Plasma fibrinogen in relation to the severity of arteriosclerosis in patients with stable angina pectoris after myocardial infarction

Contemporary Biomarkers in Pulmonary Embolism Diagnosis: Moving beyond D-Dimers

Pulmonary embolism (PE) is a rather common cardiovascular disorder constituting one of the major manifestations of venous thromboembolism (VTE). It is associated with high mortality and substantial recurrence rates, and its diagnosis may be challenging, especially in patients with respiratory comorbidities. Therefore, providing a prompt and accurate diagnosis for PE through developing highly sensitive and specific diagnostic algorithms would be of paramount importance. There is sound evidence supporting the use of biomarkers to enhance the diagnosis and predict the recurrence risk in patients with PE. Therefore, several novel biomarkers, such as factor VIII, Ischemia Modified Albumin, and fibrinogen, as well as several MicroRNAs and microparticles, have been investigated for the diagnosis of this clinical entity. The present review targets to comprehensively present the literature regarding the novel diagnostic biomarkers for PE, as well as to discuss the evidence for their use in daily routine.

Association between fibrinogen level and the severity of coronary stenosis in 418 male patients with myocardial infarction younger than 35 years old

Fibrinogen (Fib) is a useful marker for predicting the severity of coronary artery disease (CAD) in adult population. However, whether Fib can be a predictor for the presence and severity of CAD in very young MI patients (≤35 years old) remains to be determined. A total of 418 males from 61,863 patients with MI who were under 35 years old were sequentially recruited in our study. The patients were divided into two main groups and three subgroups according to coronary angiograph and Gensini score (GS) system: no coronary artery stenosis (group A), the results of the coronary artery stenosis (group B); low GS, intermediate GS and high GS. Data indicated that Fib, body mass index, current smoking, white blood cell count (WBCC) and GS were significantly higher in group B than those in group A (all P < 0.01). Moreover, there were significant differences in Fib, mean age, diabetes mellitus, family history of CAD, WBCC, left ventricular ejection fraction, and GS between high GS and low GS subgroups (all P < 0.01). A positive correlation between Fib levels and GS was found (r = 0.242, p < 0.001). Receiver operating characteristics curve analysis demonstrated that the best cut-off level of Fib predicting the severity of coronary stenosis was 3.475g/L (sensitivity 64%; specificity 70%) and the area under the curve was 0.656. Fib was also independently associated with high GS (OR=2.173, 95%CI 1.011–4.670, P = 0.047) after adjusting for potential confounders. In conclusion, Fib is significantly related to the presence and severity of coronary stenosis in male patients with MI under 35 years old.

Fibrinogen in relation to degree and composition of coronary plaque on intravascular ultrasound in patients undergoing coronary angiography

OBJECTIVE

The aim of this study was to provide additional insight into the role of fibrinogen in coronary artery disease by investigating the associations between plasma fibrinogen with both degree and composition of coronary atherosclerosis as determined by virtual histology-intravascular ultrasound.

PATIENTS AND METHODS

In 581 patients undergoing coronary angiography for acute coronary syndrome (ACS) or stable angina pectoris, preprocedural blood samples were drawn for fibrinogen, C-reactive protein (CRP), interleukin-6, and plasminogen activator inhibitor-1 measurements, and virtual histology-intravascular ultrasound of a nonculprit coronary artery was performed. The degree [plaque volume, plaque burden (PB), and lesions with PB≥70%] and the composition of coronary atherosclerotic plaque (fibrous, fibrofatty, dense calcium, necrotic core tissue, and thin-cap fibroatheroma lesions) were assessed.

RESULTS

Fibrinogen showed a tendency toward a positive association with PB [β (95% CI): 2.55 (-0.52-5.61) increase in PB per ln(g/l) fibrinogen, P=0.09], which was driven significantly by an association in the ACS subgroup [β (95% CI): 4.11 (0.01-8.21) increase in PB per ln(g/l) fibrinogen, P=0.049]. Fibrinogen was also related to the presence of lesions with PB 70% or more in both the full cohort [OR (95% CI): 2.27 (1.17-4.43), P=0.016] and ACS patients [OR (95% CI): 2.92 (1.17-7.29), P=0.022]. All associations were independent of established cardiovascular risk factors, but not CRP. Interleukin-6 and plasminogen activator inhibitor-1 did not provide incremental value to fibrinogen when examining the associations with degree of atherosclerosis. Substantial associations with plaque composition were absent.

CONCLUSION

Fibrinogen is associated with degree of coronary atherosclerosis, especially in ACS patients. However, whether this association is independent of CRP might be questioned and needs further investigation.

Elevated Levels of Serum Fibrin and Fibrinogen Degradation Products Are Independent Predictors of Larger Coronary Plaques and Greater Plaque Necrotic Core

BACKGROUND

Co-existence of vulnerable plaque and pro-thrombotic state may provoke acute coronary events. It was hypothesized that elevated serum levels of fibrin and fibrinogen degradation products (FDP) are associated with larger total plaque and necrotic core (NC) areas.

METHODS AND RESULTS

Seventy-five patients presenting with stable anginal symptoms (69%) or stabilized acute coronary syndrome (ACS; 31%), and found to have non-obstructive coronary artery disease (CAD) with a fractional flow reserve >0.8, were studied. Invasive virtual histology intravascular ultrasound (VH-IVUS) was performed in 68 LAD arteries, 6 circumflex arteries, and 1 right coronary artery. Serum FDP levels were measured using ELISA technique. Plaque volumetrics and composition were assessed in each VH-IVUS frame and averaged. The median age of patients was 56 (47-63) years; 52% were men and 23% had diabetes. The average length of coronary artery studied was 62 mm. After adjustment for systemic risk factors, medications, CRP levels and ACS, male gender (P<0.001) and serum FDP levels (P=0.02) were independent predictors of a larger NC area. Older age (P<0.001), male gender (P<0.0001) and increased serum FDP level (P=0.03) were associated with a larger plaque area.

CONCLUSIONS

In patients with CAD, a higher serum level of FDP is independently associated with larger plaques and greater plaque NC.

Association of fibrinogen with severity of stable coronary artery disease in patients with type 2 diabetic mellitus

Background. Some studies have suggested a relation of plasma fibrinogen to the severity of coronary artery disease (CAD). However, whether plasma fibrinogen can predict the presence and severity of CAD in patients with diabetes mellitus has not been determined. Methods. A total of consecutive 373 diabetic patients with typical angina pectoris who received coronary angiography were enrolled and classified into three groups by tertiles of Gensini score (GS, low group <8; intermediate group 8~28; high group >28). The relationship between fibrinogen and GS was evaluated. Results. There were correlations of fibrinogen with hemoglobin A1c, C-reactive protein, and GS (r = 0.17, r = 0.52, and r = 0.21, resp.; all P < 0.001). Area under the receivers operating characteristic curve of fibrinogen was 0.62 (95% CI 0.56–0.68, P < 0.001) for predicting a high GS. Multivariate analysis suggested that plasma fibrinogen was an independent predictor of a high GS for diabetic patients (OR = 1.40, 95% CI 1.04–1.88, and P = 0.026) after adjusting for traditional risk factors of CAD. Conclusions. The present data indicated that plasma fibrinogen, a readily measurable systematic inflammatory marker, appeared to be an independent predictor for the severity of CAD in diabetic patients.

IMPACT OF DIABETES MELLITUS ON SEVERITY OF CONCOMITANT PERIPHERAL ARTERIAL OCCLUSIVE DISEASE IN PATIENTS WITH CORONARY ARTERY DISEASE

AIM OF THE STUDY

The aim of the study was to evaluate the impact of Diabetes Mellitus (DM) on severity of concomitant Peripheral Arterial Occlusive Disease (PAOD) in patients with Coronary Artery Disease (CAD).

PATIENTS AND METHODS

This study included 302 patients (229 men) with a mean age of 62.2 +/- 11.5 years who had angiographically documented CAD. Patients were divided into Group I (severe CAD), Group II (moderate CAD) and Group III (mild CAD). Each of the groups I-III was divided into subgroups comprising diabetic patients (subgroups Ia, IIa, IIIa) and non-diabetic patients (subgroups Ib, IIb, IIIb). PAOD was evaluated by measurement of Toe-Brachial Index (TBI).

RESULTS

PAOD was diagnosed in 69 patients (22.8%). Symptoms of PAOD (intermittent claudication or rest pain) were present in 38 patients (55%), while 31 patients (45%) were asymptomatic. Frequency of symptoms attributable to PAOD did not differ (p = 0.43) between diabetic patients (25 out of 49 patients, 51%) and non-diabetic patients (13 out of 20 patients, 65%). TBI was significantly (p = 0.04) lower in diabetic (0.41 +/- 0.03) than in non-diabetic patients with PAOD (0.51 +/- 0.03). This significant difference was found in each of the Groups I-III. Severity of PAOD was significantly associated with angiographic gravity of CAD, both in diabetic (p = 0.046) and in non-diabetic patients (p = 0.047).

CONCLUSIONS

DM has an adverse impact on severity of concomitant PAOD in patients with CAD. This impact does not depend on angiographic gravity of CAD. However, the association between severity of PAOD and angiographic gravity of CAD is demonstrated both in diabetic and in non-diabetic patients.

ITIH4: A New Potential Biomarker of "Toxin Syndrome" in Coronary Heart Disease Patient Identified with Proteomic Method

Objective. This trial aims to look for the protein biomarker of "toxin syndrome" of CHD patients. Methods. We have performed two trials in this paper. The first trial was a randomized controlled trial (RCT) of the plasma proteome in unstable angina (UA) patients by Maldi-Tof Mass. The second trial was a nested case-control study in 1503 stable CHD patients with one-year followup for acute cardiovascular events (ACEs). Results. In the RCT study, 12 protein spots were found to be the differential protein for the significant differences between the difference of before and after treatment in group A and group B; 2 of them (3207.37 Da and 4279.95 Da) was considered to be unique to "toxin syndrome" for being differential proteins of group B but not group A. These 2 spots were identified as Isoform 1 of Fibrinogen alpha chain precursor (FGA, 3207.37 Da) and Isoform 2 of inter-alpha-trypsin inhibitor heavy chain H4 (ITIH4, 4279.95 Da), respectively. In the nested case-control study, the result of Western blot demonstrated that protein expression of ITIH4 in the group with followup ACEs was significantly lower than the matched group without followup ACEs (P = 0.027). Conclusion. ITIH4 might be a new potential biomarker of CHD "toxin syndrome" in TCM, indicating the potential role in early identifying high-risk CHD patients in stable period.

Accuracy of D-dimer:fibrinogen ratio to diagnose pulmonary thromboembolism in patients admitted to intensive care units

Introduction

Pulmonary thromboembolism (PTE) may increase D-dimer and decrease fibrinogen levels. However, in settings such as intensive care units (ICU) and in long-term hospitalised patients, several factors may influence D-dimer and fibrinogen concentrations and make them unreliable indicators for the diagnosis of PTE. The aim of this study was to evaluate the accuracy of D-dimer:fibrinogen ratio (DDFR) for the diagnosis of PTE in ICU patients.

Methods

ICU patients who were suspected of having a first PTE and had no history of using anti-coagulants and contraceptives were included in the study. Levels of D-dimer and fibrinogen were measured for each patient prior to any intervention. Angiography or CT angiography was done in order to establish a definite diagnosis for each patient. Suitable analytical tests were performed to compare means.

Results

Eighty-one patients were included in the study, of whom 41 had PTE and 40 did not. Mean values of D-dimer and fibrinogen were 3.97 ± 3.22 μg/ml and 560.6 ± 197.3 mg/dl, respectively. Significantly higher levels of D-dimer (4.65 ± 3.46 vs 2.25 ± 2.55 μg/ml, p = 0.006) and DDFR (0.913 ± 0.716 vs 483 ± 0.440 × 10^-3, p = 0.003) were seen in PTE patients than in those without PTE. Receiver operating characteristic (ROC) analysis showed a 70.3% sensitivity and 70.1% specificity with a D-dimer value of 2.43 μg/ml (AUC = 0.714, p = 0.002) as the best cut-off point; and a 70.3% sensitivity and 61.6% specificity with a DDFR value of 0.417 × 10^-3 (AUC = 0.710, p = 0.004) as the best cut-off point. In backward stepwise regression analysis, DDRF (OR = 0.72, p = 0.025), gender (OR = 0.76, p = 0.049) and white blood cell count (OR = 1.11, p = 0.373) were modelled (p = 0.029, R² = 0.577).

Conclusion

For diagnosis of PTE, DDFR can be considered to have almost the same importance as D-dimer level. Moreover, it was possible to rule out PTE with only a D-dimer cut-off value < 0.43 mg/dl, without the use of DDFR. However, these values cannot be used as a replacement for angiography or CT angiography

Fibrin(ogen) and its fragments in the pathophysiology and treatment of myocardial infarction

The occlusion of a coronary artery leads to ischemia of the myocardium, while permanent occlusion results in cell death and myocardial dysfunction. Early restoration of blood flow is the only means to reduce or prevent myocardial necrosis, but-paradoxically-reperfusion itself contributes to injury of the heart. In animal models, this phenomenon is well described, and there are many different unrelated approaches to reduce reperfusion injury. In humans, however, pharmacological interventions have so far failed to reduce myocardial reperfusion injury. We summarize the pathogenesis of reperfusion injury, detailing the role of fibrin(ogen) and its derivatives. Moreover, we introduce a new concept for fibrin derivatives as potential targets for reperfusion therapy.

Risk factors for concomitant peripheral arterial occlusive disease in patients with coronary artery disease: is there a difference between diabetic and non-diabetic patients?

AIM OF THE STUDY

The aim of the present study was investigation of cardiovascular risk factors for concomitant Peripheral Arterial Occlusive Disease (PAOD) in diabetic vs. non-diabetic patients with coronary artery disease (CAD).

PATIENTS AND METHODS

This study included 302 patients (229 men) with a mean age of 62.2 +/- 11.5 years and angiographically documented CAD. These were divided into Group A comprising 116 diabetic patients (79 men) and Group B comprising 186 non-diabetic patients (150 men). Peripheral Arterial Occlusive Disease (PAOD) was diagnosed using a Doppler apparatus. Cardiovascular risk factors that were investigated included age, history of myocardial infarction, smoking, Body-Mass Index, Waist-Hip-Ratio, hypertension and serum lipids.

RESULTS

PAOD was diagnosed in 49 patients of Group A (42.4%) and 20 patients of Group B (10.8%). In Group A concomitant PAOD was associated with significantly (p = 0.0001) longer diabetes duration and significantly (p = 0.0001) higher frequency of insulin treatment, as well as significantly (p = 0.02) higher triglycerides and significantly (p = 0.039) lower HDL-Cholesterol. In Group B patients with PAOD had significantly (p = 0.0001) higher age and significantly higher (p = 0.041) LDL-Cholesterol levels than those without PAOD. No association was found between PAOD and presence of remaining risk factors in either group. In multiple regression analysis, concomitant PAOD was associated with diabetes duration (p = 0.0026) and insulin treatment (p = 0.0004) in Group A, while it was associated with age (p = 0.01) in Group B. The associations with serum lipids were no longer significant.

CONCLUSIONS

Among non-diabetic patients with CAD, those who have concomitant PAOD are significantly older. Among diabetic patients with CAD, those who have concomitant PAOD show significantly longer diabetes duration and significantly higher frequency of insulin treatment.

Peripheral arterial occlusive disease as a predictor of the extent of coronary atherosclerosis in patients with coronary artery disease with and without diabetes mellitus

We evaluated the sensitivity and specificity of a diagnosis of peripheral arterial occlusive disease (PAOD) as a predictor of the severity of coronary artery disease (CAD) in patients with and without diabetes. A total of 302 patients were assigned to groups according to the angiographic severity of their CAD and their diabetes status. Both PAOD and severe PAOD were diagnosed by measuring the ankle-brachial index (ABI) and toe-brachial index (TBI). A diagnosis of PAOD had a low sensitivity (34.3%) but a high specificity (87.0%) for detecting patients with severe CAD. Sensitivity was higher in patients with diabetes (52.4%) than without (19.5%), whereas specificity was higher in patients without diabetes (95.4%) than those with diabetes (69.8%). A diagnosis of severe PAOD had a higher specificity (96.0%), but a very low sensitivity (16.4%). We conclude that a diagnosis of PAOD among patients with CAD had a low sensitivity but a high specificity for detecting those with severe CAD, particularly in patients without diabetes.

The viscosity of fibrinogen subfractions and of EDTA denatured fibrinogen do not differ from that of native fibrinogen

INTRODUCTION

Fibrinogen is a major determinant of plasma viscosity. The increased risk of atherothrombotic disease associated with a high fibrinogen concentration may partly be attributed to its effect on viscosity. Since the ratio between the three main fibrinogen subfractions high molecular weight (HMW)-, low molecular weight (LMW)-, and very low molecular weight (LMW')-fibrinogen is altered during acute phase conditions, and an increased HMW/LMW-fibrinogen ratio is associated with increased thromboembolic risk, we have examined how these subfractions affect viscosity. The viscosity of plasma is usually determined in ethylenediaminetetra-acetic acid (EDTA) plasma at 37 degrees C. Under such conditions the clotting properties of fibrinogen is affected due to denaturation. Denaturation of plasma proteins may affect their viscosity. Therefore, we have also investigated the effects of EDTA on the viscosity of fibrinogen.

MATERIALS AND METHODS

Purified fibrinogen was obtained by beta-alanine precipitation of plasma from healthy donors. Separation of the fibrinogen fractions was performed by gradual precipitation of purified fibrinogen by ammonium sulphate. The viscosity was determined using a Haake Microvisco 2 viscometer.

RESULTS

There was no statistically significant difference between the viscosity of native fibrinogen and the three fibrinogen subfractions. A substantial prolongation of the thrombin clotting time was observed in the fibrinogen solution containing EDTA at 37 degrees C compared to 20 degrees C. However, the viscosity of EDTA anticoagulated purified fibrinogen and plasma samples did not differ from that of heparin anticoagulated samples.

CONCLUSION

The viscosity of the main fibrinogen subfractions HMW-, LMW- and LMW-fibrinogen did not differ from that of native fibrinogen, and the use of EDTA as anticoagulant did not significantly affect the viscosity of fibrinogen at 37 degrees C.

Accuracy of D-dimer/fibrinogen ratio to predict pulmonary embolism: a prospective diagnostic study

D-Dimer and fibrinogen are elevated in many diseases presenting signs and symptoms similar to those seen in patients with pulmonary embolism (PE). We tested the hypothesis that patients with PE have lower fibrinogen and higher d-dimer values than patients in whom the diagnosis is suspected but safely excluded. One hundred and ninety-one consecutive patients with suspected acute PE (85 positive, 106 negative) were investigated with a diagnostic strategy including d-dimer, pretest probability, and helical computed tomography as first-line tests. In 38 of 40 patients with suspected PE and d-dimer <500 microg L(-1), PE was excluded without further testing. During a 3-month follow-up, there was no clinical PE among these 38 and the 68 patients with a negative helical CT. In 151 patients with d-dimer >500 microg L(-1), d-dimer, fibrinogen, and d-dimer/fibrinogen ratio (D/F ratio) were different in PE-positive compared with PE-negative patients [medians (and ranges) for d-dimer: 3793 (780 - 42 195) vs. 992 (621-6957) microg L(-1), fibrinogen: 3.8 (0.4-6.2) vs. 4.7 (2.2-8.4) g L(-1), and D/F ratio: 1.22 (0.15-85.45) 103 vs. 0.25 (0.09-1.03) x 103; P < 0.0001, respectively). The true positive rate was almost twice as high using D/F ratio >1.04 x 103 (49 of 85 patients; 57.6%) compared with d-dimer >7000 micro g L(-1) (25 of 85 patients; 29.4%). Patients with acute PE have lower fibrinogen values than patients with suspected but excluded PE. D/F ratio >103 is highly specific for the presence of acute PE, and causes a doubling of the diagnostic rate compared with d-dimer testing alone.

Impact of albumin synthesis rate and the acute phase response in the dual regulation of fibrinogen levels in hemodialysis patients

BACKGROUND

Fibrinogen is a risk factor for cardiovascular disease. It also is an acute phase protein (APP) and its plasma concentration increases with inflammation. Fibrinogen synthesis correlates with albumin synthesis in nephrotic patients and in patients with an expanded plasma volume even when serum albumin is normal and there is no inflammatory disease. The relationships among albumin synthesis, the acute phase response and plasma fibrinogen levels in hemodialysis patients are unknown.

METHODS

In 74 hemodialysis patients, albumin synthesis, plasma volume (PV) and acute phase proteins (APPs) C-reactive protein (CRP), alpha1 acid glycoprotein (alpha1 AG), ceruloplasmin (Cer), and interleukin 6 (IL-6) were measured in serum and fibrinogen in plasma, and the results analyzed by multiple regression analysis. CRP, IL-6, alpha1 AG, Cer and fibrinogen were measured monthly, which enabled us to determine whether changes in these APPs correlated with the levels of and variability in plasma fibrinogen over time using a longitudinal modeling approach. Length of follow-up for the 74 patients ranged from 3.25 to 67.5 months.

RESULTS

Baseline fibrinogen (548.6 +/- 106. 4 mg/dL) was significantly greater than levels reported for normal adults and correlated positively with albumin synthesis (P < 0.001), age (P < 0.001) and log CRP (P = 0.002) and negatively with PV (P < 0.001). Longitudinally, fibrinogen varied positively with long-lived APPs, Cer and alpha1 AG, as well as the short-lived APP, CRP.

CONCLUSION

Plasma fibrinogen concentration is high in HD patients and directly correlates with increased albumin synthesis rates and the serum levels of APPs. Fibrinogen levels also correlate negatively with PV. Fibrinogen levels vary over time in synchrony with levels of other long-lived APPs, supporting the hypothesis that fibrinogen is regulated in part as a component of the acute phase response and in part by factors that increase albumin synthesis.