Fibrinogen measurement to assess the risk of arterial thrombosis in individual patients: not yet

Diagnostic value of coagulation index and serum inflammatory cytokines in hemorrhagic stroke patients with pulmonary infection in the sequelae stage

BACKGROUND

Stroke is the second reason for global deaths and a major reason for disabilities.

OBJECTIVE

To unravel the clinical value of the coagulation index and serum inflammatory cytokines in hemorrhagic stroke patients with pulmonary infection in the sequelae stage.

METHODS

Altogether, 130 hemorrhagic stroke patients who received treatment in Hebei General Hospital from April 2019 to December 2020 were selected. Patients were classified into the infection group (n= 65) and non-infection group (n= 65) according to whether they had a pulmonary infection in the sequelae stage of hemorrhagic stroke. Levels of coagulation index and serum inflammatory cytokines of patients in two groups were compared. Multiple linear regression analysis was used to analyze pulmonary infection-related factors of hemorrhagic stroke patients. The diagnostic value of the coagulation index and serum inflammatory cytokines in pulmonary infection was analyzed by the receiver operating characteristic (ROC) curve.

RESULTS

Prothrombin time (PT), activated partial thromboplastin time (APTT), fibrinogen (FIB), D-dimer (D-D), platelet (PLT) related to coagulation function levels and interleukin 1β (IL-1β), interleukin 17 (IL-17) related to serum inflammatory cytokines levels of patients in the infection group were higher than those in non-infection groups (p< 0.05). Multiple linear regression analysis uncovered that FIB, D-D, PLT, and IL-17 were influencing factors of pulmonary infection in the sequelae of patients with hemorrhagic stroke (p< 0.05). Area under the curve (AUC) values of pulmonary infection in the sequelae stage of patients with hemorrhagic stroke diagnosed by FIB, D-D, PLT, and IL-17 were 0.823, 0.758, 0.660, and 0.755, respectively.

CONCLUSION

FIB, D-D, PLT, and IL-17 levels could be used for pulmonary infection diagnosis in the sequelae stage of hemorrhagic stroke patients.

The Coagulation Factors Fibrinogen, Thrombin, and Factor XII in Inflammatory Disorders-A Systematic Review

Background

The interaction of coagulation factors has been shown to go beyond their traditional roles in hemostasis and to affect the development of inflammatory diseases. Key molecular players, such as fibrinogen, thrombin, or factor XII have been mechanistically and epidemiologically linked to inflammatory disorders like multiple sclerosis (MS), rheumatoid arthritis (RA), and colitis.

Objectives

To systematically review the evidence for a role of coagulation factors, especially factor XII, fibrinogen, and thrombin in inflammatory disorders like MS, RA, and bowel disorders.

Methods

A systematic literature search was done in the PubMed database to identify studies about coagulation factors in inflammatory diseases. Original articles and reviews investigating the role of the kallikrein–kinin and the coagulation system in mouse and humans were included.

Results

We identified 43 animal studies dealing with inflammatory disorders and factors of the kallikrein–kinin or the coagulation system. Different immunological influences are described and novel molecular mechanisms linking coagulation and inflammation are reported.

Conclusion

A number of studies have highlighted coagulation factors to tip the balance between hemostasis and thrombosis and between protection from infection and extensive inflammation. To optimize the treatment of chronic inflammatory disorders by these factors, further studies are necessary.

Causal relationship between hyperfibrinogenemia, thrombosis, and resistance to thrombolysis in mice

Epidemiologic studies have correlated elevated plasma fibrinogen (hyperfibrinogenemia) with risk of cardiovascular disease and arterial and venous thrombosis. However, it is unknown whether hyperfibrinogenemia is merely a biomarker of the proinflammatory disease state or is a causative mechanism in the etiology. We raised plasma fibrinogen levels in mice via intravenous infusion and induced thrombosis by ferric chloride application to the carotid artery (high shear) or saphenous vein (lower shear); hyperfibrinogenemia significantly shortened the time to occlusion in both models. Using immunohistochemistry, turbidity, confocal microscopy, and elastometry of clots produced in cell and tissue factor-initiated models of thrombosis, we show that hyperfibrinogenemia increased thrombus fibrin content, promoted faster fibrin formation, and increased fibrin network density, strength, and stability. Hyperfibrinogenemia also increased thrombus resistance to tenecteplase-induced thrombolysis in vivo. These data indicate that hyperfibrinogenemia directly promotes thrombosis and thrombolysis resistance and does so via enhanced fibrin formation and stability. These findings strongly suggest a causative role for hyperfibrinogenemia in acute thrombosis and have significant implications for thrombolytic therapy. Plasma fibrinogen levels may be used to identify patients at risk for thrombosis and inform thrombolytic administration for treating acute thrombosis/thromboembolism.

Clinical implications of cytokines in the critical-care unit

To understand the role of different cytokines in the pathophysiology and management of different acute cardiovascular disorders in critically ill patients, we reviewed most of the pertinent articles published on Medline, Scopus and EBSCO host research databases from 1985 to January 2009. We used the indexing terms 'cytokines', 'cardiovascular', 'sepsis', 'critical care', 'myocardial dysfunction', 'shock', 'thromboembolism', 'inflammatory' and 'arrhythmias'. Myocardial dysfunction, dysrhythmic and thromboembolic disorders all appear associated with important fluctuations in cytokines. When and how to sample cytokine levels and the ways in which cytokines contribute to patient deterioration or improvement require further clinical studies. The measurement and interplay of several different cytokines may ultimately be of substantial clinical importance in the diagnosis, treatment and prognosis of patients with different acute cardiovascular disorders managed by critical-care physicians in intensive-care units. Although the role of cytokines in cardiovascular disorders is debatable, the clinical implication of cytokines in the critical-care unit is a new horizon that warrants more attention.

The effects of fibrinogen levels on thromboelastometric variables in the presence of thrombocytopenia

BACKGROUND

The binding of fibrinogen and fibrin to platelets is important in normal hemostasis. The extent of platelet-fibrin interaction can be measured as the viscoelastic strength of clot by rotational thromboelastometry (ROTEM). In this study, we investigated the effect of fibrinogen concentration and its relative contribution to overall clot strength using ROTEM.

METHODS

Blood samples were collected from healthy volunteers. The effects of platelet count on clot strength, determined by maximum clot elasticity (MCE), were evaluated on ROTEM using platelet-rich plasma (PRP) adjusted with autologous plasma to generate a range of platelet counts. PRPs were adjusted to 10 x 10(3) mm(-3), 50 x 10(3) mm(-3), and 100 x 10(3) mm(-3) and spiked with fibrinogen concentrates at 550 and 780 mg/dL. The effect of fibrin polymerization on clot strength, independent of platelet attachment, was analyzed by the cytochalasin D-modified thromboelastometry (FIBTEM) method. Additional retrospective analysis of clot strength (MCE) in two groups of thrombocytopenic patients was conducted.

RESULTS

Clot strength (MCE) decreased at a platelet count below 100 x 10(3) mm(-3), whereas increases in MCE peaked and reached a plateau at platelet counts from 400 x 10(3) mm(-3). Increasing fibrinogen concentrations in PRP increased clot strength in a concentration-dependent manner, even at low platelet counts (10 x 10(3) mm(-3)). The positive correlation between clot strength and plasma fibrinogen level was also confirmed in the analysis of the data obtained from 904 thrombocytopenic patients.

CONCLUSIONS

These in vitro and clinical data indicate that the clot strength increases in a fibrinogen concentration-dependent manner independent of platelet count, when analyzed by ROTEM. The maintenance of fibrinogen concentration is critical in the presence of thrombocytopenia. EXTEM (extrinsic activation) and FIBTEM may be useful in guiding fibrinogen repletion therapy.

Cytokines and coronary artery disease: the state of the art

Initiation and progression of coronary atherosclerosis has been associated with inflammation and cytokines balance. The objective of this study is to understand the role of cytokines in the pathophysiology and management of coronary artery disease. Coronary artery disease has been revisited with revision of the pertinent published articles in the Medline, Scopus, and EBSCO Host research from 1987 to 2007. The 2 groups of cytokines (proinflammatory and anti-inflammatory) have been detected in human atherosclerotic plaques. The balance between the 2 groups may reflect the intensity of occult plaque inflammation and the vulnerability to rupture. Multiple studies have determined that a diverse set of proinflammatory biomarkers can furnish prognostic information beyond the traditional risk factors. Inflammatory responses after coronary revascularization are known to play key role in vascular lesion formation early in atherosclerosis and restenosis. Clinical utilization of cytokines remains promising yet incompletely explored and need more studies.

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.

Circulating inflammatory markers and risks of cardiovascular and non-cardiovascular disease

There is current interest in the associations of circulating inflammatory markers (C-reactive protein, fibrinogen, white cell count, albumin, erythrocyte sedimentation rate, the factor VIII:von Willebrand factor complex, the tissue plasminogen activator:plasminogen activator inhibitor type 1 complex, fibrin D-dimer) not only with prognosis in acute coronary syndromes and acute stroke, but also in prediction of cardiovascular events in the general population. Recent meta-analyses of long-term prospective studies have established their associations with coronary heart disease (CHD) events, which may be cause, consequence or coincidence. These markers are also associated in epidemiologic studies of general populations with many cardiovascular risk factors (which may confound their associations with CHD risk), and also with asymptomatic arterial disease (of which they be consequences: 'reverse causality'). The causality of their associations with cardiovascular events is questioned by their lack of specificity for risk of cardiovascular events; and by the lack of association of their functional genotypes with CHD in 'Mendelian randomized trials'. Hence, proof of causality awaits testing in randomized-controlled trials of long-term selective reduction by future agents. Markers are of little additional predictive value to current cardiovascular risk scores, and it is premature to advocate their use in screening for cardiovascular risk prior to careful evaluation of costs, risks, and benefits.