypes, both in the acute stage (P < 0.001) and at three-month follow-up (P < 0.05). SNPs belonged to two haplotype blocks, one containing the FGB gene and the other the FGG and FGA genes. FGB haplotypes were associated with fibrinogen level (P < 0.01), but not with ischemic stroke. In contrast, FGG/FGA haplotypes showed independent association to ischemic stroke but not to fibrinogen level. In an additive model with the most common FGG/FGA haplotype (A1) as reference, the adjusted odds ratios of ischemic stroke were 1.4 [95% confidence interval (95% CI) 1.1-1.8], P < 0.01, 1.4 (95% CI 1.0-1.8), P < 0.05, and 1.5 (95% CI 1.0-2.1), P < 0.05 for the A2, A3, and A4 FGG/FGA haplotypes, respectively.

CONCLUSION

FGG/FGA haplotypes show association to ischemic stroke. This association is independent of fibrinogen level, thus suggesting that the association between ischemic stroke and variation at the FGG/FGA genes is mediated by qualitative rather than quantitative effects on fibrin(ogen).

Effect of age and glycaemic control on the association between fibrinogen and risk of acute coronary events after transient ischaemic attack or stroke

BACKGROUND

Fibrinogen is an independent risk factor for acute vascular events, but there is uncertainty as to whether it is causal. One potential causal mechanism is the formation of low permeability fibrin clot in association with raised fibrinogen. We hypothesised that if this effect of fibrinogen were causally related to risk of vascular events, the risk relationship would be affected by the two other factors that affect fibrin clot permeability - age and glycaemic control.

METHODS

We studied the relationship between fibrinogen and risk of incident coronary events by age and baseline glucose levels in pooled data from three cohorts of patients with known cerebrovascular disease (UK-TIA Aspirin trial; Dutch TIA trial; Oxford TIA Study) during 23,272 patient-years of follow-up.

RESULTS

Risk of coronary events increased linearly with fibrinogen, but there was a significant interaction with age (p = 0.01 across tertiles of age), with the association being strongest for individuals aged <60 years (upper fibrinogen quintile hazard ratio = 3.95, 95% CI = 2.67-5.85, p < 0.0001). The risk relation was diminished in individuals with impaired glucose tolerance or diabetes. The effects of age and glycaemic control were independent, such that there was an almost fivefold increase in risk across quintiles of fibrinogen in patients aged <60 years with below median normal glucose levels (upper quintile hazard ratio = 4.90, 95% CI = 2.79-8.58, p < 0.0001).

CONCLUSIONS

The effect of age and glycaemic control on the relationship between fibrinogen and risk of acute coronary events supports the hypothesis of a causal effect of fibrinogen mediated via the permeability of fibrin clot.

Feasibility of treating hyperfibrinogenemia with intermittently administered batroxobin in patients with ischemic stroke/transient ischemic attack for secondary prevention

This study evaluated the safety and efficacy of batroxobin in treating hyperfibrinogenemia for secondary stroke prevention. Patients with ischemic stroke or transient ischemic attack (TIA) were measured for plasma fibrinogen levels. Selected participants had concomitant hyperfibrinogenemia (plasma fibrinogen > or = 3.0 g/l). Patients enrolled between 1 July 2003 and 31 December 2004 were treated with batroxobin; patients enrolled between 1 January 2002 and 30 June 2003 were treated without batroxobin. Batroxobin was administered intermittently via intravenous injection at 3-monthly intervals. Patients in both groups were followed for 1 year. Any cerebrovascular events and suspected adverse events were recorded. In total, 112 ischemic stroke/TIA patients with concomitant hyperfibrinogenemia were enrolled, 52 being treated with batroxobin and 60 without batroxobin. Six patients (11.5%) with batroxobin and 16 patients (26.7%) without batroxobin had recurrent cerebral ischemic events during follow-up. Stroke/TIA recurrence in patients without batroxobin was higher than that in patients with batroxobin (P < 0.05). Two patients with batroxobin and two patients without batroxobin developed hemorrhagic stroke during follow-up. There were five deaths (9.6%) in the batroxobin group, and seven deaths (11.7%) in the nonbatroxobin group during follow-up (P > 0.05). Intermittent intravenous injection of batroxobin can efficiently reduce the risk for stroke/TIA recurrence in patients with concomitant hyperfibrinogenemia.

Plasma fibrinogen, ambulatory blood pressure, and silent cerebrovascular lesions: the Ohasama study

OBJECTIVE

Twenty-four-hour ambulatory blood pressure (24-hour ABP) values are considered a powerful predictor of stroke. Silent cerebrovascular lesions are associated with an increased risk of stroke. Because fibrinogen is a major determinant of plasma viscosity, an elevated fibrinogen level might also be associated with stroke risk. We evaluated the association of 24-hour ABP and plasma fibrinogen levels with the risk of silent cerebrovascular lesions (white matter hyperintensity and lacunar infarct) detected by MRI.

METHODS AND RESULTS

The study cohort comprised 958 individuals from the general population of Ohasama, a rural Japanese community. Multiple logistic regression analysis adjusted for age, sex, smoking and drinking status, use of antihypertensive medication, body mass index, 24-hour ABP, and a history of hypercholesterolemia, diabetes mellitus, and atrial fibrillation demonstrated that each 1-SD increase in fibrinogen level was associated with a significantly increased risk of silent cerebrovascular lesions (odds ratio, 1.26; P=0.001). The 24-hour ABP was also significantly and independently associated with the risk of silent cerebrovascular lesions. Even when 24-hour ABP values were within normal range (<135/80 mm Hg), elevated fibrinogen levels were associated with an increased risk of silent cerebrovascular lesions. Fibrinogen and 24-hour BP had additive effects on silent cerebrovascular lesions.

CONCLUSION

The 24-hour ABP and plasma fibrinogen levels were closely and independently associated with the risk of silent cerebrovascular lesions including white matter hyperintensity and lacunar infarct.

Fenofibrate Reduces Atherogenesis in ApoE*3Leiden Mice

OBJECTIVE

To demonstrate, quantify, and mechanistically dissect antiatherosclerotic effects of fenofibrate besides lowering plasma cholesterol per se.

METHODS AND RESULTS

ApoE*3Leiden transgenic mice received either a high-cholesterol diet (HC) or HC containing fenofibrate (HC+FF) resulting in 52% plasma cholesterol-lowering. In a separate low-cholesterol diet (LC) control group, plasma cholesterol was adjusted to the level achieved in the HC+FF group. Low plasma cholesterol alone (assessed in LC) resulted in reduced atherosclerosis (lesion area, number and severity) and moderately decreased plasma serum amyloid-A (SAA) concentrations. Compared with LC, fenofibrate additively reduced lesion area, number and severity, and the total aortic plaque load. This additional effect in HC+FF was paralleled by an extra reduction of aortic inflammation (macrophage content; monocyte adhesion; intercellular adhesion molecule-1 [ICAM-1], soluble vascular cell adhesion molecule-1, granulocyte-macrophage colony-stimulating factor (GM-CSF), MCP-1, and NF-kappaB expression), systemic inflammation (plasma SAA and fibrinogen levels), and by an upregulation of plasma apoE levels. Also, enhanced expression of ABC-A1 and SR-B1 in aortic macrophages may contribute to the antiatherosclerotic effect of fenofibrate by promoting cholesterol efflux.

CONCLUSIONS

Fenofibrate reduces atherosclerosis more than can be explained by lowering total plasma cholesterol per se. Impaired recruitment of monocytes/macrophages, reduced vascular and systemic inflammation, and stimulation of cholesterol efflux may all contribute to these beneficial effect of fenofibrate.

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.

C-reactive protein as a predictor of incident ischemic stroke among patients with preexisting cardiovascular disease

BACKGROUND AND PURPOSE

C-reactive protein (CRP) has emerged as an important predictor of cardiovascular disease, but there are few prospective data on its association with risk of ischemic stroke in patients at high risk.

METHODS

We examined the association between CRP levels and subsequent risk of incident ischemic stroke among 2979 patients with stable coronary heart disease included in a controlled clinical trial (Bezafibrate Infarction Prevention) that assessed the efficacy of bezafibrate, a fibric acid derivative, versus placebo for secondary prevention. CRP was measured by a high-sensitivity assay in plasma samples collected before randomization and again at the second follow-up year of an overall mean follow-up of 6.2 years.

RESULTS

Risk of ischemic stroke per 1000 person-years increased from 4.1% for baseline CRP in the lowest tertile (<2.3 mg/L; n=982) to 5.9% for levels at the middle tertile (2.3 to 5.4 mg/L; n=1013) and 10.5% for CRP levels at the upper tertile (>5.4 mg/L; n=984; P<0.001). With adjustment for potential confounders, baseline CRP levels in the top versus bottom tertile were associated with a 2.16-fold increased hazard (95% CI, 1.32 to 3.53) for ischemic stroke, and CRP levels measured after 2 years were associated with a hazard ratio of 2.43 (95% CI, 1.30 to 4.57). The risk of an incident ischemic stroke did not differ between the bezafibrate group compared with the placebo group regardless of baseline CRP levels.

CONCLUSIONS

These findings, based on a large prospective study, demonstrate the risk prediction for incident ischemic stroke conferred by CRP levels in patients at high risk.

Antiplatelet Therapy in Stroke Prevention: Present and Future

White platelet-fibrin thrombi often form on roughened endothelial surfaces and unstable arterial plaques. Agents that reduce the tendency of platelets to aggregate, agglutinate, and secrete and to attach to endothelial surfaces have been explored as agents that prevent brain and heart infarction. Aspirin, ticlopidine, clopidogrel, dipyridamole, cilostazol, and glycoprotein llb/llla inhibitors are all used now and have various different modes of action and functions.

Inflammatory response after acute ischemic stroke

BACKGROUND AND PURPOSE

This study aimed to characterize the time course of inflammatory parameters after acute ischemic stroke.

METHODS

We serially determined high sensitivity C-reactive protein (CRP), fibrinogen, and leukocyte counts at 10 time points between days 1 and 90 after ischemic stroke and in control subjects.

RESULTS

CRP did not significantly change, whereas fibrinogen increased after stroke. At all time points, CRP and fibrinogen were higher than in healthy control subjects, but not risk factor control subjects. The leukocyte count declined after stroke and was significantly elevated as compared to both control groups only on day 1 but not later. NIHSS levels were positively correlated with CRP and fibrinogen at all time points. Larger infarcts were associated with a higher CRP and leukocyte counts on day 90. Treatment with aspirin was associated with lower values for all three inflammatory parameters in the subacute phase after ischemia.

CONCLUSIONS

The course after stroke was different between the parameters of inflammation. Only the leukocytes followed the paradigm of an acute phase response.

A Systematic Comparison of the Quality and Volume of Published Data Available on Novel Risk Factors for Stroke versus Coronary Heart Disease

BACKGROUND

To identify new treatments to prevent stroke, it is important that we have reliable data on potential novel risk factors.

METHODS

We studied seven novel vascular risk factors [apo-lipoprotein (b), C-reactive protein, Chlamydia pneumoniae, fibrin-D dimer, fibrinogen, Helicobacter pylori and lipoprotein (a)] and compared the amount of published data on their relations with ischaemic stroke versus acute coronary events by systematic review of all studies published up to 2003.

RESULTS

From a total of 22,875 abstracts reviewed, 266 eligible studies were identified (167 case-control studies and 99 cohort studies). Two hundred and eleven (79%) studies included coronary events as an outcome for the purpose of a risk factor analysis. In 186 (70%) studies, coronary events were the only outcome that was analysed. Only 73 (27%) studies included stroke or TIA as an outcome event, and only 45 studies (17%) reported risk factor analyses for ischaemic stroke separately. These results were qualitatively consistent across the risk factors studied and the relative lack of data on risk factors for stroke was even greater in prospective cohort studies.

CONCLUSION

Data on novel risk factors for stroke are lacking compared with the equivalent data for acute coronary events, and there are very few data on specific subtypes of ischaemic stroke.

Fibrinogen concentration and risk of ischemic stroke and acute coronary events in 5113 patients with transient ischemic attack and minor ischemic stroke

BACKGROUND AND PURPOSE

Fibrinogen is an independent risk factor for coronary events in population-based studies and in patients with coronary heart disease, but there is uncertainty about prediction of stroke, particularly in secondary prevention.

METHODS

We studied unpublished data from 3 prospective studies of patients with recent transient ischemic attack (TIA) or minor ischemic stroke: the United Kingdom TIA Aspirin (UK-TIA) trial (n=1860); the Dutch TIA trial (n=2960); and the Oxford TIA Study (n=293). By separate and pooled analysis, we used Cox models to determine the relationship between fibrinogen and risk of ischemic stroke and other vascular events during 23,272 patient-years of follow-up and adjusted for other risk factors.

RESULTS

There was no significant heterogeneity in fibrinogen risk associations between studies. Fibrinogen predicted subsequent ischemic stroke, with a pooled hazard ratio (HR) for values above the median of 1.34 (95% CI, 1.13 to 1.60; P=0.001). The association tended to be stronger in patients with nonlacunar (HR=1.42; 95% CI, 1.13 to 1.78; P=0.002) than lacunar syndromes (HR=1.09; 95% CI, 0.80 to 1.49; P=0.58), but was not significantly so (P=0.18). There was no association with hemorrhagic stroke (adjusted HR=1.09; 95% CI, 0.55 to 2.17; P=0.81). Fibrinogen predicted acute coronary events (adjusted HR=1.42; 95% CI, 1.18 to 1.70; P<0.001) and all ischemic vascular events (adjusted HR=1.31; 95% CI, 1.15 to 1.49; P<0.001), but not nonvascular death (adjusted HR=1.24; 95% CI, 0.90 to 1.70; P=0.19).

CONCLUSIONS

In patients with a previous TIA or ischemic stroke, risks of recurrent ischemic stroke and acute coronary events increase linearly with fibrinogen levels, but the relationships are weaker than in some previous population-based studies.

Associations between White Blood Cell Count and Risk for Cerebrovascular Disease Mortality: NHANES II Mortality Study, 1976–1992

PURPOSE

To examine associations between elevated white blood cell count (WBC) and cerebrovascular disease (CeVD) mortality independent of cigarette smoking and by gender.

METHODS

We used Cox regression analyses of data from 8459 adults (3982 men; 4477 women) aged 30 to 75 years in the NHANES II Mortality Study (1976-1992) to estimate the relative risk of death from CeVD across quartiles of WBC.

RESULTS

During 17 years of follow-up, there were 192 deaths from CeVD (93 men; 99 women). Compared with those with WBC (cells/mm(3))<5700, adults with WBC>8200 were at increased risk of CeVD mortality (relative risk [RR], 2.1; 95% confidence interval [CI], 1.2-3.7) after adjustment for smoking and other cardiovascular disease risk factors. Similar results were observed among never smokers (RR, 2.0; 95% CI, 1.0-3.8). The adjusted relative risk of CeVD mortality comparing those with WBC>8200 to those with WBC<5700 was 1.5 (95% CI, 0.7-3.5) among men and 2.7 (95% CI, 1.4-5.0) among women.

CONCLUSIONS

Elevated WBC may predict CeVD mortality even after considering the effects of smoking and other cardiovascular disease risk factors.

Fibrinogen--marker or mediator of vascular disease?

Fibrinogen plays a key role in platelet aggregation, the final step of the coagulation cascade, i.e. the formation of fibrin, and it is a major determinant of plasma viscosity and erythrocyte aggregation. It is both constitutively expressed and inducible during an acute phase reaction. Increased plasma fibrinogen levels are associated with an increased risk of coronary heart disease and myocardial infarction. The question as to whether fibrinogen is only a marker of the inflammatory process involved in atherosclerosis or a mediator, i.e. a pathogenic factor, has not yet been answered. Human in vivo studies do not permit a conclusive answer to this question. If it is a pathogenic factor, fibrinogen lowering would be a therapeutic option. Selective fibrinogen-lowering agents do not exist however. All agents that lower fibrinogen also have other cardiovascular effects such as a decrease in cholesterol or inflammation. Newer information stems from molecular biology. Polymorphisms in the human fibrinogen gene with higher fibrinogen levels do not increase the risk for myocardial infarction. Fibrinogen knockout mice crossed with an atherosclerosis-susceptible strain (apoprotein E null mice) did not show a decreased extent of atherosclerosis despite the absence of fibrinogen, and a mouse strain over-expressing fibrinogen did not show an increased degree of atherosclerosis. Thus, fibrinogen seems to be a marker rather than a mediator of vascular disease, which would make selective fibrinogen lowering a useless preventive or therapeutic strategy.

Associations between inflammatory markers, traditional risk factors, and complications in patients with type 2 diabetes mellitus

OBJECTIVE

Inflammatory markers predict cardiovascular events in a wide range of patients. Two factors, fibrinogen (FIB) and high-sensitivity C reactive protein (CRP), are currently entering clinical practice as cardiovascular risk predictors. In patients with type 2 diabetes mellitus, we sought to examine the relationship between macrovascular disease, urinary albumin/creatinine ratio (ACR), and FIB or CRP, as well as the relationship of FIB and CRP with traditional risk predictors of these complications of diabetes.

METHODS

In 202 consecutive patients with type 2 diabetes mellitus from a diabetes clinic, clinical and biochemical data were obtained and a cross-sectional analysis was performed.

RESULTS

Patients with macrovascular disease had higher FIB (P=.02) but not higher CRP. They were older, more likely to have retinopathy or elevated serum creatinine, had higher ACR and lower HDL cholesterol. They were more likely to be treated with statins, beta-blockers, and ASA. Adjustment for statin therapy did not result in significant differences in CRP levels according to macrovascular disease status. Both FIB (P=.01) and CRP (P=.02) were significantly higher in patients with ACR whose values were in the proteinuria range. In multivariate analysis, both FIB (P=.001) and CRP (P=.03) were positively correlated with ACR, but no association was seen between CRP and ACR when FIB was entered in the model. Other factors positively associated with ACR were age, diastolic blood pressure, retinopathy, and hemoglobin A1c (HbA1c). FIB and CRP were strongly correlated (R=.49, P< or =.001) and this effect was independent of statin therapy. CRP was positively associated with body mass index (BMI), serum triglycerides, and sulfonylurea therapy and negatively associated with metformin therapy. Patients on statin therapy had significantly higher FIB and lower CRP. Women on hormone replacement therapy (HRT) had significantly lower FIB and higher CRP.

CONCLUSIONS

In patients with diabetes: (1) the two markers, FIB and CRP, are interrelated; (2) FIB is significantly associated with presence of microvascular disease, independent of CRP; (3) CRP is strongly associated with metabolic factors but not with complications of diabetes, independently of FIB; (4) statins and HRT were divergently associated with CRP and FIB as HRT was associated with lower FIB and higher CRP, while statins showed the reverse association; and (5) CRP and FIB provide different information about the characteristics and consequences of diabetes mellitus because of divergent associations with biological indicators and therapeutic agents.

Prospective study of serum homocysteine and risk of ischemic stroke among patients with preexisting coronary heart disease

BACKGROUND AND PURPOSE

Substantial evidence is accumulating suggesting that hyperhomocysteinemia may be a risk factor for ischemic stroke. Results of prospective studies are, however, conflicting, and the role of hyperhomocysteinemia in patients with preexisting atherosclerotic vascular disease is not clear. Our aim was to assess prospectively the risk of incident ischemic stroke conferred by serum total homocysteine among patients with preexisting stable coronary heart disease (CHD).

METHODS

We obtained baseline fasting serum samples from patients with chronic CHD enrolled in the Bezafibrate Infarction Prevention (n=3090) secondary prevention study cohort. With a nested case-control design, we measured baseline total homocysteine concentration by a high-performance liquid chromatography-based method in sera (n=160) of matched case-control pairs: patients who developed ischemic stroke during a mean follow-up of 8.2 years (cases) and age- and sex-matched controls without subsequent cardiovascular events.

RESULTS

An increase of 1 natural log unit in homocysteine concentration was associated with a >3-fold increase in relative odds of incident ischemic stroke (3.3; 95% CI, 1.2 to 10.2). Homocysteine concentrations at the highest quartile (>17.4 micromol/L) were associated with significantly higher odds of ischemic stroke compared with the lowest quartile in matched-pair analysis (3.1; 95% CI, 1.1 to 9.8) and after multivariable adjustments (4.6; 95% CI, 1.3 to 18.9). Adding fibrinogen or soluble intercellular adhesion molecule-1 concentrations, markers of inflammation, to the model did not attenuate this association. The linear trends across the quartiles were significant for all models (P<0.05).

CONCLUSIONS

Serum total homocysteine concentration is a strong predictor for incident ischemic stroke among patients at increased risk because of chronic CHD. The graded association observed is independent of traditional risk factors or inflammatory markers and indicates the importance of serum homocysteine levels in patients with preexisting vascular disease.

Spontaneous echo contrast videodensity is flow-related and is dependent on the relative concentrations of fibrinogen and red blood cells

OBJECTIVES

The purposes of the present study were to: 1) determine whether fibrinogen (Fg) is the plasma protein responsible for spontaneous echo contrast (SEC), and 2) investigate modulators of SEC.

BACKGROUND

Spontaneous echo contrast has been linked to the development of thromboemboli. The blood products and their interaction responsible for SEC formation have not been fully elucidated.

METHODS

Blood echogenicity was examined with the use of quantitative videodensitometry over a controlled range of flow velocities in an in vitro model. Human blood samples were analyzed in a manner to methodically eliminate individual blood components from whole blood to determine which components are responsible for the formation of SEC.

RESULTS

The videodensity (VD) of whole blood was found to be flow-dependent, with higher VD at lower flow rates, and correlated with visually dense SEC. The following blood products produced faint VD values: washed red blood cells (wRBCs), platelet-depleted plasma, Fg, defibrinated plasma, wRBCs plus defibrinated plasma, and physiologic saline. The VD of wRBCs increased incrementally as increasing concentrations of Fg were added. At each hematocrit (Hct) range, as Fg concentration increased, the SEC became denser, and the VD level also increased until a plateau level was reached that was distinct for each Hct. The addition of sialic acid, which inhibits RBC-RBC aggregation, decreased the amount of SEC, even in the presence of Fg.

CONCLUSION

These results demonstrated that Fg-mediated RBC aggregation may be responsible for SEC generation. Furthermore, a unique stoichiometric relationship exists between Fg and RBC concentrations that is necessary for blood echogenicity.

Soluble intercellular adhesion molecule-1 and risk of future ischemic stroke: a nested case-control study from the Bezafibrate Infarction Prevention (BIP) study cohort

BACKGROUND AND PURPOSE

Inflammation is considered to be involved in the pathogenesis of ischemic stroke. Our purpose was to assess the role of soluble intercellular adhesion molecule-1 (sICAM-1) concentration, a marker of inflammation, in predicting future ischemic stroke among patients at risk because of chronic coronary heart disease.

METHODS

We obtained baseline serum samples from patients with chronic coronary heart disease enrolled in the Bezafibrate Infarction Prevention trial (n=3090), which assessed the efficacy of bezafibrate in secondary prevention. Using a prospective nested case-control design, we measured baseline sICAM-1 concentration in sera of patients who developed ischemic stroke during a mean follow-up of 8.2 years (cases, n=134) and in age- and sex-matched controls without any subsequent cardiovascular events (n=134).

RESULTS

Baseline serum concentrations of sICAM-1 were significantly higher in cases compared with controls (379 versus 350 ng/mL, P<0.05). sICAM-1 concentration at the highest quartile (>394 ng/mL) was associated with significantly higher relative odds of ischemic stroke compared with the lower concentrations after adjustment for potential confounding variables (relative odds, 2.1; 95% CI, 1.1 to 4.3). After fibrinogen and total white blood cell count were added to the multivariable model, the relative odds were 2.1 (95% CI, 1.1 to 4.2) and 2.2 (95% CI, 1.1 to 4.8), respectively. The risk associated with raised concentrations of sICAM-1 seemed to be highest for large disabling strokes of cardioembolic origin.

CONCLUSIONS

Elevated concentrations of sICAM-1, a marker of inflammation, are associated with increased risk of ischemic stroke, independent of other traditional cerebrovascular risk factors and of plasma fibrinogen, among patients at increased risk because of manifest coronary heart disease.