Accuracy of clinical assessment of deep-vein thrombosis

Machine Learning-Based Explainable Automated Nonlinear Computation Scoring System for Health Score and an Application for Prediction of Perioperative Stroke: Retrospective Study

BACKGROUND

Machine learning (ML) has the potential to enhance performance by capturing nonlinear interactions. However, ML-based models have some limitations in terms of interpretability.

OBJECTIVE

This study aimed to develop and validate a more comprehensible and efficient ML-based scoring system using SHapley Additive exPlanations (SHAP) values.

METHODS

We developed and validated the Explainable Automated nonlinear Computation scoring system for Health (EACH) framework score. We developed a CatBoost-based prediction model, identified key features, and automatically detected the top 5 steepest slope change points based on SHAP plots. Subsequently, we developed a scoring system (EACH) and normalized the score. Finally, the EACH score was used to predict perioperative stroke. We developed the EACH score using data from the Seoul National University Hospital cohort and validated it using data from the Boramae Medical Center, which was geographically and temporally different from the development set.

RESULTS

When applied for perioperative stroke prediction among 38,737 patients undergoing noncardiac surgery, the EACH score achieved an area under the curve (AUC) of 0.829 (95% CI 0.753-0.892). In the external validation, the EACH score demonstrated superior predictive performance with an AUC of 0.784 (95% CI 0.694-0.871) compared with a traditional score (AUC=0.528, 95% CI 0.457-0.619) and another ML-based scoring generator (AUC=0.564, 95% CI 0.516-0.612).

CONCLUSIONS

The EACH score is a more precise, explainable ML-based risk tool, proven effective in real-world data. The EACH score outperformed traditional scoring system and other prediction models based on different ML techniques in predicting perioperative stroke.

Development of venous thromboembolism and its impact on hospitalized adults with covid-19: rapid systematic review

The association between COVID-19 and coagulation disorders has been discussed since the onset of the pandemic. Four years into the pandemic, it is crucial to organize the findings and evidence accumulated thus far. The objective of this study was to review and synthesize the available scientific evidence regarding the relationship between COVID-19 and development of venous thromboembolism (VTE). A rapid systematic review was conducted by searching two electronic databases, selecting systematic review articles that assessed the association between COVID-19 and development of VTE, such as deep vein thrombosis (DVT) or pulmonary embolism (PE). The studies indicated that hospitalized COVID-19 patients are at greater risk of developing VTE, especially those admitted to intensive care units (ICUs). Elevated D-dimer levels and male gender were also associated with increased risks.

Learning health system linchpins: information exchange and a common data model

OBJECTIVE

To demonstrate the potential for a centrally managed health information exchange standardized to a common data model (HIE-CDM) to facilitate semantic data flow needed to support a learning health system (LHS).

MATERIALS AND METHODS

The Rhode Island Quality Institute operates the Rhode Island (RI) statewide HIE, which aggregates RI health data for more than half of the state's population from 47 data partners. We standardized HIE data to the Observational Medical Outcomes Partnership (OMOP) CDM. Atherosclerotic cardiovascular disease (ASCVD) risk and primary prevention practices were selected to demonstrate LHS semantic data flow from 2013 to 2023.

RESULTS

We calculated longitudinal 10-year ASCVD risk on 62,999 individuals. Nearly two-thirds had ASCVD risk factors from more than one data partner. This enabled granular tracking of individual ASCVD risk, primary prevention (ie, statin therapy), and incident disease. The population was on statins for fewer than half of the guideline-recommended days. We also found that individuals receiving care at Federally Qualified Health Centers were more likely to have unfavorable ASCVD risk profiles and more likely to be on statins. CDM transformation reduced data heterogeneity through a unified health record that adheres to defined terminologies per OMOP domain.

DISCUSSION

We demonstrated the potential for an HIE-CDM to enable observational population health research. We also showed how to leverage existing health information technology infrastructure and health data best practices to break down LHS barriers.

CONCLUSION

HIE-CDM facilitates knowledge curation and health system intervention development at the individual, health system, and population levels.

Methodological quality assessment tools for diagnosis and prognosis research: overview and guidance

BACKGROUND AND OBJECTIVES

Multiple tools exist for assessing the methodological quality of diagnosis and prognosis research. It can be challenging to decide on when to use which tool. We aimed to provide an overview of existing methodological quality assessment (QA) tools for diagnosis and prognosis studies, highlight the overlap and differences among these tools, and to provide guidance for choosing the appropriate tool.

STUDY DESIGN AND SETTING

We performed a methodological review of tools designed for assessing risk of bias, applicability, or other aspects related to methodological quality in studies investigating tests/factors/markers/models for classifying or predicting a current (diagnosis) and/or future (prognosis) health state. Tools focusing exclusively on causal research or on reporting quality were excluded. Guidance was subsequently developed to assist in choosing an appropriate QA tool.

RESULTS

We identified 14 QA tools, eight of which were developed for assessment of diagnosis studies, four for prognosis studies, and two addressing both. We propose a set of five questions to help guide the process of choosing a QA tool based on the purpose or question of the user: whether the focus is on (1) diagnosis, prognosis, or another domain; (2) a prediction model vs a test/factor/marker; (3) evaluating simply the performance of a test/factor/marker vs assessing its added value over other variables; (4) comparing two or more tests/factors/markers/models; and (5) whether the user aims to assess only risk of bias or also other quality aspects.

CONCLUSION

Existing QA tools for appraising diagnosis and prognosis studies vary in purpose, scope, and contents. Our guidance may help researchers, systematic reviewers, health policy makers, and guideline developers in specifying their purpose and question to select the most appropriate QA tool for their assessment.

PLAIN LANGUAGE SUMMARY

Methodological quality assessment (QA) tools provide a set of criteria to evaluate how well a medical study was done and how trustworthy its results are. To accurately assess a study's quality, it is important to use a QA tool that matches the type of medical study. However, with many QA tools available for different study types, choosing the right one can be challenging, especially for diagnosis and prognosis studies (ie, studies that evaluate tests, factors, markers, and models used for diagnosis and prognosis). To assist in selecting the best QA tools for diagnostic and prognostic studies, we created an overview of available tools and practical tips for choosing the most appropriate one. After searching online databases and consulting experts in the field, we identified 14 QA tools specific to diagnostic and prognostic studies. Additionally, we developed five key questions to guide users in choosing the best tool for their study. While the 14 QA tools differ in their focus and content, our guidance simplifies the process of choosing the right tool and helps users refine their research question.

Artificial Intelligence Applied in Early Prediction of Lower Limb Fracture Complications

Background: Artificial intelligence has become a valuable tool for diagnosing and detecting postoperative complications early. Through imaging and biochemical markers, clinicians can anticipate the clinical progression of patients and the risk of long-term complications that could impact the quality of life or even be life-threatening. In this context, artificial intelligence is crucial for identifying early signs of complications and enabling clinicians to take preventive measures before problems worsen. Materials and methods: This observational study analyzed medical charts from the electronic archive of the Clinical Emergency Hospital in Galați, Romania, covering a four-year period from 2018 to 2022. A neural network model was developed to analyze various socio-demographic and paraclinical data. Key features included patient demographics, laboratory investigations, and clinical outcomes. Statistical analyses were performed to identify significant risk factors associated with deep venous thrombosis (DVT). Results: The analysis revealed a higher prevalence of female patients (60.78%) compared to male patients, indicating a potential gender-related risk factor for DVT. The incidence of DVT was highest among patients aged 71 to 90 years, affecting 56.86% of individuals in this age group, suggesting that advanced age significantly contributes to the risk of developing DVT. Additionally, among the DVT patients, 15.69% had a body mass index (BMI) greater than 30, categorizing them as obese, which is known to increase the risk of thrombotic events. Furthermore, this study highlighted that the highest frequency of DVT was associated with femur fractures, occurring in 52% of patients with this type of injury. The neural network analysis indicated that elevated levels of direct bilirubin (≥1.5 mg/dL) and prothrombin activity (≤60%) were strong predictors of fracture-related complications, with sensitivity and specificity rates of 78% and 82%, respectively. These findings underscore the importance of monitoring these laboratory markers in at-risk populations for early intervention. Conclusions: This study identified critical risk factors for developing DVT, including advanced age, high BMI, and femur fractures, which necessitate longer recovery periods. Additionally, the findings indicate that elevated direct bilirubin and prothrombin activity play a significant role in predicting DVT development. These results suggest that AI can effectively enhance the anticipation of clinical evolution in patients, aiding in early intervention and management strategies.

Deep vein thrombosis in patients with stroke or transient ischemic attack presenting with patent foramen ovale: a retrospective observational study

OBJECTIVE

Deep vein thrombosis (DVT) is discussed as a source of embolism for cerebral ischemia in the presence of patent foramen ovale (PFO). However, previous studies reported varying rates of DVT in stroke patients, and recommendations for screening are lacking. This study aimed to characterize patients with stroke or transient ischemic attack (TIA) and concomitant PFO and explore the rate of DVT and associated parameters.

METHODS

Medical records were screened for patients with stroke or TIA and echocardiographic evidence of PFO. Concomitant DVT was identified according to compression ultrasonography of the lower limbs. A variety of demographic, clinical, and laboratory parameters, the RoPE and Wells scores were compared between patients with and without DVT.

RESULTS

Three-hundred-thirty-nine patients (mean age 61.2 ± 15.4 years, 61.1% male) with stroke or TIA and PFO, treated between 01/2015 and 12/2020, were identified. Stroke and TIA patients did not differ for demographic and vascular risk factors. DVT was found in 17 cases out of 217 (7.8%) with compression ultrasonography. DVT was associated with a history of DVT, cancer, previous immobilization, calf compression pain, calf circumference difference, and a few laboratory abnormalities, e.g., increased D-dimer. A multivariate regression model with stepwise backward selection identified the Wells score (odds ratio 35.46, 95%-confidence interval 4.71-519.92) as a significant predictor for DVT.

CONCLUSION

DVT is present in a relevant proportion of patients with cerebral ischemia and PFO, which needs to be considered for the individual diagnostic workup. The Wells score seems suitable for guiding additional examinations, i.e., compression ultrasonography.

Comparisons of clinical scoring systems among suspected pulmonary embolism patients presenting to emergency department

Introduction

Pulmonary embolism (PE) is among the most severe cardiovascular disorders worldwide. Timely and appropriate diagnosis of PE remains an important step in reducing PE related mortality and morbidity.

Methods

In this retrospective single-center cohort study, we comprehensively compared the screening performances of several clinical scoring systems (Wells score [WS], Revised Geneva score [RGS], WS + d-Dimer [D-D], RGS + D-D, WS + PE rule-out criteria [PERC] and RGS + PERC) among PE suspected patients. Failure rates across different PE severity grades as well as overall sensitivity/specificity were considered in evaluating each screening strategy.

Results

A total of 3437 patients were included in this study and 698 of them were diagnosed with PE. Patients with and without PE were similar in demographics, while significantly different in respiration-related characteristics. Compared with WS or RGS alone, Integrating PERC or D-D with WS or RGS significantly decreased the failure rates across all PE severity grades, and increased the overall sensitivity from 88.5% and 87.2% to 96.3% and 94.8% (D-D) to 99.4% and 99.6% (PERC), respectively. However, compared with other four scoring approaches, using WS or RGS alone increased the specificity from 8.3% and 7.2%, 38.3% and 21.3%, to 63.5% and 34.8%, respectively, and increased the AUC from 0.54 to 0.54, 0.70 and 0.69, to 0.8 and 0.76, respectively. In general, all screening approaches achieved better performances among PE patients with respiratory distress compared to those without respiratory distress.

Conclusion

Combining PERC or D-D with WS or RGS, and the presence of respiratory distress provide significantly better PE rule-out performances.

Effectiveness and safety of continuous low-molecular-weight heparin versus switching to direct oral anticoagulants in cancer-associated venous thrombosis

Given the existing uncertainty regarding the effectiveness and safety of switching from low-molecular-weight heparin (LMWH) to direct oral anticoagulants (DOACs) in patients with cancer-associated venous thrombosis (CAT), we conducted a comprehensive population-based cohort study utilizing electronic health database in Hong Kong. A total of 4356 patients with CAT between 2010 and 2022 were included, with 1700 (39.0%) patients switching to DOAC treatment. Compared to continuous LMWH treatment, switching to DOACs was associated with a significantly lower risk of hospitalization due to venous thromboembolism (HR: 0.49 [95% CI = 0.35-0.68]) and all-cause mortality (HR: 0.67 [95% CI = 0.61-0.74]), with no significant difference in major bleeding (HR: 1.04 [95% CI = 0.83-1.31]) within six months. These findings provide reassurance regarding the effectiveness and safety of switching from LMWH to DOACs among patients with CAT, including vulnerable patient groups.

Bilateral lower limb examinations for deep vein thrombosis: A single-centre pilot study comparing request and report parameters for bilateral and unilateral referrals

INTRODUCTION

Deep vein thrombosis (DVT) is a common pathology with significant morbidity and mortality, often occurring in the lower limb. Ultrasound is the modality of choice for diagnosis of DVT, but all guidance in the United Kingdom assumes a single leg referral. Few studies have addressed the question of bilateral referrals and bilateral DVTs, and it is not known how these should be included in ultrasound protocols. This study aims to compare the request and report parameters of bilateral examinations with those for single leg examinations over a six-month period.

METHODS

A single-centre feasibility study collected data on all single and bilateral leg examinations performed by sonographers, over a six-month period at a small general hospital. Data collected for each examination included the referral and report findings. These were compared using basic statistical methods to compare DVT yield by laterality, referrer, DVT site, and patient factors.

RESULTS

Six hundred and thirty examinations were included, eighteen of which were bilateral examinations. Although the bilateral leg cohort was small, there were significant differences in DVT yield between the groups, with single leg referrals more than eight times more likely to demonstrate a DVT at ultrasound.

CONCLUSION

In a context of limited ultrasound resource, the low DVT yield of bilateral examinations has implications for service design. Further data collection will be needed to validate initial results, and to establish suitable criteria for acceptance of bilateral DVT referrals.

IMPLICATIONS FOR PRACTICE

Low yield of DVTs in bilateral examinations can be validated via further research. Bilateral examinations can be explicitly included in DVT service design.

The History of Diagnosing Venous Thromboembolism

An accurate and prompt diagnosis of deep vein thrombosis and/or pulmonary embolism is important to prevent serious complications and mortality. Because the clinical presentation of venous thromboembolism (VTE) is often nonspecific, objective testing by means of radiological imaging is required to confirm the diagnosis. Historically, a diagnosis of VTE involved invasive imaging techniques like contrast venography or conventional pulmonary angiography. Technological developments toward more accurate and less invasive diagnostics have driven the implementation of a variety of newer technologies over the past decades, as well as the derivation and validation of clinical decision rules (CDRs) that can be used to rule out VTE in combination with D-dimer blood tests. In this narrative review, we provide a historical overview of the most notable developments in the imaging techniques and CDRs for VTE diagnosis.

Hemostasis Testing in the Emergency Department: A Narrative Review

Routine laboratory screening is typically performed at initial evaluation of the vast majority of presentations to the emergency department (ED). These laboratory results are crucial to the diagnostic process, as they may influence up to 70% of clinical decisions. However, despite the usefulness of biological assessments, many tests performed are inappropriate or of doubtful clinical relevance. This overutilization rate of laboratory testing in hospitals, which represents a significant medical-economic burden, ranges from 20 to 67%, with coagulation tests at the top of the list. While reviews frequently focus on nonintensive care units, there are few published assessments of emergency-specific interventions or guidelines/guidance to date. The aim of this review is to highlight current recommendations for hemostasis evaluation in the emergency setting with a specific analysis of common situations leading to ED admissions, such as suspected venous thrombosis or severe bleeding. We revisit the evidence related to the assessment of patient's hemostatic capacity based on comprehensive history taking and physical examination as well as best practice recommendations for blood sample collection to ensure the reliability of results. This review also includes an examination of various currently available point of care tests and a comprehensive discussion on indications, limitations, and interpretation of these tests.

Cost-Effectiveness of Performing Reference Ultrasonography in Patients with Deep Vein Thrombosis

BACKGROUND

 The diagnosis of recurrent ipsilateral deep vein thrombosis (DVT) with compression ultrasonography (CUS) may be hindered by residual intravascular obstruction after previous DVT. A reference CUS, an additional ultrasound performed at anticoagulant discontinuation, may improve the diagnostic work-up of suspected recurrent ipsilateral DVT by providing baseline images for future comparison.

OBJECTIVES

 To evaluate the cost-effectiveness of routinely performing reference CUS in DVT patients.

METHODS

 Patient-level data (n = 96) from a prospective management study (Theia study; NCT02262052) and claims data were used in a decision analytic model to compare 12 scenarios for diagnostic management of suspected recurrent ipsilateral DVT. Estimated health care costs and mortality due to misdiagnosis, recurrent venous thromboembolism, and bleeding during the first year of follow-up after presentation with suspected recurrence were compared.

RESULTS

 All six scenarios including reference CUS had higher estimated 1-year costs (€1,763-€1,913) than the six without reference CUS (€1,192-€1,474). Costs were higher because reference CUS results often remained unused, as 20% of patients (according to claims data) would return with suspected recurrent DVT. Estimated mortality was comparable in scenarios with (14.8-17.9 per 10,000 patients) and without reference CUS (14.0-18.5 per 10,000). None of the four potentially most desirable scenarios included reference CUS.

CONCLUSION

 One-year health care costs of diagnostic strategies for suspected recurrent ipsilateral DVT including reference CUS are higher compared to strategies without reference CUS, without mortality benefit. These results can inform policy-makers regarding use of health care resources during follow-up after DVT. From a cost-effectiveness perspective, the findings do not support the routine application of reference CUS.

Tutorial: dos and don'ts in clinical prediction research for venous thromboembolism

Clinical prediction modeling has become an increasingly popular domain of venous thromboembolism research in recent years. Prediction models can help healthcare providers make decisions regarding starting or withholding therapeutic interventions, or referrals for further diagnostic workup, and can form a basis for risk stratification in clinical trials. The aim of the current guide is to assist in the practical application of complicated methodological requirements for well-performed prediction research by presenting key dos and don'ts while expanding the understanding of predictive research in general for (clinical) researchers who are not specifically trained in the topic; throughout we will use prognostic venous thromboembolism scores as an exemplar.

Management of isolated distal deep vein thrombosis

Isolated distal deep vein thrombosis (DVT) represents up to 50% of all lower limb DVT in ultrasound series and is a frequent medical condition, which management is not well established. Data arising from registries and non-randomized studies suggest that most distal DVTs do not extend to the proximal veins and have an uneventful follow-up when left untreated. This data had some impact on international recommendations like the American College of Chest Physicians (ACCP), whose last version stated that ultrasound surveillance might be an option for selected low-risk patients. However, robust data arising from randomized studies are scarce. Indeed, only seven randomized trials assessing the need for anticoagulation for calf DVT have been published. Many of these trials had an open-label design and were affected by methodological limitations. When considering randomized placebo-controlled trials, one included low-risk patients and was hampered by a limited statistical power (CACTUS study). Nevertheless, data from this trial tend to confirm that the use of therapeutic anticoagulation in low-risk patients with symptomatic calf DVT is not superior to placebo in reducing VTE but is associated with a higher risk of bleeding. A second randomized placebo-controlled trial did not assess the necessity of anticoagulant treatment but rather the long-term risk of recurrence and compared 6 weeks versus 12 weeks of treatment with rivaroxaban (RIDTS study). Finally, the last available randomized trial compared a 3-month versus a 12-month edoxaban treatment in patients with cancer and mainly asymptomatic distal DVT, detected by systematic compression ultrasonography. Overall, available data suggest that the use of therapeutic anticoagulation in low-risk patients with symptomatic calf DVT is not superior to placebo in reducing VTE. High risk patients (previous VTE, active cancer, inpatients) might benefit from a course of anticoagulant treatment. However, the optimal anticoagulant intensity and duration are uncertain and further studies are needed.

Deferring diagnostic evaluation for suspected deep venous thrombosis using a single dose of anticoagulant: Real-world data from a regionwide care pathway

BACKGROUND

Patients with suspected deep venous thrombosis (DVT) are typically referred to the emergency department (ED) for immediate evaluation. However, this often contributes to ED overcrowding and necessitates round-the-clock sonographic examinations. Therefore, we implemented a regionwide care pathway for deferring diagnostic workup of suspected DVT until the following day. Patients receive a single anticoagulant dose from their general practitioner (GP) to prevent progression of DVT in the interval between referral and diagnostic evaluation. The next day, patients undergo comprehensive evaluation at our outpatient DVT clinic, including venous ultrasound. This retrospective study aims to provide real-world data on the safety of this care pathway regarding the occurrence of bleeding complications and pulmonary embolism (PE).

METHODS

We included all GP-referred patients with suspected DVT in 2018 and 2019. Patients with absolute contraindications to deferred evaluation or anticoagulation were excluded. The primary endpoint was the occurrence of bleeding complications. Secondary endpoints included PE events and all-cause mortality within seven days following DVT evaluation.

RESULTS

Among 1,024 included patients, DVT was confirmed in 238 patients (23.2%) and superficial thrombophlebitis in 98 patients (9.6%). No bleeding events were recorded in patients in whom DVT was ruled out. PE was confirmed in eight patients on the same day as DVT evaluation (0.8%, 95%CI 0.4-1.6) and in six patients within seven days following DVT evaluation (0.6%, 0.2-1.3%). No deaths occurred during this timeframe.

CONCLUSION

This real-world study observed a very low incidence of bleeding complications and PE events, indicating that this care pathway of deferred DVT workup is safe and may offer a more streamlined diagnostic approach for patients with suspected DVT.

Diagnostic strategies in postpartum individuals with suspected venous thromboembolism: A scoping review

BACKGROUND

The risk of venous thromboembolism (VTE) is increased postpartum and contributes to important morbidity and mortality. While there have been advances in evaluating diagnostic algorithms for suspected VTE during pregnancy, there is limited data for postpartum individuals.

OBJECTIVE

We conducted a scoping review to describe and evaluate diagnostic strategies used to investigate suspected VTE in postpartum individuals.

METHODS

A comprehensive search strategy was conducted in Ovid MEDLINE, Embase and the Cochrane Central Register of Controlled Trials (January 1, 2000-September 30, 2022) to identify original articles that reported on diagnostic strategies in postpartum individuals with suspected VTE. We extracted demographics, clinical decision rules used, D-dimer and imaging completed, including test performance and VTE outcomes.

RESULTS

A total of 13 studies conducted across 11 countries with separate postpartum data were included for 759 individuals with suspected PE (n = 634) or DVT (n = 125), including unpublished data (n = 251). Among those with suspected PE, computed tomography pulmonary angiography was conducted more commonly (n = 522) than ventilation-perfusion scans (n = 69), with PE positivity rates that ranged from 4 %-27.6 % and 0-50 % across studies, respectively. Among 131 postpartum individuals with suspected PE who had a D-dimer measured, only 4.6 % (6/131) had a negative D-dimer test. For postpartum individuals with suspected DVT, the most common diagnostic test was compression ultrasonography (positivity rate 12.2 %-18.6 %). There were limited retrospective data evaluating the clinical decision rules.

CONCLUSIONS

There are heterogeneous approaches globally in the diagnosis of suspected postpartum VTE. Limited high-quality data available underscores the need for more robust evidence to inform clinical practice.

[Pelvic vein thrombosis : Current treatment options and importance of recanalization procedures]

Venous thrombosis is a frequent disorder. A distinction is made between an acute phase of the disease and a chronic manifestation, the postthrombotic syndrome. In particular, proximal venous thrombosis/pelvic vein thrombosis can cause a life-threatening pulmonary embolism during the acute phase of the disease. The postthrombotic syndrome is characterized by the remodeling of the affected venous section, which is often caused by inflammation. Locally, the typical clinical finding is caused by scarred stricture of the vein with restricted drainage and peripheral venous hypertension. Acute thrombosis should be primarily treated by therapeutic anticoagulation and compression therapy of the affected extremity. The duration of these measures depends on clinical presentation, cause (provoked, unprovoked) and risk factors for venous thrombosis/recurrent thrombosis. Venous revascularization procedures are important both in the acute phase of the disease and in the treatment of postthrombotic syndrome. The recanalization treatment is mostly carried out as an endovascular or hybrid intervention and venous bypass procedures are reserved for special situations.

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.

Deep Vein Thrombosis in a Patient with Negative Age-Adjusted D-Dimer Level

D-dimer level, along with a clinical probability tool that uses the Wells score, is commonly used to exclude deep vein thrombosis (DVT). Age-adjusted D-dimer values are routinely used in clinical practice to increase the negative predictive value and avoid unnecessary Doppler ultrasound imaging. We describe a patient with a low pre-test probability of DVT upon admission and a negative D-dimer level based on age-adjusted values who was later diagnosed with DVT. Our experiences with this case highlight that the geriatric population is unique and, at times, frail.

Acute and chronic venous occlusion

This review article provides an overview of acute and chronic venous occlusion, a condition that can cause significant morbidity and mortality if not diagnosed and treated promptly. The article begins with an introduction to the anatomy of the venous system, followed by a discussion of the causes and clinical features of venous occlusion. The diagnostic tools available for the assessment of venous occlusion, including imaging modalities such as ultrasound, CT, and MRI, are then discussed, along with their respective advantages and limitations. The article also covers the treatment options for acute and chronic venous occlusion, including anticoagulant therapy and endovascular interventions. This review aims to provide radiologists with an updated understanding of the pathophysiology, diagnosis, and management of acute and chronic venous occlusion.

Development and validation of a nomogram model for central venous access device-related thrombosis in hospitalized children

This study aimed to develop and validate a nomogram model of central venous access device-related thrombosis (CRT) for hospitalized children. A total of 503 consecutive cases from a hospital in Changsha City, Hunan Province were stochastically classified into the training set and internal validation set at a ratio of 7:3, and 85 consecutive cases in two hospitals in Urumqi City, Xinjiang Uygur Autonomous Region were collected as an external validation set. Univariate analysis and multivariate analysis on CRT-related risk factors of hospitalized children were conducted, a logistic regression model was employed to establish the nomogram, and the discrimination, calibration, and decision curve analysis was performed to assess the proposed nomogram model. The nomogram model involved seven independent risk factors, including blind catheterization, abnormal liver function, central line-associated bloodstream infection, infection, number of catheter lines, leukemia, and bed rest > 72 h. The discrimination results showed that the area under the receiver operating characteristic curve of the training set, internal validation set, and external validation set was 0.74, 0.71, and 0.76 respectively, and the accuracy rates of the proposed nomogram model were 79%, 72%, and 71% in the training set, internal validation set, and external validation set. The calibration results also showed that the calibration curve had great fitness for each dataset. More importantly, the decision curve suggested that the proposed nomogram model had a prominent clinical significance.

CONCLUSION

The nomogram model can be used as a risk assessment tool to reduce the missed diagnosis rate and the incidence of CRT in hospitalized children.

WHAT IS KNOWN

• Central venous access device-related thrombosis is generally asymptomatic for hospitalized children, causing the missed diagnosis of central venous access device-related thrombosis easily. • No risk prediction nomogram model for central venous access device-related thrombosis in hospitalized children has been established.

WHAT IS NEW

• A visual and personalized nomogram model was built by seven accessible variables (blind catheterization, abnormal liver function, central line-associated bloodstream infection, infection, number of catheter lines, leukemia, and bed rest > 72 h). • The model can effectively predict the risk of central venous access device-related thrombosis for hospitalized children.

Excluding pregnancy-associated deep vein thrombosis with whole-leg ultrasound

Background

Deep vein thrombosis (DVT) is common in pregnancy, yet data are limited on the best diagnostic strategies in pregnant patients suspected of DVT.

Objectives

We conducted a prospective cohort study to evaluate the rate of symptomatic DVT in the 90 days after a negative whole-leg compression ultrasound (CUS) in pregnant women presenting with DVT symptoms.

Methods

In this prospective cohort study, we enrolled pregnant patients suspected of DVT between 2011 and 2019 who were referred to the vascular imaging laboratory at a tertiary care center and had anticoagulation held after a negative whole-leg CUS. Primary outcome was objectively confirmed DVT or pulmonary embolism or death due to venous thromboembolism (VTE).

Results

Whole-leg CUS yielded normal results in 186 patients (97.9%) and identified DVT in 4 (2.1%). The mean age was 30 and 164 were White. Among the 186 patients with a negative, initial whole-leg CUS who did not receive anticoagulation, there were 2 DVT events identified over the 90-day follow-up period, for an overall rate of 1.1% (95% CI: 0.2-3.4%). The study was terminated before full planned accrual for administrative reasons.

Conclusion

The rate of symptomatic DVT is low in pregnant patients who have a single, negative whole-leg CUS and did not receive anticoagulation. Adequately powered studies should prospectively assess whole-leg CUS in a larger population alone and in combination with pre-test probability scores and/or D-dimer to determine its role in the evaluation of suspected DVT in pregnancy.

Health system-scale language models are all-purpose prediction engines

Physicians make critical time-constrained decisions every day. Clinical predictive models can help physicians and administrators make decisions by forecasting clinical and operational events. Existing structured data-based clinical predictive models have limited use in everyday practice owing to complexity in data processing, as well as model development and deployment1-3. Here we show that unstructured clinical notes from the electronic health record can enable the training of clinical language models, which can be used as all-purpose clinical predictive engines with low-resistance development and deployment. Our approach leverages recent advances in natural language processing4,5 to train a large language model for medical language (NYUTron) and subsequently fine-tune it across a wide range of clinical and operational predictive tasks. We evaluated our approach within our health system for five such tasks: 30-day all-cause readmission prediction, in-hospital mortality prediction, comorbidity index prediction, length of stay prediction, and insurance denial prediction. We show that NYUTron has an area under the curve (AUC) of 78.7-94.9%, with an improvement of 5.36-14.7% in the AUC compared with traditional models. We additionally demonstrate the benefits of pretraining with clinical text, the potential for increasing generalizability to different sites through fine-tuning and the full deployment of our system in a prospective, single-arm trial. These results show the potential for using clinical language models in medicine to read alongside physicians and provide guidance at the point of care.

Deep vein thrombosis screening in pediatric orthopedic patients

Background

Deep vein thrombosis (DVT) is an important clinical condition that leads to subsequent morbidity and mortality in children, particularly those who involved operative procedures. The preoperative assessment for DVT in children may vary among different population risk factors and types of surgery. This study aimed to evaluate the screening methods for DVT in pediatric orthopedic patients.

Method

We performed a retrospective cohort study of orthopedic patients aged <18 years at Ramathibodi Hospital, Bangkok, Thailand, from 2015 to 2019. The inclusion criteria were children scheduled for orthopedic surgery; who performed a D-dimer test, Wells score, and Caprini score; and who underwent Doppler ultrasonography for DVT screening. The exclusion criteria were incomplete data or inconclusive ultrasonographic results. Age and results of the D-dimer test, Wells score, and Caprini score were collected from all patients. The outcome assessment was ultrasound-proven DVT. The screening abilities of each test were analyzed in terms of sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), likelihood ratio (LR) for positive and negative tests, and area under the receiver operating characteristic curve (AUC).

Results

A total of 419 children were included in the study. Five (1.19%) patients were diagnosed with DVT. The mean age was 10.16 ± 4.83 years. D-dimer ≥500 ng/mL had a sensitivity of 100% (95% CI: 47.8%–100%), a specificity of 36.7% (95% CI: 32.1%–41.6%), a PPV of 1.9% (95% CI: 0.6%–4.3%), and an NPV of 100% (95% CI: 97.6%–100%). Wells score ≥3 demonstrated a sensitivity of 0% (95% CI: 0%–52.2%), a specificity of 99.3% (95% CI: 97.9%–99.9%), and an LR for a negative test of 1.00 (95% CI: 1.00–1.01). Caprini score ≥11 had a sensitivity of 0% (95% CI: 0%–52.2%) and a specificity of 99.8% (95% CI: 98.7%–100%). The parallel test included D-dimer ≥500 ng/mL, Wells score ≥3, or Caprini score ≥11 points, generating a sensitivity of 100% (95% CI: 47.8%–100%), a specificity of 36.7% (95% CI: 32.1%–41.6%), an LR for a positive test of 1.58 (95% CI: 1.47–1.70), and an AUC of 0.68 (95% CI: 0.66–0.71).

Conclusions

The D-dimer test exhibited moderate ability in predicting the development of DVT among pediatric orthopedic patients requiring surgery. The Wells score and Caprini score had low performance in identifying hospitalized children at increased risk of DVT events.

ClotTriever system for mechanical thrombectomy of deep vein thrombosis

There is increasing evidence that early and comprehensive removal of thrombus in deep vein thrombosis is associated with improved outcomes, including decreased incidence of post-thrombotic syndrome and debilitating long-term symptoms. Catheter-directed thrombolysis is effective for the rapid removal of clot, but it is associated with high bleeding risk. Percutaneous mechanical thrombectomy is a highly effective method for the removal of clot without the use of systemic or catheter-directed thrombolytic therapy. The Inari ClotTriever system (Inari Medical Inc., CA, USA) is a thrombectomy device, which is approved for deep vein thrombosis by the US FDA in 2017. Herein we review the current treatment strategies using the ClotTriever system, its specifications, indications and current state of literature.

Comparing the application of three thrombosis risk assessment models in patients with acute poisoning: A cross-sectional survey

Background

Patients with acute toxic hemoperfusion are prone to deep vein thrombosis. However, there is no risk assessment model for thrombosis in patients with acute toxic hemoperfusion. Therefore, we compared three commonly used risk assessment models for deep vein thrombosis to determine the model most suitable for assessment of deep vein thrombosis in patients with acute toxic hemoperfusion.

Methods

Caprini, Autar, and Padua thrombosis risk assessment models were used to assess the risk of deep vein thrombosis in patients with acute poisoning and hemoperfusion admitted to a grade A hospital in Shandong province from October 2017 to February 2019. The predictive values of the three models were compared using receiver operating characteristic (ROC) curve analysis.

Results

The risk assessment model scores of Caprini, Autar, and Padua were 7.55 ± 1.76, 8.63 ± 2.36, and 3.92 ± 0.55, respectively. The Caprini risk assessment model was significantly different (p < 0.05) in high-risk patients in the thrombus and non-thrombotic groups; the difference between the other two models was not significant (p > 0.05). The areas under the ROC curve of the Caprini, Autar, and Padua risk assessment models were 0.673, 0.585, and 0.535, respectively. The difference in areas under the ROC curve between the Caprini risk assessment model and the Autar risk assessment model as well as the Padua risk assessment model was significant (p < 0.05), but the areas under the ROC curve of the Autar risk assessment model and the Padua risk assessment model were not statistically significant (p > 0.05). The Caprini risk assessment model had a sensitivity of 91.9%, specificity of 33.1%, and a Youden index of 0.249. The sensitivity and specificity of Autar’s risk assessment model were 37.0 and 77.2%, respectively, and the Youden index was 0.141. The Padua risk assessment model had a sensitivity of 91.3%, specificity of 15.0%, and a Youden index of 0.063.

Conclusion

The three thrombosis risk assessment models were not suitable for patients with acute poisoning and hemoperfusion.

The use of tranexamic acid reduces blood loss in osteotomy at knee level: a systematic review

PURPOSE

Aim of this systematic review was to evaluate the literature regarding the effect of tranexamic acid (TXA) on the outcome after knee osteotomy.

METHODS

A systematic literature search was carried out in various databases on studies on the use of tranexamic acid in osteotomies around the knee. Primary outcome criterion was the hemoglobin (drop). Secondary outcome criteria were total blood loss, drainage volume, adverse effects such as thromboembolic events, blood transfusions, wound complications and clinical scores. A meta-analysis was performed for quantitative measures. The present study was registered prospectively ( www.crd.york.ac.uk/PROSPERO ; no.: CRD42021229624).

RESULTS

Seven studies with 584 patients (TXA group: 282 patients, non TXA group: 302 patients) Hemoglobin decrease (1.54 g/dl vs. 2.28 g/dl), blood loss (394.49 ml vs. 595.54 ml) and drainage volume (266.5 ml vs. 359.05 ml) were significantly less in the TXA group compared to the non TXA group. No thromboembolic event was noted in any study. In the non TXA group four blood transfusions were given. Eleven wound complications occurred in the non TXA group in comparison to two wound complications in the TXA group.

CONCLUSIONS

The results of the present study show that the application of TXA reduces hemoglobin drop, blood loss and drainage volume. These effects could be responsible for the lesser rate of side effects after administration of TXA during knee osteotomy.

Pulmonary Embolism After in vitro Fertilization and Cesarean Section: Two Case Reports and Brief Review of the Literature

This paper reports two cases of postpartum pulmonary embolism in Taicang First People's Hospital affiliated to Soochow University. They share many similarities in age, fertilization way, birthing method, incidence of pulmonary embolism, treatment and prognosis. The main purpose is to inspire the current maternal PTE risk assessment, diagnosis and treatment, as well as to explore the existing limitations and problems.

Use of tranexamic acid in medial open wedge high tibial osteotomy

PURPOSE

Aim of this study was to evaluate the effect of tranexamic acid (TXA) on the outcome after medial open wedge osteotomy.

MATERIAL AND METHODS

A prospective non-randomized comparative study with 52 patients has been performed. In both treatment groups, the same surgical technique for the medial open wedge HTO was used. In group 1 (N: 26) the patients received 1 g TXA i.v. preoperatively, in group 2 (N: 26) no TXA was given. Primary outcome measure was the decrease in hemoglobin concentration. Secondary outcome criteria were postoperative pain, intraarticular effusion (measured by ultrasound), range of motion (ROM) at discharge, peri- and postoperative complications and the KOOS PS (pre- and postoperatively at 1 year follow up).

RESULTS

Hemoglobin decrease was significantly less in the TXA group compared to the non TXA group. Postoperative pain and intraarticular effusion was also significantly lower and ROM at discharge was higher in the TXA group. There was no group difference in peri- and postoperative complications and the pre- and postoperatively KOOS PS.

CONCLUSIONS

The results of the present study show the systemic application of 1 g TXA reduces hemoglobin drop and postoperative morbidity (pain, intraarticular effusion, and ROM) after tibial open wedge HTO.

Stockholm score of lesion detection on computed tomography following mild traumatic brain injury (SELECT-TBI): study protocol for a multicentre, retrospective, observational cohort study

INTRODUCTION

Mild traumatic brain injury (mTBI) is one of the most common reasons for emergency department (ED) visits. A portion of patients with mTBI will develop an intracranial lesion that might require medical or surgical intervention. In these patients, swift diagnosis and management is paramount. Several guidelines have been developed to help direct patients with mTBI for head CT scanning, but they lack specificity, do not consider the interactions between risk factors and do not provide an individualised estimate of intracranial lesion risk. The aim of this study is to create a model that estimates individualised intracranial lesion risks in patients with mTBI who present to the ED.

METHODS AND ANALYSIS

This will be a retrospective cohort study conducted at ED hospitals in Stockholm, Sweden. Eligible patients are adults (≥15 years) with mTBI who presented to the ED within 24 hours of injury and performed a CT scan. The primary outcome will be a traumatic lesion on head CT. The secondary outcomes will be any clinically significant lesion, defined as an intracranial finding that led to neurosurgical intervention, hospital admission ≥48 hours due to TBI or death due to TBI. Machine-learning models will be applied to create scores predicting the primary and secondary outcomes. An estimated 20 000 patients will be included.

ETHICS AND DISSEMINATION

The study has been approved by the Swedish Ethical Review Authority (Dnr: 2020-05728). The research findings will be disseminated through peer-reviewed scientific publications and presentations at international conferences.

TRIAL REGISTRATION NUMBER

NCT04995068.

Histology of Cerebral Clots in Cryptogenic Stroke Varies According to the Presence of a Patent Foramen Ovale

Although a pathophysiological impact remains difficult to prove in individual patient care, a patent foramen ovale (PFO) is currently considered of high relevance for secondary prophylaxis in selected patients with cryptogenic ischemic stroke. By quantification of histological clot composition, we aimed to enhance pathophysiological understanding of PFO attributable ischemic strokes. Retrospectively, we evaluated all cerebral clots retrieved by mechanical thrombectomy for acute ischemic stroke treatment between 2011 and 2021 at our comprehensive stroke care center. Inclusion criteria applied were cryptogenic stroke, age (≤60 years), and PFO status according to transesophageal echocardiography, resulting in a study population of 58 patients. Relative clot composition was calculated using orbit image analysis to define the ratio of main histologic components (fibrin/platelets (F/P), red blood cell count (RBC), leukocytes). Cryptogenic stroke patients with PFO (PFO+, n = 20) displayed a significantly higher percentage of RBC (0.57 ± 0.17; p = 0.002) and lower percentage of F/P (0.38 ± 0.15; p = 0.003) compared to patients without PFO (PFO–, n = 38) (RBC: 0.41 ± 0.21; F/P: 0.52 ± 0.20). In conclusion, histologic clot composition in cryptogenic stroke varies depending on the presence of a PFO. Our findings histologically support the concept that a PFO may be of pathophysiological relevance in cryptogenic ischemic stroke.

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.

Better prediction of stroke in atrial fibrillation with incorporation of cancer in CHA2DS2VASC score: CCHA2DS2VASC score

Introduction

Atrial fibrillation (AF) is associated with an increased risk of stroke. Despite evidence linking cancer and thrombosis, cancer is not part of the CHA₂DS₂VASc score.

Hypothesis

Cancer is an independent risk factor for thromboembolic stroke in patients with AF.

Method

The SEER database was utilized to identify patients with lung, colon, breast, and prostate cancers with AF and no prior diagnosis of stroke and. compared to controls within the dataset. The primary endpoint was rates of stroke per 100 person-years. Cox regression modeling and a nested model comparing CHA₂DS₂VASc score (Model 1) with a complete model including cancer diagnosis (Model 2) were performed. Models were compared using Akaike Information Criterion (AIC) and Net Reclassification Index (NRI). A propensity-matched cohort with equivalent CHA₂DS₂VASc scores determining stroke-free survival was also performed.

Results

A total of 101,185 patients were included in the analysis, with 48,242 in the Cancer and 52,943 in the Non-cancer Group. Stroke rate per 100 person-years was significantly higher in the Cancer Group. The CHA₂DS₂VASc model (Model 1) was compared against a model including cancer (Model 2) showing improved predictability as assessed by both NRI and AIC. Cox regression analysis calculated a hazard ratio of 1.085 for Cancer, which was comparable to age >75, female sex, and diabetes. Propensity matched Kaplan-Meier curve demonstrated a decreased probability of stroke-free survival in the Cancer Group.

Conclusion

Cancers increase the risk of stroke in patients with AF. Consideration should be given to the addition of cancer to the clinical scoring system.

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.

VENOUS THROMBOEMBOLISM IN THE EMERGENCY DEPARTMENT - SINGLE-CENTER EXPERIENCE

Given the importance of early recognition of acute venous thromboembolism (VTE) and the nonspecificity of its symptoms and signs, it is essential to follow the guidelines for diagnostic and therapeutic decisions. Ultrasound examination of the entire lower extremity is currently the standard diagnostic method for symptomatic patients with a clinical probability of deep vein thrombosis (DVT) according to the Wells scoring system. The aim of this study is to show the demographic structure and analyze the number of patients in the emergency department with suspected venous thrombosis. In the past 10 years, 2,022 patients with DVT and 686 with pulmonary emboli have been diagnosed. Despite adherence to the diagnostic protocol, nearly two-thirds of patients require early ultrasound diagnosis. One-fifth of patients had thrombosis of the superficial venous system of the leg or arm. Thrombus was present in the veins of the lower leg in 37% of patients with DVT. The presence of thrombi above the knee, involving the deep femoropopliteal venous system, was found in as much as one-third of patients. These findings and current guidelines suggest that there is a paradigm shift toward more frequent use of DOAC in patients with DVT. However, greater educational efforts may be needed for many physicians to become comfortable with the use of DOAC in the outpatient management of patient populations at low risk for pulmonary embolism.

Wichtige Differentialdiagnosen des Beinödems – ein kurzer Praxisleitfaden

Das differenzialdiagnostische Spektrum der Beinödeme ist vielfältig und umfasst sowohl phlebologische, entzündliche, traumatologische, medikamentöse und andere systemische und regionale Ursachen und Erkrankungen.

Um die Ursachen für Beinödeme bestmöglich abzuklären, sind eine ausführliche Anamnese und klinische Untersuchung entscheidend. Die Lokalisation der Beinschwellung, Beginn und Dauer der Beschwerden, Schmerzsymptomatik, Allgemeinsymptome, Vorerkrankungen und bestehende Hautveränderungen können wichtige Hinweise auf mögliche zugrunde liegende Ursachen liefern. Nach Eingrenzung der möglichen Differenzialdiagnosen können gezielte apparative und laborchemische Untersuchungen ergänzend angeschlossen werden, um die Diagnose zu sichern und die richtige Therapie einzuleiten.

D-dimer: an analyte with increasing application in Covid-19 infection

INTRODUCTION

: D- Dimer levels from peripheral blood are increasingly used to assess various pathological conditions. Initially an area for haematologists, now this analyte is evaluated more extensively from many specialities of medicine. Covid-19 infection has not only added a new dimension to D-Dimer level assessment in this disease but has also shed newer lights to the underlying pathophysiological mechanisms for its elevation in this disease.

AREAS COVERED

Innate variability in measuring D- Dimer levels, Impact of various techniques in measuring D- Dimer, non availability of uniform controls and standards, molecular heterogeneity of the product, how it is produced. Reasons for raised D- Dimer in covid-19 infection. D- Dimer in other pathological states. Articles with relevant key words from 1990 searched in PubMed were utilized for review.

EXPERT OPINION

: D-Dimer has important application in diagnosis, prognosis, management and understanding various conditions. Its level can rise with increased coagulability of blood, sepsis, cytokine storm and snake bite etc. Renal function, age influences its reference ranges. Units of measurement, its expression varies in different reports needing international standardization. In Covid-19 infection its levels correlate with stage of the disease, pathology and complications.

Cancer-associated venous thromboembolism

Cancer-associated thrombosis (including venous thromboembolism (VTE) and arterial events) is highly consequential for patients with cancer and is associated with worsened survival. Despite substantial improvements in cancer treatment, the risk of VTE has increased in recent years; VTE rates additionally depend on the type of cancer (with pancreas, stomach and primary brain tumours having the highest risk) as well as on individual patient's and cancer treatment factors. Multiple cancer-specific mechanisms of VTE have been identified and can be classified as mechanisms in which the tumour expresses proteins that alter host systems, such as levels of platelets and leukocytes, and in which the tumour expresses procoagulant proteins released into the circulation that directly activate the coagulation cascade or platelets, such as tissue factor and podoplanin, respectively. As signs and symptoms of VTE may be non-specific, diagnosis requires clinical assessment, evaluation of pre-test probability, and objective diagnostic testing with ultrasonography or CT. Risk assessment tools have been validated to identify patients at risk of VTE. Primary prevention of VTE (thromboprophylaxis) has long been recommended in the inpatient and post-surgical settings, and is now an option in the outpatient setting for individuals with high-risk cancer. Anticoagulant therapy is the cornerstone of therapy, with low molecular weight heparin or newer options such as direct oral anticoagulants. Personalized treatment incorporating risk of bleeding and patient preferences is essential, especially as a diagnosis of VTE is often considered by patients even more distressing than their cancer diagnosis, and can severely affect the quality of life. Future research should focus on current knowledge gaps including optimizing risk assessment tools, biomarker discovery, next-generation anticoagulant development and implementation science.

Incidence of proximal deep vein thrombosis in medical critical care patients

Background

Approximately 13-31% of medical critical care patients develop deep vein thrombosis (DVT). However, there are very few reports regarding the incidence of DVT among Asian patients without routine prophylaxis. The objectives of this study were to assess the prevalence and incidence proportion of proximal DVT in Thai medical critical care patients not receiving thrombosis prophylaxis.

Methods

We conducted a prospective cohort study in medical critical care patients admitted to Siriraj Hospital, Thailand between November 2008 and November 2009. Patients were screened for proximal DVT by duplex ultrasonography performed 48 h, 7, 14 and 28 days after admission. Primary outcomes were prevalence and incidence proportion of DVT. Factors associated with the development of proximal DVT were evaluated by multivariate analysis.

Results

Of the 158 patients enrolled in the study, 25 had proximal DVT (15.8%). Nine patients (5.7%) had DVT on the first test at 48 h, while 10 (6.3%), 2 (1.3%) and 4 (2.5%) patients had developed DVT on days 7, 14, and 28, respectively. Thus, the prevalence at the beginning of the study was 5.7% (95%CI 2.6-10.5) and the incidence proportion was 10.1% (95%CI 5.9-15.9). The multivariate analysis showed that age (odds ratio [OR] per 1-year increase was 1.04, 95% confidence interval [CI] 1.01-1.07), female gender (OR 4.05, 95%CI 1.51-12.03), femoral venous catheter (OR 11.18, 95%CI 3.19-44.83), and the absence of platelet transfusion (OR 0.07, 95%CI 0.003-0.43) were associated with the development of proximal DVT. Patients with proximal DVT had a longer hospital length of stay (22 days [IQR 11-60] vs. 14 days [7-23], p = 0.03) and spent more time on mechanical ventilation (10 days (3.3-57) vs. 6 days (3-12), p = 0.053) than patients without DVT. Patient mortality was not affected by the presence of DVT (52% vs. 38.3%, p = 0.29).

Conclusions

Routine thromboprophylaxis is not used in our institution and the prevalence and incidence proportion of proximal DVT in Asian medical critical care patients were both substantial. Patients with older age, female gender, an intravenous femoral catheter, and the absence of platelet transfusion all had a higher chance of developing proximal DVT.

Patterns and Distribution of Deep Vein Thrombosis and Its Effects on Clinical Outcomes After Opening-Wedge High Tibial Osteotomy

Background:

Although a few studies have reported the incidence of deep vein thrombosis (DVT) after opening-wedge high tibial osteotomy (OWHTO), previous studies focused only on symptomatic DVT. Information is lacking regarding the overall incidence of DVT after OWHTO, thrombus location, and the relationship between DVT and clinical outcome.

Purpose:

To determine the overall incidence of DVT and classify the location of DVT after OWHTO. We also determined whether significant differences in clinical improvement exist in patients with and without DVT at 6 months and at 2 years after OWHTO.

Study Design:

Case-control study; Level of evidence, 3.

Methods:

This study included 46 patients (47 knees) who underwent OWHTO. All patients were instructed to perform knee range of motion exercises and partial weightbearing after drain removal. None of the patients received a chemoprophylaxis for DVT except intermittent pneumatic compression. DVT was diagnosed using 128-row multidetector computed tomography performed before discharge on the fourth postoperative day. The location was classified into 6 segments in the distal portion (muscular and axial veins) and proximal portion (popliteal, femoral, and common femoral veins and veins located above the iliac vein). International Knee Documentation Committee (IKDC) score was assessed preoperatively and postoperatively at 6 months, 1 year, and 2 years using a linear mixed model.

Results:

Although the incidence of symptomatic DVT was 8.5% (n = 4), the overall incidence of early DVT was 44.7% (n = 21). All DVTs were located in the distal portion of the lower extremity vein, and 76.2% of the DVTs were located in an axial vein. The IKDC scores were 33.6 ± 7.2 and 35.3 ± 9.1 (P = .910) preoperatively, 38.1 ± 5.6 and 40.6 ± 8.4 (P = .531) at 6 months after surgery, and 44.8 ± 6.9 and 45.9 ± 11.4 (P = .786) at 2 years after surgery in patients without and those with DVT, respectively.

Conclusion:

The overall incidence of early DVT after OWHTO was 44.7%. DVT after OWHTO was found particularly around the osteotomy site (76.2%). Patients with DVT did not have inferior short-term clinical outcomes after surgery.

D-dimer to rule out venous thromboembolism during pregnancy: A systematic review and meta-analysis

BACKGROUND

The usefulness of D-dimer measurement to rule out venous thromboembolism (VTE) during pregnancy is debated.

OBJECTIVES

We performed a systematic review and meta-analysis to investigate the safety of D-dimer to rule out acute VTE in pregnant women with suspected pulmonary embolism and/or deep vein thrombosis.

METHODS

Two reviewers independently identified studies through PubMed and Embase until June 2021, week 1. We supplemented our search by manually reviewing reference lists of all retrieved articles, clinicalTrials.gov, and reference literature. Prospective or retrospective studies in which a formal diagnostic algorithm was used to evaluate the ability of D-dimer to rule out VTE during pregnancy were eligible.

RESULTS

We identified 665 references through systematic database and additional search strategies; 45 studies were retrieved in full, of which four were included, after applying exclusion criteria. Three studies were prospective, and one had a retrospective design. The 3-month thromboembolic rate in pregnant women left untreated after a negative D-dimer was 1/312 (0.32%; 95% CI, 0.06-1.83). The pooled estimate values were 99.5% for sensitivity (95% CI, 95.0-100.0; I², 0%) and 100% for negative predictive value (95% CI, 99.19-100.0; I², 0%). The prevalence of VTE and the yield of D-dimer were 7.4% (95% CI, 3.8-12; I², 83%) and 34.2% (95% CI, 15.9-55.23; I², 89%) respectively.

CONCLUSION

Our results suggest that D-dimer allows to safely rule out VTE in pregnant women with suspected VTE and a disease prevalence consistent with a low/intermediate or unlikely pretest probability.

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.