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

Diagnostic value of fibrinogen in lower extremity deep vein thrombosis caused by rib fracture: A retrospective study

Objectives: To investigate the diagnostic value of fibrinogen (FIB) in patients with rib fractures complicated by lower extremity deep venous thrombosis (DVT).Methods: Analyzing data from 493 patients at Shijiazhuang Third Hospital, FIB levels at 24, 48, and 72 h post-injury were compared between DVT and non-DVT groups.Results: DVT group had elevated FIB levels at all times (p < .001). FIB at 24 h showed highest AUC, particularly in patients with BMI <28.Conclusion: In conclusion, measuring FIB at 24 h post-injury enhances DVT detection in rib fracture patients, with potential BMI-related variations.

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

Background

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

Methods

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

Results

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

Conclusion

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

D-Dimer and Fibrinogen Values according to the Localization of Deep Venous Thrombosis

D-dimer and fibrinogen are nonspecific diagnostic biomarkers for venous thromboembolism (VTE). The aim of this article was to present the values of D-dimer and fibrinogen in relation to the anatomical localization of deep vein thrombosis (DVT). This was an observational study, which included 1,142 patients hospitalized from 2010 to 2019 at the Department of Angiology, Clinical Center University of Sarajevo. Data on gender, age, and thrombosis location were collected of all patients. Fibrinogen and D-dimer values were available for 983 and 500 patients, respectively. Thrombosis location was classified as iliofemoral (521-45.6% patients), femoral-popliteal (486-42.6% patients), isolated calf DVT (63-5.5% patients), and upper extremity DVT (UEDVT in 72-6.3% patients). A majority, 448 (89.6%), of patients had high D-dimer (the cutoff is 0.55 mg/L) and 662 (67.3%) patients had high fibrinogen (reference range: 1.8-3.8 g/L). The highest D-dimer was detected in patients with iliofemoral DVT (mean: 10.48 mg/L), χ2 = 50.78, p  = 0.00. The highest fibrinogen was detected in patients with iliofemoral DVT as well (mean 4.87 g/L), χ2 = 11.1, p  = 0.01. D-dimer and fibrinogen values are significantly higher in patients iliofemoral DVT than femoral-popliteal and isolated calf DVT, and D-dimer values are significantly higher in lower extremity DVT than UEDVT, but these biomarkers cannot be used alone to discriminate between thrombosis locations. Further imaging is required.

D-dimer to fibrinogen ratio predicts early neurological deterioration in ischemic stroke with atrial fibrillation

INTRODUCTION

The D-dimer to fibrinogen ratio (DFR) is a good indicator of clot-producing activity in thrombotic disease, but its clinical usefulness in stroke patients with nonvalvular atrial fibrillation (NVAF) has not been studied. We evaluated the association between the DFR and early neurological deterioration (END) in acute ischemic stroke (AIS) patients with NVAF.

METHODS

We included consecutive AIS patients with NVAF between 2013 and 2015 from the registry of a real-world prospective cohort from 11 large centers in South Korea. END was defined as an increase ≥2 in the total NIHSS score or ≥ 1 in the motor NIHSS score within the first 72 h of admission. The DFR was calculated as follows: DFR = D-dimer (mg/L)/fibrinogen (mg/dL) x 100.

RESULTS

A total of 1018 AIS patients with NVAF were evaluated. In multivariable logistic regression analysis, the highest DFR tertile was closely associated with END (adjusted odds ratio [aOR] = 2.14, 95 % confidence interval [CI]: 1.24-3.69). Hypertension (aOR = 1.71, 95 % CI: 1.09-2.70), initial NIHSS score (aOR = 1.05, 95 % CI: 1.02-1.07) and use of anticoagulants (aOR = 0.41, 95 % CI: 0.28-0.60) were also correlated with END. In addition to END, the DFR was correlated with discharge NIHSS and modified Rankin Scale (mRS) scores and the 3-month mRS score.

CONCLUSIONS

High DFR values were associated with END in AIS patients with NVAF. As the DFR is an indicator directly related to the main pathological mechanism of NVAF patients (fibrinolysis and coagulation), it may be useful in predicting their prognosis.

D-dimer/fibrinogen ratio for the prediction of deep venous thrombosis after traumatic spinal cord injury

STUDY DESIGN

Retrospective cohort study.

OBJECTIVES

To evaluate the predictive value of D-dimer/fibrinogen (D/F) ratio for deep vein thrombosis (DVT) in patients with traumatic spinal cord injury (SCI).

SETTING

Department of Rehabilitation Medicine Center, West China Hospital, Sichuan University.

METHODS

SCI patients within 24 h of trauma were consecutively enrolled. DVT was diagnosed by DUS examination during hospitalization. Multivariable logistic regression analysis was performed to determine the relationship between D/F ratio and DVT. Stratified logistic regression analysis was performed to identify effect modifiers. The receiver operating characteristic (ROC) curve was conducted to assess the predictive value of D/F ratio.

RESULTS

A total of 284 patients with SCI were included, of whom 106 (37.3%) developed DVT. D/F ratio was positively correlated with DVT (OR 1.17, 95% confidence interval [CI] 1.04-1.31, p = 0.009). Patients in the upper D/F ratio tertile (3.15-18.27) had a higher risk of DVT than patients in the lower tertile (0.08-0.97) after adjustment for potential confounders (OR 6.01, 95% CI 2.24-16.15, p < 0.001). The risk of DVT increased stepwise across D/F ratio tertiles (p for trend = 0.003). The area under the ROC curve (AUC) was 0.758 (95% CI 0.704-0.806). There was a significant interaction between D/F ratio and neurological level of injury (p for interaction = 0.003) and the association between D/F ratio and DVT remained significant only in patients with cervical injury.

CONCLUSIONS

A higher D/F ratio was independently associated with a higher risk of DVT in a dose-dependent manner in patients with cervical SCI.

Using an age and fibrinogen levels adjusted D-dimer cutoff significantly improves the specificity of two equivalent D-dimer assays for excluding pulmonary embolism

OBJECTIVES

Our single-center prospective study compared two methods of D-dimer determination used in the exclusion of pulmonary embolism: bioMérieux method, VIDAS® D-Dimer Exclusion™ II, and Diagnostica Stago method, STA®-Liatest® D-Di Plus. For each of these two methods, we calculated optimized variable cutoffs based on fibrinogen and/or age to improve the specificity of the methods.

PATIENTS - METHODS

2530 patients admitted to the Emergency Department of the Brest University Hospital for suspected pulmonary embolism were included in this study. The comparison of the two methods was performed by calculating their different characteristics: sensitivity, specificity and negative predictive value for different cutoffs systems: fixed or age-adjusted according to Douma et al. An optimization of the variable cutoff according to age and fibrinogen was then performed.

RESULTS

The two methods VIDAS and STAGO are approximately equivalent in terms of performance even if the STAGO method presents a better specificity (57.1 %) at the fixed cutoff of 0.5 μg/mL. The adoption of age-adjusted, fibrinogen-adjusted or doubly-adjusted (age and fibrinogen) cutoffs, significantly improves the specificity of the tests without affecting their excellent sensitivity. These specificities peak respectively at 75.8 % and 76 % for the VIDAS and STAGO tests when using a doubly-adjusted, age and fibrinogen, cutoff, i.e. a gain in specificity of approximately 10 % compared with the age-adjusted cutoff of Douma et al. and of approximately 20 % compared with the fixed cutoff of 0.5 μg/mL.

CONCLUSION

Adopting an optimized variable cutoff based on fibrinogen and/or age significantly improves specificity of D-dimer methods for pulmonary embolism exclusion.

Development of a Decision Support Tool for Anticoagulation in Critically Ill Patients Admitted for SARS-CoV-2 Infection: The CALT Protocol

Severe COVID-19 infections are at high risk of causing thromboembolic events (TEEs). However, the usual exams may be unavailable or unreliable in predicting the risk of TEEs at admission or during hospitalization. We performed a retrospective analysis of two centers (n = 124 patients) including severe COVID-19 patients to determine the specific risk factors of TEEs in SARS-CoV-2 infection at admission and during stays at the intensive care unit (ICU). We used stepwise regression to create two composite scores in order to predict TEEs in the first 48 h (H0-H48) and during the first 15 days (D1-D15) in ICU. We then evaluated the performance of our scores in our cohort. During the period H0-H48, patients with a TEE diagnosis had higher D-Dimers and ferritin values at day 1 (D1) and day 3 (D3) and a greater drop in fibrinogen between D1 and D3 compared with patients without TEEs. Over the period D1-D15, patients with a diagnosis of a TEE showed a more marked drop in fibrinogen and had higher D-Dimers and lactate dehydrogenase (LDH) values at D1 and D3. Based on ROC analysis, the COVID-related acute lung and deep vein thrombosis (CALT) 1 score, calculated at D1, had a diagnostic performance for TEEs at H0-H48, estimated using an area under the curve (AUC) of 0.85 (CI95%: 0.76-0.93, p < 10^-3). The CALT 2 score, calculated at D3, predicted the occurrence of TEEs over the period D1-D15 with an estimated AUC of 0.85 (CI95%: 0.77-0.93, p < 10^-3). These two scores were used as the basis for the development of the CALT protocol, a tool to assist in the decision to use anticoagulation during severe SARS-CoV-2 infections. The CALT scores showed good performances in predicting the risk of TEEs in severe COVID-19 patients at admission and during ICU stays. They could, therefore, be used as a decision support protocol on whether or not to initiate therapeutic anticoagulation.

Developing a nomogram-based scoring model to estimate the risk of pulmonary embolism in respiratory department patients suspected of pulmonary embolisms

Objective

Pulmonary embolisms (PE) are clinically challenging because of their high morbidity and mortality. This study aimed to create a nomogram to accurately predict the risk of PE in respiratory department patients in order to enhance their medical treatment and management.

Methods

This study utilized a retrospective method to collect information on medical history, complications, specific clinical characteristics, and laboratory biomarker results of suspected PE patients who were admitted to the respiratory department at Affiliated Dongyang Hospital of Wenzhou Medical University between January 2012 and December 2021. This study involved a total of 3,511 patients who were randomly divided into a training group (six parts) and a validation group (four parts) based on a 6:4 ratio. The LASSO regression and multivariate logistic regression were used to develop a scoring model using a nomogram. The performance of the model was evaluated using receiver operating characteristic curve (AUC), calibration curve, and clinical decision curve.

Results

Our research included more than 50 features from 3,511 patients. The nomogram-based scoring model was established using six predictive features including age, smoke, temperature, systolic pressure, D-dimer, and fibrinogen, which achieved AUC values of 0.746 in the training cohort (95% CI 0.720-0.765) and 0.724 in the validation cohort (95% CI 0.695-0.753). The results of the calibration curve revealed a strong consistency between probability predicted by the nomogram and actual probability. The decision curve analysis (DCA) also demonstrated that the nomogram-based scoring model produced a favorable net clinical benefit.

Conclusion

In this study, we successfully developed a novel numerical model that can predict the risk of PE in respiratory department patients suspected of PE, which can not only appropriately select PE prevention strategies but also decrease unnecessary computed tomographic pulmonary angiography (CTPA) scans and their adverse effects.

Predictors and outcomes of acute pulmonary embolism in COVID-19; insights from US National COVID cohort collaborative

OBJECTIVES

To investigate whether COVID-19 patients with pulmonary embolism had higher mortality and assess the utility of D-dimer in predicting acute pulmonary embolism.

PATIENTS AND METHODS

Using the National Collaborative COVID-19 retrospective cohort, a cohort of hospitalized COVID-19 patients was studied to compare 90-day mortality and intubation outcomes in patients with and without pulmonary embolism in a multivariable cox regression analysis. The secondary measured outcomes in 1:4 propensity score-matched analysis included length of stay, chest pain incidence, heart rate, history of pulmonary embolism or DVT, and admission laboratory parameters.

RESULTS

Among 31,500 hospitalized COVID-19 patients, 1117 (3.5%) patients were diagnosed with acute pulmonary embolism. Patients with acute pulmonary embolism were noted to have higher mortality (23.6% vs.12.8%; adjusted Hazard Ratio (aHR) = 1.36, 95% CI [1.20-1.55]), and intubation rates (17.6% vs. 9.3%, aHR = 1.38[1.18-1.61]). Pulmonary embolism patients had higher admission D-dimer FEU (Odds Ratio(OR) = 1.13; 95%CI [1.1-1.15]). As the D-dimer value increased, the specificity, positive predictive value, and accuracy of the test increased; however, sensitivity decreased (AUC 0.70). At cut-off D-dimer FEU 1.8 mcg/ml, the test had clinical utility (accuracy 70%) in predicting pulmonary embolism. Patients with acute pulmonary embolism had a higher incidence of chest pain and history of pulmonary embolism or deep vein thrombosis.

CONCLUSIONS

Acute pulmonary embolism is associated with worse mortality and morbidity outcomes in COVID-19. We present D-dimer as a predictive risk tool in the form of a clinical calculator for the diagnosis of acute pulmonary embolism in COVID-19.

Discussion on operation: To compare the curative effect of PMT and CDT in the treatment of middle and high risk stratified APE and the clinical application value of serum BNP, TnI and plasma DFR levelse

Objective

To compare the efficacy of Percutaneous mechanical thrombectomy (PMT) and Catheter directed thrombolysis (CDT) in the treatment of patients with moderate and high-risk ape and explore the clinical application value of biomarkers in the treatment of moderate and high-risk ape.

Method

A total of 84 patients with ape were selected from the Department of vascular surgery of the Second Affiliated Hospital of Shandong First Medical University and the Department of vascular surgery of Shanghai Ninth People's Hospital Affiliated with Shanghai Jiao Tong University School of Medicine. According to the relevant guidelines, they were divided into high-risk and medium-risk groups, including PMT groups (35 cases) and CDT groups (49 cases). To detect the changes of serum B-type brain natriuretic peptide (BNP),Troponin I (TnI) and plasma D-dimer/fibrinogen ratio (DFR) levels in different risk stratification before and after PMT and CDT, the correlation and diagnostic value of each index, and compare the thrombus clearance rate, pulmonary artery pressure, average dosage of urokinase, effective thrombolytic time, average hospitalization time and complications of PMT and CDT.

Result

Under different treatment methods and risk stratification, there was no statistically significant difference in the clinical data of patients at general baseline;The preoperative BNP, TnI and DFR levels of PMT and CDT in the middle and high risk stratification were significantly lower than those in the other groups (P < 0.005),Compared with the CDT group, PMT has significantly better therapeutic effect on ape than the CDT group in terms of thrombus clearance rate, pulmonary artery pressure, average dosage of urokinase, effective thrombolytic time and average hospitalization time (P < 0.05),meanwhile,there was no significant difference in postoperative complications between the two groups (P < 0.05). After half a year of follow-up, the levels of BNP, TnI and DFR in the cured group were significantly lower than those in the effective group and the ineffective group. The areas under the curve of serum BNP, TnI and plasma DFR were 0.91, 0.87 and 0.93 and the area under the curve DFR has higher diagnostic efficiency than BNP and TnI, while the sensitivity and specificity of TnI are significantly higher than BNP and DFR.

Conclusion

Serum BNP, TnI and plasma DFR levels can reflect the risk stratification and better clinical diagnostic value of ape,PMT and CDT are used to treat high-risk ape. For hospitals with medical conditions, PMT is more worthy of clinical recommendation.

Prevalence and Risk Factors of Venous Thromboembolism in Critically Ill Patients with Severe COVID-19 and the Association between the Dose of Anticoagulants and Outcomes

Introduction

COVID-19 is characterized by a procoagulant state that increases the risk of venous and arterial thrombosis. The dose of anticoagulants in patients with severe COVID-19 pneumonia without suspected or confirmed thrombosis has been debated.

Aim of the study

We evaluated the prevalence, predictors, and outcomes of venous thromboembolism (VTE) in critically ill COVID-19 patients and assessed the association between the dose of anticoagulants and outcomes.

Materials and methods

This retrospective cohort included patients with COVID-19 who were admitted to the ICU between March and July 2020. Patients with clinically suspected and confirmed VTE were compared to those not diagnosed to have VTE.

Results

The study enrolled 310 consecutive patients with severe COVID-19 pneumonia: age 60.0±15.1 years, 67.1% required mechanical ventilation and 44.7% vasopressors. Most (97.1%) patients received anticoagulants during ICU stay: prophylactic unfractionated heparin (N=106), standard-dose enoxaparin (N=104) and intermediate-dose enoxaparin (N=57). Limb Doppler ultrasound was performed for 49 (15.8%) patients and chest computed tomographic angiography for 62 (20%). VTE was diagnosed in 41 (13.2%) patients; 20 patients had deep vein thrombosis and 23 had acute pulmonary embolism. Patients with VTE had significantly higher D-dimer on ICU admission. On multivariable Cox regression analysis, intermediate-dose enoxaparin versus standard-dose unfractionated heparin or enoxaparin was associated with lower VTE risk (hazard ratio, 0.06; 95% confidence interval, 0.01-0.74) and lower risk of the composite outcome of VTE or hospital mortality (hazard ratio, 0.42; 95% confidence interval, 0.23-0.78; p=0.006). Major bleeding was not different between the intermediate- and prophylactic-dose heparin groups.

Conclusions

In our study, clinically suspected and confirmed VTE was diagnosed in 13.2% of critically ill patients with COVID-19. Intermediate-dose enoxaparin versus standard-dose unfractionated heparin or enoxaparin was associated with decreased risk of VTE or hospital mortality.

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.

Diagnostic Value of Galectin-3 for Identifying Acute Pulmonary Embolism in the Emergency Department

BACKGROUND

Pulmonary embolism (PE) is a common disease associated with high mortality and morbidity. Diagnosing PE is challenging due to diverse clinical presentations and the lack of specific biomarkers.

OBJECTIVE

We hypothesized that plasma galectin-3 (Gal-3) levels might reflect the severity of acute PE and be useful for diagnostic assessment.

METHODS

In this prospective study, 150 patients (100 patients with PE and 50 control patients) were included. Patients were stratified into high-risk, medium-risk, and low-risk groups according to the Wells and revised Geneva scoring systems, and Gal-3 levels were compared among the groups. PE was diagnosed by means of computed tomography pulmonary angiography.

RESULTS

In this study, of the 100 PE patients included in the study, 69 patients recovered and were discharged and 31 patients died. Median Gal-3 value in the PE group was 27.0 ng/mL (range 11.5-35.0 ng/mL), whereas the median Gal-3 value in the control group was significantly lower at 8.8 ng/mL (range 1.0-21.0 ng/mL) (p < 0.001). When the Gal-3 values of the PE group and the control group were evaluated with the receiver operator characteristic curve, the area under the curve was calculated as 0.99 (95% confidence interval 0.979-1). At a Gal-3 cutoff value of 13.55 ng/mL, which was determined to be the most appropriate value for PE diagnosis, the sensitivity was 98% and the specificity was 92%.

CONCLUSIONS

A biomarker that rapidly and accurately diagnoses acute PE in the emergency department can be an extremely useful tool. We concluded that plasma Gal-3 levels can be regarded as a promising marker of acute PE.

Hypercoagulation Detected by Rotational Thromboelastometry Predicts Mortality in COVID-19: A Risk Model Based on a Prospective Observational Study

Background  Severe disease due to the novel coronavirus disease 2019 (COVID-19) has been shown to be associated with hypercoagulation. The aim of this study was to assess the Rotational Thromboelastometry (ROTEM) as a marker of coagulopathy in hospitalized COVID-19 patients. Methods  This was a prospective, observational study where patients hospitalized due to a COVID-19 infection were eligible for inclusion. Conventional coagulation tests and ROTEM were taken after hospital admission, and patients were followed for 30 days. A prediction model, including variables ROTEM EXTEM-MCF (Maximum Clot Firmness) which in previous data has been suggested a suitable marker of hypercoagulation, age, and respiratory frequency, was developed using logistic regression to evaluate the probability of death. Results  Out of the 141 patients included, 18 (13%) died within 30 days. In the final prediction model, the risk of death within 30 days for a patient hospitalized due to COVID-19 was increased with increased EXTEM-MCF, age, and respiratory frequency. Longitudinal ROTEM data in the severely ill subpopulation showed enhanced hypercoagulation. In an in vitro analysis, no heparin effect on EXTEM-coagulation time (CT) was observed, supporting a severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) effect on prolonged initiation of coagulation. Conclusion  Here, we show that hypercoagulation measured with ROTEM predicts 30-day mortality in COVID-19. Longitudinal ROTEM data strengthen the hypothesis of hypercoagulation as a driver of severe disease in COVID-19. Thus, ROTEM may be a useful tool to assess disease severity in COVID-19 and could potentially guide anticoagulation therapy.

Prognostic value of D-dimer/fibrinogen ratio on in-hospital outcomes of patients with heart failure and COVID-19

Aim: In the present study, the relationship between D-dimer/fibrinogen ratio (DFR) and in-hospital outcomes was evaluated in patients with COVID-19 and a diagnosis of heart failure (HF). Materials & methods: In-hospital outcomes were compared in patients with high and low DFR values. Results: With regard to in-hospital outcomes, patients in the third tertile of DFR had a higher rate of mechanical ventilation, cardiogenic shock and death (p < 0.001). The length of ICU stay was longer in the third tertile group (p < 0.001). When evaluated together with infection markers, DFR was found to be an independent predictor of outcomes. Conclusion: DFR can be used as a prognostic marker in patients with COVID-19 with a diagnosis of HF, and perhaps more valuable than other infection markers.

Could a D-dimer/fibrinogen ratio have a role in ruling-out venous thromboembolism?

BACKGROUND

Diagnosis of venous thromboembolism (VTE) requires chest CT angiography for pulmonary embolism and venous ultrasound for deep vein thrombosis. To reduce imaging, guidelines recommend D-dimer levels to rule-out VTE in patients with a low pre-test probability. The most widely used D-dimer cut-off is 500 ng/mL. This cut-off has low specificity, meaning many patients without disease require imaging.

METHODS

In this retrospective chart review, we evaluated the diagnostic performance of the D-dimer/fibrinogen ratio (DFR) for identifying thromboembolism and compared it to the performance of two different D-dimer cut-offs (500 ng/mL and 1000 ng/mL) in patients who underwent a chest CT angiography or a venous ultrasound in the ED of San Raffaele Hospital, Italy, in 2017. Patients had a retrospective Wells score calculated after chart review, identifying both high-risk and low-risk pre-test probability patients for this study and low probability patients were further stratified into low-risk of deep vein thrombosis or pulmonary embolism.

RESULTS

Enrolled patients included 92 with suspected pulmonary embolism and 154 with suspected deep vein thrombosis; of whom 67 (27%) were diagnosed with VTE. The most accurate cut-off for DFR in terms of discriminative power was 2.65. In the whole sample and in low-risk patients, this cut-off had the same sensitivity values of the 500 ng/mL D-dimer cut-off (97% (95% CI: 89.8% to 99.2%)), while slightly lower sensitivity values were found for the 1000 ng/mL D-dimer cut-off (95.5% (95% CI: 87.6% to 98.5%)). Specificity was higher for the 2.65 DFR cut-off (55.3% (95% CI: 48.0% to 62.4%)) in the whole sample compared with both 500 ng/mL D-dimer cut-off (22.9% (95% CI: 17.4% to 29.6%)) and 1000 ng/mL D-dimer cut-off (45.8% (95% CI: 38.7% to 53.1%)). Similar results were found in all subgroups.

CONCLUSION

A DFR, with a cut-off of 2.65, may improve the specificity for VTE patients when compared with D-dimer alone in high-risk VTE emergency medicine populations. This is exploratory information only, needing evaluation in prospective, multicentre studies, prior to consideration for use in routine clinical work.

D-Dimer to Fibrinogen Ratio as a Novel Prognostic Marker in Patients After Undergoing Percutaneous Coronary Intervention: A Retrospective Cohort Study

The role of activation of the coagulation and fibrinolysis system in the pathogenesis and prognosis of cardiovascular diseases (CVDs) has drawn wide attention. Recently, the D-dimer to fibrinogen ratio (DFR) is considered as a useful biomarker for the diagnosis and prognosis of ischemic stroke and pulmonary embolism. However, few studies have explored the relationship between DFR and cardiovascular disease. In our study, patients were divided into 2 groups according to DFR value: the lower group (DFR < 0.52, n = 2123) and the higher group (DFR ≥ 0.52, n = 1073). The primary outcome was all-cause mortality (ACM) and cardiac mortality (CM). The average follow-up time was 37.59 ± 22.24 months. We found that there were significant differences between the 2 groups in term of ACM (2.4% vs 6.6%, P < 0.001) and CM (1.5% vs 4.0%, P < 0.001). Kaplan-Meier analyses showed that elevated DFR had higher incidences of ACM (log rank P < 0.001) and CM (log rank P < 0.001). Multivariate Cox regression analyses showed that DFR was an independent predictor of ACM (HR = 1.743, 95%CI: 1.187-2.559 P = 0.005) and CM (HR = 1.695, 95%CI: 1.033-2.781 P = 0.037). This study indicates that DFR is an independent and novel predictor of long-term ACM and CM in post-PCI patients with CAD.

Serial markers of coagulation and inflammation and the occurrence of clinical pulmonary thromboembolism in mechanically ventilated patients with SARS-CoV-2 infection; the prospective Maastricht intensive care COVID cohort

Background

The incidence of pulmonary thromboembolism is high in SARS-CoV-2 patients admitted to the Intensive Care. Elevated biomarkers of coagulation (fibrinogen and D-dimer) and inflammation (c-reactive protein (CRP) and ferritin) are associated with poor outcome in SARS-CoV-2. Whether the time-course of fibrinogen, D-dimer, CRP and ferritin is associated with the occurrence of pulmonary thromboembolism in SARS-CoV-2 patients is unknown. We hypothesise that patients on mechanical ventilation with SARS-CoV-2 infection and clinical pulmonary thromboembolism have lower concentrations of fibrinogen and higher D-dimer, CRP, and ferritin concentrations over time compared to patients without a clinical pulmonary thromboembolism.

Methods

In a prospective study, fibrinogen, D-dimer, CRP and ferritin were measured daily. Clinical suspected pulmonary thromboembolism was either confirmed or excluded based on computed tomography pulmonary angiography (CTPA) or by transthoracic ultrasound (TTU) (i.e., right-sided cardiac thrombus). In addition, patients who received therapy with recombinant tissue plasminogen activator were included when clinical instability in suspected pulmonary thromboembolism did not allow CTPA. Serial data were analysed using a mixed-effects linear regression model, and models were adjusted for known risk factors (age, sex, APACHE-II score, body mass index), biomarkers of coagulation and inflammation, and anticoagulants.

Results

Thirty-one patients were considered to suffer from pulmonary thromboembolism ((positive CTPA (n = 27), TTU positive (n = 1), therapy with recombinant tissue plasminogen activator (n = 3)), and eight patients with negative CTPA were included. After adjustment for known risk factors and anticoagulants, patients with, compared to those without, clinical pulmonary thromboembolism had lower average fibrinogen concentration of − 0.9 g/L (95% CI: − 1.6 – − 0.1) and lower average ferritin concentration of − 1045 μg/L (95% CI: − 1983 – − 106) over time. D-dimer and CRP average concentration did not significantly differ, 561 μg/L (− 6212–7334) and 27 mg/L (− 32–86) respectively. Ferritin lost statistical significance, both in sensitivity analysis and after adjustment for fibrinogen and D-dimer.

Conclusion

Lower average concentrations of fibrinogen over time were associated with the presence of clinical pulmonary thromboembolism in patients at the Intensive Care, whereas D-dimer, CRP and ferritin were not. Lower concentrations over time may indicate the consumption of fibrinogen related to thrombus formation in the pulmonary vessels.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12959-021-00286-7.

Hypercoagulable viscoelastic blood clot characteristics in critically ill coronavirus disease 2019 patients and associations with thrombotic complications

BACKGROUND

Critically ill coronavirus disease 2019 (COVID-19) patients have frequent thrombotic complications and laboratory evidence of hypercoagulability. The relationship of coagulation tests and thrombosis requires investigation to identify best diagnostic and treatment approaches. We assessed for hypercoagulable characteristics in critically ill COVID-19 patients using rotational thromboelastometry (ROTEM) and explored relationships of D-dimer and ROTEM measurements with thrombotic complications.

METHODS

Critically ill adult COVID-19 patients receiving ROTEM testing between March and April 2020 were analyzed. Patients receiving therapeutic anticoagulation before ROTEM were excluded. Rotational thromboelastometry measurements from COVID-19 patients were compared with non-COVID-19 patients matched by age, sex, and body mass index. Intergroup differences in ROTEM measurements were assessed using t tests. Correlations of D-dimer levels to ROTEM measurements were assessed in COVID-19 patients who had available concurrent testing. Intergroup differences of D-dimer and ROTEM measurements were explored in COVID-19 patients with and without thrombosis.

RESULTS

Of 30 COVID-19 patients receiving ROTEM, we identified hypercoagulability from elevated fibrinogen compared with non-COVID-19 patients (fibrinogen assay maximum clot firmness [MCF], 47 ± 13 mm vs. 20 ± 7 mm; mean intergroup difference, 27.4 mm; 95% confidence interval [CI], 22.1-32.7 mm; p < 0.0001). In our COVID-19 cohort, thrombotic complications were identified in 33%. In COVID-19 patients developing thrombotic complications, we identified higher D-dimer levels (17.5 ± 4.3 μg/mL vs. 8.0 ± 6.3 μg/mL; mean difference, 9.5 μg/mL; 95% CI, 13.9-5.1; p < 0.0001) but lower fibrinogen assay MCF (39.7 ± 10.8 mm vs. 50.1 ± 12.0 mm; mean difference, -11.2 mm; 95% CI, -2.1 to -20.2; p = 0.02) compared with patients without thrombosis. We identified negative correlations of D-dimer levels and ROTEM MCF in these patients (r = -0.61; p = 0.001).

CONCLUSION

We identified elevated D-dimer levels and hypercoagulable blood clot characteristics from increased fibrinogen on ROTEM testing in critically ill COVID-19 patients. However, we identified lower, albeit still hypercoagulable, ROTEM measurements of fibrinogen in COVID-19 patients with thrombotic complications compared with those without. Further work is required to externally validate these findings and to investigate the mechanistic drivers for these relationships to identify best diagnostic and treatment approaches for these patients.

LEVEL OF EVIDENCE

Epidemiologic, level IV.

Prognostic value of D-dimer/fibrinogen ratio in the adverse outcomes of patients hospitalized for heart failure

Aim: To evaluate the clinical value of plasma D-dimer/fibrinogen ratio (DFR) in patients hospitalized for heart failure (HF). Methods: Clinical data of 235 patients were retrospectively analyzed. Kaplan-Meier method and Cox regression analysis were used to identify significant prognosticators. Results: The Kaplan-Meier analysis showed that a higher DFR level was significantly associated with an increase in the end point outcomes, including HF readmission, thrombotic events and death (log-rank test: p < 0.001). The multivariate Cox regression analysis showed that the high tertile of DFR was significantly associated with the study end points (HR: 2.18; 95% CI: 1.31-3.62; p = 0.003), compared with the low tertile. Conclusion: DFR is a reliable prognostic indicator for patients hospitalized for HF.

Role of Serum Markers in Combination as a Diagnostic Tool for Acute Pulmonary Embolism: Cross-Sectional Study

Background and objective Acute pulmonary embolism (APE) is a serious cardiovascular emergency, mainly secondary to deep vein thrombosis (DVT), which causes death. The goal of the current study was to determine the levels of different serum markers in combination among patients with and without acute pulmonary embolism in order to use them as a diagnostic tool. Methodology A sample of 96 patients was kept with a 90% power of study and a 5% level of significance in the current study. It was carried from January to June 2020 in the Department of Medicine, Bahawal Victoria Hospital, Bahawalpur, after the hospital's Ethical Committee approval. Written informed consent was taken. Serum levels of C-reactive protein (CRP), D-dimer, fibrinogen, and Troponin-I between both groups were done once enrolled. SPSS software, version 25 (IBM Corp. Armonk, NY) was used to analyze the collected data. Results Patients with acute pulmonary embolism had a mean age of 50.4 ± 10.4 years. All serum markers were significantly raised in patients suffering from acute pulmonary embolism with a p-value of <0.05. Conclusion We concluded that all these serum markers can be used together as a tool in making the correct diagnosis of acute pulmonary embolism in our setup.

The protective rather than prothrombotic fibrinogen in COVID-19 and other inflammatory states

Hypercoagulability has been recognized as a common complication of COVID-19. Exact mechanisms for this extreme coagulation activation have not yet been elucidated. However, one of the consistent laboratory finding is the increase in fibrinogen, in some cases, marked elevation. High circulating levels of fibrinogen have been linked to thrombosis for years and for this reason, hyperfibrinogenemia is considered one of the mechanisms for COVID-19 coagulopathy. In this forum article, instead of the prothrombotic role, a protective function for fibrinogen is discussed. Fibrinogen, like the other well-known acute phase reactants, is increased in COVID-19 possibly to protect the host.

Reference Values of D-Dimers and Fibrinogen in the Course of Physiological Pregnancy: the Potential Impact of Selected Risk Factors-A Pilot Study

Pregnancy predisposes to thrombotic hemostasis, reflected in the laboratory as, e.g., increased levels of D-Dimers and fibrinogen, but in physiological pregnancy, the risk of venous thrombosis does not increase. Risk may increase if gestational diabetes mellitus (GDM) or nicotinism coexists. Study aims were to determine reference values for D-Dimers and fibrinogen concentrations in each trimester of pregnancy, corrected for GDM and nicotinism. Subjects and Methods. The study involved 71 pregnant women aged 25-44 y. Venous blood was collected three times: in the first (11-14 weeks), second (20-22 weeks), and third (30-31 weeks) trimesters. D-Dimer concentrations were determined by an enzyme-linked fluorescence assay, fibrinogen concentrations by a coagulation method according to Clauss. Results. Significant increases in D-Dimers and fibrinogen concentrations were observed, increasing with successive trimesters (p ANOVA < 0.0001). Furthermore, a positive correlation between D-Dimers and fibrinogen was detected in the second trimester of pregnancy (r = 0.475; p < 0.0001). In addition, a significantly higher fibrinogen concentration was found in women with GDM compared to without GDM (p = 0.0449). Reference ranges for D-Dimers were established, in trimester order, as follows: 167-721 ng/mL, 298-1653 ng/mL, and 483-2256 ng/mL. After adjusting for risk factors, significantly higher D-Dimer values (mainly second and third trimesters) were obtained: 165-638 ng/mL, 282-3474 ng/mL, and 483-4486 ng/mL, respectively. Reference ranges for fibrinogen were, in trimester order, 2.60-6.56 g/L, 3.40-8.53 g/L, and 3.63-9.14 g/L and, after adjustment for risk factors, 3.34-6.73 g/L, 3.40-8.84 g/L, and 3.12-9.91 g/L. Conclusions. We conclude that the increase in D-Dimers and fibrinogen levels in women with physiological pregnancy was compounded by gestational diabetes (GDM) and nicotinism. Therefore, D-Dimers and fibrinogen pregnancy reference values require correction for these risk factors.

The Potential Value of D-Dimer to Fibrinogen Ratio in Diagnosis of Acute Ischemic Stroke

INTRODUCTION AND OBJECTIVE

At present, there is no hematology marker with high specificity to the diagnosis and differential diagnosis of acute ischemic stroke (AIS). How to use the existing test items to improve the diagnosis efficiency worthy of discussion. D-Dimer (DD) and fibrinogen (FIB) were the common indicators in thrombotic diseases, but D-dimer to fibrinogen ratio (D/F) in AIS has not been used in clinical practice. In this work, we focus on the evaluation of D/F.

METHODS

90 AIS patients were selected as the observation group and 65 other patients without coagulation function disorder as the control group. Meanwhile, a total of 33 patients with other diseases with impaired consciousness in the same period were collected. Based on the AIS patients with or without consciousness disorder divided it into consciousness disorder group and unconsciousness disorder group. Then based on the patients with or without consciousness disorder divided it into other diseases with unconsciousness disorder group and Other diseases with lacunar cerebral infarction (LCI)and disturbance of consciousness group. then compare the differences of plasma DD, FIB and D/F between groups.

RESULTS

All plasma DD, FIB and D/F ratio in AIS patients were significantly higher than in other disease group (P = 0.000, P = 0.001, P = 0.000), but DD, D/F in disorders of consciousness group was significantly higher than in unconsciousness disorders group (P = 0.007, P = 0.005). The DD of the AIS with consciousness disorder group were significantly higher than that of the other disease with consciousness disorder group (P = 0.042), and the DD, D/F ratio of Other diseases with lacunar cerebral infarction and disturbance of consciousness group were significantly higher than one(P = 0.000, P = 0.003). All others are undifferentiated.

CONCLUSIONS

When DD, D/F ratio is high, other diseases caused by consciousness disorders are likely to be combined with infarcts, which can be used for the diagnosis and differential diagnosis of patients with different types of consciousness disorders, especially hospitalized patients.

Outcomes following a negative computed tomography pulmonary angiography according to pulmonary embolism prevalence: a meta-analysis of the management outcome studies

Essentials Computed tomographic pulmonary angiography (CTPA) is used to exclude pulmonary embolism. This meta-analysis explores the occurrence of venous thromboembolic events (VTE) after a CTPA. Occurrence of VTE after a negative CTPA is ˜8% in study subgroups with a prevalence of PE ≥ 40%. CTPA may be insufficient to safely rule out VTE as a stand-alone diagnostic test for this subgroup.

SUMMARY

Background Outcome studies have reported the safety of computed tomographic pulmonary angiography (CTPA) as a stand-alone imaging technique to rule out pulmonary embolism (PE). Whether this can be applied to all clinical probabilities remains controversial. Objectives We performed a meta-analysis to determine the proportion of patients with venous thromboembolic events (VTE) despite a negative CTPA according to pretest PE prevalence. Methods We searched MEDLINE, EMBASE and the Cochrane Library (January 1990 to May 2017) for outcome studies recruiting patients with suspected PE using CTPA as a diagnostic strategy. The primary outcome was the cumulative occurrence of VTE at 3 months following a negative CTPA. Results Twenty-two different studies were identified. VTE was confirmed in 2.4% of patients (95% CI, 1.3-3.8%) either at the time of the index event or in the 3 months follow-up. Subgroup analyses suggested that the cumulative occurrence of VTE was related to pretest prevalence of PE, as VTE occurred in 1.8% (95% CI, 0.5-3.7%), 1.4% (95% CI, 0.7-2.3%), 1.0% (95% CI, 0.5-1.8%) and 8.1% (95% CI, 3.5-14.5%) of subgroups of patients with a PE prevalence < 20%, 20-29%, 30-39% and ≥ 40%, respectively. This was further confirmed using meta-regression analysis. Conclusions The negative predictive value of CTPA for VTE varies according to pretest prevalence of PE, and is likely to be insufficient to safely rule out VTE as a stand-alone diagnostic test amongst patients at the highest pretest probability of VTE. Prospective studies are required to validate the appropriate diagnostic algorithm for this subgroup of patients.

Fibrinogen consumption is related to intracranial clot burden in acute ischemic stroke: a retrospective hyperdense artery study

Background

Understanding the underlying mechanism of thrombus formation and its components is critical for effective prevention and treatment of ischemic stroke. The generation of thrombotic clots requires conversion of soluble fibrinogen to an insoluble fibrin network. Quantitative features of intracranial clots causing acute ischemic stroke can be studied on non-contrast enhanced CT (NECT). Here, we evaluated on-admission fibrinogen and clot burden in relation to stroke severity, final infarct volume and in-hospital mortality.

Methods

We included 132 consecutive patients with ischemic stroke and presence of hyperdense artery sign admitted within 6 h from symptom onset. Radiological parameters including clot area (corresponding to clot burden) and final infarct volume were manually determined on NECT. National Institute of Health Stroke Scale (NIHSS) was used to quantify disease severity and short-term outcome.

Results

Median patient age was 77, 58 % were women, and 63 % had an occlusion of the proximal middle cerebral artery segment. Thrombolysis was performed in 60 % and thrombectomy in 44 %. We identified several independent associations. Higher fibrinogen levels on admission were associated with smaller clot burden (p = 0.033) and lower NIHSS on admission (p = 0.022). Patients with lower fibrinogen had a higher clot burden (p = 0.028) and greater final infarct volume (p = 0.003). Higher fibrinogen was associated with a lower risk of in-hospital death or NIHSS score >15 if discharged alive (p = 0.028).

Conclusions

Our study suggests that intracranial clot burden in acute ischemic stroke is associated with fibrinogen consumption, and shows a complex relationship with disease severity, infarct size and in-hospital survival.

Electronic supplementary material

The online version of this article (doi:10.1186/s12967-016-1006-6) contains supplementary material, which is available to authorized users.

Protein S deficiency present in a pregnant woman with dyspnea, abdominal pains, restlessness, agitation and hypofibrinogenemia

Hypofibrinogenemia is rare in pulmonary thromboembolism. A pregnant woman with dyspnea, abdominal pain, restlessness, agitation and protein S deficiency exhibited normal blood oxygenation and high D-dimer (370 μg/mL) and undetectable fibrinogen levels in the blood. The pathogenesis responsible for present findings may have some features similar to amniotic fluid embolism.

Effectiveness of d-dimer as a screening test for venous thromboembolism: an update

Venous thromboembolism (VTE) is the leading cause of morbidity and mortality among hospitalized patients. We searched the PubMed database and reviewed the articles published until June 2011. Articles related to the D-dimer and VTE were considered to write this paper. Many factors play a key role in changing the sensitivity and specificity of D-dimer testing, including the extent of thrombosis and fibrinolytic activity, duration of symptoms, anticoagulant therapy, comorbidity due to surgical or medical illnesses, inflammatory diseases, cancer, elderly age, pregnancy and the postpartum period, and previous VTE. Many previous studies have shown that the D-dimer test is highly sensitive (>95%) in acute deep venous thrombosis or pulmonary embolism, usually with a cut-off value of 500 μg FEU/l, which reasonably rules out acute VTE, particularly in patients with low clinical probability (LCP) or intermediate clinical probability. Patients with high D-dimer levels upon presentation may prompt a more intense diagnostic approach, irrespective of pretest probability. Studies performed after a negative D-dimer for 3 months proved the high negative predictive value (NPV) of D-dimer testing together with LCP in patients with suspected VTE. Among oncology patients, D-dimer testing has the highest sensitivity and NPV in excluding VTE. The new cutoff values of D-dimer testing were analyzed in a recent prospective study of pregnant women; they are 286 ng DDU/ml, 457 ng DDU/ml, and 644 ng DDU/ml for the first, second, and third trimesters, respectively.

Should we look for silent pulmonary embolism in patients with deep venous thrombosis?

Background

Asymptomatic or silent pulmonary embolism (S-PE) in patients with deep vein thrombosis has been the focus of numerous publications with the objective of determining the incidence of S-PE and assessing whether its existence has any clinical or therapeutic consequences that outweigh the risks associated with the diagnostic tests performed and the increased healthcare costs. The objectives were to assess the incidence of S-PE using computed tomography angiogram (CTA), to understand the epidemiological factors that might trigger embolism, and to assess whether D-dimer (DD) predicts the existence of S-PE’s.

Methods

A prospective and consecutive assessment of 103 hospitalized patients with lower limb DVT in the absence of PE symptoms, using CT scan. DD was quantified before anticoagulation. The risk factors and characteristics of the DVT were studied. A three-year follow-up assessing risk recurrence and clinical outcome was performed.

Results

The incidence of S-PE was 66%. In 77% of these cases, the main and lobar pulmonary arteries were affected. Iliac and femoral DVTs most often produced S-PE. ROC curve with a DD value higher than 578 ng/ml provided good sensitivity but low specificity to identify patients with S-PE. Diagnosis entailed higher hospitalization expenses. No significant recurrence rate of thrombotic events was observed in the S-PE group during the follow-up.

Conclusions

The incidence of S-PE in lower-limb DVT is high, but in the absence of symptoms, diagnosis does not appear to be necessary, as there are no short- or long-term clinical or therapeutic consequences.

D-dimer and D-dimer/fibrinogen ratio in predicting pulmonary embolism in patients evaluated in a hospital emergency department

OBJECTIVES

The D-dimer level, fibrinogen level, and D-dimer/fibrinogen ratio are used in the diagnosis of pulmonary embolism, but results vary. We evaluated these parameters in the diagnosis of pulmonary embolism in emergency clinic patients.

METHODS

In this prospective study, 200 patients (pulmonary embolism, 100 patients; no pulmonary embolism, 100 patients) had D-dimer and fibrinogen levels measured before intervention. Pulmonary embolism was diagnosed with computed tomography angiography or ventilation-perfusion scintigraphy.

RESULTS

Compared with patients who did not have pulmonary embolism, patients who had pulmonary embolism had significantly greater mean D-dimer level (pulmonary embolism, 6±7 μg/ml; no pulmonary embolism, 1±1 μg/ml; P⩽0·001) and D-dimer/fibrinogen ratio (pulmonary embolism, 3±3; no pulmonary embolism, 0·4±0·4; P⩽0·001), but similar mean fibrinogen levels (pulmonary embolism, 337±184 mg/dl; no pulmonary embolism, 384±200 mg/dl; not significant). In patients who had pulmonary embolism, mean D-dimer level and D-dimer/fibrinogen ratio were greater in high-risk than non-high-risk patients. With D-dimer cutoff 0·35 μg/ml, sensitivity was high (100%) and specificity was low (27%) for pulmonary embolism. With D-dimer/fibrinogen ratio cutoff 0·13, sensitivity was high (100%) and specificity was low (37%) for pulmonary embolism.

CONCLUSION

A D-dimer level <0·35 μg/ml may exclude the diagnosis of pulmonary embolism. At a D-dimer cutoff 0·5 μg/ml and D-dimer/fibrinogen ratio cutoff 1·0, the D-dimer/fibrinogen ratio may have better specificity than D-dimer level in the diagnosis of pulmonary embolism, but the D-dimer/fibrinogen ratio may lack sufficient specificity in screening.

Pregnancy-associated pulmonary embolism during the peripartum period: An 8-year experience at a single center

Objective

The purpose of this study was to estimate the incidence, timing of onset, risk factors, and mortality rate of pregnancy-associated pulmonary embolism (PAPE).

Methods

We analyzed PAPE cases that occurred between January 2005 and December 2012 at Cheil General Hospital & Women's Healthcare Center. Those cases that were not confirmed by computed tomography scan or were confirmed as amniotic fuid embolisms were excluded. We analyzed various risk factors such as previous surgery, mode of delivery, maternal age, and obesity in PAPE.

Results

There were 57,092 deliveries over 8 years. Of them, 13 cases (0.023%) were diagnosed with PAPE. All cases occurred in the postpartum period after cesarean delivery. There were no cases of PAPE after vaginal deliveries. Of the total cases, 10 cases (76.9%) were diagnosed in the early postpartum period within 48 hours. Eight cases (61.5%) had a history of previous surgery. There were 3 cases (23.1%) of multiple pregnancy and 3 cases (23.1%) of preterm delivery. No cases had a history of venous thromboembolism. Among 13 cases, 10 cases improved with only anticoagulation, 2 cases received surgical thrombectomy, and one case was maternal death.

Conclusion

Our results indicated that the incidence of PAPE was very low (0.023%) and occurred mainly in the postpartum period after cesarean section. However, its maternal mortality rate was significantly high (7.7%). Therefore, we suggest that immediate diagnosis and prompt treatment should be prioritized for improvement of PAPE patients' survival rate.

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

Challenges in the evaluation of D-dimer and fibrinogen levels in pregnant women

INTRODUCTION

Normal pregnancy is associated with hypercoagulable state. Elevated markers of coagulation and fibrinolytic system activation indicate increased thrombin activity and increased fibrinolysis following fibrin formation throughout pregnancy. These changes exceed the biological variability in most cases. Haemostatic reference intervals are generally based on samples from non-pregnant women. Thus, they may not be relevant to pregnant women, a problem that may hinder accurate diagnosis and treatment of haemostatic disorders during pregnancy. The aim of the study was to follow the changes of haemostatic parameters and to establish gestational age-specific reference intervals during normal pregnancy.

MATERIALS AND METHODS

Blood samples of 83 pregnant women were collected at gestational weeks 16, 26 and 36. Fibrinogen, D-dimer, and C-Reactive Protein (CRP) were examined. Reference intervals were calculated for fibrinogen, D-dimer tests with two different methods (mean±2 SD or median and 2.5th and 97.5th percentiles with 90% confidence intervals).

RESULTS

fibrinogen and D-dimer increased progressively throughout pregnancy. Mean fibrinogen levels were higher than the maximum of the conventional reference interval, already in the 16th week of pregnancy. D-dimer levels were at or above the conventional cutoff point (250ng/mL) throughout the pregnancy in 42% of pregnant women, while in the 36th week 98% of them displayed elevated D-dimer levels. CRP did not increase in normal pregnancy.

CONCLUSIONS

There seems to be an emerging need to reconsider fibrinogen and D-dimer values from a different aspect in pregnancy compared to non-pregnant reference intervals. New reference ranges are suggested to be established in pregnancy.

Imaging of acute pulmonary embolism

Acute pulmonary thromboembolism (PE) is a cardiovascular emergency associated with significant morbidity and a 5-35 % mortality for untreated pulmonary embolism. If promptly diagnosed and treated, the mortality rate can be significantly reduced. Diagnosis of acute PE continues to be a clinical challenge, with diagnostic imaging playing an important role. This review discusses the clinical challenges of diagnosing acute PE, presents an evidence-based review of the current tests and ever-evolving imaging technology, and highlights special considerations related to radiation dose, contrast media use, and pregnant patients.

Nitrated fibrinogen is a biomarker of oxidative stress in venous thromboembolism

The pathogenesis of venous thromboembolism (VTE) is linked to inflammation and oxidant production, although specific markers for these pathways with pathological relevance to VTE have not been explored. The coagulant protein fibrinogen is posttranslationally modified by nitric oxide-derived oxidants to nitrated fibrinogen in both acute and chronic inflammatory states. Therefore, nitrated fibrinogen may serve as a marker of inflammation and oxidative stress in VTE. To test this hypothesis we enrolled subjects (n=251) presenting with suspected VTE at the University of Pennsylvania Hospital emergency department, 50 (19.9%) of whom were positive by imaging or 90-day follow-up. Mean nitrated fibrinogen was elevated in VTE-positive (62.7 nM, 95% CI 56.6-68.8) compared to VTE-negative patients (54.2 nM, 95% CI 51.4-57.1; P<0.01). Patients in the highest quartile of nitrated fibrinogen had an increased risk of VTE compared with patients in the lowest quartile (OR 3.30; 95% CI 1.25-8.68; P<0.05). This risk persisted after univariate adjustment for age, active cancer, and recent surgery, but not after multivariate adjustment. Mean fibrinogen levels measured either by the Clauss assay or by ELISA were not different between VTE-negative and VTE-positive patients. These data indicate that nitrated fibrinogen is an oxidative risk marker in VTE, providing a novel mechanistic link between oxidant production, inflammation, and VTE.

Plasma fibrinogen levels after vaccination with a native outer membrane vesicle vaccine for Neisseria meningitidis

Several studies have shown plasma fibrinogen increases following some vaccinations, but the specific triggers and the kinetics of this response are not well understood. We conducted a phase I trial of an outer membrane vesicle vaccine for Neisseria meningitidis. Plasma fibrinogen was measured on days 0, 2 and 14 following each of 3 doses. The highest dose of vaccine was associated with the greatest increase in fibrinogen at day 2, which decreased by day 14. The first vaccination caused a greater increase than either subsequent vaccination. These transient increases in fibrinogen are comparable to what occurs with upper respiratory infections and have not been demonstrated to represent an increased risk of adverse vascular events.

D-Dimer for venous thromboembolism diagnosis: 20 years later

Twenty years after its first use in the diagnostic workup of suspected venous thromboembolism (VTE), fibrin D-dimer (DD) testing has gained wide acceptance for ruling out this disease. The test is particularly useful in the outpatient population referred to the emergency department because of suspected deep vein thrombosis (DVT) or pulmonary embolism (PE), in which the ruling out capacity concerns every third patient clinically suspected of having the disease. This usefulness is based on the high sensitivity of the test to the presence of VTE, at least for some assays. Due to its poor specificity precluding its use for ruling in VTE, DD testing must be integrated in comprehensive, sequential diagnostic strategies that include clinical probability assessment and imaging techniques such as lower limb venous compression ultrasonography for suspected DVT or multi-slice helical computed tomography for suspected PE. The present narrative review updates the data available on the use of the various commercially available DD assays in the diagnostic approach of clinically suspected VTE in distinct patient populations or situations, including outpatients and inpatients, patients with cancer, older age, pregnancy, a suspected recurrent event, limited thrombus burden, and patients already on anticoagulant treatment.

Uses of different D-dimer levels can reduce the need for venous duplex scanning to rule out deep vein thrombosis in patients with symptomatic pulmonary embolism

OBJECTIVE

This study investigated the prevalence and distribution of deep vein thrombosis (DVT) in patients with symptomatic pulmonary embolism (PE) to establish a screening protocol to reduce unnecessary venous duplex scanning using different D-dimer level rather than single cutoff point of 0.5 microg/mL in patients with low and moderate pretest clinical probability (PTP).

METHODS

The PTP score and D-dimer testing were used to evaluate 85 consecutive patients with symptomatically proven PE before venous duplex scanning. After calculating the PTP score, patients were divided into low (<or=0 points), moderate (1 to 2 points), and high (>or=3 points) PTP groups. The receiver operating characteristic (ROC) curves analysis was used to determine the appropriate D-dimer cutoff point in low and moderate PTP, with a negative predictive value of >98%.

RESULTS

The study enrolled 81 patients. The prevalence of DVT was 63%, with 27 patients (33%) classified as low, 38 (47%) as moderate, and 16 (20%) as high PTP. DVT was detected in nine patients (33%) in the low PTP group, in 27 (71%) in the moderate group, and in 15 (94%) in the high group. In the low PTP patients, the difference in the value of D-dimer assay between positive-scan and negative-scan patients was statistically significant (9.99 +/- 7.33 vs 3.46 +/- 4.20, respectively; P = .008). Conversely, no significant difference in the D-dimer assay value between positive and negative scan results was found in the moderate PTP patients. ROC curves analysis were used to select D-dimer cutoff points of 2.0 microg/mL for the low PTP group and 0.7 microg/mL for the moderate PTP groups. For both groups, D-dimer testing provided 100% sensitivity and 100% negative predictive value in the diagnosis of DVT. In the low PTP group, specificity increased from 33% to 67% (P = .046). In the moderate PTP group, however, the determined D-dimer level did not improve the specificity. Overall, venous duplex scanning could have been reduced by 17% (14/81) by using different D-dimer cutoff points.

CONCLUSIONS

A combination of specific D-dimer level and clinical probability score is most effective in the low PTP patients in excluding DVT. In the moderate PTP group, however, the recommended cutoff point of 0.5 microg/mL may be preferable. These results show that a different D-dimer level is more useful than single cutoff point of 0.5 microg/mL in excluding DVT in established PE patients.

Quantitative high D-dimer value is predictive of pulmonary embolism occurrence independently of clinical score in a well-defined low risk factor population

We performed a prospective study to assess whether positive quantitative D-dimer (DD) levels could be integrated for a selected population in a defined strategy to accurately diagnose pulmonary embolism (PE). For this purpose, 1528 in- or outpatients with clinically suspected PE were investigated according to our prescription rules. Clinical probability was defined as low, intermediate or high. Patients in whom DD levels were measured met criteria defined by our previously described decision-making algorithm: in- and outpatients, < 80 years, without surgery in the previous 30 days or active cancer. Nine hundred and twenty-three patients (60.4%) had quantitative DD measurement using automated latex DD assay (STA-Liatest D-Di). According to our decision-making algorithm, DD measurement was applied to 70.5% of out-, and 55.7% of inpatients, and PE diagnosis was ruled out in 49.5% of the 923 patients. This allowed us to confirm prospectively that our specific rules greatly improve the DD testing efficiency. PE was diagnosed in 115 (12.5%) patients. For a 0.5 mg L(-1) cut-off, the test sensitivity was 97.4%, but its specificity was only 56.7%. However, PE prevalence increased gradually with DD levels. The true observed PE prevalence, according to the quantitative assessment of DD levels, differed from that predicted with pretest clinical probability only. Moreover, in this well-defined patient group, a quantitative DD level > 2 mg L(-1) was predictive of PE occurrence independently of the clinical score (odds ratio 6.9, 95% confidence interval 3.7, 12.8). As part of a defined strategy, knowledge of positive DD quantitative value, together with the clinical probability score, improves the PE predictive model. A clinical validation of these results in a follow-up study would now be necessary before considering the implementation of this strategy into clinical practice.