D-dimer test for excluding the diagnosis of pulmonary embolism

[Pulmonary Embolism]

Pulmonary embolism (PE), the most severe form of presentation of venous thromboembolic disease (VTE), currently represents a foremost healthcare issue due to its high impact in terms of morbidity, mortality, costs, and resource consumption. Early mortality associated with PE is primarily due to hemodynamic instability, exacerbation of pre-existing conditions, or major complications of antithrombotic therapies. Beyond the risk of death, there are relevant complications related to PE, such as bleedings, VTE recurrences, and persistence of residual respiratory symptoms; the latter complication related to PE is mainly characterized by two entities, chronic thromboembolic pulmonary hypertension and chronic thromboembolic disease. Significant scientific advances made in recent years have allowed for the improvement of both diagnostic and therapeutic management of the disease, as outlined in this document through a series of relevant issues about PE that are answered with the most up-to-date scientific evidence.

How we manage a high D-dimer

D-dimer, a soluble fibrin degradation product that originates from plasmin-induced degradation of cross-linked fibrin, is an important biomarker of coagulation activation and secondary fibrinolysis that is routinely used to rule out venous thromboembolism (VTE), and to evaluate the risk of VTE recurrence, as well as the optimal duration of anticoagulant therapy. Besides VTE, D-dimer may be high due to physiologic conditions, including aging, pregnancy, and strenuous physical activity. In addition, several disorders have been associated with increased D-dimer levels, ranging from disseminated intravascular coagulation to infectious diseases and cancers. Thus, it is far from unusual for hematologists to have to deal with ambulatory individuals with increased D-dimer without signs or symptoms of thrombus formation. This narrative review is dedicated to the management of these cases by the hematologist.

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.

Clinical Characteristics of Asymptomatic Thromboembolism in Psychiatric Inpatients: A Retrospective Study

Purpose

Venous thromboembolism (VTE) poses a significant threat to individuals' health, yet its correlation with mental disorders remains underappreciated. Here, we conducted a retrospective analysis to explore the characteristics of psychiatric patients presenting with VTE.

Methods

We retrospectively analyzed psychiatric inpatients with elevated plasma D-dimer levels at the Mental Health Center, First Affiliated Hospital, Zhejiang University School of Medicine, from January 2014 to January 2022. The inclusion criteria comprised comprehensive demographic and clinical profiles, including laboratory and imaging findings.

Results

A cohort of 33 eligible patients was included, with plasma D-dimer levels ranging from 880 to 10,700 μg/L FEU. Significantly higher D-dimer levels were observed in patients diagnosed with severe mental disorders (SMD), such as schizophrenia and bipolar disorder, compared to those with mild mental disorders (MMD), including depression and anxiety disorders (p = 0.007). Furthermore, individuals receiving antipsychotic medications for less than one year exhibited elevated D-dimer levels compared to those on treatment for over one year (p = 0.005). However, normalization of D-dimer levels did not demonstrate a significant association with psychiatric diagnosis or treatment duration (p > 0.05).

Conclusion

Our findings suggest that patients diagnosed with SMD or those undergoing antipsychotic treatment for less than one year may have elevated D-dimer levels, indicating a potential predisposition to VTE severity. This underscores the importance of recognizing VTE risk in individuals with severe mental disorders and warrants further investigation into the impact of antipsychotic treatment duration on thrombotic risk.

Fast screening using attenuated total reflectance- fourier transform infrared (ATR-FTIR) spectroscopy of patients based on D-dimer threshold value

Attenuated Total Reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy is an emerging technology in the medical field. Blood D-dimer was initially studied as a marker of the activation of coagulation and fibrinolysis. It is mainly used as a potential diagnosis screening test for pulmonary embolism or deep vein thrombosis but was recently associated with COVID-19 severity. This study aimed to evaluate the use of ATR-FTIR spectroscopy with machine learning to classify plasma D-dimer concentrations. The plasma ATR-FTIR spectra from 100 patients were studied through principal component analysis (PCA) and two supervised approaches: genetic algorithm with linear discriminant analysis (GA-LDA) and partial least squares with linear discriminant (PLS-DA). The spectra were truncated to the fingerprint region (1800-1000 cm-1). The GA-LDA method effectively classified patients according to D-dimer cutoff (≤0.5 μg/mL and >0.5 μg/mL) with 87.5 % specificity and 100 % sensitivity on the training set, and 85.7 % specificity, and 95.6 % sensitivity on the test set. Thus, we demonstrate that ATR-FTIR spectroscopy might be an important additional tool for classifying patients according to D-dimer values. ATR-FTIR spectral analyses associated with clinical evidence can contribute to a faster and more accurate medical diagnosis, reduce patient morbidity, and save resources and demand for professionals.

Fibrinogen contribution to clot strength in patients with sepsis and hematologic malignancies and thrombocytopenia-a prospective, single-center, analytical, cross-sectional study

Background

Patients with hematological malignancies (HM) frequently present thrombocytopenia and higher risk of bleeding. Although transfusion is associated with higher risk of adverse events and poor outcomes, prophylactic transfusion of platelets is a common practice to prevent hemorrhagic complications. Thromboelastometry has been considered a better predictor for bleeding than isolated platelet counts in different settings. In early stages of sepsis, hypercoagulability may occur due to higher fibrinogen levels.

Objectives

To evaluate the behavior of coagulation in patients with HM who develop sepsis and to verify whether a higher concentration of fibrinogen is associated with a proportional increase in maximum clot firmness (MCF) even in the presence of severe thrombocytopenia.

Methods

We performed a unicentric analytical cross-sectional study with 60 adult patients with HM and severe thrombocytopenia, of whom 30 had sepsis (sepsis group) and 30 had no infections (control group). Coagulation conventional tests and specific coagulation tests, including thromboelastometry, were performed. The main outcome evaluated was MCF.

Results

Higher levels of fibrinogen and MCF were found in sepsis group. Both fibrinogen and platelets contributed to MCF. The relative contribution of fibrin was significantly higher (60.5 ± 12.8% vs 43.6 ± 9.7%; P < .001) and that of platelets was significantly lower (39.5 ± 12.8% vs 56.4 ± 9.7%; P < .001) in the sepsis group compared with the control group.

Conclusion

Patients with sepsis and HM presented higher concentrations of fibrinogen than uninfected patients, resulting in greater MCF amplitudes even in the presence of thrombocytopenia.

Values of Caprini Risk Assessment Scale and D-Dimer for Predicting Venous Thromboembolism During Puerperium

Purpose

To evaluate the predictive value of the combination of the Caprini risk assessment model (RAM) and D-dimer for venous thromboembolism (VTE) during puerperium.

Patients and Methods

This was a retrospective case-control study. Thirty-one puerperium patients with VTE were included as cases, and 279 puerperium women without VTE were matched to cases according to age, number of fetuses, birth day and delivery mode at the ratio of 9:1. Demographic data, clinical data and laboratory parameters within postpartum 24 h were collected. Multivariate analysis, employing the forward stepwise model, was conducted to identify independent factors associated with VTE during puerperium. The predictive values of Caprini RAM, D-dimer and their combination were evaluated using receiver operating characteristic (ROC) curve, and the area under curve (AUC) was compared using Z test.

Results

Univariate analysis demonstrated that there were significant differences in D-dimer levels, Caprini score, scarred uterus, adherent placenta, postpartum hemorrhage and intrauterine infection between cases and controls (P<0.05). Multivariate analysis demonstrated that D-dimer levels (OR: 1.754, 95% CI: 1.237-3.182), Caprini score (OR: 1.209, 95% CI: 1.058-2.280), scarred uterus (OR: 1.978, 95% CI: 1.258-3.794), postpartum hemorrhage (OR: 2.276, 95% CI: 1.334-4.347) and intrauterine infection (OR: 2.575, 95% CI: 1.463-4.618) were independently associated with VTE during puerperium with adjustment for adherent placenta and fetal birth weight. The AUCs of D-dimer levels, Caprini score and their combination were 0.748 (SE: 0.030, 95% CI: 0.688-0.807), 0.647 (SE: 0.035, 95% CI: 0.578-0.716) and 0.840 (SE: 0.025, 95% CI: 0.791-0.888). Combination prediction had a higher AUC compared with that of independent prediction (0.840 vs 0.748, Z=2.356, P=0.009; 0.840 vs 0.647, Z=4.487, P<0.001) with a sensitivity of 83.9% and specificity of 80.3%.

Conclusion

The combination of the Caprini RAM and D-dimer could significantly elevate the predictive value for VTE during puerperium, and this new tool had the potential in the prediction of VTE during puerperium.

Chlamydia psittaci Pneumonia-Induced Pulmonary Thrombosis: A Case Report

Chlamydia psittaci pneumonia frequently leads to various extrapulmonary complications; however, reports of C. psittaci-pneumonia complicated by pulmonary thrombosis are uncommon. We report a case of severe C. psittaci pneumonia in a patient with a history of poultry contact and clinical manifestations including hyperpyrexia, dyspnea, and respiratory failure, which necessitated tracheal intubation for assisted ventilation. C. psittaci in bronchoalveolar lavage fluid was detected with metagenomic next-generation sequencing. Following targeted antibiotic therapy, the fever subsided, although dyspnea persisted without significant improvement, and chest pain developed. Compared to previous measurements, the D-dimer level increased, and CT pulmonary angiography revealed thromboses in the pulmonary artery trunk and left pulmonary artery. The symptoms improved after anticoagulant treatment, and the patient was discharged subsequently. This study suggests that C. psittaci infection may be associated with the formation of pulmonary thrombosis. Additional clinical data are required to support this inference. Following targeted antibiotic therapy, if persistent dyspnea, chest pain, and increased D-dimer level are present, pulmonary thrombosis should be considered, and pulmonary artery angiography can confirm the diagnosis.

Neutrophil gelatinase-associated lipocalin: a biochemical marker for acute kidney injury and long-term outcomes in patients presenting to the emergency department

Introduction

Creatinine has limitations in identifying and predicting acute kidney injury (AKI). Our study examined the utility of neutrophil gelatinase-associated lipocalin (NGAL) in predicting AKI in patients presenting to the emergency department (ED), and in predicting the need for renal replacement therapy (RRT), occurrence of major adverse cardiac events (MACE) and all-cause mortality at three months post visit.

Methods

This is a single-centre prospective cohort study conducted at Singapore General Hospital (SGH). Patients presenting to SGH ED from July 2011 to August 2012 were recruited. They were aged ≥21 years, with an estimated glomerular filtration rate <60 mL/min/1.73 m2, and had congestive cardiac failure, systemic inflammatory response syndrome or required hospital admission. AKI was diagnosed by researchers blinded to experimental measurements. Serum NGAL was measured as a point-of-care test.

Results

A total of 784 patients were enrolled, of whom 107 (13.6%) had AKI. Mean serum NGAL levels were raised (P < 0.001) in patients with AKI (670.0 ± 431.9 ng/dL) compared with patients without AKI (490.3 ± 391.6 ng/dL). The sensitivity and specificity of NGAL levels >490 ng/dL for AKI were 59% (95% confidence interval [CI] 49%-68%) and 65% (95% CI 61%-68%), respectively. Need for RRT increased 21% per 100 ng/dL increase in NGAL (P < 0.001), whereas odds of death in three months increased 10% per 100 ng/dL increase in NGAL (P = 0.028). No clear relationship was observed between NGAL levels and MACE.

Conclusion

Serum NGAL identifies AKI and predicts three-month mortality.

Diagnostic Yield of CT Pulmonary Angiogram in the Diagnosis of Pulmonary Embolism and Its Predictive Factors

Introduction Computed tomography pulmonary angiography (CTPA) is the reference investigation of choice to diagnose pulmonary embolism (PE). Nevertheless, the use of CTPA should be weighed against its risks, such as radiation and contrast-induced nephropathy. We aim to assess the yield of CTPA in diagnosing PE at a tertiary centre in Malaysia. We also identify predictive factors associated with the yield of CTPA in this cohort. Methods This was a cross-sectional study involving all patients who had had CTPA done at Hospital Tengku Ampuan Afzan, Kuantan, Malaysia, from January 1, 2021, to November 30, 2021. All patients' records were retrieved and reviewed. CTPA images were retrieved from the Radiology Information System (RIS) and Picture Archiving and Communication System (PACS). They were double-reviewed by the authors, with the initial reports redacted from reporting radiologists to prevent reporting bias. The predictive factors were determined using simple logistic regression and multiple logistic regression. Results A total of 351 CTPAs were reviewed, of which 93 were found to be positive for PE, giving rise to an overall CTPA yield of 26.5%. Upon simple logistic regression, factors such as gender, discipline, history of trauma, presence of COVID-19 infection, and pneumonia were found to be associated with positive CTPA. Upon multiple logistic regression, male patients were found to have a higher chance of positive CTPA results. On the other hand, patients with COVID-19 infection and pneumonia have a lower chance of positive results in CTPA. Conclusion The yield of CTPA in diagnosing PE at our institution was acceptable at 26.5%. Upon multiple logistic regression, patients with COVID-19 infection and pneumonia were more likely to have a negative CTPA result, highlighting the need for clinicians to be more prudent in requesting CTPAs in these patients.

Development and Validation of a Prediction Model for Venous Thrombus Embolism (VTE) in Patients With Colorectal Cancer

Cancer patients are at high risk of developing venous thromboembolism (VTE). The risk of VTE could be mitigated with the administration of prophylactic anticoagulants. Therefore, risk assessment models would be a useful tool in order to identify those patients who are at higher risk and will be benefited more by prophylactic anticoagulants. This study retrospectively examined 528 newly diagnosed colorectal cancer patients from January 2019 to January 2021. Specified logistic regression models were employed to screen the factors and establish prediction tools based on nomograms according to the final included variables. Discrimination, calibration, and clinical applicability were used to assess the performance of screening tools. In addition, internal verifications were conducted through 10-fold cross-verification, leave-one-out cross-validation, and Bootstrap verification. Four risk factors, closely related to the occurrence of VTE in colorectal cancer patients, were identified after univariate and multivariate logistic regression, including age, body mass index, activated partial thromboplastin time, and D-Dimer value. Besides, the risk assessment model named ABAD was built on the basis, displaying good discriminations and calibrations. The area under the curve was 0.705 (95% confidence interval [CI], 0.644 to 0.766). According to Hosmer-Lemeshow goodness-of-fit test, a good agreement between the predicted and observed VTE events in patients with newly-diagnosed gastrointestinal cancer was observed for χ2 = 6.864, P = .551. Internal validation was applied with a C-index of 0.669 in the 10-fold cross-verification, 0.658 in the leave-one-out cross verification and 0.684 in the bootstrap verification. We developed a prediction model called ABAD for newly diagnosed colorectal cancer patients, which can be used to predict the risk of VTE. After evaluation and internal verification, we believe that ABAD exhibited high predictive performance and availability and could be recommended.

Disposable Voltammetric Immunosensor for D-Dimer Detection as Early Biomarker of Thromboembolic Disease and of COVID-19 Prognosis

In this work, we report on the development of a simple electrochemical immunosensor for the detection of D-dimer protein in human plasma samples. The immunosensor is built by a simple drop-casting procedure of chitosan nanoparticles (CSNPs) as biocompatible support, Protein A (PrA), to facilitate the proper orientation of the antibody sites to epitopes as a capture biomolecule, and the D-dimer antibody onto a carboxyl functionalized multi-walled carbon nanotubes screen printed electrode (MWCNTs-SPE). The CSNPs have been morphologically characterized by Scanning Electron Microscopy (SEM) and Dynamic Light Scattering (DLS) techniques. Successively, the electrochemical properties of the screen-printed working electrode after each modification step have been characterized by differential pulse voltammetry (DPV) and electrochemical impedance spectroscopy (EIS). The resulting MWCNTs-CSNPs-PrA-D-dimer Ab immunosensor displays an optimal and promising platform for antibody immobilization and specific D-dimer detection. DPV has been used to investigate the antigen/antibody interaction at different D-dimer concentrations. The proposed voltammetric immunosensor allowed a linear range from 2 to 500 μg L^-1 with a LOD of 0.6 μg L^-1 and a sensitivity of 1.3 μA L μg^-1 cm^-2. Good stability and a fast response time (5 s) have been reported. Lastly, the performance of the voltammetric immunosensor has been tested in human plasma samples, showing satisfactory results, thus attesting to the promising feasibility of the proposed platform for detecting D-dimer in physiological samples.

Pulmonary Embolism Risk Assessment Using Blood Copeptin Concentration and Pulmonary Arteries Thrombotic Burden Evaluated by Computer Tomography

(1) Background: Pulmonary embolism (PE) represents the third most important cardiovascular cause of death after myocardial infarction and stroke. The proper management of this condition is dependent on adequate risk stratification, due to the life-threatening complications of more aggressive therapies such as thrombolysis. Copeptin is a surrogate marker of vasopressin which is found increased in several cardiovascular conditions. The Mastora score is an imagistic evaluation of the degree of pulmonary arteries thrombotic burden based on computed tomography angiography. In this study, we aimed to evaluate the diagnostic and prognostic role of copeptin in patients with acute PE. Furthermore, we analyzed the relationship between copeptin and Mastora score and their role in PE risk profiling. (2) Methods: We conducted a single center prospective study that included 112 patients with PE and 53 healthy volunteers. Clinical and paraclinical parameters, together with plasma levels of copeptin and the Mastora score, were evaluated in all patients after admission. (3) Results: Copeptin levels were significantly increased in PE patients compared with the general population (26.05 vs. 9.5 pmol/L, p < 0.001), while receiver operating characteristic (ROC) analysis revealed an AUC of 0.800 (95% CI 0.728−0.873, p < 0.001). Copeptin directly correlated with the Mastora score (r = 0.535, p = 0.011) and both parameters were strong predictors for adverse clinical events and death. Receiver operating characteristic (ROC) analysis for death within 30 days revealed a copeptin cut-off of 38.36 pmol/L, which presented a specificity of 79.6% and a sensitivity of 88.9%, and a Mastora score cut-off of 82 points, which presented a specificity of 74.8% and a sensitivity of 77.8%. (4) Conclusions: Our results showed that copeptin and the Mastora score are both correlated with adverse cardiovascular events and mortality in PE patients, and this may pave the way for their use in clinical practice, helping physicians to select the best therapeutical management.

Thrombosis and thromboembolism: Brighton collaboration case definition and guidelines for data collection, analysis, and presentation of immunization safety data

This is a Brighton Collaboration case definition of thrombosis and thromboembolism to be used in the evaluation of adverse events following immunization, and for epidemiologic studies for the assessment of background incidence or hypothesis testing. The case definition was developed by a group of experts convened by the Coalition for Epidemic Preparedness Innovations (CEPI) in the context of active development of SARS-CoV-2 vaccines. The case definition format of the Brighton Collaboration was followed to develop a consensus definition and defined levels of certainty, after an exhaustive review of the literature and expert consultation. The document underwent peer review by the Brighton Collaboration Network and by selected expert reviewers prior to submission.

Pursuing appropriateness of laboratory tests: a 15-year experience in an academic medical institution

Appropriateness in Laboratory Medicine has been the object of various types of interventions. From published experiences, it is now clear that to effectively manage the laboratory test demand it is recommended to activate evidence-based preventative strategies stopping inappropriate requests before they can reach the laboratory. To guarantee appropriate laboratory test utilization, healthcare institutions should implement and optimize a computerized provider order entry (CPOE), exploiting the potential of electronic requesting as "enabling factor" for reinforcing appropriateness and sustaining its effects over time. In our academic institution, over the last 15 years, our medical laboratory has enforced various interventions to improve test appropriateness, all directly or indirectly based on CPOE use. The following types of intervention were implemented: (1) applying specific recommendations supported by monitoring by CPOE as well as a continuous consultation with clinicians (tumour markers); (2) removing outdated tests and avoiding redundant duplications (cardiac markers, pancreatic enzymes); (3) order restraints to selected wards and gating policy (procalcitonin, B-type natriuretic peptide, homocysteine); (4) reflex testing (bilirubin fractions, free prostate-specific antigen, aminotransferases, magnesium in hypocalcemia); and (5) minimum retesting interval (D-Dimer, vitamin B₁₂, C-reactive protein, γ-glutamyltranspeptidase). In this paper, we reviewed these interventions and summarized their outcomes primarily related to the changes in total test volumes and cost savings, without neglecting patient safety. Our experience confirmed that laboratory professionals have an irreplaceable role as "stewards" in designing, implementing, evaluating, and maintaining interventions focused to improving test appropriateness.

An Update on the Management of Acute High-Risk Pulmonary Embolism

Hemodynamic instability and right ventricular (RV) dysfunction are the key determinants of short-term prognosis in patients with acute pulmonary embolism (PE). High-risk PE encompasses a wide spectrum of clinical situations from sustained hypotension to cardiac arrest. Early recognition and treatment tailored to each individual are crucial. Systemic fibrinolysis is the first-line pulmonary reperfusion therapy to rapidly reverse RV overload and hemodynamic collapse, at the cost of a significant rate of bleeding. Catheter-directed pharmacological and mechanical techniques ensure swift recovery of echocardiographic parameters and may possess a better safety profile than systemic thrombolysis. Further clinical studies are mandatory to clarify which pulmonary reperfusion strategy may improve early clinical outcomes and fill existing gaps in the evidence.

Rotational thromboelastometry in critically ill COVID-19 patients does not predict thrombosis

Background

Critically ill COVID‐19 patients are in a hypercoagulable state with increased risk of thrombotic complications. Rotational thromboelastometry (ROTEM) is a viscoelastic test with the potential to reflect COVID‐19‐associated hypercoagulability and may therefore be useful to predict thrombotic complications.

Objective

To investigate the potential of ROTEM profiles to predict thrombotic complications in critically ill COVID‐19 patients.

Patients/Methods

Retrospective multicenter cohort study in 113 adult patients with confirmed COVID‐19 infection admitted to the intensive care unit (ICU) of two large teaching hospitals in the United States and in the Netherlands. ROTEM profiles of the EXTEM, INTEM, and FIBTEM tracings were measured within 72 h of ICU admission. Thrombotic complications encompass both arterial and venous thromboembolic complications, diagnosed with electrocardiogram, ultrasound, or computed tomography. ROTEM profiles were compared between patients with and without thrombosis. Univariable logistic regression followed by receiver operating characteristic (ROC) curves analysis was performed to identify ROTEM parameters associated with thrombosis.

Results and Conclusions

Of 113 patients, 27 (23.9%) developed a thrombotic event. In the univariable analysis, EXTEM clot amplitude at 10 min (CA10) and EXTEM maximum clot formation (MCF) were associated with thrombosis with a p < 0.2 (p = 0.07 and p = 0.05, respectively). In ROC curve analysis, EXTEM CA10 had an area under the curve (AUC) of 0.58 (95% CI 0.47–0.70) and EXTEM MCF had an AUC of 0.60 (95% CI 0.49–0.71). Thereby, ROTEM profiles at ICU admission did not have the potential to differentiate between patients with a high and low risk for thrombotic complications.

Procalcitonin as a Predictive Tool for Death and ICU Admission among Febrile Neutropenic Patients Visiting the Emergency Department

Background and Objectives: Risk stratification tools for febrile neutropenia exist but are infrequently utilized by emergency physicians. Procalcitonin may provide emergency physicians with a more objective tool to identify patients at risk of decompensation. Materials and Methods: We conducted a retrospective cohort study evaluating the use of procalcitonin in cases of febrile neutropenia among adult patients presenting to the Emergency Department compared to a non-neutropenic, febrile control group. Our primary outcome measure was in-hospital mortality with a secondary outcome of ICU admission. Results: Among febrile neutropenic patients, a positive initial procalcitonin value was associated with significantly increased odds of inpatient mortality after adjusting for age, sex, race, and ethnicity (AOR 9.912, p < 0.001), which was similar, though greater than, our non-neutropenic cohort (AOR 2.18, p < 0.001). All febrile neutropenic patients with a positive procalcitonin were admitted to the ICU. Procalcitonin had a higher sensitivity and negative predictive value (NPV) in regard to mortality and ICU admission for our neutropenic group versus our non-neutropenic control. Conclusions: Procalcitonin appears to be a valuable tool when attempting to risk stratify patients with febrile neutropenia presenting to the emergency department. Procalcitonin performed better in the prediction of death and ICU admission among patients with febrile neutropenia than a similar febrile, non-neutropenic control group.

Current use of D-dimer for the exclusion of venous thrombosis in hospitalized patients

D-dimer assay’s utility for excluding venous thromboembolism (VTE) in hospitalized patients is debatable. We aimed to assess the current use of D-dimer as a diagnostic tool for excluding VTE in hospitalized patients and examine a mandatory age-adjusted D-dimer (AADD) threshold for diagnostic imaging. Retrospective cohort study between 2014 to 2019 that included patients from medical and surgical wards with a positive AADD result drawn during their hospitalization. The outcomes were determining a D-dimer threshold requiring further evaluation and assessing the prognostic value of D-dimer in predicting clinically relevant VTE in hospitalized patients. The cohort included 354 patients, 56% of them underwent definitive diagnostic imaging, and 7.6% were diagnosed with VTE after a positive AADD within 90 days of follow-up. Mortality rates were higher in patients diagnosed with VTE (33.3% vs. 15.9%, p = 0.03). Patients with pneumonia and other infectious etiologies were less likely to be further evaluated by definitive imaging (p = 0.001). Patients with a respiratory complaint (p = 0.02), chest pain (p < 0.001), or leg swelling (p = 0.01) were more likely to undergo diagnostic imaging. Patients with D-dimer levels > X2 the AADD were at increased risk of VTE [OR 3.87 (1.45–10.27)]. At 90 days of follow-up, no excess mortality was observed for patients without diagnostic evaluation following elevated AADD. D-dimer may be used in hospitalized patients to exclude VTE using the traditional AADD thresholds, with a high negative predictive value. D-dimer levels > X2 the AADD usually mandates further diagnostic imaging, while lower levels, probably do not require additional workup, with a sensitivity of almost 80% and no excess mortality.

'Penelope test': a practical instrument for checking appropriateness of laboratory tests

In medical laboratories, the appropriateness challenge directly revolves around the laboratory test and its proper selection, data analysis, and result reporting. However, laboratories have also a role in the appropriate management of those phases of total testing process (TTP) that traditionally are not under their direct control. So that, the laboratory obligation to act along the entire TTP is now widely accepted in order to achieve better care management. Because of the large number of variables involved in the overall TTP structure, it is difficult to monitor appropriateness in real time. However, it is possible to retrospectively reconstruct the body of the clinical process involved in the management of a specific laboratory test to track key passages that may be defective or incomplete in terms of appropriateness. Here we proposed an appropriateness check-list scheme along the TTP chain to be potentially applied to any laboratory test. This scheme consists of a series of questions that healthcare professionals should answer to achieve laboratory test appropriateness. In the system, even a single lacking answer may compromise the integrity of all appropriateness evaluation process as the inability to answer may involve a significant deviation from the optimal trajectory, which compromise the test appropriateness and the quality of subsequent steps. Using two examples of the check-list application, we showed that the proposed instrument may offer an objective help to avoid inappropriate use of laboratory tests in an integrated way involving both laboratory professionals and user clinicians.

Tissue Factor Pathway Inhibitor 2: A Novel Biomarker for Predicting Asymptomatic Venous Thromboembolism in Patients with Epithelial Ovarian Cancer

OBJECTIVES

Patients with asymptomatic venous thromboembolism (VTE) are associated with an increased risk of pulmonary thromboembolism events. However, due to low specificity and high false-positive rates, D-dimer testing cannot be used alone to diagnose VTE. Tissue factor pathway inhibitor 2 (TFPI2), a new serodiagnostic marker for ovarian cancer, plays a role in blood coagulation system regulation. We hypothesized that combining D-dimer and TFPI2 would improve its utility in diagnosing VTE. This study aimed to look into the clinical utility of serum D-dimer and TFPI2 levels in detecting asymptomatic VTE in patients with epithelial ovarian cancer (EOC).

DESIGN

From January 2008 to December 2015, researchers at Nara Medical University Hospital's Department of Gynecology conducted a single-center retrospective study. The receiver operating characteristic (ROC) curve analysis was used to determine the diagnostic value of preoperative D-dimer, TFPI2, and D-dimer combined with TFPI2 in distinguishing VTE patients from those who did not have VTE.

PARTICIPANTS

This study included 122 patients with EOC who met the inclusion and exclusion criteria out of 223 admitted to the hospital with EOC. The patients were divided into two groups: VTE (n = 25) and non-VTE (n = 97).

RESULTS

There were significant differences in D-dimer, TFPI2, and CA125 levels and residual tumor between the VTE and non-VTE groups. The D-dimer level was found to be significantly related to age, body mass index, VTE, massive ascites, residual tumor, histology, and Federation of Gynecology and Obstetrics stage, whereas the TFPI2 level was only related to VTE. Multivariate analysis revealed that D-dimer (the optimal cutoff value, 3.5 μg/mL) and TFPI2 (the optimal cutoff value, 400 pg/mL) are independent risk factors for preoperative VTE. ROC analysis revealed that the area under the curve was 0.8266 for D-dimer, 0.7963 for TFPI2, and 0.8495 for the combination of D-dimer and TFPI2. When compared to the D-dimer test alone, the combination of D-dimer and TFPI2 had higher specificity (77.3-96.9%) and positive predictive value (48.8-81.2%) for the diagnosis of VTE.

LIMITATIONS

This is a single-center retrospective study.

CONCLUSION

The combination of D-dimer and TFPI2 may be useful to safely exclude VTE and select patients at high risk of VTE.

Increased Prevalence of Elevated D-Dimer Levels in Patients on Direct Oral Anticoagulants: Results of a Large Retrospective Study

Elevated D-dimer levels during anticoagulant therapy with vitamin K antagonists (VKA) are associated with an increased risk of thrombosis. It has been hypothesized that elevated D-dimer levels in patients receiving direct oral anticoagulants (DOACs) also indicate an increased risk of thrombosis recurrence, but data on the distribution of D-dimer levels in patients with VTE on DOACs are sparse. In the present study we retrospectively analyzed D-dimer levels in patients taking DOACs after first or recurrent venous thrombosis (n = 1,716, 1,126 thereof rivaroxaban, 481 apixaban, 62 edoxaban, and 47 dabigatran). Patients on VKA (n = 402) served as control group. Thrombotic events in the study population were categorized into distal deep venous thrombosis (DVT, n = 552 patients), distal DVT with pulmonary embolism (PE, n = 166), proximal DVT (n = 685), proximal DVT with PE (n = 462), PE without DVT (n = 522), DVT of the upper extremity (n = 78), cerebral venous sinus thrombosis (CVST, n = 48), and other venous thrombosis (n = 74). In VKA users a median D-dimer level of 0.20 mg/l was observed. In patients on DOACs D-dimer levels were significantly higher, with 0.26 mg/l for rivaroxaban, 0.31 mg/l for apixaban (P &lt; 10−16 each), 0.24 mg/l for edoxaban (P = 2 × 10−5), and 0.25 mg/l for dabigatran (P = 4 × 10−4). These differences in comparison to patients on VKA treatment could not be explained by the patients' age, sex, body mass index, and type of thrombosis as these characteristics did not differ significantly between cohorts. Moreover, the prevalence of D-dimer levels above age-adjusted cut-offs [≥0.50 mg/l in ≤50-year-old patients, ≥(age × 0.01) mg/l in &gt;50-year-old patients] was higher in patients on rivaroxaban (13.9%, RR 1.74, 95% CI 1.21–2.50), apixaban (17.0%, RR 2.14, 95% CI 1.45–3.15) and dabigatran (23.4%, RR 2.94, 95% CI 1.59–5.44) than in patients on VKA (8.0%). In patients on edoxaban D-dimer levels above the reference range were observed in 14.5%, but no statistical significance was reached in comparison to the VKA cohort. In conclusion, the obtained data suggest, that the type of oral anticoagulant should be considered in the clinical assessment of D-dimer levels in thrombosis patients. Further studies are warranted to evaluate a potential association between elevated D-dimer levels and thrombosis risk in patients on DOACs.

Prothrombotic Milieu, Thrombotic Events and Prophylactic Anticoagulation in Hospitalized COVID-19 Positive Patients: A Review

The Coronavirus Disease 2019 (COVID-19) pandemic has resulted in significant morbidity and mortality worldwide. Although initial reports concentrated on severe respiratory illness, emerging literature has indicated a substantially elevated risk of thromboembolic events in patients with COVID-19 disease. Pro-inflammatory cytokine release has been linked to endothelial dysfunction and activation of coagulation pathways, as evident by elevated D-dimer levels and deranged coagulation parameters. Both macrovascular and microvascular thromboses have been described in observational cohort and post-mortem studies. Concurrently, preliminary data have suggested the role of therapeutic anticoagulation in preventing major thromboembolic complications in moderately but not critically ill patients. However, pending results from randomized controlled trials, clear guidance is lacking regarding the intensity and duration of anticoagulation in such patients. Herein, we review the existing evidence on incidence and pathophysiology of COVID-19 related thromboembolic complications and guide anticoagulation therapy based on current literature and societal consensus statements.

Age-Adjusted D-Dimer in the Prediction of Pulmonary Embolism: Systematic Review and Meta-analysis

Background:

Pulmonary embolism (PE), depending on the severity, carries a high mortality and morbidity. Proper evaluation, especially in patients with low probability for PE, is important to avoid unnecessary diagnostic testing.

Objective:

To review the diagnostic utility of conventional versus age-adjusted D-dimer cutoff values in patients 50 years and older with suspected pulmonary embolism.

Methods:

Systematic review with univariant and bivariant meta-analysis.

Data sources:

We searched PubMed, MEDLINE, and EBSCO for studies published before September 20th, 2020. We cross checked the reference list of relevant studies that compares conventional versus age-adjusted D-dimer cutoff values in patients with suspected pulmonary embolism.

Study selection:

We included primary published studies that compared both conventional (500 µg/L) and age-adjusted (age × 10 µg/L) cutoff values in patients with non-high clinical probability for pulmonary embolism.

Results:

Nine cohorts that included 47 720 patients with non-high clinical probability were included in the meta-analysis. Both Age-adjusted D-dimer and conventional D-dimer have high sensitivity. However, conventional D-dimer has higher false positive rate than age-adjusted D-dimer.

Conclusion:

Age-adjusted D-dimer cutoffs combined with low risk clinical probability assessment ruled out PE diagnosis in suspected patients with a decreased rate of false positive tests.

The impact of COVID-19 on the sensitivity of D-dimer for pulmonary embolism

Objective

This study seeks to evaluate the test characteristics of D‐dimer for pulmonary embolism (PE) in patients with a concurrent diagnosis of COVID‐19. We hypothesized that the sensitivity of D‐dimer for PE at current institutional cut points would be similar to those without COVID‐19.

Methods

This is a multicenter retrospective observational cohort study across five urban and suburban EDs in the same health care system. The electronic health record was queried for all computed tomography pulmonary angiography (CTPA) studies from December 1, 2019, to October 22, 2020. All ED patients who underwent CTPA had D‐dimer and COVID‐19 testing completed in a single encounter were included in the study. Baseline demographics were obtained. Test characteristics of D‐dimer for PE were calculated for patients with and without COVID‐19. Additionally, receiver operator characteristics (ROC) curves were constructed for two different D‐dimer assays.

Results

There were 1158 patient encounters that met criteria for analysis. Performance of D‐dimer testing for PE was similar between COVID‐19–positive and –negative patients. In COVID‐19–positive patients, the sensitivity was 100% (95% confidence interval [CI] = 87.6%–100%), specificity was 11.9% (95% CI = 7.9%–17.1%), and negative predictive value (NPV) was 100%. In COVID‐19–negative patients the sensitivity was 97.6% (95% CI = 91.5%–99.7%), specificity was 14.4% (95% CI = 12.1%–17%), and NPV was 98.3% (95% CI = 93.8%–99.6%). For assay 1 the area under the curve (AUC) for COVID‐19–positive patients was 0.76 (95% CI = 0.68–0.83), and for COVID‐19–negative patients, 0.73 (95% CI = 0.69–0.77). For assay 2, AUC for COVID‐19–positive patients was 0.85 (95% CI = 0.77–0.92), and for COVID‐19–negative patients, 0.80 (95% CI = 0.77–0.84). Inspection of the ROC curve for assay 1 revealed that 100% sensitivity was maintained up to a threshold of 0.67 FEU (fibrinogen equivalent units; from 0.50 FEU) with an increase in specificity to 29% (from 18.7%), and for assay 2, 100% sensitivity was maintained up to a threshold of 662 D‐dimer units (DDU; from 230 DDU) with an increased specificity to 59% (from 6.1%).

Conclusion

Results from this multicenter retrospective study did not find a significant difference in sensitivity of D‐dimer for PE due to concomitant COVID‐19 infection. Further study is required to determine if PE can safely be excluded based on D‐dimer results alone in patients with suspected or proven COVID‐19 or if adjusted D‐dimer levels could have a role in management.

Acute Pulmonary Embolism–Its Diagnosis and Treatment From a Multidisciplinary Viewpoint

BACKGROUND

Physicians from many different specialties see patients suffering from acute pulmonary embolism (PE), which has an incidence of 39-115 cases per 100 000 persons per year. Because PE can be life-threatening, a rapid, targeted response is essential.

METHODS

This review is based on pertinent publications retrieved by a selective literature search of international databases, with particular attention to current guidelines and expert opinions.

RESULTS

Whenever PE is suspected, clinical assessment tools must be applied for risk stratification and diagnostic evaluation. The PERC (Pulmonary Embolism Rule-out Criteria) and the YEARS algorithm lead to more effective diagnosis. For hemodynamically unstable patients, bedside echocardiography is of high value and enables risk stratification. New oral anticoagulants have fewer hemorrhagic complications than vitamin K antagonists and are not inferior to them with respect to the risk of recurrent PE (hazard ratio 0.84-1.09). The duration of anticoagulation is set according to the risk of recurrence. Systemic thrombolysis is recommended for patients with a high-risk PE, in whom it significantly reduces mortality (odds ratio 0.53, number needed to treat 59). Surgical or interventional techniques can be considered if thrombolysis is contraindicated or unsuccessful.

CONCLUSION

Newly introduced diagnostic aids and algorithms simplify the diagnosis and treatment of acute PE while continuing to assure a high degree of patient safety.

Development and validation of a novel risk assessment model to estimate the probability of pulmonary embolism in postoperative patients

Pulmonary embolism (PE) is a leading cause of mortality in postoperative patients. Numerous PE prevention clinical practice guidelines are available but not consistently implemented. This study aimed to develop and validate a novel risk assessment model to assess the risk of PE in postoperative patients. Patients who underwent Grade IV surgery between September 2012 and January 2020 (n = 26,536) at the Affiliated Dongyang Hospital of Wenzhou Medical University were enrolled in our study. PE was confirmed by an identified filling defect in the pulmonary artery system in CT pulmonary angiography. The PE incidence was evaluated before discharge. All preoperative data containing clinical and laboratory variables were extracted for each participant. A novel risk assessment model (RAM) for PE was developed with multivariate regression analysis. The discrimination ability of the RAM was evaluated by the area under the receiver operating characteristic curve, and model calibration was assessed by the Hosmer–Lemeshow statistic. We included 53 clinical and laboratory variables in this study. Among them, 296 postoperative patients developed PE before discharge, and the incidence rate was 1.04%. The distribution of variables between the training group and the validation group was balanced. After using multivariate stepwise regression, only variable age (OR 1.070 [1.054–1.087], P < 0.001), drinking (OR 0.477 [0.304–0.749], P = 0.001), malignant tumor (OR 2.552 [1.745–3.731], P < 0.001), anticoagulant (OR 3.719 [2.281–6.062], P < 0.001), lymphocyte percentage (OR 2.773 [2.342–3.285], P < 0.001), neutrophil percentage (OR 10.703 [8.337–13.739], P < 0.001), red blood cell (OR 1.872 [1.384–2.532], P < 0.001), total bilirubin (OR 1.038 [1.012–1.064], P < 0.001), direct bilirubin (OR 0.850 [0.779–0.928], P < 0.001), prothrombin time (OR 0.768 [0.636–0.926], P < 0.001) and fibrinogen (OR 0.772 [0.651–0.915], P < 0.001) were selected and significantly associated with PE. The final model included four variables: neutrophil percentage, age, malignant tumor and lymphocyte percentage. The AUC of the model was 0.949 (95% CI 0.932–0.966). The risk prediction model still showed good calibration, with reasonable agreement between the observed and predicted PE outcomes in the validation set (AUC 0.958). The information on sensitivity, specificity and predictive values according to cutoff points of the score in the training set suggested a threshold of 0.012 as the optimal cutoff value to define high-risk individuals. We developed a new approach to select hazard factors for PE in postoperative patients. This tool provided a consistent, accurate, and effective method for risk assessment. This finding may help decision-makers weigh the risk of PE and appropriately select PE prevention strategies.

Impact of routine preoperative sonographic screening with early intervention for deep venous thrombosis in lower extremities on preventing postoperative venous thromboembolism in patients with gastric cancer scheduled for minimally invasive surgery

PURPOSE

This study aimed to investigate the clinical efficacy of lower-extremity ultrasonography screening with early intervention for deep venous thrombosis (DVT) on the incidence of venous thromboembolism (VTE) after minimally invasive surgery (MIS) for gastric cancer (GC).

METHODS

Between January 2012 and December 2019, 1070 patients were diagnosed with both clinical and pathological stage I-III GC and underwent MIS at our institution. Routine ultrasonographic screening for DVT in lower extremities is performed before MIS. Patients diagnosed with DVT were preoperatively administered anticoagulant therapy. Enoxaparin was routinely administrated after surgery irrespective of the presence of DVT. The incidence of postoperative symptomatic VTE was examined retrospectively.

RESULTS

A total of 74 (6.9%) patients were preoperatively diagnosed with DVT. Multivariate analyses revealed that age > 70 years (p = 0.015), female sex (p < 0.001), and positive serum D-dimer test (p < 0.001) were significant and independent risk factors for preoperative DVT. The incidence of symptomatic postoperative VTE was 1 (0.09%); symptomatic VTE developed in one patient among patients without DVT, whereas no patient with DVT developed VTE.

CONCLUSIONS

Preoperative DVT screening using lower-extremity ultrasonography followed by preoperative anticoagulant therapy should be considered as a useful strategy to safely perform MIS for GC without increasing the incidence of VTE.

Inflammatory and Hypercoagulable Biomarkers and Clinical Outcomes in COVID-19 Patients

Systemic inflammation and hypercoagulopathy are known pathophysiological processes of coronavirus disease 2019 (COVID-19), particularly in patients with known cardiovascular disease or its risk factors (CVD). However, whether a cumulative assessment of these biomarkers at admission could contribute to the prediction of in-hospital outcomes remains unknown. The CLAVIS-COVID registry was a Japanese nationwide retrospective multicenter observational study, supported by the Japanese Circulation Society. Consecutive hospitalized patients with pre-existing CVD and COVID-19 were enrolled. Patients were stratified by the tertiles of CRP and D-dimer values at the time of admission. Multivariable Cox proportional hazard models were constructed. In 461 patients (65.5% male; median age, 70.0), the median baseline CRP and D-dimer was 58.3 (interquartile range, 18.2-116.0) mg/L and 1.5 (interquartile range, 0.8-3.0) mg/L, respectively. Overall, the in-hospital mortality rate was 16.5%, and the rates steadily increased in concordance with both CRP (5.0%, 15.0%, and 28.2%, respectively p < 0.001) and D-dimer values (6.8%, 19.6%, and 22.5%, respectively p = 0.001). Patients with the lowest tertiles of both biomarkers (CRP, 29.0 mg/L; D-dimer, 1.00 mg/L) were at extremely low risk of in-hospital mortality (0% until day 50, and 1.4% overall). Conversely, the elevation of both CRP and D-dimer levels was a significant predictor of in-hospital mortality (Hazard ratio, 2.97; 95% confidence interval, 1.57-5.60). A similar trend was observed when the biomarker threshold was set at a clinically relevant threshold. In conclusion, the combination of these abnormalities may provide a framework for rapid risk estimation for in-hospital COVID-19 patients with CVD.

Reliability and validity of D-dimer monitoring for pulmonary thromboembolism in patients with unresectable, advanced or recurrent colorectal cancer treated with bevacizumab

Pulmonary thromboembolism (PTE) is one of the leading causes of death among cancer outpatients. The aim of the present study was to investigate the reliability and validity of D-dimer monitoring for PTE in patients with unresectable, advanced or recurrent colorectal cancer treated with bevacizumab. A total of 25 patients with advanced colorectal cancer who received bevacizumab combination chemotherapy as primary treatment were retrospectively reviewed. The selection criteria included that D-dimer tests were performed repetitively, and that chest and abdominal contrast-enhanced CT scans were completed. The D-dimer levels and the presence or absence of PTE on CT images were retrospectively examined. Four cases (16%) were detected as having asymptomatic PTE. The D-dimer values at the onset of PTE were 14.2, 4.6, 1.1 and 0.9 µg/ml. The negative predictive value was 90.5% when 3.0 µg/ml was set as the D-dimer level cutoff value. The incidence of PTE, including asymptomatic PTE, in the present study was higher compared with that reported in previous studies on various types of cancer, of various stages and treated with different chemotherapy regimens. In patients with bevacizumab-treated unresectable, advanced or recurrent colorectal cancer, the D-dimer test was found to be less useful for exclusion diagnosis; however, along with chest CT, it may be useful in the detection and diagnosis of PTE. However, the determination of the optimal reference values and appropriate measurement timing of D-dimer testing requires further study.

Biomarkers of Thrombo-Inflammatory Responses in Pulmonary Embolism Patients With Pre-Existing Versus New-Onset Atrial Fibrillation

Pulmonary embolism (PE) patients have an increased prevalence and incidence of atrial fibrillation (AF). Because comorbid AF increases risk of morbidity and mortality, we sought to investigate the role of thrombo-inflammatory biomarkers in risk stratifying patients who experience an acute PE episode. Study participants were enrolled from a Pulmonary Embolism Response Team (PERT) registry between March 2016 and March 2019 at Loyola University Medical Center and Gottlieb Memorial Hospital. This cohort was divided into 3 groups: PE patients with a prior diagnosis of AF (n = 8), PE patients with a subsequent diagnosis of AF (n = 11), and PE patients who do not develop AF (n = 71). D-dimer, CRP, PAI-1, TAFIa, FXIIIa, A2A, MP, and TFPI were profiled using the ELISA method. All biomarkers were significantly different between controls and PE patients (P < 0.05). Furthermore, TFPI was significantly elevated in PE patients who subsequently developed AF compared to PE patients who did not develop AF (157.7 ± 19.0 ng/mL vs. 129.0 ± 9.3 ng/mL, P = 0.0386). This study suggests that thrombo-inflammatory biomarkers may be helpful in indicating an acute PE episode. Also, elevated TFPI levels may be associated with an increased risk of developing AF after a PE.

Machine learning is the key to diagnose COVID-19: a proof-of-concept study

The reverse transcription-polymerase chain reaction (RT-PCR) assay is the accepted standard for coronavirus disease 2019 (COVID-19) diagnosis. As any test, RT-PCR provides false negative results that can be rectified by clinicians by confronting clinical, biological and imaging data. The combination of RT-PCR and chest-CT could improve diagnosis performance, but this would requires considerable resources for its rapid use in all patients with suspected COVID-19. The potential contribution of machine learning in this situation has not been fully evaluated. The objective of this study was to develop and evaluate machine learning models using routine clinical and laboratory data to improve the performance of RT-PCR and chest-CT for COVID-19 diagnosis among post-emergency hospitalized patients. All adults admitted to the ED for suspected COVID-19, and then hospitalized at Rennes academic hospital, France, between March 20, 2020 and May 5, 2020 were included in the study. Three model types were created: logistic regression, random forest, and neural network. Each model was trained to diagnose COVID-19 using different sets of variables. Area under the receiving operator characteristics curve (AUC) was the primary outcome to evaluate model’s performances. 536 patients were included in the study: 106 in the COVID group, 430 in the NOT-COVID group. The AUC values of chest-CT and RT-PCR increased from 0.778 to 0.892 and from 0.852 to 0.930, respectively, with the contribution of machine learning. After generalization, machine learning models will allow increasing chest-CT and RT-PCR performances for COVID-19 diagnosis.

Novel Blood Biomarkers for a Diagnostic Workup of Acute Aortic Dissection

Acute aortic dissection (AAD) is a rare condition, but together with acute myocardial infarction (AMI) and pulmonary embolism (PE) it belongs to the most relevant and life-threatening causes of acute chest pain. Until now, there has been no specific blood test in the diagnostic workup of AAD. To identify clinically relevant biomarkers for AAD, we applied Proseek^® Multiplex assays to plasma samples from patients with AAD, AMI, PE, thoracic aortic aneurysm (TAA), and non-cardiovascular chest pain (nonCVD). Subsequently, we validated top hits using conventional immunoassays and examined their expression in the aortic tissue. Interleukin 10 (IL-10) alone showed the best performance with a sensitivity of 55% and a specificity of 98% for AAD diagnosis. The combination of D-dimers, high-sensitive troponin T (hs-TnT), interleukin 6 (IL-6), and plasminogen activator inhibitor 1 (PAI1) correctly classified 75% of AAD cases, delivering a sensitivity of 83% and specificity of 95% for its diagnosis. Moreover, this model provided the correct classification of 77% of all analyzed cases. Our data suggest that IL-10 shows potential to be a rule-in biomarker for AAD. Moreover, the addition of PAI1 and IL-6 to hs-TnT and D-dimers may improve the discrimination of suspected AAD, AMI, and PE in patients presenting with acute chest pain.

COVID-19 and venous thromboembolism: Known and unknown for imaging decisions

As we continue to fight against the current coronavirus disease-2019 (COVID-19) pandemic, healthcare professionals across the globe are trying to answer questions surrounding how to best help patients with the up-to-date available science while awaiting the development of new therapies and mass vaccination. Since early in the pandemic, studies indicated a heightened risk of venous thromboembolism (VTE) in COVID-19 infected patients. There have been differing expert opinions about how to assess pretest probability of VTE in this patient population. This has been partly due to the high prevalence of respiratory failure in this patient population and the use of D-dimer as a prognostic test which is also frequently elevated in patients with COVID-19 in absence of VTE. Some experts have argued for an approach similar to usual care with testing if clinical suspicion is high enough. Some have argued for more routine screening at different points of care. Others have even suggested empiric therapeutic anti-coagulation in moderate to severely ill COVID-19 patients. In the following article, we review and summarize the most current literature in hopes of assisting clinicians in decision making and guidance for when to be concerned for VTE in COVID-19 patients. We also discuss research gaps and share pathways currently being used within our institution.

Approach to pulmonary embolism: A clinical care pathway

ABSTRACT

Acute pulmonary embolism (PE) is a potentially fatal condition that is often underdiagnosed due to its ambiguous and generalized symptoms. As such, nurse practitioners (NPs) may struggle to respond in a timely and accurate manner to clients presenting with acute PE. Given the complexities of diagnosing and managing PE, we propose a visual clinical care pathway to support NPs in recognizing and stratifying clients' risks of PE. The article provides guidance regarding PE diagnostic testing and offers a summary of effective, evidence-based treatment options for adult clients, including those with cancer.

Current Status of Clinical Application of Point-of-Care Testing

CONTEXT.—

The clinical applications of point-of-care testing (POCT) are gradually increasing in many health care systems. Recently, POCT devices using molecular genetic method techniques have been developed. We need to examine clinical pathways to see where POCT can be applied to improve them.

OBJECTIVE.—

To introduce up-to-date POCT items and equipment and to provide the content that should be prepared for clinical application of POCT.

DATA SOURCES.—

Literature review based on PubMed searches containing the terms point-of-care testing, clinical chemistry, diagnostic hematology, and clinical microbiology.

CONCLUSIONS.—

If medical resources are limited, POCT can help clinicians make quick medical decisions. As POCT technology improves and menus expand, areas where POCT can be applied will also increase. We need to understand the limitations of POCT so that it can be optimally used to improve patient management.

To scan or not to scan - D-dimers and computed tomography pulmonary angiography in the era of COVID-19

The COVID-19 pandemic has had many ramifications on healthcare delivery and practice. As part of this, utilising biomarkers to risk stratify patients has become increasingly popular. During the COVID-19 pandemic the use of D-dimer has increased due to the evidence of COVID-19 induced thrombo-embolic disease. We evaluated the use of D-dimer on all hospital admissions during the peak of the pandemic and evaluated its sensitivity in diagnosing pulmonary embolic disease (PE). Patients without COVID-19 infection were as likely to have evidence of PE as their COVID-positive counterparts. However, the sensitivity of a D-dimer was higher in COVID-positive patients at a lower D-dimer level (>1,500 μg/L, sensitivity 81%, specificity 70%) than in those without clinical, immunological or radiological evidence of COVID-19 infection (D-dimer >2,000 μg/L, sensitivity 80%, specificity 76%). These data suggest higher D-dimer thresholds should be considered for the exclusion of pulmonary emboli.

Diagnostic management of inpatients with a positive D-dimer test: developing a new clinical decision-making rule for pulmonary embolism

Background

A positive D-dimer test has high sensitivity but relatively poor specificity for the diagnosis of pulmonary embolism, causing difficulty for clinicians unskilled in pulmonary embolism diagnosis in determining whether a patient with a positive D-dimer test needs to undergo computed tomographic pulmonary angiography.

Objectives

We sought to develop a new clinical decision-making rule based on a positive D-dimer result to predict the probability of pulmonary embolism and to guide clinicians in making decisions regarding the need for computed tomographic pulmonary angiography.

Methods

We conducted a prospective, multicenter study in three hospitals in China. A total of 3014 inpatients with positive D-dimer results were included. In the derivation group, we built a multivariate logistic regression model and deduced a regression equation from which our score was derived. Finally, we validated the score in an independent cohort.

Results

Our score included nine variables (points): chest pain (1.4), chest tightness (2.3), shortness of breath (3.6), hemoptysis (3.4), heart rate ≥100 beats/min (3.6), blood gas analysis (2.9), electrocardiogram presenting a typical S1Q3T3 pattern (4.1), electrocardiogram findings (2.4), and ultrasonic cardiogram findings (3.7). The sensitivities and specificities were 100% and 86.94%, respectively, in the derivation group and 100% and 90.82%, respectively, in the validation group. Additionally, the observed and predicted proportions of patients who underwent computed tomographic pulmonary angiography were 16.82% and 10.76%, respectively, in the derivation group and 18.72% and 11.40%, respectively, in the validation group.

Conclusions

The new score can categorize inpatients with a positive D-dimer test as pulmonary embolism-likely or pulmonary embolism-unlikely, thus reducing unnecessary computed tomographic pulmonary angiography examinations.

Predictive Value of Circulating microRNA-134 Levels for Early Diagnosis of Acute Pulmonary Embolism: Meta-analysis

Acute pulmonary embolism (APE) is a common sudden venous thromboembolism with high rates of morbidity and mortality. Several studies have concluded that microRNA-134 could be a potential biomarker for APE. However, the sensitivity of these studies varies widely. This study aimed to evaluate the diagnostic value of circulating microRNA-134 levels for APE. Four databases were searched to retrieve articles focusing on microRNA-134 detection in APE diagnosis. The Quality Assessment of Diagnostic Accuracy Studies-2 was used to evaluate the quality of the included literature. This meta-analysis included seven studies and 383 subjects. The microRNA-134 levels in APE patients were higher than those in controls (SMD = 2.84, z = 3.69, p < 0.001). The pooled sensitivity, specificity, and diagnostic odds ratio were 0.86 (0.72-0.94), 0.75 (0.66-0.82), and 19 (7-51), respectively. The positive and negative likelihood ratios were 3.4 (2.4-4.8) and 0.18 (0.08-0.40), respectively. The area under the summary receiver operating characteristic curve was 0.81 (0.77-0.84). Circulating microRNA-134 may be a new biomarker for the diagnosis of APE, but more tests and studies are needed to further explore and prove this. Trial registration number: PROSPERO registration #CRD42020184072.

D-Dimer Combined with Fibrinogen Predicts the Risk of Venous Thrombosis in Fracture Patients

Objective

While D-dimer can successfully diagnose venous thrombosis due to its excellent negative predictive value (NPV), it cannot be used to detect venous thromboembolism (VTE) because of its low positive predictive value (PPV). This study aims to investigate if a combination of using D-dimer and fibrinogen can improve PPV in the VTE diagnosis.

Methods

We retrospectively analyzed various data including D-dimer, fibrinogen, C-reactive protein, ultrasound, and others collected from 10775 traumatic fracture patients and categorized them into two groups of VTE and non-VTE. By comparing the difference between the two groups, we employ multiple logistic regression to find risk factors that are useful to detect VTE. The receiver operating characteristic (ROC) curve was used to evaluate the diagnostic yield of using fibrinogen, D-dimer, and their combination, respectively. Also, these data were classified into quartiles by patient age. We perform the same analysis on the quartiles and find if the patient's age has an impact on diagnosing VTE.

Results

The univariate analysis demonstrated that five factors of age, D-dimer, fibrinogen, C-reactive protein, and high-density lipoprotein cholesterol were significant to predict VTE. ROC showed that D-dimer was more useful than fibrinogen for the diagnosis of VTE, while the area under the curve (AUC) was 0.7296 for D-dimer and 0.5209 for fibrinogen. The cutoff point of D-dimer and fibrinogen was 424.89 ng/ml and 3.543 g/L, respectively. The specificity of fibrinogen was 0.777 which was better than D-dimer, while the sensitivity of fibrinogen was lower than that of D-dimer. Both PPV and NPV were similar in D-dimer and fibrinogen. The PPV of combining D-dimer and fibrinogen in ages Q3 (60 < age ≤ 70) and Q4 (age > 70) was better than using either D-dimer or fibrinogen.

Conclusions

Fibrinogen is a promising strategy for the diagnosis of subclinical VTE and postoperative VTE. In particular, a combination of D-dimer and fibrinogen can improve the PPV to successfully diagnose VTE in traumatic fracture patients who are more than 60 years old. Levels of Evidence. This assay is a diagnostic test at level II.

CT imaging of pulmonary embolism in patients with COVID-19 pneumonia: a retrospective analysis

Objectives

To describe imaging and laboratory findings of confirmed PE diagnosed in COVID-19 patients and to evaluate the characteristics of COVID-19 patients with clinical PE suspicion. Characteristics of patients with COVID-19 and PE suspicion who required admission to the intensive care unit (ICU) were also analysed.

Methods

A retrospective study from March 18, 2020, until April 11, 2020. Inclusion criteria were patients with suspected PE and positive real-time reverse-transcription polymerase chain reaction (RT-PCR) for SARS-CoV-2. Exclusion criteria were negative or inconclusive RT-PCR and other chest CT indications. CTPA features were evaluated and severity scores, presence, and localisation of PE were reported. d-dimer and IL-6 determinations, ICU admission, and previous antithrombotic treatment were registered.

Results

Forty-seven PE suspicions with confirmed COVID-19 underwent CTPA. Sixteen patients were diagnosed with PE with a predominant segmental distribution. Statistically significant differences were found in the highest d-dimer determination in patients with PE and ICU admission regarding elevated IL-6 values.

Conclusion

PE in COVID-19 patients in our series might predominantly affect segmental arteries and the right lung. Results suggest that the higher the d-dimer concentration, the greater the likelihood of PE. Both assumptions should be assessed in future studies with a larger sample size.

Key Points

• On CT pulmonary angiography, pulmonary embolism in COVID-19 patients seems to be predominantly distributed in segmental arteries of the right lung, an assumption that needs to be approached in future research.

• Only the highest intraindividual determination ofd-dimer from admission to CT scan seems to differentiate patients with pulmonary embolism from patients with a negative CTPA. However, interindividual variability calls for future studies to establish cut-off values in COVID-19 patients.

• Further studies with larger sample sizes are needed to determine whether the presence of PE could increase the risk of intensive care unit (ICU) admission in COVID-19 patients.

Diagnostic and prognostic value of the D-dimer test in emergency department patients: secondary analysis of an observational study

Background D-dimer measurement improves the rule-out of thromboembolic disease. However, little is known about the risk of false positive results for the diagnosis of thromboembolic disease and its prognostic value. Herein, we investigated factors influencing the accuracy of D-dimer and its prognostic value in a large cohort of emergency department (ED) patients. Methods This is a secondary analysis of a prospective observational single center, cohort study. Consecutive patients, for whom a D-dimer test was requested by the treating physician, were included. Associations of clinical parameters on admission with false positive D-dimer results for the diagnosis of thromboembolic disease were investigated with logistic regression analysis. Results A total of 3301 patients were included, of which 203 (6.1%) had confirmed thromboembolic disease. The negative and positive predictive values of the D-dimer test at the 0.5 mg/L cut-off were 99.9% and 11.4%, respectively. Several factors were associated with positive D-dimer results potentially falsely indicating thromboembolic disease in multivariate analysis including advanced age (odds ratio [OR] 1.04, 95% confidence interval [CI] 1.04-1.05, p < 0.001), congestive heart failure (CHF) (OR 2.79, 95% CI 1.77-4.4, p < 0.01), renal failure (OR 2.00, 95% CI 1.23-3.24, p = 0.005), history of malignancy (OR 2.6, 95% CI 1.57-4.31, p < 0.001), C-reactive protein (CRP) (OR 1.02, 95% CI 1.01-1.02, p < 0.001) and glomerular filtration rate (GFR) (OR 0.99, 95% CI 0.99-1.00, p = 0.003). Regarding its prognostic value, D-dimer was associated with a 30-day mortality (adjusted OR 1.05, 95% CI 1.02-1.09, p = 0.003) with an area under the curve (AUC) of 0.79. Conclusions While D-dimer allows an accurate rule-out of thromboembolic disease, its positive predictive value in routine ED patients is limited and largely influenced by age, comorbidities and acute disease factors. The strong prognostic value of D-dimer in this population warrants further investigation.

Biomarkers for the prediction of venous thromboembolism in critically ill COVID-19 patients

Background

Venous thromboembolism (VTE) is a frequent complication in critically ill patients with coronavirus disease 2019 (COVID-19) and is associated with mortality. Early diagnosis and treatment of VTE is warranted.

Objective

To develop a prediction model for VTE in critically ill COVID-19 patients.

Patients and methods

In this retrospective cohort study, 127 adult patients with confirmed COVID-19 infection admitted to the intensive care unit of two teaching hospitals were included. VTE was diagnosed with either ultrasound or computed tomography scan.

Univariate receiver operating characteristic (ROC) curves were constructed for Positive End Expiratory Pressure, PaO₂/FiO₂ ratio, platelet count, international normalized ratio, activated partial thromboplastin time as well as levels of fibrinogen, antithrombin, D-dimer and C-reactive protein (CRP). Multivariate analysis was done using binary linear regression.

Results

Variables associated with VTE in both univariate and multivariate analysis were D-dimer and CRP with an area under the curve (AUC) of 0.64, P = 0.023 and 0.75, P = 0.045, respectively. Variables indicating hypoxemia were not predictive. The ROC curve of D-dimer and CRP combined had an AUC of 0.83, P < 0.05. Categorized values of D-dimer and CRP were used to compute a mean absolute risk for the combination of these variables with a high positive predictive value. The predicted probability of VTE with a D-dimer > 15 in combination with a CRP > 280 was 98%. The negative predictive value of D-dimer was low.

Conclusion

Elevated CRP and D-dimer have a high positive predictive value for VTE in critically ill COVID-19 patients. We developed a prediction table with these biomarkers that can aid clinicians in the timing of imaging in patients with suspected VTE.

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Venous thromboembolisms are a frequently observed complication of COVID-19.

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Markers of oxygenation are not predictive of venous thromboembolism.

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Elevated C-reactive protein and D-dimer have the potential to predict venous thromboembolism.

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We created a prediction tool based on elevations in both CRP and D-dimer to optimize time of imaging.

Comparison of the D-dimer concentration in pregnant women with or without pulmonary thromboembolism

Introduction and Objectives:

Pulmonary thromboembolism is the third most common vascular disease after coronary heart disease and stroke and is approximately 10 times more common in pregnant women compared with the nonpregnant population at the same age. The purpose of the current work is to evaluate D-dimer plasma concentration in pregnant women with or without pulmonary thromboembolism.

Methods:

The present study was a cross-sectional study in which 100 pregnant women with suspected pulmonary embolism referred to Imam Khomeini Hospital in Ahwaz in 1398 were studied. After imaging and approving or rejecting a pulmonary embolism, simultaneously the D-dimer sample was taken from them; then the dimer level in each trimester was compared in positive or negative cases of pulmonary embolism. The SPSS software version 22 was used for data analysis.

Results:

The results showed that 12 patients in the study population had pulmonary embolism and 88 patients did not have pulmonary embolism. According to the results of patients with pulmonary embolism based on CT angiography results, there was no significant relationship with increasing gestational age and mean dimer level (P = 0.41). But there was a significant relationship between gestational age and mean dimer level in the group with no pulmonary embolism (P = 0.0001). There was no significant relationship between maternal age and mean dimer level in patients with pulmonary embolism (P = 0.376) and without pulmonary embolism (P = 0.1). Also, there was no significant relationship between the number of pregnancies in both groups with and without pulmonary embolism (P = 0456, P = 0.392).

Conclusion:

Concomitant use of D-dimer and Wells' criteria can help us to diagnose or rule out pulmonary thromboembolism and minimize the risk of pregnant women being exposed to X-rays; given the biodiversity of the D-dimer of every woman during a natural pregnancy, repeated D-dimer measurements in the evaluation of thromboembolic pregnancy during pregnancy have no clinical application.

Order Indication Solicitation to Assess Clinical Laboratory Test Utilization: D-Dimer Order Patterns as an Illustrative Case

Background:

A common challenge in the development of laboratory clinical decision support (CDS) and laboratory utilization management (UM) initiatives stems from the fact that many laboratory tests have multiple potential indications, limiting the ability to develop context-specific alerts. As a potential solution, we designed a CDS alert that asks the ordering clinician to provide the indication for testing, using D-dimer as an exemplar. Using data collected over a nearly 3-year period, we sought to determine whether the indication capture was a useful feature within the CDS alert and whether it provided actionable intelligence to guide the development of an UM strategy.

Methods:

We extracted results and ordering data for D-dimer testing performed in our laboratory over a 35-month period. We analyzed order patterns by clinical indication, hospital service, and length of hospitalization.

Results:

Our final data set included 13,971 result-order combinations and indeed provided actionable intelligence regarding test utilization patterns. For example, pulmonary embolism was the most common emergency department indication (86%), while disseminated intravascular coagulation was the most common inpatient indication (56%). D-dimer positivity rates increased with the duration of hospitalization and our data suggested limited utility for ordering this test in the setting of suspected venous thromboembolic disease in admitted patients. In addition, we found that D-dimer was ordered for unexpected indications including the assessment of stroke, dissection, and extracorporeal membrane oxygenation.

Conclusions:

Indication capture within a CDS alert and correlation with result data can provide insight into order patterns which can be used to develop future CDS strategies to guide appropriate test use by clinical indication.

Blood Biomarkers for Stroke Diagnosis and Management

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

Biosensing of D-dimer, making the transition from the central hospital laboratory to bedside determination

Since the disclosure of the fibrinogen degradation mechanism, around half a century ago, a significant number of papers have been published related to the clinical relevance of D-dimer, a molecule immune to additional enzymatic decomposition by plasmin. Due to the obliquity of regulating blood coagulation in pathological events, the number of diseases and conditions associated with abnormal levels of D-dimer includes deep vein thrombosis, pulmonary embolism, sepsis, myocardial infarction, disseminated intravascular coagulation, among many others. D-dimer not only is an important player in medical diagnosis but also its role as a prognosis biomarker is being revealed. However, the number of analytical alternative methods has not accompanied this trend, even though novel simple point-of-care devices would certainly boost the relevance of D-dimer in emergency medicine. Some reasons for that could be related to the fact that D-dimer is a challenging analyte present in complex samples like blood. In this manuscript, subsequent to a fibrinogen degradation process introduction, it is provided a historical overview of the early D-dimer assays, followed by an extended focus on innovative solutions, with a spotlight on the electrochemical bioanalytical devices. The discussion is accompanied with a critical analysis and concluding thoughts concerning future perspectives.

Cough syncope and tracheal compression secondary to a retrosternal goitre: looking for a pulmonary embolism

A 51-year-old man presented acutely with recurrent bouts of coughing associated with transient and brief loss of consciousness consistent with cough syncope, mild stridor and a recent history of a respiratory tract infection. A chest X-ray demonstrated tracheal narrowing. His D-dimer was negative. A non-contrast CT scan of the chest demonstrated a large retrosternal goitre causing tracheal compression, and further investigation with a contrast-enhanced CT scan of the neck and chest demonstrated an incidental finding of a large pulmonary embolus (PE). The full extent of the PE was determined through performing a CT pulmonary angiography. Doppler ultrasound demonstrated a left leg deep vein thrombosis as the primary cause of the PE. His cough syncope improved in response to anticoagulation treatment, to the point where he could be safely discharged home. He had a further significant improvement in symptoms following an elective hemithyroidectomy for retrosternal goitre.