Exclusion of deep vein thrombosis using the Wells rule in clinically important subgroups: individual patient data meta-analysis

Cohort study of prediction of venous thromboembolism in emergency department patients with extremity symptoms

Despite diagnostic algorithms, identification of venous thromboembolism (VTE) in emergency departments (ED) remains a challenge. We evaluated symptoms, background, and laboratory data in 27,647 ED patients presenting with pain, swelling, or other symptoms from the extremities, and identified predictors of VTE diagnosis within one year. Predictors of a clinical decision to perform phlebography, ultrasound, or computer tomography (CT) angiography of pelvic, lower, or upper extremity veins, CT of pulmonary arteries, or pulmonary scintigraphy at the ED or within 30 days, and the results of such investigations were also evaluated. A total of 3195 patients (11.6%) were diagnosed with VTE within one year. In adjusted analysis of patients in whom all laboratory data were available, a d-dimer value ≥ 0.5 mg/l (odds ratio [OR]: 2.602; 95% confidence interval [CI] 1.894-3.575; p < 0.001) at the ED and a previous diagnosis of VTE (OR: 6.037; CI 4.465-8.162; p < 0.001) independently predicted VTE within one year. Of diagnosed patients, 2355 (73.7%) had undergone imaging within 30 days after the ED visit and 1730 (54.1%) were diagnosed at this examination. Lower age (OR: 0.984; CI 0.972-0.997; p = 0.014), higher blood hemoglobin (OR: 1.023; CI 1.010-1.037; p < 0.001), C-reactive protein (OR: 2.229; CI 1.433-3.468; p < 0.001), d-dimer (OR: 8.729; CI 5.614-13.574; p < 0.001), and previous VTE (OR: 7.796; CI 5.193-11.705; p < 0.001) predicted VTE on imaging within 30 days, whereas female sex (OR 0.602 [95% CI 0.392-0.924]; p = 0.020) and a previous diagnosis of ischemic heart disease (OR 0.254 [95% CI 0.113-0.571]; p = 0.001) were negative predictors of VTE. In conclusion, analysis of 27,647 ED patients with extremity symptoms confirmed the importance of well-established risk factors for VTE. Many patients developing VTE within one year had initial negative imaging, highlighting the importance of continued symptom vigilance.

Predictive modeling of deep vein thrombosis risk in hospitalized patients: A Q-learning enhanced feature selection model

Deep vein thrombosis (DVT) represents a critical health concern due to its potential to lead to pulmonary embolism, a life-threatening complication. Early identification and prediction of DVT are crucial to prevent thromboembolic events and implement timely prophylactic measures in high-risk individuals. This study aims to examine the risk determinants associated with acute lower extremity DVT in hospitalized individuals. Additionally, it introduces an innovative approach by integrating Q-learning augmented colony predation search ant colony optimizer (QL-CPSACO) into the analysis. This algorithm, then combined with support vector machines (SVM), forms a bQL-CPSACO-SVM feature selection model dedicated to crafting a clinical risk prognostication model for DVT. The effectiveness of the proposed algorithm's optimization and the model's accuracy are assessed through experiments utilizing the CEC 2017 benchmark functions and predictive analyses on the DVT dataset. The experimental results reveal that the proposed model achieves an outstanding accuracy of 95.90% in predicting DVT. Key parameters such as D-dimer, normal plasma prothrombin time, prothrombin percentage activity, age, previously documented DVT, leukocyte count, and thrombocyte count demonstrate significant value in the prognostication of DVT. The proposed method provides a basis for risk assessment at the time of patient admission and offers substantial guidance to physicians in making therapeutic decisions.

Sex Differences in Clinical Presentation of Lower Extremity Deep Vein Thrombosis

Background: Differences between men and women in the clinical features and extent of lower limb deep vein thrombosis (DVT) may influence DVT diagnostic algorithms involving pretest clinical probability (PTP) assessment, D-dimer, and compression ultrasonography (CUS). Aims: To assess differences in DVT clinical presentation between men and women and their effect on PTP and D-dimer. Methods: We conducted a retrospective study in outpatients referred for suspected DVT of the lower limbs to our vascular emergency department from January 2005 to December 2019. Patients underwent PTP assessment with the Wells score, D-dimer testing, and CUS. Results: More women were referred for suspected DVT than men (M/F: 1,785/2,821; F: 61.4%; p < 0.0001). Women were older than men (median age: 71 vs. 67 years; p = 0.0001), DVT was diagnosed in 436 patients (9.4%) but in more men than women (M: 210 [11.8%] vs. F: 226 [8%]; p = 0.0002), with more proximal DVT in men than women (M: 131 7.3% vs. F: 124 [4.4%]; p = 0.00021). PTP was more likely in men (355 [19.9%]) than women (455 [16.2%]) (p = 0.0011); more men had swelling in the entire limb, increased calf circumference by >3 cm compared with the contralateral limb, and pitting edema, than women. D-dimer levels (available in 65% of patients) were more frequently positive in women with DVT than in men (94.6% vs. 85.7%; p = 0.016). However, a positive D-dimer and/or likely PTP was similarly frequent in men (92%) and women (96%) with DVT. Conclusions: More women than men are referred for suspected DVT, and men have a higher prevalence of proximal DVT. However, current algorithms for DVT diagnosis perform similarly in men and in women.

Venous Thrombosis in Acute Pancreatitis: What to and Not to Do?

Acute pancreatitis is an acute inflammatory condition of the pancreas that has not only local but systemic effects as well. Venous thrombosis is one such complication which can give rise to thrombosis of the peripheral vasculature in the form of deep vein thrombosis, pulmonary embolism, and splanchnic vein thrombosis. The prevalence of these complications increases with the severity of the disease and adds to the adverse outcomes profile. With better imaging and awareness, more cases are being detected, although many at times it can be an incidental finding. However, it remains understudied and strangely, most of the guidelines on the management of acute pancreatitis are silent on this aspect. This review offers an overview of the incidence, pathophysiology, symptomatology, diagnostic work-up, and management of venous thrombosis that develops in AP.

Does hormone therapy exacerbate other venous thromboembolism risk factors?

OBJECTIVE

Postmenopausal symptoms in women at higher risk for venous thromboembolism (VTE) due to comorbidities are often undertreated because of concerns that hormone therapy (HT) may increase VTE risk; however, it is unclear how much HT impacts risk of VTE when compared with other risk factors.

METHODS

This is a case-control study in a commercial claims database from 2007 to 2019. Women aged 50 to 64 years (n = 223,949) were classified as cases if they had an International Classification of Diseases code indicating an acute VTE plus a filled prescription for an anticoagulant, placement of intravascular vena cava filter, or death within 30 days of diagnosis. Controls were matched 10:1 to each case by index date and age. Risk factors and comorbidities present within the year before index were examined. Exposure was defined as a HT prescription within 60 days before index.

RESULTS

There were 20,359 VTE cases and 203,590 matched controls. A conditional logistic regression indicated that the greatest risks for VTE were from metastatic cancer (odds ratio [OR], 13.66; 95% CI, 12.64-14.75), hospitalization/surgery (OR, 8.51; 95% CI, 8.09-8.96), trauma (OR, 3.52; 95% CI, 3.32-3.73), comorbidity burden (OR, 3.51; 95% CI, 3.34-3.69), history of hypercoagulable condition (OR, 3.10; 95% CI, 2.87-3.36), and varicose veins (OR, 2.87; 95% CI, 2.56-3.22). Regarding hormone exposure, we observed ORs of 1.51 (95% CI, 1.43-1.60) for any recent hormone exposure; 1.13 (95% CI, 1.04-1.23; number needed to harm, 4,274) for unopposed estrogen menopausal HT; 1.23 (95% CI, 1.10-1.38; number needed to harm, 2,440) for combined menopausal HT; and 5.22 (95% CI, 4.67-5.84) for combined hormonal contraceptives compared with no recent HT exposure.

CONCLUSIONS

Hormone therapy exposure did not appear to adversely influence other risk factors, and exposure generally played a minor role in VTE risk. Contraceptives, however, were a strong risk factor.

Guidance for clinical practice using emergency and point-of-care ultrasonography

Owing to the miniaturization of diagnostic ultrasound scanners and their spread of their bedside use, ultrasonography has been actively utilized in emergency situations. Ultrasonography performed by medical personnel with focused approaches at the bedside for clinical decision-making and improving the quality of invasive procedures is now called point-of-care ultrasonography (POCUS). The concept of POCUS has spread worldwide; however, in Japan, formal clinical guidance concerning POCUS is lacking, except for the application of focused assessment with sonography for trauma (FAST) and ultrasound-guided central venous cannulation. The Committee for the Promotion of POCUS in the Japanese Association for Acute Medicine (JAAM) has often discussed improving the quality of acute care using POCUS, and the "Clinical Guidance for Emergency and Point-of-Care Ultrasonography" was finally established with the endorsement of JAAM. The background, targets for acute care physicians, rationale based on published articles, and integrated application were mentioned in this guidance. The core points include the fundamental principles of ultrasound, airway, chest, cardiac, abdominal, and deep venous ultrasound, ultrasound-guided procedures, and the usage of ultrasound based on symptoms. Additional points, which are currently being considered as potential core points in the future, have also been widely mentioned. This guidance describes the overview and future direction of ultrasonography for acute care physicians and can be utilized for emergency ultrasound education. We hope this guidance will contribute to the effective use of ultrasonography in acute care settings in Japan.

Risk Scores in Venous Thromboembolism Guidelines of ESC, ACCP, and ASH: An Updated Review

Venous thromboembolism (VTE) is associated with high morbidity and mortality. Risk scores associated with VTE have been widely used in clinical practice. Among numerous scores published, those included in guidelines are usually typical risk scores which have been extensively validated and globally recognized. This review provides an updated overview of the risk scores associated with VTE endorsed by 3 guidelines which are highly recognized in the field of VTE including the European Society of Cardiology, American College of Chest Physicians, and American Society of Hematology, focusing on the development, modification, validation, and comparison of these scores, to provide a comprehensive and updated understanding of all the classic risk scores associated with VTE to medical readers including but not limited to cardiologists, pulmonologists, hematologists, intensivists, physicians, surgeons, and researchers. Although each score recommended by these guidelines was more or less validated, there may still be room for further improvement. It may still be necessary to seek simpler, more practical, and more universally applicable VTE-related risk scores in the future.

Safety and efficacy of tamoxifen in boys with Duchenne muscular dystrophy (TAMDMD): a multicentre, randomised, double-blind, placebo-controlled, phase 3 trial

BACKGROUND

Drug repurposing could provide novel treatment options for Duchenne muscular dystrophy. Because tamoxifen-an oestrogen receptor regulator-reduced signs of muscular pathology in a Duchenne muscular dystrophy mouse model, we aimed to assess the safety and efficacy of tamoxifen in humans as an adjunct to corticosteroid therapy over a period of 48 weeks.

METHODS

We did a multicentre, randomised, double-blind, placebo-controlled, phase 3 trial at 12 study centres in seven European countries. We enrolled ambulant boys aged 6·5-12·0 years with a genetically confirmed diagnosis of Duchenne muscular dystrophy and who were on stable corticosteroid treatment for more than 6 months. Exclusion criteria included ophthalmological disorders, including cataracts, and haematological disorders. We randomly assigned (1:1) participants using an online randomisation tool to either 20 mg tamoxifen orally per day or matched placebo, stratified by centre and corticosteroid intake. Participants, caregivers, and clinical investigators were masked to treatment assignments. Tamoxifen was taken in addition to standard care with corticosteroids, and participants attended study visits for examinations every 12 weeks. The primary efficacy outcome was the change from baseline to week 48 in scores on the D1 domain of the Motor Function Measure in the intention-to-treat population (defined as all patients who fulfilled the inclusion criteria and began treatment). This study is registered with ClinicalTrials.gov (NCT03354039) and is completed.

FINDINGS

Between May 24, 2018, and Oct 14, 2020, 95 boys were screened for inclusion, and 82 met inclusion criteria and were initially enrolled into the study. Three boys were excluded after initial screening due to cataract diagnosis or revoked consent directly after screening, but before randomisation. A further boy assigned to the placebo group did not begin treatment. Therefore, 40 individuals assigned tamoxifen and 38 allocated placebo were included in the intention-to-treat population. The primary efficacy outcome did not differ significantly between tamoxifen (-3·05%, 95% CI -7·02 to 0·91) and placebo (-6·15%, -9·19 to -3·11; 2·90% difference, -3·02 to 8·82, p=0·33). Severe adverse events occurred in two participants: one participant who received tamoxifen had a fall, and one who received placebo suffered a panic attack. No deaths or life-threatening serious adverse events occurred. Viral infections were the most common adverse events.

INTERPRETATION

Tamoxifen was safe and well tolerated, but no difference between groups was reported for the primary efficacy endpoint. Slower disease progression, defined by loss of motor function over time, was indicated in the tamoxifen group compared with the placebo group, but differences in outcome measures were neither clinically nor statistically significant. Currently, we cannot recommend the use of tamoxifen in daily clinical practice as a treatment option for boys with Duchenne muscular dystrophy due to insufficient clinical evidence.

FUNDING

Thomi Hopf Foundation, ERA-Net, Swiss National Science Foundation, Duchenne UK, Joining Jack, Duchenne Parent Project, Duchenne Parent Project Spain, Fondation Suisse de Recherche sur les Maladies Musculaires, Association Monegasque contre les Myopathies.

Propensity-based standardization to enhance the validation and interpretation of prediction model discrimination for a target population

External validation of the discriminative ability of prediction models is of key importance. However, the interpretation of such evaluations is challenging, as the ability to discriminate depends on both the sample characteristics (ie, case-mix) and the generalizability of predictor coefficients, but most discrimination indices do not provide any insight into their respective contributions. To disentangle differences in discriminative ability across external validation samples due to a lack of model generalizability from differences in sample characteristics, we propose propensity-weighted measures of discrimination. These weighted metrics, which are derived from propensity scores for sample membership, are standardized for case-mix differences between the model development and validation samples, allowing for a fair comparison of discriminative ability in terms of model characteristics in a target population of interest. We illustrate our methods with the validation of eight prediction models for deep vein thrombosis in 12 external validation data sets and assess our methods in a simulation study. In the illustrative example, propensity score standardization reduced between-study heterogeneity of discrimination, indicating that between-study variability was partially attributable to case-mix. The simulation study showed that only flexible propensity-score methods (allowing for non-linear effects) produced unbiased estimates of model discrimination in the target population, and only when the positivity assumption was met. Propensity score-based standardization may facilitate the interpretation of (heterogeneity in) discriminative ability of a prediction model as observed across multiple studies, and may guide model updating strategies for a particular target population. Careful propensity score modeling with attention for non-linear relations is recommended.

Neonatal portal vein thrombosis: risk factors, diagnosis, treatment recommendations and review of the literature

BACKGROUND

Neonatal portal vein thrombosis (PVT) is currently more commonly encountered as a result of advances in diagnostic tools and increase in invasive interventions.

METHODS

In this study, 11 premature and 12 term infants diagnosed with PVT were retrospectively evaluated for clinical and laboratory characteristics, umbilical catheterization procedure, PVT location, risk factors, treatments, and long-term outcomes.

RESULTS

Median age of the patients at diagnosis was 10 days (range 3-90 days), and 69.6% of patients were girls. Of the 23 patients, 87% had left PVT and, 91.3% had at least one thrombosis risk factor, which was sepsis in 73.9% of patients, and presence of umbilical venous catheter in 87%. Totally, 59.1% of PVTs were completely resolved in a median follow-up of 7 months (1 month to 12 months), and 78.3% of these patients had no anticoagulant therapy (ACT). Partial thrombus resolution was achieved in 9 patients (40.9%). Five patients (%21) received ACT. Overall, 34.8% of patients had long-term complications. neonatal PVT is most commonly reported in the left portal vein and there is no evidence for the impact of ACT on reducing the short- or long-term complications. Well designed and larger studies are necessary to clarify this issue, which can facilitate developing appropriate management algorithms.

CONCLUSION

Neonatal PVT is most commonly reported in the left portal vein and there is no evidence for the impact of ACT on reducing the short- or long-term complications. Well designed and larger studies are necessary to clarify this issue, which can facilitate developing appropriate management algorithms.

Different diagnostic strategies using D-dimer for peripherally inserted central catheter-related upper extremity deep vein thrombosis

OBJECTIVE

Deep vein thrombosis (DVT) in the upper extremities caused by a peripherally inserted central venous catheter (PICC) is distinct from the typical DVT. This specific type of mural thrombus might have an effect on the D-dimer levels. In the present study, we aimed to ascertain whether the D-dimer level might be considered an independent diagnostic marker to rule out upper extremity DVT caused by PICCs.

METHODS

We performed a retrospective case-cohort study of 205 patients who had undergone D-dimer measurement and color Doppler ultrasound within 14 days after placement of a PICC to December 31, 2020, from January 1, 2018. The participants were followed up for 3 months to evaluate for upper extremity DVT. In addition, different D-dimer diagnostic strategies were analyzed.

RESULTS

Of the 205 included patients, 53 (25.9%) had had a negative D-dimer level. Of the 53 patients, 10 had had upper extremity DVT attributable to a PICC using color Doppler ultrasound. Of these 10 patients, 3 had developed upper extremity DVT during the 3-month follow-up. Using the various D-dimer diagnostic techniques, the negative predictive value for the D-dimer levels was 81.1%.

CONCLUSIONS

The present study has shown that the different D-dimer diagnostic strategies are not effective for safely excluding the diagnosis of suspected PICC-related upper extremity DVT. Adding PICC placement as a special factor in the modified Wells score, in addition to the D-dimer level, could securely rule out PICC-related upper extremity DVT; however, the diagnostic efficacy was low.

Haemostasis and Inflammatory Parameters as Potential Diagnostic Biomarkers for VTE in Trauma-Immobilized Patients

Venous thromboembolism (VTE), which encompasses deep venous thrombosis (DVT) and pulmonary embolism (PE), is a major public health concern due to its high incidences of morbidity and mortality. Patients who have experienced trauma with prolonged immobilization are at an increased risk of developing VTE. Plasma D-dimer levels have been known to be elevated in trauma patients, and they were closely correlated with the number of fractures. In other words, plasma D-dimer levels cannot be used as the only indicator of VTE in trauma cases. Given the limitations, further study is needed to explore other potential biomarkers for diagnosing VTE. To date, various established and novel VTE biomarkers have been studied in terms of their potential for predicting VTE, diagnostic performance, and improving clinical therapy for VTE. Therefore, this review aims to provide information regarding classic and essential haemostasis (including prothrombin time (PT), activated partial thromboplastin time (aPTT), D-dimer, fibrinogen, thrombin generation, protein C, protein S, antithrombin, tissue factor pathway inhibitor, and platelet count) and inflammatory biomarkers (C-reactive protein, erythrocyte sedimentation rate, and soluble P-selectin) as potential diagnostic biomarkers that can predict the risk of VTE development among trauma patients with prolonged immobilization. Thus, further advancement in risk stratification using these biomarkers would allow for a better diagnosis of patients with VTE, especially in areas with limited resources.

Cost-Effectiveness Rivaroxaban versus Enoxaparin for Prevention of Venous Thromboembolism after Knee Replacement Surgery in Iran

Background

The highest risk of developing venous thromboembolism (VTE) is seen in patients who have undergone orthopedic surgery. One of the most common methods to reduce the risk of thromboembolism in these patients is anticoagulant prophylaxis. Rivaroxaban is one of the anticoagulants that has a lower cost than other anticoagulants and has a significant effect on people's quality of life as it is edible. The study aimed to determine the cost-effectiveness of rivaroxaban as compared with enoxaparin for venous thromboembolism prophylaxis in knee replacement patients in Iran.

Methods

It was a quantitative and economic evaluation study with a cost-effectiveness approach and an applied study because its results could be used directly for policy-making and decision-making in the health system. The study was conducted in 2019 and 2020. This study considered the health system perspective. The study population included all knee replacement patients. The sample included 203 patients referred to Shafa Yahyaeian Hospital and 300 patients referred to Rasoul Hospital in Tehran. The study was conducted in two steps. A systematic review of studies was conducted in the first step. The CHEERS checklist was used to evaluate the quality of the studies in the systematic review. The EQ-5D questionnaire was used in the second step to calculate the QALY, and the cost collection form was used to calculate the direct medical cost. The data were analyzed through a decision tree, and Stata and Tree age pro softwares were the analysis tools. Also, according to the per capita GDP index for Iran in 2018, the incremental cost-effectiveness threshold was considered to be $10,000.

Results

The results of this study showed that during the prophylaxis period, rivaroxaban was one and a half times less costly than enoxaparin. Quality of life in uncomplicated conditions were 0.85 QALY for rivaroxaban and 0.69 QALY for enoxaparin. Based on the results of this study, the cost of rivaroxaban during the prophylaxis was $ 160.97 and the quality of life was 0.85 QALY and the cost of enoxaparin was $ 276.07 and the quality of life was 0.69 QALY. The cost difference between the two interventions was $ 115.09 and the outcome difference was 0.16 QALY. The incremental cost-effectiveness ratio was $ 189.40 for rivaroxaban and $ 416.28 for enoxaparin. According to the results of this study, rivaroxaban reduced the duration of hospitalization by an average of 2 days in asymptomatic patients (prophylaxis period) compared to enoxaparin.

Conclusion

Rivaroxaban, an oral medication, reduced costs and increased the quality of life in people undergoing knee replacement surgery compared with an enoxaparin injection vial. This drug was less costly for the patient and health systems and its use was cost-effective as a thromboprophylaxis drug following knee replacement surgery.

Understanding patient assessment and treatment in deep vein thrombosis

Deep vein thrombosis (DVT) commonly develops in the deep veins of the legs, but it can potentially form in any part of the body. There are several risk factors associated with DVT including prolonged immobility, malignancy, recent surgery and family history. One of the main risks of DVT is that the thrombus that has formed in a vein may travel through the body and become lodged in the pulmonary system, causing a pulmonary embolism, which is life-threatening. In the UK, specialist services and diagnostic pathways have been developed to speed up the diagnosis and treatment of DVT, many of which are now nurse-led. This article uses a case study to outline the assessment of patients with suspected DVT and the treatment of patients with a confirmed diagnosis of DVT.

Deep Venous Thrombosis

Venous thromboembolism (VTE) is the third most common cardiovascular disorder, affecting up to 5% of the population. VTE commonly manifests as lower-extremity deep venous thrombosis (DVT) or pulmonary embolism. Half of these events are associated with a transient risk factor and may be preventable with prophylaxis. Direct oral anticoagulants are effective and safe and carry a lower risk for bleeding than vitamin K antagonists. Many patients with VTE will have a chronic disease requiring long-term anticoagulation. Postthrombotic syndrome affects 25% to 40% of patients with DVT and significantly impacts function and quality of life.

Role of Physical Therapists in the Management of Individuals at Risk for or Diagnosed With Venous Thromboembolism: Evidence-Based Clinical Practice Guideline 2022

No matter the practice setting, physical therapists work with patients who are at risk for or who have a history of venous thromboembolism (VTE). In 2016, the first clinical practice guideline (CPG) addressing the physical therapist management of VTE was published with support by the American Physical Therapy Association's Academy of Cardiovascular and Pulmonary Physical Therapy and Academy of Acute Care, with a primary focus on lower extremity deep vein thrombosis (DVT). This CPG is an update of the 2016 CPG and contains the most current evidence available for the management of patients with lower extremity DVT and new key action statements (KAS), including guidance on upper extremity DVT, pulmonary embolism, and special populations. This document will guide physical therapist practice in the prevention of and screening for VTE and in the management of patients who are at risk for or who have been diagnosed with VTE. Through a systematic review of published studies and a structured appraisal process, KAS were written to guide the physical therapist. The evidence supporting each action was rated, and the strength of statement was determined. Clinical practice algorithms based on the KAS were developed that can assist with clinical decision-making. Physical therapists, along with other members of the health care team, should implement these KAS to decrease the incidence of VTE, improve the diagnosis and acute management of VTE, and reduce the long-term complications of VTE.

Correlation of Inflammation and Coagulation Markers with the Incidence of Deep Vein Thrombosis in Cancer Patients with High Risk of Thrombosis

Background

Deep vein thrombosis (DVT) is a common complication and the second leading cause of death in cancer patients. Pro-inflammatory stimuli in the cancer microenvironment induce nuclear factor kappa B (NF-κB) signaling pathway that plays an integral role in immunothrombosis mechanism.

Objective

To investigate the role of inflammatory and coagulation biomarkers in the development of DVT in cancer patients with high risk of thrombosis (Khorana score ≥2).

Subjects and methods

This study was a cross-sectional study at Dr. Kariadi General Hospital. The serum levels of proinflammatory cytokines, ie, NF-κB, interleukin-6 (IL-6), C-reactive protein (CRP), tumor necrosis factor-alpha (TNF-α), and coagulation biomarkers, ie, tissue factor (TF), prothrombin fragment F1+2 (F1+2), fibrinogen and D-dimer were measured in newlydiagnosed cancer patients with a highrisk of thrombosis. Color duplex sonography was used for DVT screening.

Results

From January to November 2021, there were 83 eligible patients. DVT was confirmed in 8 subjects (9.63%). Univariate analysis revealed a significant difference between the median age of patients with DVT compared to non-DVT patients, 49.5 years (range: 23–60 years) and 42 years (range: 19–60 years), with p=0.046. D-dimer level was higher in DVT patients [(6.020 µg/L, range 2.090–20.000) vs (1.940 µg/L, range 270–20.000), p=0.005]. Multivariate analysis revealed age and D-dimer were significantly correlated with DVT incidence. In all patients, there were significant positive correlations between several inflammatory and coagulation activation parameters, which were IL-6 with D-dimer and F1+2, CRP with F1+2 and D-dimer as well as TNF-α with F1+2. However, these findings were not shown in DVT patients.

Conclusion

In cancer patients with a high risk of thrombosis, age and D-dimer level are the significant variables towards the incidence of DVT. In patients with DVT, there was no significant correlation between inflammatory and coagulation activation parameters.

Lower-Extremity Venous Ultrasound in DVT-Unlikely Patients with Positive D-Dimer Test

RATIONALE AND OBJECTIVES

To review the clinical data, D-dimer level and the ultrasonographic findings from complete venous ultrasound of the lower extremity in deep venous thrombosis (DVT)-unlikely patients with abnormal D-dimer test were compared to DVT-likely patients to ascertain the appropriate ultrasound examination protocol for patients in this group.

MATERIAL AND METHODS

A retrospective cohort study was conducted of all patients who underwent a complete (whole leg) venous ultrasound in one 13-month period. The medical history, demographic, clinical risk factors, and ultrasonographic findings of the patients with high clinical probability for deep vein thrombosis (Wells score ≥2), along with patients with a low clinical probability of deep vein thrombosis (Wells score ≤1) but with a D-dimer level higher than the threshold (≥500 ng/ml FEU) were evaluated.

RESULTS

There were 96 patients in the DVT-likely group and 86 patients in the DVT-unlikely group. The indication for ultrasound examination in the DVT-unlikely group was preoperative assessment to avoid the risk of pulmonary thromboembolism. The patients in the DVT-likely group had more positive ultrasound results for DVT (15.63% vs. 5.18%, p value = 0.03) than the patients in the DVT-unlikely group. In the DVT-unlikely group, the median D-dimer level in the patients with positive ultrasound for DVT showed statistically significantly higher levels than the patients with negative ultrasound for DVT did (2208 vs. 921 ng/ml FEU, p value = 0.02). The optimal D-dimer cut-off from the receiver operating characteristics analysis shows the maximized summation of sensitivity and specificity (80% and 66.67%) at 1251 ng/ml FEU. The prevalence of acute thrombus in a thigh vein in DVT-unlikely, preoperative patients is low (1.2%).

CONCLUSION

To minimize the number of unnecessary complete venous ultrasound lower-extremity examinations, the use of a higher D-dimer cut-off level and limiting proximal or thigh vein ultrasound examinations in the preoperative patient is considered.

Evaluation of the modified Wells score in predicting venous thromboembolic disease in patients with tuberculosis or HIV in a South African setting

Background

There is paucity of data on the modified Wells score (MWS) utility on patients with venous thromboembolism (VTE) in a South African setting where there is a high burden of HIV and tuberculosis (TB). This study analyses the performance of this score in HIV/TB-infected patients compared with non-infected patients.

Objectives

To assess the performance of the MWS as an additional risk factor for VTE in hospitalised patients with a high burden of HIV/TB infections.

Method

This study was a retrospective cross-sectional cohort analysis of the utility of the MWS in 156 HIV/TB-infected and non-infected adult patients diagnosed with VTE on compression ultrasonography (CUS) or computed tomography pulmonary angiography (CTPA) in a medical inpatient setting over six months. Patients with HIV and/or TB were assessed as having an additional risk factor (1 point for each), and this was compared with the MWS. A McNeymar’s paired sample chi-squared test was used to compare the sensitivity of this score against the MWS.

Results

Of the 156 patients with VTE who were enrolled, HIV was the commonest risk factor (42.31%) with TB accounting for 10.90% of cases. When the MWS adjusted for HIV/TB was used, the sensitivity increased from 25% to 100% for the HIV–/TB+ category, it increased from 77.36% to 98.11% in the HIV+/TB– category and it increased from 84.62% to 92.95% in the HIV+/TB+ category. These differences were statistically significant at P < 0.05 in all categories.

Conclusion

The MWS performs better when the infectivity of HIV/TB is included as an additional risk factor in the score.

Diagnosis of deep vein thrombosis with D-dimer adjusted to clinical probability: prospective diagnostic management study

Objective

To evaluate the safety and efficiency of a diagnostic algorithm for deep vein thrombosis (DVT) that uses clinical pretest probability based D-dimer thresholds to exclude DVT.

Design

Prospective diagnostic management study.

Setting

University based emergency departments or outpatient clinics in Canada.

Participants

Patients with symptoms or signs of DVT.

Intervention

DVT was considered excluded without further testing by Wells low clinical pretest probability and D-dimer <1000 ng/mL or Wells moderate clinical pretest probability and D-dimer <500 ng/mL. All other patients had proximal ultrasound imaging. Repeat proximal ultrasonography was restricted to patients with initially negative ultrasonography, low or moderate clinical pretest probability, and D-dimer >3000 ng/mL or high clinical pretest probability and D-dimer >1500 ng/mL. If DVT was not diagnosed, patients did not receive anticoagulant treatment.

Main outcome measure

Symptomatic venous thromboembolism at three months.

Results

1508 patients were enrolled and analysed, of whom 173 (11.5%) had DVT on scheduled diagnostic testing. Of the 1275 patients with no proximal DVT on scheduled testing who did not receive anticoagulant treatment, eight (0.6%, 95% confidence interval 0.3% to 1.2%) were found to have venous thromboembolism during follow-up. Compared with a traditional DVT testing strategy, this diagnostic approach reduced the need for ultrasonography from a mean of 1.36 scans/patient to 0.72 scans/patient (difference −0.64, 95% confidence interval −0.68 to −0.60), corresponding to a relative reduction of 47%.

Conclusions

The diagnostic strategy using a combination of clinical pretest probability and D-dimer identified a group of patients at low risk for DVT during follow-up while substantially reducing the need for ultrasound imaging.

Registration

ClinicalTrials.gov NCT02038530.

Artificial Intelligence Evidence-Based Current Status and Potential for Lower Limb Vascular Management

Consultation prioritization is fundamental in optimal healthcare management and its performance can be helped by artificial intelligence (AI)-dedicated software and by digital medicine in general. The need for remote consultation has been demonstrated not only in the pandemic-induced lock-down but also in rurality conditions for which access to health centers is constantly limited. The term “AI” indicates the use of a computer to simulate human intellectual behavior with minimal human intervention. AI is based on a “machine learning” process or on an artificial neural network. AI provides accurate diagnostic algorithms and personalized treatments in many fields, including oncology, ophthalmology, traumatology, and dermatology. AI can help vascular specialists in diagnostics of peripheral artery disease, cerebrovascular disease, and deep vein thrombosis by analyzing contrast-enhanced magnetic resonance imaging or ultrasound data and in diagnostics of pulmonary embolism on multi-slice computed angiograms. Automatic methods based on AI may be applied to detect the presence and determine the clinical class of chronic venous disease. Nevertheless, data on using AI in this field are still scarce. In this narrative review, the authors discuss available data on AI implementation in arterial and venous disease diagnostics and care.

Deep Vein Thrombosis in Intravenous Drug Users: An Invisible Global Health Burden

The prevalence of intravenous drug use has increased in the past decade and it represents an important risk factor for deep vein thrombosis. Intravenous drug use is a global problem, with the main culprit being heroin. Peer pressure and poverty in high-risk groups such as sex workers, females, and young adults raise the risk of intravenous drug use, which expresses itself in the form of venous thromboembolism eventually. Deep vein thrombosis typically manifests itself eight years after the initial intravenous drug administration, rendering it a silent killer. Aiming to review and summarize existing articles in this context, we performed an exhaustive literature search online on PubMed and Google Scholar indexes using the keywords "Deep Venous Thrombosis (DVT)" and "Intravenous Drug Users (IVDU)." English articles that addressed epidemiology, pathogenesis, clinical manifestations, diagnosis, differential diagnosis, management, and outcomes of DVT, including those in IVDU, were selected and analyzed. The pathogenesis of DVT development in IVDU is mainly attributed to the interplay of trauma to the vessel by repeated injection and the injected drug itself. The right-sided femoral vein is the most common vein affected. Prevalent clinical presentations include local pain, swelling, and redness with typical systemic symptoms including fever, cough, dyspnea, and chest pain on top of addiction features. There appeared to be a delay in reporting symptoms, which was most likely due to the social stigma attached to IVDU. There are over 50 conditions that present with swollen and painful limbs comparable to DVT in IVDU, making precise diagnosis critical for timely treatment. Venous ultrasound is the method of choice for diagnosing DVT. Extended anticoagulant therapy with low-molecular-weight heparin combined with warfarin is the recommended treatment. Intravenous drug abusers having DVT are affected by multiple complications and poorer outcomes such as slower recovery, recurrent venous thromboembolism (VTE), and a longer hospital stay, which put them at higher risk of morbidity, mortality, reduced productivity, and economic burden.

Management of superficial venous thrombosis based on individual risk profiles: protocol for the development and validation of three prognostic prediction models in large primary care cohorts

BACKGROUND

Superficial venous thrombosis (SVT) is considered a benign thrombotic condition in most patients. However, it also can cause serious complications, such as clot progression to deep venous thrombosis (DVT) and pulmonary embolism (PE). Although most SVT patients are encountered in primary healthcare, studies on SVT nearly all were focused on patients seen in the hospital setting. This paper describes the protocol of the development and external validation of three prognostic prediction models for relevant clinical outcomes in SVT patients seen in primary care: (i) prolonged (painful) symptoms within 14 days since SVT diagnosis, (ii) for clot progression to DVT or PE within 45 days and (iii) for clot recurrence within 12 months.

METHODS

Data will be used from four primary care routine healthcare registries from both the Netherlands and the UK; one UK registry will be used for the development of the prediction models and the remaining three will be used as external validation cohorts. The study population will consist of patients ≥18 years with a diagnosis of SVT. Selection of SVT cases will be based on a combination of ICPC/READ/Snowmed coding and free text clinical symptoms. Predictors considered are sex, age, body mass index, clinical SVT characteristics, and co-morbidities including (history of any) cardiovascular disease, diabetes, autoimmune disease, malignancy, thrombophilia, pregnancy or puerperium and presence of varicose veins. The prediction models will be developed using multivariable logistic regression analysis techniques for models i and ii, and for model iii, a Cox proportional hazards model will be used. They will be validated by internal-external cross-validation as well as external validation.

DISCUSSION

There are currently no prediction models available for predicting the risk of serious complications for SVT patients presenting in primary care settings. We aim to develop and validate new prediction models that should help identify patients at highest risk for complications and to support clinical decision making for this understudied thrombo-embolic disorder. Challenges that we anticipate to encounter are mostly related to performing research in large, routine healthcare databases, such as patient selection, endpoint classification, data harmonisation, missing data and avoiding (predictor) measurement heterogeneity.

Elevated D-Dimer Levels Predict a Poor Outcome in Critically Ill Patients

D-dimer is a biomarker of thrombosis and recently been considered to predict a poor outcome in patients with infectious diseases. Plasma D-dimer levels were measured in critically ill patients to examine their relationship with the poor outcome. The plasma D-dimer levels were markedly higher in the patients with various underlying disease especially venous thromboembolism in comparison to those without severe underlying diseases. The plasma D-dimer levels in non-survivors were significantly higher than those in survivors. In a receiver operating characteristic analysis, the area under the curve was high for the disseminated intravascular coagulation (DIC) score, the D-dimer value, and the prothrombin time-international normalize ratio (PT-INR). Adequate cut-off values for predicting the outcome were 3 as follows: DIC score, 3 points; D-dimer, 4.2 mg/L; and PT-INR, 1.08. D-dimer, which is a biomarker for thrombosis, is increased in various underlying diseases and predicts a poor outcome.

Diagnosis and Treatment of Deep Vein Thrombosis in the Emergency Department: Results of an Italian Nominal Group Technique Study

Early diagnosis and treatment of deep vein thrombosis (DVT) is a main issue in the Emergency setting. With the aim of assisting clinicians in the diagnosis and the subsequent management of DVT in the Emergency Departments, a Nominal Group Technique (NGT) study was conducted. A panel of 5 Italian experts developed 21 consensus statements based on available evidence and their clinical experience. The agreed consensus statements may assist clinicians in applying the results of clinical studies and clinical experience to routine care settings, providing guidance on all aspects of the risk assessment, prophylaxis, early diagnosis and appropriate treatment of DVT in the EDs.

Venous thromboembolism

Venous thromboembolism, comprising both deep vein thrombosis and pulmonary embolism, is a chronic illness that affects nearly 10 million people every year worldwide. Strong provoking risk factors for venous thromboembolism include major surgery and active cancer, but most events are unprovoked. Diagnosis requires a sequential work-up that combines assessment of clinical pretest probability for venous thromboembolism using a clinical score (eg, Wells score), D-dimer testing, and imaging. Venous thromboembolism can be considered excluded in patients with both a non-high clinical pretest probability and normal D-dimer concentrations. When required, ultrasonography should be done for a suspected deep vein thrombosis and CT or ventilation-perfusion scintigraphy for a suspected pulmonary embolism. Direct oral anticoagulants (DOACs) are the first-line treatment for almost all patients with venous thromboembolism (including those with cancer). After completing 3-6 months of initial treatment, anticoagulation can be discontinued in patients with venous thromboembolism provoked by a major transient risk factor. Patients whose long-term risk of recurrent venous thromboembolism outweighs the long-term risk of major bleeding, such as those with active cancer or men with unprovoked venous thromboembolism, should receive indefinite anticoagulant treatment. Pharmacological venous thromboembolism prophylaxis is generally warranted in patients undergoing major orthopaedic or cancer surgery. Ongoing research is focused on improving diagnostic strategies for suspected deep vein thrombosis, comparing different DOACs, developing safer anticoagulants, and further individualising approaches for the prevention and management of venous thromboembolism.

A simplified decision rule to rule out deep vein thrombosis using clinical assessment and D-dimer

BACKGROUND

Current clinical decision rules to exclude deep vein thrombosis (DVT) are underused partly because of their complexity. A simplified rule that can be easily applied would be more appealing to use in clinical practice.

METHODS

We used individual patient data from prospective diagnostic studies of patients suspected of DVT to develop a new clinical decision rule. The primary outcome was presence of DVT either at initial testing or during follow-up. DVT was considered safely excluded if the upper 95% confidence interval (CI) of DVT prevalence was <2%.

RESULTS

Four studies and 3368 patients were eligible for this analysis. Overall prevalence of DVT was 17%. In addition to D-dimer, two variables, calf swelling and DVT as the most likely diagnosis, are included in the new rule. Based on these two variables, two clinical pretest probability (CPTP) groups were defined; low (none of the two items present) and high (at least one of the items present). DVT can be safely excluded in patients with low CPTP with a D-dimer <500 ng/mL (prevalence = 0.1%; 95% CI, 0.0-0.8), low CPTP with a D-dimer between 500 ng/ml and 1000 ng/ml (prevalence = 0.3%; 95% CI, 0.0-1.7), and D-dimer <500 ng/ml in patients with high CPTP (prevalence = 0.3%; 95% CI, 0.0-1.0).

CONCLUSIONS

The combination of D-dimer and Wells items resulted in a simple clinical decision rule with 3 items. The results suggest that the rule can safely exclude DVT. Prospective validation is required.

Incidence of venous thromboembolism in patients with solid cancers in Japan: retrospective study of 2735 patients

BACKGROUND

The incidence of cancer-associated venous thromboembolism (CA-VTE) in Japan has not been fully investigated.

METHODS AND RESULTS

Clinicopathological information from patients with solid malignancies who first visited our department between November 2011 and March 2018 were retrospectively reviewed from medical records. The primary outcome was incidence of CA-VTE, defined as deep-vein thrombosis (DVT) and/or pulmonary embolism (PE). On median follow-up of 187 days, 91 of 2735 patients (3.3%) developed CA-VTE during their clinical course, giving an incidence rate of 40.7 per 1000 person-years. Of the 91 patients, 75 (82%) were diagnosed with DVT alone, 6 (7%) with PE alone, and 10 (11%) with both DVT and PE. CA-VTE was most frequent in non-small cell lung cancer (10.8%), followed by cancer of unknown origin (5.8%). Forty-four patients (48%) had one or more symptoms at the initial diagnosis of VTE. Five patients (6%) had a normal D-dimer level (≤ 1.0 µg/mL); of these, 2 were asymptomatic.

CONCLUSIONS

In this retrospective study, the incidence of CA-VTE in Japanese patients with cancer was equivalent to that in Western populations. Approximately half of CA-VTE patients were asymptomatic and 6% had normal D-dimer levels, indicating the need for closer attention to occult CA-VTE.

Diagnostic Value of Neutrophil Lymphocyte Ratio and D-Dimer as Biological Markers of Deep Vein Thrombosis in Patients Presenting with Unilateral Limb Edema

Introduction

Patients with deep vein thrombosis (DVT) pose high morbidity and mortality risk thus needing fast and accurate diagnosis. Wells clinical prediction scores with D-dimer testing are traditionally used to rule out patients with low probability of DVT. However, D-dimer testing has a few limitations regarding its relatively low specificity. Neutrophil-lymphocyte ratio (NLR), a marker of inflammation, was found to increase in DVT. Hence, we aimed to evaluate the role of NLR for DVT diagnosis.

Methods

Data were collected from medical records of patients with suspected DVT at Cipto Mangunkusumo National General Hospital during January–December 2014. Diagnosis of DVT was conducted using lower limb ultrasonography. Diagnostic values for NLR, D-dimer, and NLR + D-dimer were determined by receiver operating characteristic (ROC) analysis to obtain area under the curve (AUC), sensitivity, specificity, negative predictive value, and positive predictive values. Sensitivity and specificity analyses of NLR and D-dimer were also conducted based on Wells score and divided into groups of low and high probability of DVT.

Results

The AUC values for NLR, D-dimer, and NLR + D-dimer were 72.6%, 70.4%, and 76.1%, respectively. The optimal cut-off value determined for NLR was 5.12 with sensitivity of 67.7%, specificity of 67.9%, PPV of 68.85%, and NPV of 64.91% in differentiating subjects with and without DVT. This study also found that D-dimer had sensitivity of 69.4%, specificity of 71.4%, PPV of 72.88%, and NPV of 67.8%. Meanwhile, the NLR + D-dimer combination had sensitivity of 66.1% and specificity of 72.6%. Multivariate analysis showed that NLR (OR: 2.636; 95% CI: 1.144–6.076; p: 0.023) and D-dimer (OR: 4.175; 95% CI: 1.810–9.633; p: 0.001) were associated with DVT.

Conclusion

NLR value has wider AUC than D-Dimer and is relatively easier to obtain and does not require specific assay, thus enabling rapid evaluation of symptomatic patients suspected of having DVT. Adding NLR to D-dimer increased AUC to detect DVT. Therefore, NLR could serve as a complementary diagnostic tool for D-dimer to exclude DVT, especially in low clinical probability patients.

Diagnosis of deep vein thrombosis of the lower extremity: a systematic review and meta-analysis of test accuracy

Deep vein thrombosis (DVT) of the lower extremities can be associated with significant morbidity and may progress to pulmonary embolism and postthrombotic syndrome. Early diagnosis and treatment are important to minimize the risk of these complications. We systematically reviewed the accuracy of diagnostic tests for first-episode and recurrent DVT of the lower extremities, including proximal compression ultrasonography (US), whole leg US, serial US, and high-sensitivity quantitative D-dimer assays. We searched Cochrane Central, MEDLINE, and EMBASE for eligible studies, reference lists of relevant reviews, registered trials, and relevant conference proceedings. Two investigators screened and abstracted data. Risk of bias was assessed using Quality Assessment of Diagnostic Accuracy Studies-2 and certainty of evidence using the Grading of Recommendations Assessment, Development and Evaluation framework. We pooled estimates of sensitivity and specificity. The review included 43 studies. For any suspected DVT, the pooled estimates for sensitivity and specificity of proximal compression US were 90.1% (95% confidence interval [CI], 86.5-92.8) and 98.5% (95% CI, 97.6-99.1), respectively. For whole-leg US, pooled estimates were 94.0% (95% CI, 91.3-95.9) and 97.3% (95% CI, 94.8-98.6); for serial US pooled estimates were 97.9% (95% CI, 96.0-98.9) and 99.8% (95% CI, 99.3-99.9). For D-dimer, pooled estimates were 96.1% (95% CI, 92.6-98.0) and 35.7% (95% CI, 29.5-42.4). Recurrent DVT studies were not pooled. Certainty of evidence varied from low to high. This systematic review of current diagnostic tests for DVT of the lower extremities provides accuracy estimates. The tests are evaluated when performed in a stand-alone fashion, and in a diagnostic pathway. The pretest probability of DVT often assessed by a clinical decision rule will influence how, together with sensitivity and specificity estimates, patients will be managed.

Diagnosis of deep vein thrombosis of the upper extremity: a systematic review and meta-analysis of test accuracy

Upper extremity deep vein thrombosis (UEDVT) accounts for ≤10% of DVT and can be associated with morbidity and mortality. Accurate diagnosis and treatment are necessary for safe and effective patient management. We systematically reviewed the accuracy of D-dimer and duplex ultrasonography (US) for the evaluation of suspected first-episode UEDVT. We searched the Cochrane Central Register, OVID MEDLINE, EMBASE, and PubMed for eligible studies, reference lists of relevant reviews, registered trials, and relevant conference proceedings. We included prospective cross-sectional and cohort studies that evaluated test accuracy. Two investigators independently screened and collected data. The risk of bias was assessed using Quality Assessment of Diagnostic Accuracy Studies 2 and certainty of evidence using the Grading of Recommendations Assessment, Development and Evaluation framework. We pooled estimates of sensitivity and specificity. The review included 9 studies. The pooled estimates for D-dimer sensitivity and specificity were 0.96 (95% confidence interval [CI], 0.87-0.99) and 0.47 (95% CI, 0.43-0.52), respectively. The pooled estimates for duplex US sensitivity and specificity were 0.87 (95% CI, 0.73-0.94) and 0.85 (95% CI, 0.72-0.93), respectively. Certainty of evidence was moderate. In this review, we summarized the test accuracy (sensitivity and specificity) of D-dimer and duplex US for this indication. The sensitivity and specificity of the tests found in the present review should be considered in the context of whether they are used alone or in combination, which is dependent on the prevalence of disease in the population, the clinical setting in which the patient is being evaluated, cost, potential harms, and patient outcomes. This study was registered at PROSPERO as Systematic Review Registration Number CRD42018098488.

Developing more generalizable prediction models from pooled studies and large clustered data sets

Prediction models often yield inaccurate predictions for new individuals. Large data sets from pooled studies or electronic healthcare records may alleviate this with an increased sample size and variability in sample characteristics. However, existing strategies for prediction model development generally do not account for heterogeneity in predictor‐outcome associations between different settings and populations. This limits the generalizability of developed models (even from large, combined, clustered data sets) and necessitates local revisions. We aim to develop methodology for producing prediction models that require less tailoring to different settings and populations. We adopt internal‐external cross‐validation to assess and reduce heterogeneity in models' predictive performance during the development. We propose a predictor selection algorithm that optimizes the (weighted) average performance while minimizing its variability across the hold‐out clusters (or studies). Predictors are added iteratively until the estimated generalizability is optimized. We illustrate this by developing a model for predicting the risk of atrial fibrillation and updating an existing one for diagnosing deep vein thrombosis, using individual participant data from 20 cohorts (N = 10 873) and 11 diagnostic studies (N = 10 014), respectively. Meta‐analysis of calibration and discrimination performance in each hold‐out cluster shows that trade‐offs between average and heterogeneity of performance occurred. Our methodology enables the assessment of heterogeneity of prediction model performance during model development in multiple or clustered data sets, thereby informing researchers on predictor selection to improve the generalizability to different settings and populations, and reduce the need for model tailoring. Our methodology has been implemented in the R package metamisc.

Clinical prediction models: diagnosis versus prognosis

Clinical prediction models play an increasingly important role in contemporary clinical care, by informing healthcare professionals, patients and their relatives about outcome risks, with the aim to facilitate (shared) medical decision making and improve health outcomes. Diagnostic prediction models aim to calculate an individual's risk that a disease is already present, whilst prognostic prediction models aim to calculate the risk of particular heath states occurring in the future. This article serves as a primer for diagnostic and prognostic clinical prediction models, by discussing the basic terminology, some of the inherent challenges, and the need for validation of predictive performance and the evaluation of impact of these models in clinical care.

Performance of the Wells score in predicting deep vein thrombosis in medical and surgical hospitalized patients with or without thromboprophylaxis: The R-WITT study

The Wells score had shown weak performance to determine pre-test probability of deep vein thrombosis (DVT) for inpatients. So, we evaluated the impact of thromboprophylaxis on the utility of the Wells score for risk stratification of inpatients with suspected DVT. This bicentric cross-sectional study from February 1, 2018 to January 31, 2019 included consecutive medical and surgical inpatients who underwent lower limb ultrasound study for suspected DVT. Wells score clinical predictors were assessed by both ordering and vascular physicians within 24 h after clinical suspicion of DVT. Primary outcome was the Wells score's accuracy for pre-test risk stratification of suspected DVT, accounting for anticoagulation (AC) treatment (thromboprophylaxis for ⩾ 72 hours or long-term anticoagulation). We compared prevalence of proximal DVT among the low, moderate and high pre-test probability groups. The discrimination accuracy was defined as area under the receiver operating characteristics (ROC) curve. Of the 415 included patients, 30 (7.2%) had proximal DVT. Prevalence of proximal DVT was lower than expected in all pre-test probability groups. The prevalence in low, moderate and high pre-test probability groups was 0.0%, 3.1% and 8.2% (p = 0.22) and 1.7%, 4.2% and 25.8% (p < 0.001) for inpatients with or without AC, respectively. Area under ROC curves for discriminatory accuracy of the Wells score, for risk of proximal DVT with or without AC, was 0.72 and 0.88, respectively. The Wells score performed poorly for discrimination of risk for proximal DVT in hospitalized patients with AC but performed reasonably well among patients without AC; and showed low inter-rater reliability between physicians. ClinicalTrials.gov Identifier: NCT03784937.

Practical Utility of D-dimer Test for Venous Thromboembolism in Systemic Lupus Erythematosus Depends on Disease Activity: a Retrospective Cohort Study

BACKGROUND

The D-dimer test is a screening tool for venous thromboembolism (VTE); however, its utility for patients with systemic lupus erythematosus (SLE) remains unclear. Here, we examined the utility of the D-dimer test as a screening tool for VTE in SLE patients.

METHODS

SLE patients (n = 276) and age- and sex-matched patients with non-rheumatic disease (n = 1,104), all of whom underwent D-dimer testing to screen for VTE, were enrolled. The sensitivity and specificity and receiver operating characteristics curve of the D-dimer test were compared in both groups. Then, subgroup of SLE patients in whom the D-dimer test can be useful was sought.

RESULTS

The incidence of VTE was more common in SLE patients than controls (10.9% vs. 4.0%). Although the sensitivity of the D-dimer test was comparable between SLE patients and controls (93.3% vs. 90.9%), the specificity of the test was profoundly lower in SLE patients compared to controls (28.4% vs. 84.4%). The area under the curve (AUC) of the D-dimer for VTE was 0.669 in SLE patients and 0.90 in control group. Multiple linear regression analysis demonstrated that SLE disease activity index-2000 (SLEDAI-2K) was significantly associated with D-dimer levels in SLE patients (β = 0.155; P = 0.022). Subgroup analysis showed that the AUC is moderate (0.768) with low disease activity, while it is low (0.518) with high SLEDAI-2K.

CONCLUSION

The D-dimer test may not be a useful screening tool for VTE in patients with active SLE. D-dimer test for predicting VTE in SLE patients should be differentially applied according to disease activity of SLE.

Diagnosis and Treatment of Lower Extremity Venous Thromboembolism: A Review

IMPORTANCE

Incidence rates for lower extremity deep vein thrombosis (DVT) range from 88 to 112 per 100 000 person-years and increase with age. Rates of recurrent VTE range from 20% to 36% during the 10 years after an initial event.

OBSERVATIONS

PubMed and Cochrane databases were searched for English-language studies published from January 2015 through June 2020 for randomized clinical trials, meta-analyses, systematic reviews, and observational studies. Risk factors for venous thromboembolism (VTE), such as older age, malignancy (cumulative incidence of 7.4% after a median of 19 months), inflammatory disorders (VTE risk is 4.7% in patients with rheumatoid arthritis and 2.5% in those without), and inherited thrombophilia (factor V Leiden carriers with a 10-year cumulative incidence of 10.9%), are associated with higher risk of VTE. Patients with signs or symptoms of lower extremity DVT, such as swelling (71%) or a cramping or pulling discomfort in the thigh or calf (53%), should undergo assessment of pretest probability followed by D-dimer testing and imaging with venous ultrasonography. A normal D-dimer level (ie, D-dimer <500 ng/mL) excludes acute VTE when combined with a low pretest probability (ie, Wells DVT score ≤1). In patients with a high pretest probability, the negative predictive value of a D-dimer less than 500 ng/mL is 92%. Consequently, D-dimer cannot be used to exclude DVT without an assessment of pretest probability. Postthrombotic syndrome, defined as persistent symptoms, signs of chronic venous insufficiency, or both, occurs in 25% to 50% of patients 3 to 6 months after DVT diagnosis. Catheter-directed fibrinolysis with or without mechanical thrombectomy is appropriate in those with iliofemoral obstruction, severe symptoms, and a low risk of bleeding. The efficacy of direct oral anticoagulants-rivaroxaban, apixaban, dabigatran, and edoxaban-is noninferior to warfarin (absolute rate of recurrent VTE or VTE-related death, 2.0% vs 2.2%). Major bleeding occurs in 1.1% of patients treated with direct oral anticoagulants vs 1.8% treated with warfarin.

CONCLUSIONS AND RELEVANCE

Greater recognition of VTE risk factors and advances in anticoagulation have facilitated the clinical evaluation and treatment of patients with DVT. Direct oral anticoagulants are noninferior to warfarin with regard to efficacy and are associated with lower rates of bleeding, but costs limit use for some patients.

Current Challenges in Diagnosis of Venous Thromboembolism

In patients with suspected venous thromboembolism, the goal is to accurately and rapidly identify those with and without thrombosis. Failure to diagnose venous thromboembolism (VTE) can lead to fatal pulmonary embolism (PE), and unnecessary anticoagulation can cause avoidable bleeding. The adoption of a structured approach to VTE diagnosis, that includes clinical prediction rules, D-dimer testing and non-invasive imaging modalities, has enabled rapid, cost-effective and accurate VTE diagnosis, but problems still persist. First, with increased reliance on imaging and widespread use of sensitive multidetector computed tomography (CT) scanners, there is a potential for overdiagnosis of VTE. Second, the optimal strategy for diagnosing recurrent leg deep venous thrombosis remains unclear as is that for venous thrombosis at unusual sites. Third, the conventional diagnostic approach is inefficient in that it is unable to exclude VTE in high-risk patients. In this review, we outline pragmatic approaches for the clinician faced with difficult VTE diagnostic cases. In addition to discussing the principles of the current diagnostic framework, we explore the diagnostic approach to recurrent VTE, isolated distal deep-vein thrombosis (DVT), pregnancy associated VTE, subsegmental PE, and VTE diagnosis in complex medical patients (including those with impaired renal function).

Safety of a strategy combining D-dimer testing and whole-leg ultrasonography to rule out deep vein thrombosis

Guidelines for the diagnostic workup of deep vein thrombosis (DVT) recommend assessing the clinical pretest probability before proceeding to D-dimer testing and/or compression ultrasonography (CUS) if the patient has high pretest probability or positive D-dimer. Referring only patients with positive D-dimer for whole-leg CUS irrespective of pretest probability may simplify the workup of DVT. In this prospective management outcome study, we assessed the safety of such a strategy. We included consecutive outpatients referred to the Emergency Department at Østfold Hospital, Norway, with suspected DVT between February 2015 and November 2018. STA-Liatest D-Di Plus D-dimer was analyzed for all patients, and only patients with levels ≥0.5 µg/mL were referred for CUS. All patients with negative D-dimer or negative CUS were followed for 3 months to assess the venous thromboembolic rate. One thousand three hundred ninety-seven patients were included. Median age was 64 years (interquartile range, 52-73 years), and 770 patients (55%) were female. D-dimer was negative in 415 patients (29.7%) and positive in 982 patients (70.3%). DVT was diagnosed in 277 patients (19.8%). Six patients in whom DVT was ruled out at baseline were diagnosed with DVT within 3 months of follow-up for a thromboembolic rate of 0.5% (95% confidence interval, 0.2-1.2). A simple diagnostic approach with initial stand-alone D-dimer followed by a single whole-leg CUS in patients with positive D-dimer safely ruled out DVT. We consider this strategy to be a valuable alternative to the conventional workup of DVT in outpatients. This trial was registered at www.clinicaltrials.gov as #NCT02486445.

Direct-access to sonographic diagnosis of deep vein thrombosis in general practice: a descriptive cohort study

Background

Suspicion of deep vein thrombosis (DVT) is common and requires urgent and efficient investigation due to hazardous prognosis. The traditional diagnostic pathway can be complex and time-consuming, and innovative solutions may provide easy access to diagnostics and better use of healthcare resources. We aimed to describe use, clinical outcomes and time used when providing general practitioners (GPs) with a direct-access pathway to hospital-based, single whole-leg compression ultrasound (CUS) for patients with suspected DVT. Furthermore we aimed to describe the resources used in the new direct-access pathway and compare it with the previous pathway.

Methods

We conducted a 2-year descriptive cohort study (2016–2017) including 449 consecutively referred patients for diagnosis of DVT in a Danish regional hospital. The previous pathway included pre-test at the medical department, a proximal leg CUS if required based on the pre-test and a re-scan if the first CUS was negative. The new pathway included two strategies: 1) a ‘yes-no strategy’, where GPs referred patients directly to whole-leg CUS and if positive, treated at the medical department and if negative, discharged to the GP, 2) a ‘follow-up strategy’ where GPs could require that patients were seen at the medical department, irrespective of the CUS result. Data included extractions from the Radiology Information and Patient Administrative Systems, and mean salaries of healthcare professionals at Silkeborg Regional Hospital, Denmark. Descriptive statistics were used to describe prevalence, timelines and costs.

Results

GPs referred 318 (71%) patients through the yes-no strategy and 131 (29%) via the follow-up strategy with DVT diagnosed in 48 (15%) and 51 (39%) patients, respectively (p < 0.001). For the 263 patients completed after CUS in the yes-no strategy, median pathway time was 24 min (IQI: 16–36), and for those with DVT (including both strategies) 202 min (IQI: 158–273). Direct-access pathway costs were €49.7 less per patient than the previous pathway.

Conclusion

Direct-access to CUS for suspected DVT was achievable, had short time intervals and required fewer resources. The difference in DVT prevalence indicates that GPs distinguish between patients with low and high risk of DVT.

Incidence and Risk Factors of Deep Vein Thrombosis in Hospitalized COVID-19 Patients

Deep vein thrombosis (DVT) is prevalent in patients with coronavirus disease 2019 (COVID-19). However, the risk factors and incidence rate of DVT remains elusive. Here, we aimed to assess the incidence rate and risk factors of DVT. All patients diagnosed with COVID-19 and performed venous ultrasound by ultrasound deparment between December 2019 and April 2020 in Wuhan Jin Yin-tan hospital were enrolled. Demographic information and clinical features were retrospectively collected. Notably, a comparison between the DVT and the non-DVT groups was explored. The incidence rate of venous thrombosis was 35.2% (50 patients out of 142). Moreover, the location of thrombus at the proximal extremity veins was 5.6% (n = 8), while at distal extremity veins was 35.2% (n = 50) of the patients. We also noted that patients with DVT exhibited a high level of D-dimer (OR 10.9 (95% CI, 3.3-36.0), P < 0.001), were admitted to the intensive care unit (OR 6.5 (95% CI, 2.1-20.3), P = 0.001), a lower usage of the anticoagulant drugs (OR 3.0 (95% CI, 1.1-7.8), P < 0.001). Finally, this study revealed that a high number of patients with COVID-19 developed DVT. This was observed particularly in critically ill patients with high D-dimer levels who required no anticoagulant medication.

Safety of using the combination of the Wells rule and D-dimer test for excluding acute recurrent ipsilateral deep vein thrombosis

BACKGROUND

The diagnostic accuracy of clinical probability assessment and D-dimer testing for clinically suspected recurrent deep vein thrombosis (DVT) is largely unknown.

AIM

To evaluate the safety of ruling out acute recurrent DVT based on an unlikely Wells score for DVT and a normal D-dimer test.

METHODS

This was a predefined endpoint of the Theia study in which the diagnostic accuracy of magnetic resonance direct thrombus imaging in acute recurrent ipsilateral DVT was validated. The Wells rule and D-dimer test, performed as part of the study protocol, were not used for management decisions. The primary outcome of this analysis was the incidence of recurrent DVT at baseline or during 3-month follow-up for patients with an unlikely Wells score and a normal D-dimer test.

RESULTS

Results of both Wells score and D-dimer tests were available in 231 patients without anticoagulant treatment. The recurrent DVT prevalence was 45% (103/231). Forty-nine patients had an unlikely Wells score and normal D-dimer test, of whom 3 (6.1%, 95% confidence interval [CI] 1.3%-18%) had recurrent DVT at baseline/follow-up, yielding a sensitivity of 97% (95% CI 92%-99%) and specificity of 36% (95% CI 28%-45%). Thus, if clinical probability scoring and D-dimer testing would have been applied, radiological imaging could have been omitted in 21% of patients with a diagnostic failure rate of 6.1%.

CONCLUSION

By applying clinical probability scoring and D-dimer testing, radiological imaging could be spared in one fifth of patients with suspected recurrent ipsilateral DVT. However, the high failure rate does not support implementation of this strategy in daily practice.

Diagnosing deep vein thrombosis in cancer patients with suspected symptoms: An individual participant data meta-analysis

BACKGROUND

A previous individual participant data (IPD) meta-analysis showed that the Wells rule and D-dimer testing cannot exclude suspected deep vein thrombosis (DVT) in cancer patients.

OBJECTIVES

To explore reasons for this reduced diagnostic accuracy and to optimize the diagnostic pathway for cancer patients suspected of DVT.

PATIENTS AND METHODS

Using IPD from 13 studies in patients with suspected DVT, DVT prevalence and the predictive value of the Wells rule items and D-dimer testing were compared between patients with and without cancer. Next, we developed a prediction model with five variables selected from all available diagnostic predictors.

RESULTS

Among the 10 002 suspected DVT patients, there were 834 patients with cancer. The median prevalence of DVT in these patients with cancer was 37.5% (interquartile range [IQR], 30.8-45.5), whereas it was 15.1% (IQR, 11.5-16.7) in patients without cancer. Diagnostic performance of individual Wells rule items and D-dimer testing was similar across patients with and without cancer, except "immobility" and "history of DVT." The newly developed rule showed a pooled c-statistic 0.80 (95% confidence interval [CI], 0.75-0.83) and good calibration. However, using this model, still only 4.3% (95% CI, 3.0-5.7) of the suspected patients with cancer could be identified with a predicted DVT posttest probability of <2%.

CONCLUSIONS

Likely because of the high prevalence of DVT, clinical models followed by D-dimer testing fail to rule out DVT efficiently in cancer patients suspected of DVT. Direct referral for compression ultrasonography appears to be the preferred approach for diagnosis of suspected DVT in cancer patients.