Non-invasive diagnosis of venous thromboembolism in outpatients

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.

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

Background

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

Methods

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

Results

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

Conclusion

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

Scintigraphic Diagnosis of Acute Pulmonary Embolism: From Basics to Best Practices

In this article the technique, interpretation, and diagnostic performance of scintigraphy for the diagnosis of acute pulmonary embolism (PE) are reviewed. Lung scintigraphy has stood the test of time as a reliable and validated examination for the determination of PE. Ventilation/perfusion (V/Q) lung scintigraphy assesses the functional consequences of the clot on its downstream vascular bed in conjunction with the underlying ventilatory status of the affected lung region, in contrast to CT pulmonary angiography (CTPA), which visualizes presence of the clot within affected vessels. Most-commonly used ventilation radiopharmaceuticals are Technetium-99m labeled aerosols (such as 99mTechnetium-DTPA), or ultrafine particle suspensions (99mTc-Technegas) which reach the distal lung in proportion to regional distribution of ventilation. Perfusion images are obtained after intravenous administration 99mTc-labeled macro-aggregated albumin particles which lodge in the distal pulmonary capillaries. Both planar and tomographic methods of imaging, each favored in different geographical regions, will be described. Guidelines for interpretation of scintigraphy have been issues by both the Society of Nuclear Medicine and Molecular Imaging, and by the European Association of Nuclear Medicine. Breast tissue is particularly radiosensitive during pregnancy due to its highly proliferative state and many guidelines recommend use of lung scintigraphy rather than CTPA in this population. Several maneuvers are available in order to further reduce radiation exposure including reducing radiopharmaceutical dosages or omitting ventilation altogether, functionally converting the study to a low-dose screening examination; if perfusion defects are present, further testing is necessary. Several groups have also performed perfusion-only studies during the COVID epidemic in order to reduce risk of respiratory contagion. In patients where perfusion defects are present, further testing is again necessary to avoid false-positive results. Improved availability of personal protective equipment, and reduced risk of serious infection, have rendered this maneuver moot in most practices. First introduced 60 years ago, subsequent advances in radiopharmaceutical development and imaging methods have positioned lung scintigraphy to continue to play an important clinical and research role in the diagnosis of acute PE.

Comparison of circulating lipid profiles, D-dimer and fibrinogen levels between hypertensive patients with and without stroke

BACKGROUND

Stroke is one of the leading causes of global mortality and disability, particularly in hypertensive patients. This study aimed to compare lipid profile, fibrinogen, and D-dimer levels between hypertensive patient with and without stroke.

METHODS

This was a facility-based cross-sectional study conducted from November 2022 to January 2023 among 115 hypertensive patients (70 patients without stroke and 45 with stroke) who had follow-up at Yikatit 12 Hospital Medical College, Ethiopia. All data analyses were done using SPSS version 25.0 and comparisons of variables between groups were made using the Chi-square test, independent sample t-test, and Mann-Whitney U test. Multiple logistic regression analysis was done to identify predictors of stroke among hypertensive patients. A p-value <0.05 was assumed to be statistically significant for all statistical tests.

RESULTS

Significantly elevated levels of TC, LDL-C, D-DI, and fibrinogen were observed in the stroke group than in the non-stroke group (p-value<0.05). The mean values of TC, D-DI, and fibrinogen were significantly higher in patients with ischemic stroke compared to those with hemorrhagic stroke. Duration of hypertension (AOR: 1.21; CI: 1.10, 2.09), TC (AOR:1.07; CI: 1.01, 1.22), D-DI (AOR: 1.15; CI: 1.05, 1.69) and fibrinogen (AOR:1.19; CI: 1.10, 2.89) were identified to be independent predictors of stroke in hypertensive patients.

CONCLUSION

The circulating levels of TC, LDL-C, D-DI and fibrinogen in hypertensive patients with stroke were significantly higher than in those without stroke. But only TC, D-DI, and fibrinogen were found to be predictors of stroke in hypertensives. Considerably higher TC, D-DI, and fibrinogen levels were also seen in patients with ischemic stroke than in those with hemorrhagic stroke. This confirms the key roles of dyslipidemia (hypercholesterolemia) and aberrant hemostatic activation to stroke development, notably ischemic stroke.

Ventilation Scintigraphy With Radiolabeled Carbon Nanoparticulate Aerosol (Technegas): State-of-the-Art Review and Diagnostic Applications to Pulmonary Embolism During COVID-19 Pandemic

ABSTRACT

Invented and first approved for clinical use in Australia 36 years ago, Technegas is the technology that enabled ventilation scintigraphy with 99m Tc-labeled carbon nanoparticles ( 99m Tc-CNP). The US Food and Drug Administration (FDA) has considered this technology for more than 30 years but only now is getting close to approving it. Meanwhile, more than 4.4 million patients benefited from this technology in 64 countries worldwide. The primary application of 99m Tc-CNP ventilation imaging is the diagnostic evaluation for suspicion of pulmonary embolism using ventilation-perfusion quotient (V/Q) imaging. Because of 99m Tc-CNP's long pulmonary residence, tomographic imaging emerged as the preferred V/Q methodology. The FDA-approved ventilation imaging agents are primarily suitable for planar imaging, which is less sensitive. After the FDA approval of Technegas, the US practice will likely shift to tomographic V/Q. The 99m Tc-CNP use is of particular interest in the COVID-19 pandemic because it offers an option of a dry radioaerosol that takes approximately only 3 to 5 tidal breaths, allowing the shortest exposure to and contact with possibly infected patients. Indeed, countries where 99m Tc-CNP was approved for clinical use continued using it throughout the COVID-19 pandemic without known negative viral transmission consequences. Conversely, the ventilation imaging was halted in most US facilities from the beginning of the pandemic. This review is intended to familiarize the US clinical nuclear medicine community with the basic science of 99m Tc-CNP ventilation imaging and its clinical applications, including common artifacts and interpretation criteria for tomographic V/Q imaging for pulmonary embolism.

D-dimer Testing in Pulmonary Embolism with a Focus on Potential Pitfalls: A Narrative Review

D-dimer is a multifaceted biomarker of concomitant activation of coagulation and fibrinolysis, which is routinely used for ruling out pulmonary embolism (PE) and/or deep vein thrombosis (DVT) combined with a clinical pretest probability assessment. The intended use of the tests depends largely on the assay used, and local guidance should be applied. D-dimer testing may suffer from diagnostic errors occurring throughout the pre-analytical, analytical, and post-analytical phases of the testing process. This review aims to provide an overview of D-dimer testing and its value in diagnosing PE and discusses the variables that may impact the quality of its laboratory assessment.

2021 AHA/ACC/ASE/CHEST/SAEM/SCCT/SCMR Guideline for the Evaluation and Diagnosis of Chest Pain: A Report of the American College of Cardiology/American Heart Association Joint Committee on Clinical Practice Guidelines

AIM

This clinical practice guideline for the evaluation and diagnosis of chest pain provides recommendations and algorithms for clinicians to assess and diagnose chest pain in adult patients.

METHODS

A comprehensive literature search was conducted from November 11, 2017, to May 1, 2020, encompassing randomized and nonrandomized trials, observational studies, registries, reviews, and other evidence conducted on human subjects that were published in English from PubMed, EMBASE, the Cochrane Collaboration, Agency for Healthcare Research and Quality reports, and other relevant databases. Additional relevant studies, published through April 2021, were also considered.

STRUCTURE

Chest pain is a frequent cause for emergency department visits in the United States. The "2021 AHA/ACC/ASE/CHEST/SAEM/SCCT/SCMR Guideline for the Evaluation and Diagnosis of Chest Pain" provides recommendations based on contemporary evidence on the assessment and evaluation of chest pain. This guideline presents an evidence-based approach to risk stratification and the diagnostic workup for the evaluation of chest pain. Cost-value considerations in diagnostic testing have been incorporated, and shared decision-making with patients is recommended.

2021 AHA/ACC/ASE/CHEST/SAEM/SCCT/SCMR Guideline for the Evaluation and Diagnosis of Chest Pain: A Report of the American College of Cardiology/American Heart Association Joint Committee on Clinical Practice Guidelines

AIM

This clinical practice guideline for the evaluation and diagnosis of chest pain provides recommendations and algorithms for clinicians to assess and diagnose chest pain in adult patients.

METHODS

A comprehensive literature search was conducted from November 11, 2017, to May 1, 2020, encompassing randomized and nonrandomized trials, observational studies, registries, reviews, and other evidence conducted on human subjects that were published in English from PubMed, EMBASE, the Cochrane Collaboration, Agency for Healthcare Research and Quality reports, and other relevant databases. Additional relevant studies, published through April 2021, were also considered.

STRUCTURE

Chest pain is a frequent cause for emergency department visits in the United States. The "2021 AHA/ACC/ASE/CHEST/SAEM/SCCT/SCMR Guideline for the Evaluation and Diagnosis of Chest Pain" provides recommendations based on contemporary evidence on the assessment and evaluation of chest pain. This guideline presents an evidence-based approach to risk stratification and the diagnostic workup for the evaluation of chest pain. Cost-value considerations in diagnostic testing have been incorporated, and shared decision-making with patients is recommended.

2021 AHA/ACC/ASE/CHEST/SAEM/SCCT/SCMR Guideline for the Evaluation and Diagnosis of Chest Pain: Executive Summary: A Report of the American College of Cardiology/American Heart Association Joint Committee on Clinical Practice Guidelines

AIM

This executive summary of the clinical practice guideline for the evaluation and diagnosis of chest pain provides recommendations and algorithms for clinicians to assess and diagnose chest pain in adult patients.

METHODS

A comprehensive literature search was conducted from November 11, 2017, to May 1, 2020, encompassing studies, reviews, and other evidence conducted on human subjects that were published in English from PubMed, EMBASE, the Cochrane Collaboration, Agency for Healthcare Research and Quality reports, and other relevant databases. Additional relevant studies, published through April 2021, were also considered.

STRUCTURE

Chest pain is a frequent cause for emergency department visits in the United States. The "2021 AHA/ACC/ASE/CHEST/SAEM/SCCT/SCMR Guideline for the Evaluation and Diagnosis of Chest Pain" provides recommendations based on contemporary evidence on the assessment and evaluation of chest pain. These guidelines present an evidence-based approach to risk stratification and the diagnostic workup for the evaluation of chest pain. Cost-value considerations in diagnostic testing have been incorporated and shared decision-making with patients is recommended.

2021 AHA/ACC/ASE/CHEST/SAEM/SCCT/SCMR Guideline for the Evaluation and Diagnosis of Chest Pain: A Report of the American College of Cardiology/American Heart Association Joint Committee on Clinical Practice Guidelines

AIM

This clinical practice guideline for the evaluation and diagnosis of chest pain provides recommendations and algorithms for clinicians to assess and diagnose chest pain in adult patients.

METHODS

A comprehensive literature search was conducted from November 11, 2017, to May 1, 2020, encompassing randomized and nonrandomized trials, observational studies, registries, reviews, and other evidence conducted on human subjects that were published in English from PubMed, EMBASE, the Cochrane Collaboration, Agency for Healthcare Research and Quality reports, and other relevant databases. Additional relevant studies, published through April 2021, were also considered. Structure: Chest pain is a frequent cause for emergency department visits in the United States. The "2021 AHA/ACC/ASE/CHEST/SAEM/SCCT/SCMR Guideline for the Evaluation and Diagnosis of Chest Pain" provides recommendations based on contemporary evidence on the assessment and evaluation of chest pain. This guideline presents an evidence-based approach to risk stratification and the diagnostic workup for the evaluation of chest pain. Cost-value considerations in diagnostic testing have been incorporated, and shared decision-making with patients is recommended.

2021 AHA/ACC/ASE/CHEST/SAEM/SCCT/SCMR Guideline for the Evaluation and Diagnosis of Chest Pain: Executive Summary: A Report of the American College of Cardiology/American Heart Association Joint Committee on Clinical Practice Guidelines

AIM

This executive summary of the clinical practice guideline for the evaluation and diagnosis of chest pain provides recommendations and algorithms for clinicians to assess and diagnose chest pain in adult patients.

METHODS

A comprehensive literature search was conducted from November 11, 2017, to May 1, 2020, encompassing studies, reviews, and other evidence conducted on human subjects that were published in English from PubMed, EMBASE, the Cochrane Collaboration, Agency for Healthcare Research and Quality reports, and other relevant databases. Additional relevant studies, published through April 2021, were also considered. Structure: Chest pain is a frequent cause for emergency department visits in the United States. The "2021 AHA/ACC/ASE/CHEST/SAEM/SCCT/SCMR Guideline for the Evaluation and Diagnosis of Chest Pain" provides recommendations based on contemporary evidence on the assessment and evaluation of chest pain. These guidelines present an evidence-based approach to risk stratification and the diagnostic workup for the evaluation of chest pain. Cost-value considerations in diagnostic testing have been incorporated and shared decision-making with patients is recommended.

Lung scintigraphy for pulmonary embolism diagnosis in COVID-19 patients: a multicenter study

In patients with novel coronavirus disease 2019 (COVID-19) referred for lung scintigraphy for suspected pulmonary embolism (PE), there has been an ongoing debate within the nuclear medicine community as to whether and when the ventilation study should be performed. Indeed, while PE diagnosis typically relies on the recognition of ventilation/perfusion (V/P) mismatched defects, the ventilation procedure potentially increases the risk of contamination to the healthcare workers. The primary aim of this study was to assess the role of ventilation imaging when performing lung scintigraphy for suspected PE in COVID-19 patients. The secondary aim was to describe practices and imaging findings in this specific population. Methods: A national registry was created in collaboration with the French Society of Nuclear Medicine to collect lung scans performed in COVID-19 patients for suspected PE. Practices of departments were assessed regarding imaging protocols and aerosol precautions. A retrospective review of V/P SPECT/CT scans was then conducted. Two physicians blinded to clinical information reviewed each case by sequentially using P SPECT, P SPECT/CT and V/P SPECT/CT images. Scans were classified in one of the four following categories: patients for whom PE could reasonably be excluded based on 1) perfusion SPECT only, 2) P SPECT/CT, 3) V/P SPECT/CT; or 4) patients with mismatched defects suggestive of PE according to the EANM criteria. Results: Data from 12 French nuclear medicine departments were collected. Lung scans were performed between 03/2020 and 04/2021. Personal protective equipment and dedicated cleaning procedures were used in all departments. Out of the 145 V/Q SPECT/CT included in the central review, PE could be excluded using only P SPECT, P SPECT/CT and V/P SPECT/CT in 27 (19%), 55 (38%) and 45 (31%) patients, respectively. V/P SPECT/CT was positive for PE in 18 (12%) patients, including 12 (67%) with a low burden of PE (≤10%). Conclusion: In this population of COVID-19 patients assessed with lung scintigraphy, PE could be confidently excluded without ventilation in only 57% of patients. Ventilation imaging was required to confidently rule out PE in 31% of patients. Overall, the prevalence of PE was low (12%).

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.

Systematic review and meta-analysis of outcomes in patients with suspected pulmonary embolism

Prompt evaluation and therapeutic intervention of suspected pulmonary embolism (PE) are of paramount importance for improvement in outcomes. We systematically reviewed outcomes in patients with suspected PE, including mortality, incidence of recurrent PE, major bleeding, intracranial hemorrhage, and postthrombotic sequelae. We searched the Cochrane Central Register of Controlled Trials, MEDLINE, and Embase for eligible studies, reference lists of relevant reviews, registered trials, and relevant conference proceedings. We included 22 studies with 15 865 patients. Among patients who were diagnosed with PE and discharged with anticoagulation, 3-month follow-up revealed that all-cause mortality was 5.69% (91/1599; 95% confidence interval [CI], 4.56-6.83), mortality from PE was 1.19% (19/1597; 95% CI, 0.66-1.72), recurrent venous thromboembolism (VTE) occurred in 1.38% (22/1597; 95% CI: 0.81-1.95), and major bleeding occurred in 0.90% (2/221%; 95% CI, 0-2.15). In patients with a low pretest probability (PTP) and negative D-dimer, 3-month follow-up revealed mortality from PE was 0% (0/808) and incidence of VTE was 0.37% (4/1094; 95% CI: 0.007-0.72). In patients with intermediate PTP and negative D-dimer, 3-month follow-up revealed that mortality from PE was 0% (0/2747) and incidence of VTE was 0.46% (14/3015; 95% CI: 0.22-0.71). In patients with high PTP and negative computed tomography (CT) scan, 3-month follow-up revealed mortality from PE was 0% (0/651) and incidence of VTE was 0.84% (11/1302; 95% CI: 0.35-1.34). We further summarize outcomes evaluated by various diagnostic tests and diagnostic pathways (ie, D-dimer followed by CT scan).

Clinical factors and outcomes of subsegmental pulmonary embolism in cancer patients

In the cancer population, patients diagnosed with venous thromboembolism (VTE) are considered to have a threefold increased risk of mortality compared with those without VTE. With the advent of modern computed tomography (CT), the rate of diagnosis of subsegmental pulmonary embolism (SSPE) has increased, likely as a result of improved visualization of the peripheral pulmonary arteries. The clinical significance of SSPE remains unclear because of the lack of randomized controlled clinical trials. The aim of this study was to identify the incidence and risk factors of recurrent proximal PE within 12 months of diagnosis of SSPE in cancer. We performed a retrospective analysis of 206 adult cancer patients who were diagnosed with SSPE from 2014 to 2016 at the University of Texas MD Anderson Cancer Center. At the time of SSPE diagnosis, the majority had metastatic cancer, 108 patients (53.2%) were undergoing chemotherapy, and 23 patients (11.2%) had a history of VTE. Most patients had an Eastern Cooperative Oncology Group (ECOG) performance status of 0 to 2. Sixty-seven percent of SSPE was discovered incidentally on restaging CT scans, with the majority being a single and isolated event (70.9%). Within 12 months of SSPE diagnosis, 18 patients (8.7%) were found to have a recurrent PE. The patients treated with anticoagulation had a lower rate of PE recurrence (8% vs 13% in those not treated with anticoagulation). Treatment with anticoagulation did not appear to have a significant impact on overall survival (P = .48) when adjusted for ECOG performance status and cancer stage.

Systematic review and meta-analysis of test accuracy for the diagnosis of suspected pulmonary embolism

Pulmonary embolism (PE) is a common, potentially life-threatening yet treatable condition. Prompt diagnosis and expeditious therapeutic intervention is of paramount importance for optimal patient management. Our objective was to systematically review the accuracy of D-dimer assay, compression ultrasonography (CUS), computed tomography pulmonary angiography (CTPA), and ventilation-perfusion (V/Q) scanning for the diagnosis of suspected first and recurrent PE. We searched Cochrane Central, MEDLINE, and EMBASE for eligible studies, reference lists of relevant reviews, registered trials, and relevant conference proceedings. 2 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 61 studies. The pooled estimates for D-dimer sensitivity and specificity were 0.97 (95% confidence interval [CI], 0.96-0.98) and 0.41 (95% CI, 0.36-0.46) respectively, whereas CTPA sensitivity and specificity were 0.94 (95% CI, 0.89-0.97) and 0.98 (95% CI, 0.97-0.99), respectively, and CUS sensitivity and specificity were 0.49 (95% CI, 0.31-0.66) and 0.96 (95% CI, 0.95-0.98), respectively. Three variations of pooled estimates for sensitivity and specificity of V/Q scan were carried out, based on interpretation of test results. D-dimer had the highest sensitivity when compared with imaging. CTPA and V/Q scans (high probability scan as a positive and low/non-diagnostic/normal scan as negative) both had the highest specificity. This systematic review was registered on PROSPERO as CRD42018084669.

Safety and feasibility of rivaroxaban in deferred workup of patients with suspected deep vein thrombosis

Guidelines suggest using empiric low-molecular-weight heparin if the diagnostic workup of deep vein thrombosis (DVT) is expected to be delayed. The role of direct oral anticoagulants for deferred compression ultrasound imaging (CUS) in patients with suspected DVT remains unexplored. The main objective of the study was to assess the safety of deferring CUS with therapeutic doses of rivaroxaban. We prospectively included consecutive outpatients referred to the Emergency Department at Østfold Hospital, Norway, with suspected first or recurrent lower-extremity DVT between February 2015 and November 2018. Patients were discharged with rivaroxaban 15 mg twice daily while awaiting CUS within 24 hours if D-dimer level was ≥0.5 mg/L fibrinogen-equivalent units. The primary outcome was the rate of major bleeding incidents from study inclusion until DVT was confirmed and anticoagulation therapy continued, or otherwise up to 48 hours following administration of the last tablet of rivaroxaban. The secondary outcome was the rate of progressive DVT symptoms or symptoms or signs of pulmonary embolism between hospital discharge until venous thromboembolism was diagnosed. Six hundred twenty-four of 1653 patients referred with suspected DVT were included (37.7%; 95% confidence interval [CI], 35.4-40.1). DVT was diagnosed in 119 patients (19.1%; 95% CI, 16.1-22.3). There were no major bleeding incidents, yielding an observed major bleeding rate of 0% (1-sided 95% CI <0.4). No patients experienced major complications in the interval that CUS was deferred (0%; 95% CI, 0.0-0.6). Deferring CUS for up to 24 hours in patients with suspected DVT with therapeutic doses of rivaroxaban is a safe strategy. This trial was registered at www.clinicaltrials.gov as #NCT02486445.

Cardiopulmonary Emergencies in Older Adults

Older adults are susceptible to serious illnesses, including atrial fibrillation, congestive heart failure, pneumonia, and pulmonary embolism. Atrial fibrillation is the most common arrhythmia in this age group and can cause complications such as thromboembolic events and stroke. Congestive heart failure is the most common cause of hospital admission and readmission in the older adult population. Older adults are at higher risk for pulmonary embolism because of age-related changes and comorbidities. Pneumonia is also prevalent and is one of the leading causes of death.

Suspected Acute Pulmonary Embolism: Gestalt, Scoring Systems, and Artificial Intelligence

Pulmonary embolism (PE) remains a diagnostic challenge in 2021. As the pathology is potentially fatal and signs and symptoms are nonspecific, further investigations are classically required. Based on the Bayesian approach, clinical probability became the keystone of the diagnostic strategy to rule out PE in the case of a negative testing. Several clinical probability assessment methods are validated: gestalt, the Wells score, or the revised Geneva score. While the debate persists as to the best way to assess clinical probability, its assessment allows for the good interpretation of the investigation results and therefore directs the correct diagnostic strategy. The wide availability of computed tomography pulmonary angiography (CTPA) resulted in a major increase in investigations with a moderate increase in diagnosis, without any notable improvement in patient outcomes. This leads to a new challenge for PE diagnosis which is the limitation of the number of testing for suspected PE. We review different strategies recently developed to achieve this goal. The last challenge concerns the implementation in clinical practice. Two approaches are developed: simplification of the strategies versus the use of digital support tools allowing more sophisticated strategies. Artificial intelligence with machine-learning algorithms will probably be a future tool to guide the physician in this complex approach concerning acute PE suspicion.

Pulmonary embolism prevalence among emergency department cohorts: A systematic review and meta-analysis by country of study

Essentials The threshold to test for pulmonary embolism (PE) might be lower in North America than Europe. We compared the PE prevalence and positive yield of imaging in Europe and North America. More patients tested in Europe are diagnosed with PE, and imaging is more often positive. Our systematic review supports the hypothesis of overtesting for PE in North America. ABSTRACT: Background There is an impression that North American emergency department (ED) patients tested for pulmonary embolism (PE) differ from European ones. Objectives We compared the PE prevalence, frequency of use, and positive yield of imaging among ED patients tested for PE in Europe and North America. Methods We searched for studies reporting consecutive ED patients tested for PE. Two authors screened full texts, performed risk of bias assessment, and data extraction. We conducted a meta-analysis of proportions for each outcome and a multiple meta-regression. Results From 3109 publications, 44 were included in the systematic review. The prevalence of PE in Europe was 23% (95% confidence interval [CI], 21-26) and in North America 8% (95% CI, 6-9). The adjusted mean difference (aMD) in the prevalence of PE in the European compared with North American studies, was 15% (95% CI, 10-20). Computed tomography pulmonary angiography (CTPA) was used in 60% (95% CI, 52%-68) of European and 38% (95% CI, 24-51) of North American patients tested for PE (aMD, 23% [95% CI, 7-39]). The CTPA diagnostic yield was 29% (95% CI, 26-32) in Europe and 13% (95% CI, 9-17) in North America (aMD, 15% [95% CI, 8-21]). Conclusion Compared with North America, European ED studies have a higher prevalence of PE and diagnostic yield from CTPA, despite a higher frequency of CTPA use among patients tested for PE. This supports the hypothesis that those tested for PE in North American EDs have a lower risk of PE compared with Europe.

Challenging anticoagulation cases: A case of incidental subsegmental pulmonary embolism in a patient with cancer

Cancer therapy and progress in quality of imaging technologies for cancer surveillance and staging are in cause for the increase incidence of smaller incidental pulmonary embolism (PE). The clinical significance of incidental subsegmental pulmonary embolism (SSPE) is hard to define, balancing between possible false positive result, hypercoagulability signal, and truly venous thromboembolism (VTE) event. Evidence for optimal management of such findings are largely extrapolated from symptomatic SSPE in non-cancer patients and from symptomatic, more proximal PE in cancer patients. Current practice guidelines vary but some suggest withholding anticoagulation in selected patients. However, most SSPEs, incidental or not, should be treated as any other cancer-associated PE due to likely similar prognosis. Choice and duration of anticoagulation are extended from existing knowledge on more proximal PE.

Ventilation/perfusion SPECT for the diagnosis of pulmonary embolism: A systematic review

BACKGROUND

Ventilation/perfusion (V/Q) single-photon emission computed tomography (SPECT) has largely replaced conventional planar V/Q scan in nuclear medicine departments for pulmonary embolism (PE) diagnosis. However, the diagnostic performance of the test and its role in the diagnostic management of acute PE are still a matter of debate.

OBJECTIVE

The primary aim was to establish the diagnostic accuracy (sensitivity, specificity) of V/Q SPECT for PE diagnosis. The secondary aim was to review the clinical outcomes of patients investigated for PE suspicion with a standardized algorithm based on V/Q SPECT.

METHODS

We conducted a systematic review of diagnostic accuracy and management outcome studies involving patients evaluated with V/Q SPECT for suspected acute PE. We searched from inception to June 23, 2020, MEDLINE, Embase, and the Cochrane Central Register of Controlled Trials for diagnostic accuracy studies, randomized controlled trials, and observational cohort studies. The methodological quality and risk of bias of eligible studies were assessed using the Quality Assessment of Diagnostic Accuracy Studies-2 (QUADAS-2) and the Risk of Bias in Nonrandomized Studies of Interventions tools.

RESULTS

We identified 13 accuracy studies and one prospective outcome study. Eleven diagnostic accuracy studies were deemed at high risk of bias in at least two of the four domains of QUADAS-2 evaluation and a further two studies raised concerns regarding the applicability of results, precluding the meta-analysis for accuracy indices. The only prospective cohort study demonstrated critical risk of bias.

CONCLUSIONS

Although V/Q SPECT has been widely implemented in daily clinical practice, the exact diagnostic performance of V/Q SPECT for PE is still unknown. This systematic review clearly identifies knowledge gaps and sets the agenda for future research.

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.

Elevated D-Dimers and Right Ventricular Dysfunction on Echocardiography for Diagnosis of Pulmonary Embolism: A Validation Study

Background

There is an increasing need to explore other non-invasive techniques for the diagnosis of pulmonary embolism in resource-limited countries.

Objective

To assess the validity of elevated D-dimer levels and right ventricular (RV) dysfunction on echocardiography in predicting definite massive pulmonary embolism among patients diagnosed with massive pulmonary embolism using computed tomography (CT) pulmonary angiography as the gold standard.

Methods

The patients with acute massive pulmonary embolism on CT pulmonary angiography were included. The participants underwent 12-lead electrocardiography, assessment of D-dimer levels, and bedside echocardiography to determine right ventricular dysfunction. The data were recorded on a proforma and analyzed using IBM SPSS software version 26.0 (IBM Corp., Armonk, NY).

Results

There were 160 patients in the study. The mean age was 49.19 ± 14.89 years. Elevated D-dimer levels were seen in 80.60% of the patients whereas ventricular dysfunction on echocardiography was seen in 90.00% of the patients. The sensitivity and specificity of elevated D dimer levels were 78.99% and 14.60%, respectively. The positive predictive values (PPV) and negative predictive values (NPV) for elevated D-dimer levels were 72.87% and 19.35%, respectively. In contrast, the sensitivity of ventricular dysfunction was 94.96% and specificity 24.39%. PPV was found to be 78.47% and NPV was 62.50%.

Conclusion

Positive D-dimer levels and ventricular dysfunction on echocardiography are sensitive enough to consider the diagnosis of massive pulmonary embolism but lack adequate specificity, thus, necessitating the presence of other noninvasive tests.

Usefulness of a Novel Electrocardiographic Score to Estimate the Pre-Test Probability of Acute Pulmonary Embolism

According to our experience the 12-lead electrocardiogram (ECG) may be used to estimate the pretest probability of acute pulmonary embolism (acPE). To this end, we devised a novel ECG score (nECGs) composed of 5 known ECG criteria, best characterizing the key pathogenetic steps of acPE. A retrospective derivation cohort including 136 patients with acPE and a prospective validation cohort including 149 consecutive patients were used to devise and validate the nECGs. The latter cohort consisted of 76 patients with acPE and 73 controls presenting with characteristic symptoms of acPE, in whom the work-up ruled out acPE. We compared the diagnostic value of our nECGs with those of another ECG score (Daniel-ECG-score) and of the best prediction rules (3 Wells score and 2 Geneva score variants). The sensitivity (98.7%), negative predictive value (98%), test accuracy (84.4%) and the negative likelihood ratio (LR) (0.019) of the nECGs were superior to those of all other investigated methods. There was no between-groups difference in the positive LR. The specificity (69%) of the nECGs was inferior to those of the Daniel-ECG-score and Wells scores and did not differ or was superior to those of the Geneva score variants. The positive predictive value (77.3%) of the nECGs was superior to those of the 2 Geneva scores and did not differ from those of the other methods. In conclusion, the nECGs due to its superior sensitivity, negative predictive value, test accuracy, and negative LR estimated the pretest probability of acPE better than the Daniel-ECG-score and the prediction rules.

Advances in the Diagnosis of Venous Thromboembolism: A Literature Review

The incidence of venous thromboembolism (VTE), including lower extremity deep vein thrombosis (DVT) and pulmonary embolism (PE) is increasing. The increase in suspicion for VTE has lowered the threshold for performing imaging studies to confirm diagnosis of VTE. However, only 20% of suspected cases have a confirmed diagnosis of VTE. Development of pulmonary embolism rule-out criteria (PERC) and update in pre-test probability have changed the paradigm of ruling-out patient with low index of suspicion. The D-dimer test in conjunction to the pre-test probability has been utilized in VTE diagnosis. The age appropriate D-dimer cutoff and inclusion of YEARS algorithm (signs of the DVT, hemoptysis and whether PE is the likely diagnosis) for the D-dimer cutoff have been recent updates in the evaluation of suspected PE. Multi-detector computed tomography pulmonary angiography (CTPA) and compression ultrasound (CUS) are the preferred imaging modality to diagnose PE and DVT respectively. The VTE diagnostic algorithm do differ in pregnant individuals. The prerequisite of avoiding excessive radiation has recruited planar ventilation-perfusion (V/Q) scan as preferred in pregnant patients to evaluate for PE. The modification of CUS protocol with addition of the Valsalva maneuver should be performed while evaluating DVT in pregnant individual.

D-dimer as a stand-alone test to rule out deep vein thrombosis

BACKGROUND

Current guidelines recommend the use of clinical decision rules, such as Wells score, in combination with D-dimer to assess the need for objective imaging to rule out deep vein thrombosis (DVT). However, the clinical decision rule has limitations, and use of D-dimer as a stand-alone test has been suggested.

OBJECTIVE

We aimed to assess the safety and efficiency of D-dimer as a stand-alone test to rule out DVT in outpatients referred with suspected DVT.

METHODS

We collected data from consecutive outpatients referred to our hospital with suspected DVT in 2008-2018. D-dimer levels were analyzed using STA® Liatest® D-Di assay. D-dimer as a stand-alone test was theoretically applied in retrospect, and the number of misdiagnosed events were estimated as if such an approach had been initially used. All patients were followed for three months.

RESULTS

Of 1765 included patients, 293 (16.6%) were diagnosed with DVT. A total of 491 patients (27.8%) had a negative D-dimer (<500 ng/mL). Of these, nine were diagnosed with DVT, yielding a failure rate for D-dimer as a stand-alone test of 1.8% (95% CI 0.8%-3.5%). The majority of the misdiagnosed patients had distal DVT. In analyses restricted to proximal DVTs, the failure rate was 0.6% (95% CI 0.1%-1.8%). D-dimer as a stand-alone approach reduced the proportion of required ultrasounds from 81.8% to 72.2%.

CONCLUSION

D-dimer as a stand-alone test may be safe for excluding proximal DVT and reduce the proportion of required ultrasounds. Prospective management studies are needed to confirm our findings.

Anticoagulant treatment for subsegmental pulmonary embolism

BACKGROUND

Acute pulmonary embolism (PE) is a common cause of death, accounting for 50,000 to 200,000 deaths annually. It is the third most common cause of mortality among the cardiovascular diseases, after coronary artery disease and stroke. The advent of multi-detector computed tomographic pulmonary angiography (CTPA) has allowed better assessment of PE regarding visualisation of the peripheral pulmonary arteries, increasing its rate of diagnosis. More cases of peripheral PEs, such as isolated subsegmental PE (SSPE) and incidental PE, have thereby been identified. These two conditions are usually found in patients with few or none of the classic PE symptoms such as haemoptysis or pleuritic pain, acute dyspnoea or circulatory collapse. However, in patients with reduced cardiopulmonary reserve, classic PE symptoms can be found with isolated SSPEs. Incidental SSPE is found casually in asymptomatic patients, usually by diagnostic imaging performed for other reasons (for example routine CT for cancer staging in oncology patients). Traditionally, all PEs are anticoagulated in a similar manner independent of their location, or number and size of the thrombi. It has been suggested that many patients with SSPE may be treated without benefit, increasing adverse events by a possible unnecessary use of anticoagulants. Patients with isolated SSPE, or incidental PE, may have a more benign clinical presentation compared to those with proximal PEs. However, the clinical significance in patients, and their prognosis, needs to be studied to evaluate whether anticoagulation therapy is required. This is the second update of the Cochrane systematic review published in 2014.

OBJECTIVES

To assess the effectiveness and safety of anticoagulation therapy versus control in patients with isolated subsegmental pulmonary embolism (SSPE) or incidental SSPE.

SEARCH METHODS

The Cochrane Vascular Information Specialist searched the Cochrane Vascular Specialised Register, CENTRAL, MEDLINE, Embase, CINAHL and AMED databases and World Health Organization International Clinical Trials Registry Platform and ClinicalTrials.gov trials registers to 26 November 2019. We also undertook reference checking to identify additional studies.

SELECTION CRITERIA

We included randomised controlled trials of anticoagulation therapy versus control in patients with SSPE or incidental SSPE.

DATA COLLECTION AND ANALYSIS

Two review authors inspected all citations identified to ensure reliable assessment. If relevant studies were identified, we planned for two review authors to independently extract data and to assess the methodological quality of identified trials using the criteria recommended in the Cochrane Handbook for Systematic Reviews of Interventions.

MAIN RESULTS

We did not identify any studies that met the inclusion criteria.

AUTHORS' CONCLUSIONS

There is no evidence from randomised controlled trials to assess the effectiveness and safety of anticoagulation therapy versus control in patients with isolated subsegmental pulmonary embolism (SSPE) or incidental SSPE. Well-conducted research is required before informed practice decisions can be made.

Is Bedside End-Tidal CO2 Measurement a Screening Tool to Exclude Pulmonary Embolism in Emergency Department?

Background

Pulmonary embolism (PE) is among the most difficult conditions to diagnose in emergency department. The majority of patients thought to have PE are tested positive for D-dimer and subsequently tested with advanced diagnostic modalities. Novel noninvasive tests capable of excluding PE may obviate the need for advanced imaging tests. We studied the role of combined clinical probability assessment and end-tidal carbon dioxide (ETCO₂) measurement for diagnosis of possible PE in emergency department.

Methods

We included 100 consecutive subjects suspected to have PE and a positive D-dimer test to study clinical probability of PE and ETCO₂ levels. ETCO₂ > 34 mm Hg was found to be the best cut-off point for diagnosing PE. PE was ultimately eliminated or diagnosed by spiral computed tomography (CT).

Results

Diagnostic performances of tests were as follows: ETCO₂ and D-dimer had a sensitivity of 100% and a negative predictive value (NPV) of 100% at the cut-off levels of 34 mm Hg and 500 ng/mL, respectively; Wells score had a sensitivity of 80% and NPV of 69.7% at a score of 4.

Conclusions

ETCO₂ alone cannot reliably exclude PE. Combining it with clinical probability, however, reliably and correctly eliminates or diagnoses PE and prevents further testing to be done.

American Society of Hematology 2018 guidelines for management of venous thromboembolism: diagnosis of venous thromboembolism

BACKGROUND

Modern diagnostic strategies for venous thromboembolism (VTE) incorporate pretest probability (PTP; prevalence) assessment. The ability of diagnostic tests to correctly identify or exclude VTE is influenced by VTE prevalence and test accuracy characteristics.

OBJECTIVE

These evidence-based guidelines are intended to support patients, clinicians, and health care professionals in VTE diagnosis. Diagnostic strategies were evaluated for pulmonary embolism (PE), deep vein thrombosis (DVT) of the lower and upper extremity, and recurrent VTE.

METHODS

The American Society of Hematology (ASH) formed a multidisciplinary panel including patient representatives. The McMaster University GRADE Centre completed systematic reviews up to 1 October 2017. The panel prioritized questions and outcomes and used the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach to assess evidence and make recommendations. Test accuracy estimates and VTE population prevalence were used to model expected outcomes in diagnostic pathways. Where modeling was not feasible, management and accuracy studies were used to formulate recommendations.

RESULTS

Ten recommendations are presented, by PTP for patients with suspected PE and lower extremity DVT, and for recurrent VTE and upper extremity DVT.

CONCLUSIONS

For patients at low (unlikely) VTE risk, using D-dimer as the initial test reduces the need for diagnostic imaging. For patients at high (likely) VTE risk, imaging is warranted. For PE diagnosis, ventilation-perfusion scanning and computed tomography pulmonary angiography are the most validated tests, whereas lower or upper extremity DVT diagnosis uses ultrasonography. Research is needed on new diagnostic modalities and to validate clinical decision rules for patients with suspected recurrent VTE.

D-dimer: Preanalytical, analytical, postanalytical variables, and clinical applications

D-dimer is a soluble fibrin degradation product deriving from the plasmin-mediated degradation of cross-linked fibrin. D-dimer can hence be considered a biomarker of activation of coagulation and fibrinolysis, and it is routinely used for ruling out venous thromboembolism (VTE). D-dimer is increasingly used to assess the risk of VTE recurrence and to help define the optimal duration of anticoagulation treatment in patients with VTE, for diagnosing disseminated intravascular coagulation, and for screening medical patients at increased risk of VTE. This review is aimed at (1) revising the definition of D-dimer; (2) discussing preanalytical variables affecting the measurement of D-dimer; (3) reviewing and comparing assay performance and some postanalytical variables (e.g. different units and age-adjusted cutoffs); and (4) discussing the use of D-dimer measurement across different clinical settings.

Time-resolved dynamic computed tomography venography (CTV) of the lower limbs - using ultra-low dosage of contrast media: a case report

Deep vein thrombosis affects approximately 1–2 per 1000 individuals each year. We present an alternative imaging option for detecting deep vein thrombosis in the lower legs using time-resolved dynamic computed tomography venography with ultra-low contrast medium dosage.

Independent and incremental value of ventilation/perfusion PET/CT and CT pulmonary angiography for pulmonary embolism diagnosis: results of the PECAN pilot study

PURPOSE

This pilot study assessed the independent and incremental value of ⁶⁸Ga-V/Q PET/CT as compared with CT pulmonary angiography (CTPA) for the management of cancer patients with suspected acute pulmonary embolism (PE).

METHODS

All 24 cancer patients with suspected acute PE prospectively recruited underwent both ⁶⁸Ga-V/Q PET/CT and CTPA within 24 h. PET/CT was acquired after inhalation of Galligas prepared using a Technegas generator and administration of ⁶⁸Ga-macroaggregated albumin. Initially, PET/CT and CTPA scans were read independently with the reader blinded to the results of the other imaging study. CTPA and PET/CT were then coregistered and reviewed by consensus between a radiologist and nuclear medicine physician. The therapeutic management was established by the managing physician based on all available data.

RESULTS

The diagnostic conclusion was concordantly negative in 18 patients (75%). Of the six discordant diagnoses on independent reading, combined interpretation of V/Q PET/CTPA enabled a consensus conclusion in two patients, excluding PE in one and confirming PE in the other, similar to the initial diagnostic conclusion of the V/Q PET/CT. Of the remaining four patients, three had a single subsegmental thrombus on CTPA but a negative V/Q PET/CT scan, and two of these did not receive long-term anticoagulation and did not have a venous thromboembolic event during a 3-year follow-up period. The third patient, along with a patient with a positive V/Q PET/CT scan but a negative CTPA scan, presented with acute complications preventing any conclusions with regard to the appropriateness of the V/Q PET/CT results in the management of PE. Overall, V/Q PET had an impact on management in four patients (17%).

CONCLUSION

In this pilot study, we demonstrated the feasibility and potential utility of V/Q PET/CT for the management of patients with suspected PE. V/Q PET/CT may be of particular relevance in patients with equivocal findings or isolated subsegmental findings on CTPA, adding further discriminatory information to allow important decision-making regarding the use or withholding of anticoagulation. Given the other advantages of V/Q PET/CT (reduced acquisition time, low radiation dose), and with the increasing availability of ⁶⁸Ga generators, PET/CT is a potential replacement for V/Q SPECT/CT imaging.

[Diagnosis of pulmonary embolism]

The diagnosis of pulmonary embolism (PE) is nowadays based on the sequential use of several diagnostic tests rather than on a single test. These diagnostic strategies are safe and have been prospectively validated. The first step after identifying patients with suspicion of PE is to establish the pre-test clinical probability. Several scores are available in order to make a standardised and reproducible assessment of the clinical probability, and therefore represent precious diagnostic tools. Indeed, clinical probability guides further investigations. Indeed, in patients with a low or an intermediate clinical probability or an "unlikely" probability, PE can be safely ruled out by negative D-dimers in approximately one third of outpatients without additional imaging. In case of positive D-dimers and a high clinical probability or a "likely" clinical probability, CT pulmonary angiography is now the recommended imaging technique. However, lower limb venous compression ultrasound and ventilation/perfusion scans remain useful in patients with contra-indications to CT, mainly those with renal insufficiency. Finally, some novel diagnostic tests seem promising. For example, V/Q SPECT has arisen as a highly accurate test and a potential alternative to CTPA. However, prospective management outcome studies are still lacking and are warranted before its implementation in routine clinical practice.

A Study of Risk Factors of Chronic Venous Insufficiency and its Association with Features Suggestive of Preceding or Present Deep Venous Thrombosis

Background:

Deep venous thrombosis (DVT), even though resolved, may damage the valves and may lead to chronic venous insufficiency (CVI). We designed the present study to examine the thrombotic markers or other ultrasound features in the absence of active thrombosis in patients presenting with features suggestive of CVI.

Materials and Methods:

It was a cross-sectional study of 50 DVT patients. We collected a detailed history of presenting symptoms (onset, progression, and duration) and associated history of aggravating factors. After classifying the patients, color Doppler investigation for DVT and venous incompetence and blood investigations such as Factor V, D-Dimer, total cholesterol, total triglycerides, homocysteine, high-density lipoproteins, low-density lipoproteins (LDL), and very LDL were done.

Results:

We found a raised Factor V significantly more in patients classified as severe under clinical classification compared with nonsevere (19% and 0%; P = 0.05) and in patients with a high Venous Severity Clinical Score (VSCS) compared to those with a low VSCS score (17% and 0%; P = 0.03). We also found that perforators were significantly more in patients with a high VSCS score (88% and 58%; P = 0.02), in patients with a primary venous etiology compared with those without any venous etiology (97% and 1%; P < 0.0001), in patients with obstruction/reflux compared to those without any pathology (95% and 0%; P < 0.0001), and in patients with severe clinical classification compared with nonsevere patient (95% and 55%; P = 0.002).

Conclusions:

Clinical or subclinical DVT, an important cause of CVI, may not always be seen on ultrasound, especially after resolution. However, they may have the presence of blood parameters (Factor V and hyperhomocysteinemia) suggestive of DVT; these can be used as proxy markers for the current or previous DVT.

Safety of D-dimer testing as a stand-alone test for the exclusion of deep vein thrombosis as compared with other strategies

Essentials The aim of deep vein thrombosis (DVT) diagnostic work-up is to maximize both safety and efficiency. We explored whether D-dimer is safe and efficient as a stand-alone test to exclude DVT. Our findings suggest it is a safe, efficient and simplified diagnostic strategy. The safety of age-adjusted D-dimer as a stand-alone test requires further investigation. SUMMARY: Background Several strategies for safely excluding deep vein thrombosis (DVT) while limiting the number of imaging tests have been explored. Objectives To determine whether D-dimer testing could safely and efficiently exclude DVT as a stand-alone test, and evaluate its performance as compared with strategies that incorporate the Wells score and age-adjusted D-dimer. Patients/Methods We included consecutive outpatients referred with suspected DVT to the Emergency Department at Østfold Hospital, Norway. STA-Liatest D-Di PLUS D-dimer was analyzed for all patients. Patients with a D-dimer level of ≥ 0.5 μg mL-1 were referred for compression ultrasonography (CUS). In patients with a D-dimer level of < 0.5 μg mL-1 , no further testing was performed and anticoagulation was withheld. Patients were followed for 3 months for venous thromboembolism (VTE). Results Of the 913 included patients, 298 (33%) had a negative D-dimer result. One hundred and seventy-three patients (18.9%) were diagnosed with DVT at baseline. One of 298 patients had DVT despite having a negative D-dimer result, resulting in a failure rate of 0.3% (95% confidence interval [CI] 0.1-1.9%). Adding the modified Wells score would have yielded a failure rate of 0.0% (95% CI 0.0-1.8%) while necessitating 87 more CUS examinations. Age-adjusted D-dimer as a stand-alone test would have necessitated 80 fewer CUS examinations than fixed D-dimer as a stand-alone test, at the cost of a failure rate of 1.6% (95% CI 0.7-3.4%). Conclusions This outcome study shows that a negative high-sensitivity D-dimer result safely excludes DVT in an outpatient population, and necessitates fewer CUS than if used in combination with Wells score. The safety of stand-alone age-adjusted D-dimer needs further assessment in prospective outcome studies.

Long-Term Experience With a Mandatory Clinical Decision Rule and Mandatory d-Dimer in the Evaluation of Suspected Pulmonary Embolism

PURPOSE

This study evaluated the long-term effectiveness of mandatory assignment of both a clinical decision rule (CDR) and highly sensitive d-dimer in the evaluation of patients with suspected pulmonary embolism (PE).

MATERIALS AND METHODS

Institutional guidelines with a CDR and highly sensitive d-dimer were embedded in an order entry menu with mandatory assignment of key components before ordering a CT pulmonary angiogram (CTPA). Data were retrospectively extracted from the electronic health record.

RESULTS

This was a retrospective review of 1,003 CTPA studies (905 patients, 845 male and 60 female patients, age 63.7 ± 13.5 years). CTPAs were positive for PE in 170 studies (17%), representing an average yield of 15% (year [average]; 2007 [15%], 2008 [18%], 2009 [15%], 2010 [15%], 2011 [17%], 2012 [15%], 2013 [23%]). The increased yield represented efforts of mandatory order entry assignments, educational sessions, and clinical champions. Different d-dimer thresholds with or without age adjustments in combination with the CDR identified about 10% of patients who may have been managed without CTPA.

CONCLUSION

Mandatory assignment of a CDR and highly sensitive d-dimer clinical decision pathway can be successfully incorporated into an order entry menu and produce a sustained increase in CTPA yield of patients with suspected PE.