Ultrasound for Lower Extremity Deep Venous Thrombosis

Where There's Smoke, There's Fire: A Case Report of Turbulent Blood Flow in Lower Extremity Point-of-care Ultrasound in COVID-19

INTRODUCTION

Coronavirus disease 2019 (COVID-19) may predispose patients to increased risk of venous thromboembolism (VTE) due to various pathophysiological mechanisms, including but not limited to endothelial injury, inflammation, cytokine-mediated microvascular damage, and reactive thrombocytosis. A high risk of vessel thrombosis correlates with disease severity, making early identification and treatment of prime consideration.Although identification of a deep venous thrombosis (DVT) or pulmonary embolism warrants immediate treatment with anticoagulation, trying to predict which COVID-19 patients may be at increased risk for developing these pathologies is challenging.

CASE REPORTS

We present two cases of patients with COVID-19 who had ultrasonographic findings of turbulent blood flow within the deep venous system, without clear evidence of acute proximal DVT, who were subsequently found to have significant VTE.

CONCLUSION

Point-of-care lower extremity ultrasound has become one of the core applications used by emergency physicians. Typically we perform compression ultrasound for DVT evaluation. This novel finding of turbulent blood flow, or "smoke," within the deep venous system, may serve as a marker of increased risk of clot development and could be an indication to consider early anticoagulation.

Prevalence and Predictors of Venous Thromboembolism or Mortality in Hospitalized COVID-19 Patients

BACKGROUND

 We aimed to identify the prevalence and predictors of venous thromboembolism (VTE) or mortality in hospitalized coronavirus disease 2019 (COVID-19) patients.

METHODS

 A retrospective cohort study of hospitalized adult patients admitted to an integrated health care network in the New York metropolitan region between March 1, 2020 and April 27, 2020. The final analysis included 9,407 patients with an overall VTE rate of 2.9% (2.4% in the medical ward and 4.9% in the intensive care unit [ICU]) and a VTE or mortality rate of 26.1%. Most patients received prophylactic-dose thromboprophylaxis. Multivariable analysis showed significantly reduced VTE or mortality with Black race, history of hypertension, angiotensin converting enzyme/angiotensin receptor blocker use, and initial prophylactic anticoagulation. It also showed significantly increased VTE or mortality with age 60 years or greater, Charlson Comorbidity Index (CCI) of 3 or greater, patients on Medicare, history of heart failure, history of cerebrovascular disease, body mass index greater than 35, steroid use, antirheumatologic medication use, hydroxychloroquine use, maximum D-dimer four times or greater than the upper limit of normal (ULN), ICU level of care, increasing creatinine, and decreasing platelet counts.

CONCLUSION

 In our large cohort of hospitalized COVID-19 patients, the overall in-hospital VTE rate was 2.9% (4.9% in the ICU) and a VTE or mortality rate of 26.1%. Key predictors of VTE or mortality included advanced age, increasing CCI, history of cardiovascular disease, ICU level of care, and elevated maximum D-dimer with a cutoff at least four times the ULN. Use of prophylactic-dose anticoagulation but not treatment-dose anticoagulation was associated with reduced VTE or mortality.

Point-of-Care Ultrasound (POCUS) for the Cardiothoracic Anesthesiologist

Point-of-Care Ultrasound (POCUS) is a valuable bedside diagnostic tool for a variety of expeditious clinical assessments or as guidance for a multitude of acute care procedures. Varying aspects of nearly all organ systems can be evaluated using POCUS and, with the increasing availability of affordable ultrasound systems over the past decade, many now refer to POCUS as the 21^st-century stethoscope. With the current available and growing evidence for the clinical value of POCUS, its utility across the perioperative arena adds enormous benefit to clinical decision-making. Cardiothoracic anesthesiologists routinely have used portable ultrasound systems for nearly as long as the technology has been available, making POCUS applications a natural extension of existing cardiothoracic anesthesia practice. This narrative review presents a broad discussion of the utility of POCUS for the cardiothoracic anesthesiologist in varying perioperative contexts, including the preoperative clinic, the operating room (OR), intensive care unit (ICU), and others. Furthermore, POCUS-related education, competence, and certification are addressed.

Pathophysiological Processes Underlying the High Prevalence of Deep Vein Thrombosis in Critically Ill COVID-19 Patients

Coronavirus disease 2019 (COVID-19) predisposes to deep vein thrombosis (DVT) and pulmonary embolism (PE) particularly in mechanically ventilated adults with severe pneumonia. The extremely high prevalence of DVT in the COVID-19 patients hospitalized in the intensive care unit (ICU) has been established between 25 and 84% based on studies including systematic duplex ultrasound of the lower limbs when prophylactic anticoagulation was systematically administrated. DVT prevalence has been shown to be markedly higher than in mechanically ventilated influenza patients (6-8%). Unusually high inflammatory and prothrombotic phenotype represents a striking feature of COVID-19 patients, as reflected by markedly elevated reactive protein C, fibrinogen, interleukin 6, von Willebrand factor, and factor VIII. Moreover, in critically ill patients, venous stasis has been associated with the prothrombotic phenotype attributed to COVID-19, which increases the risk of thrombosis. Venous stasis results among others from immobilization under muscular paralysis, mechanical ventilation with high positive end-expiratory pressure, and pulmonary microvascular network injuries or occlusions. Venous return to the heart is subsequently decreased with increase in central and peripheral venous pressures, marked proximal and distal veins dilation, and drops in venous blood flow velocities, leading to a spontaneous contrast "sludge pattern" in veins considered as prothrombotic. Together with endothelial lesions and hypercoagulability status, venous stasis completes the Virchow triad and considerably increases the prevalence of DVT and PE in critically ill COVID-19 patients, therefore raising questions regarding the optimal doses for thromboprophylaxis during ICU stay.

Agreement between emergency physicians and radiologists for the diagnosis of deep venous thrombosis with compression ultrasound: a prospective study

INTRODUCTION

The time factor in diagnosis and management of a deep vein thrombosis of the lower extremities (LE DVT) is of increasing importance in the era of crowding of emergency departments (ED). Current techniques used to detect LE DVT include a two-point regional compression ultrasound (rCUS), yet assessments are usually performed only during office hours. Outside office hours ultrasonography is postponed and low molecular weight heparin (LMWH) prescribed.

OBJECTIVES

Primary outcome of the study was to assess the level of agreement in rCUS for LE DVT when performed by Dutch emergency physicians compared to rCUS by a radiologist. Secondary outcome was time to diagnosis.

METHOD

We performed a single-blind cohort study. All consecutive patients aged 18 years and older attending the ED with clinical suspicion of LE DVT were considered eligible for study enrolment. rCUS was ordered at the radiology department; subsequently, the bedside rCUS examination was also performed in the ED by the emergency physicians or ED residents.

RESULTS

A total of 138 patients were included, of whom 28 patients were diagnosed with DVT by a radiologist. Emergency physicians and radiologists showed comparable agreement [absolute agreement 94% (P < 0.001), Cohen's Kappa 0.87]. Emergency physicians decreased overall time to diagnosis by 01:04 h, ED residents showed comparable results. During out-of-office hours, time benefit was 16:39 h on weekdays and 18:40 h during weekends.

CONCLUSION

Emergency physicians show comparable agreement in diagnosing LE DVT using rCUS when compared to radiologists. Average time benefit is over an hour, thereby reducing unnecessary waiting and improving time to disposition. ED residents demonstrated similar results in both agreement and time-saving.

Prevalence and predictors of alternative diagnoses on whole-leg ultrasound negative for acute deep venous thrombosis

Background

To investigate the prevalence, spectrum, and predictors of alternative diagnoses explaining leg symptoms in patients negative for suspected acute deep venous thrombosis (DVT), which can be detected with whole-leg ultrasound.

Methods

We retrospectively analyzed a cohort of 789 patients (median age 70 years, 50.6% women) evaluated with a whole-leg ultrasound examination for suspected acute DVT within one year. All findings in the radiology report were analyzed and electronic chart review was performed to collect clinical information.

Results

Ultrasound was negative for acute DVT in 531 patients (67.3%). Among these, alternative diagnoses explaining leg symptoms were seen in 349 patients (65.7%). The most frequent alternative diagnoses were chronic venous insufficiency (147 patients, 27.7%), followed by lymphedema (48 patients, 9.0%) and chronic post-thrombotic changes (41 patients, 7.7%). Patients with alternative diagnoses were older (median 71 vs. 66 years, p = 0.0226), as well as more likely to present with leg swelling (39.5% vs. 23.1%, p = 0.0002), difference in leg circumference (25.5% vs. 14.8%, p = 0.0055) and redness (7.7% vs. 2.7%, p = 0.0213) than patients without alternative diagnosis. Independent predictors of finding alternative diagnoses on whole-leg ultrasound were older age (odds ratio 1.014 per year, p = 0.0119), leg swelling (OR 1.949, p = 0.0020) and history of previous DVT (OR 2.235, p = 0.0154).

Conclusions

Alternative diagnoses explaining leg symptoms can be detected on whole-leg ultrasound in two thirds of patients with no evidence of acute DVT. Our data supports performing a comprehensive ultrasound evaluation beyond the venous system, particularly, in older patients, who present with leg swelling and a past history of DVT.

Diagnosis and Treatment of Lower Extremity Venous Thromboembolism: A Review

IMPORTANCE

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

OBSERVATIONS

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

CONCLUSIONS AND RELEVANCE

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

Prevalence of asymptomatic deep vein thrombosis in patients hospitalized with SARS-CoV-2 pneumonia: a cross-sectional study

The association between coronavirus disease 2019 (COVID-19) pneumonia and venous thrombotic disorders is still unclear. We assessed the association between COVID-19 infection-related pneumonia and proximal deep-vein thrombosis (DVT) in a cohort of patients admitted to our hospital during the European outbreak in the front line of Cremona, Lombardy. In a single-center cross-sectional study, all patients hospitalized for more than 5 days in Internal Medicine Department with confirmed COVID-19 pneumonia received 2-point compressive ultrasound assessment (CUS) of the leg vein system during a single day. Ninety-four percent of patients received enoxaparin as standard pharmacological prophylaxis for venous thromboembolism. The presence of DVT was defined as incompressibility of popliteal or common femoral vein. Out of 121 patients with COVID-19 pneumonia (mean age 71.8, 66.3% males) hospitalized on March 31st, 70 stayed in hospital for over 5 days and 66 of them underwent CUS of deep venous system of the legs. The presence of asymptomatic DVT was found in 9 patients (13.6%). No symptomatic DVT was found. Patients with DVT showed mean age = 75.7 years, mean D-dimer levels = 4.02 ng/ml and all of them received enoxaparin for thromboprophylaxis, except one. Computed tomography pulmonary angiogram confirmed pulmonary embolism in five patients. One every seven patients with COVID-19-related pneumonia, hospitalized for more than 5 days, had asymptomatic proximal DVT and half of them had confirmed PE despite standard pharmacological thromboprophylaxis. This observational study suggests the need of an active surveillance through CUS in patients hospitalized with acute SARS-COV-2 and underline the need of a more intense thromboprophylaxis.

Current Challenges in Diagnosis of Venous Thromboembolism

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

Dating thrombus organization with eosinophil counts in deep venous thrombosis

OBJECTIVE

It is known that eosinophils (EOS) are essential for thrombus formation. Studies have demonstrated the association of EOS with coronary artery disease, stent thrombosis, coronary collateral development, and vasospastic angina. However, there is little data about the association of hemogram parameters, especially EOS counts, with deep venous thrombosis (DVT) subgroups.

METHODS

The present study comprised 243 patients diagnosed with DVT (of whom 86 were acute, 72 were indeterminate, and 85 were chronic) and 75 control patients. Medical records of all the patients were reviewed, and relevant data were collected retrospectively. The baseline characteristics, as well as hemogram and biochemistry parameters, were recorded.

RESULTS

The patients with DVT had significantly lower median EOS count yet higher median neutrophil to lymphocyte ratio (NLR) than those of control patients (P < .001). Similarly, acute DVT patients had lower EOS count yet higher NLR values compared with those of indeterminate and chronic DVT patients. However, EOS count was not significantly different between chronic DVT and control groups. While NLR ratio was significantly correlated with acute DVT (r = 0.34; P < .001), Spearman's correlation test revealed that EOS count was inversely correlated with the presence of acute DVT (r = -0.52; P < .001).

CONCLUSIONS

Low EOS count may lead the physician to a higher probability of acute DVT rather than indeterminate and chronic DVT.

Prevention of venous thromboembolic events occurring in myeloma patients treated with second-generation novel agents

Thrombosis and neoplasms are strictly linked, and the diagnosis of a malignancy is a relevant risk factor for venous thromboembolism (VTE). In particular, between gammopathies, the VTE risk is known to be increased in both monoclonal gammopathy of uncertain significance and in multiple myeloma, with a 3- and 9-fold increase respectively, when compared to the general population. The risk appears to be further increased in patients treated with immunomodulating drugs, such as thalidomide, especially when in combination with dexamethasone or conventional cytotoxic chemotherapies, and lenalidomide. In 2008 the International Myeloma Working Group put out thrombosis prophylaxis recommendations for myeloma patients treated with IMiDs. Current recommendations for thromboprophylaxis suggest the use of low-dose acetylsalicylic acid in patients with low risk for thrombosis and therapeutic dose anticoagulation with LMWH or warfarin for high-risk patients. However, these recommendations have been frequently not followed in the clinical practice, due to various reasons that involve the patients' will, the level of evidence of the recommendations and some selection biases in the studies that were taken as basis for writing down the indications. The new direct oral anticoagulants have been preliminarily evaluated for the prophylaxis of thrombotic events in IMiDs-treated myelomas, being promising, even if more expensive. Currently, the most reliable tool for a correct thrombotic risk stratification appears to be the complete clinical and anamnestic evaluation of the myeloma patients added to a strong physician awareness of the evidences that the literature contains until now.

Deep vein thrombosis in noncritically ill patients with coronavirus disease 2019 pneumonia: deep vein thrombosis in nonintensive care unit patients

Background

Venous thromboembolic events have been one of the main causes of mortality among hospitalized patients with coronavirus disease 2019 (COVID-19) pneumonia. The aim of our study was to describe the prevalence of deep vein thrombosis (DVT) in noncritically ill patients with COVID-19 pneumonia and correlate such observations with the thromboprophylaxis received.

Methods

We performed a prospective cohort study of 67 patients admitted to the hospital for COVID-19 pneumonia. The diagnosis was confirmed using polymerase chain reaction testing of nasopharyngeal specimens. The deep veins were examined using compression duplex ultrasonography with the transducer on B-mode. The patients were separated into two groups for statistical analysis: those receiving low-molecular-weight heparin prophylaxis and those receiving intermediate or complete anticoagulation treatment. Risk analysis and logistic regression were performed.

Results

Of the 67 patients, 57 were included in the present study after applying the inclusion and exclusion criteria; 49.1% were women, and the patient mean age was 71.3 years. All 57 patients had undergone compression duplex ultrasonography. Of these 57 patients, 6 were diagnosed with DVT, for an in-hospital rate of DVT in patients with COVID-19 pneumonia of 10.5%. All the patients who had presented with DVT had been receiving low-molecular-weight heparin prophylaxis. The patients receiving prophylactic anticoagulation treatment had a greater risk of DVT (16.21%; 95% confidence interval, 0.04-0.28; P = .056) compared with those receiving intermediate or complete anticoagulation treatment. We also found a protective factor for DVT in the intermediate or complete anticoagulation treatment group (odds ratio, 0.19; 95% confidence interval, 0.08-0.46; P < .05).

Conclusions

Noncritically ill, hospitalized patients with COVID-19 pneumonia have a high risk of DVT despite receipt of correct, standard thromboprophylaxis.

A Real-Life Survey of Venous Thromboembolic Events Occurring in Myeloma Patients Treated in Third Line with Second-Generation Novel Agents

Compared to the general population, patients with multiple myeloma (MM) have a nine-fold increased risk of developing venous thromboembolism (VTE). Little is known about VTE prophylaxis in relapsed/refractory (RR) MM patients treated with next generation anti-myeloma drugs, such as pomalidomide (Poma) and carfilzomib (K), and monoclonal antibodies daratumumab (Dara) and elotuzumab (Elo), alone or in combination with dexamethasone at high- (D, 40 mg/week) or low-dose (d, 20 mg/week). Here, we describe the incidence of VTE in a retrospective cohort of 112 consecutive relapsed and refractory myeloma (RRMM) patients who received a third line of treatment from April 2013 to February 2020. Anti-MM regimens included combinations of pomalidomide and dexamethasone (PomaD, N = 61), carfilzomib, lenalidomide and dexamethasone (KRd, N = 31), and elotuzumab, lenalidomide and dexamethasone (EloRd, N = 10), while the remaining 10 patients received daratumumab as a single agent. According to National Comprehnsive Cancer Network (NCCN), International Myeloma Working Group (IMWG) and 2015 European Myeloma Network (EMN) guidelines, 42 patients (38%) were classified as high-risk patients. According to the IMPEDE VTE score, 32 patients (28%) were classified as low-risk, with a score ≤ 3 (most of them in the PomaD and Dara group), 70 (63%) were classified as intermediate-risk, with a score of 4–7 (most of them in PomaD and KRd group), and 10 (9%) were classified as high-risk, with a score ≥8 (most of them in the PomaD group). All patients received a prophylaxis, consisting generally of low-doses of acetylsalicylic acid. VTE was recorded in 9% of our patients, all of them with an intermediate or high-risk IMPEDE score, treated with low doses aspirin (ASA). No VTE occurred in patients treated with daratumumab. Thus, our real-life experience documents that (1) in RRMM patients treated with continuative regimens of third line, the incidence of VTE is similar to the setting of newly-diagnosed patients; (2) many patients in real-life received prophylaxis with ASA, irrespective of the risk classification; (3) the IMPEDE VTE score seems to be more appropriate to define the risk categories. Randomized clinical trials are required to better define the VTE prophylaxis strategy in the RRMM setting.

In Well-Selected Patients With a Femoral Deep Vein Thrombosis Central Venous Imaging May Identify Additional Iliocaval Disease

OBJECTIVE

Patients who present acutely with a femoral deep vein thrombosis (DVT) diagnosed by ultrasound are often treated with anticoagulation and instructed to follow-up electively. This study sought to assess whether obtaining axial imaging of the central venous system results in the identification of additional iliocaval pathology warranting treatment.

METHODS

This study was a retrospective review of a prospectively maintained registry from November 2014 through April 2017 with follow-up through March 2020. Consecutive patients with a diagnosis of femoral DVT diagnosed by ultrasound were evaluated; those who underwent axial imaging of the iliocaval system (Group A) were compared to those who did not undergo imaging of the central veins (Group B). The primary outcome was the performance of any percutaneous central venous intervention. Secondary outcomes included the extent of DVT identified on duplex and after axial imaging, follow-up duplex patency and persistence of severe symptoms.

RESULTS

Eighty patients presented with an ultrasound diagnosis of a femoral vein DVT. Mean follow-up was 551 ± 502 days. Group A comprised 24 patients (30%) and Group B comprised 56 patients (70%). Baseline demographics did not differ significantly between the 2 groups. After duplex imaging, Group A exhibited an increased prevalence of DVT in the common femoral vein. After central imaging, Group A exhibited an increased prevalence of DVT in the iliocaval veins. The number of patients who underwent invasive treatment differed significantly between the 2 groups, Group A 16/24 (67%) vs. Group B 9/56 (16%), P < 0.0001. The number of patients that demonstrated duplex patency and had persistent symptoms on follow-up did not differ significantly.

CONCLUSIONS

Patients with an ultrasound diagnosis of femoral DVT may have additional iliocaval pathology warranting intervention. Well-selected imaging of the central veins may reveal a more complete picture, potentially altering management.

Calf deep vein thrombosis – clinical relevance, diagnostic approaches and therapeutic options

Summary. Isolated distal deep vein thromboses (IDDVT) represent up to 50 % of legs deep vein thromboses (DVT). However, since their natural history is to date unknown, the need to diagnose and treat them is a matter of debate. The diagnostic strategy based on the assessment of pre-test probability and D-dimer demonstrated a scarse efficiency for IDDVT. The choice between a proximal and a complete ultrasonographic approach should be guided by the clinical context, the local expertise and the patient characteristics. Randomized and observational studies have analyzed the need of therapy and compared different regimens of anticoagulation, with conflicting results. Systematic reviews and meta-analyses tend to support the usefulness of an anticoagulant treatment, even if the optimal dose and duration are not still defined. A careful stratification of the patient’s profile, taking into account risk factors for proximal extension, recurrence and bleeding should address the therapeutic approach, which must always be discussed with an adequately informed patient. Further studies aimed to clarify the natural history of IDDVT, and to assess safety and efficacy of lower intensity and shorter duration protocols are urgently needed.

Evaluation of stability of deep venous thrombosis of the lower extremities using Doppler ultrasound

Objective

This study aimed to assess using Doppler ultrasound for analyzing stability of deep venous thrombosis (DVT) of the lower extremities.

Methods

Patients with DVT of the lower extremities who were treated from August 2017 to December 2019 were selected. The patients were divided into stable and unstable groups according to whether thrombus was collected in a filter. Related ultrasound and blood test results were analyzed and compared.

Results

A total of 126 patients with DVT of the lower extremities were included, of whom 74 were in the stable group and 52 were in the unstable group. There were significant differences in the prothrombin time (PT), and lipoprotein alpha, D-dimer, and triglyceride levels between the groups. D-dimer levels >2800 ug/L, smoking, history of venous thrombosis, PT >13.15 s, and body mass index >24.45 kg/m² were independent risk factors for stability of DVT of the lower extremities. The area under the curve with combined detection of DVT was significantly higher than that for body mass index, PT, and D-dimer alone.

Conclusion

Doppler ultrasound may be reliable for analyzing the stability of DVT of the lower extremities. Related strategies targeting risk factors are required for reducing DVT of the lower extremities.

An RGD modified water-soluble fluorophore probe for in vivo NIR-II imaging of thrombosis

Venous thrombosis leads to severe symptoms and death through pulmonary embolism. There is a great need for high sensitivity imaging methods to identify acute patients who would benefit from thrombolysis. We designed a novel, organic near-infrared second-window (NIR-II) probe, which targets the glycoprotein IIb/IIIa receptor (GPIIb/IIIa) on activated platelets. The probe's structure was characterized by MALDI-TOF-MS, TEM, UV-visible absorption and NIR-II fluorescent spectroscopy. The probe's specificity for activated platelets was investigated in vitro and in vivo. Thrombosis in mice was induced by administration of FeCl₃ in the external jugular vein and imaged by using a NIR-II imager. The donor-acceptor-donor fluorescent core TTQ was prepared from donor and acceptor units. TTQ-PEG-NH₂ was synthesized by sequential modification of PEGylated TTQ, followed by c(RGD) condensation. Signal strength was continuously monitored for 24 h following TTQ-PEG-c(RGD) or non-specific fluorescent dye injection. The contralateral external jugular vein, sham surgery and a competitive inhibition experiment served as controls. TTQ-PEG-c(RGD) presented high NIR-II intensity, good stability and excellent affinity for activated platelets. The NIR-II fluorescence signal of TTQ-PEG-c(RGD) injected mice significantly increased at the thrombus site and peaked at 4 h, whereas there was no significant change in the control mice, and the competitive inhibition of the RGD antagonist suppressed the enhancement of the NIR-II fluorescence signal. Comparison between fresh and old thrombi confirmed that TTQ-PEG-c(RGD) could be used to distinguish a fresh thrombus from an old thrombus. TTQ-PEG-c(RGD) can specifically target thrombosis in vitro and in vivo, providing a potential tool for noninvasive diagnosis of early thrombi.

Non-contrast-enhanced magnetic resonance imaging: Objective figures in differentiation between acute and chronic deep venous thrombosis in the lower extremities

BACKGROUND

Deep vein thrombosis is a severe health problem. Treatment options may differ between acute and chronic deep vein thrombosis. Thus, distinguishing acute from chronic deep vein thrombosis is essential for patients with deep vein thrombosis.Triggered angiography non-contrast enhanced is an innovative magnetic resonance imaging protocol that may provide objective evidence in differentiating acute from chronic deep vein thrombosis.

METHOD

We prospectively collected information on consecutive patients who had been evaluated through triggered angiography non-contrast enhanced magnetic resonance imaging for venous pathology in their lower extremities at a vascular wound care center in a tertiary hospital between April 2017 and January 2020. Patients included were divided into two groups with the onset time cutoff point of 21 days. All were undergone non-contrast-enhanced magnetic resonance imaging evaluation. Non-contrast-enhanced magnetic resonance imaging images were evaluated by a radiologist, and lower extremity venous thrombosis, collateral-vein development, and subcutaneous honeycombing were emphasized. Cohen's kappa coefficient was used to measure interrater agreement between the development of collateral veins, subcutaneous honeycombing, and symptom onset over 21 days.

RESULTS

Interrater agreement analysis revealed that the development of collateral veins was substantially correlated with the onset of symptoms over 21 days (Table 1). Additionally, the development of subcutaneous honeycombing detected through triggered angiography non-contrast enhanced magnetic resonance imaging also substantially agreed with the onset of symptoms over 21 days (Table 2).

CONCLUSION

The diagnostic power of triggered angiography non-contrast enhanced magnetic resonance imaging in deep vein thrombosis is rival to current gold standard, color Doppler sonography. Triggered angiography non-contrast enhanced magnetic resonance imaging provides objective information on onset timing in patients with deep vein thrombosis that could differentiate acute from chronic deep vein thrombosis and provides guidance for treatment planning.

Prediction of deep vein thrombosis by ultrasonography and D-dimer in Asian patients with ischemic stroke

Background

Deep vein thrombosis (DVT) is an important complication of ischemic stroke, although the incidence of DVT is regarded as being lower in Asian than in non-Asian patients. Here, we investigated the incidence and factors associated with DVT in Asian patients with ischemic stroke.

Methods

Acute ischemic stroke patients received lower extremity ultrasonography (LEUS) to diagnose the presence of DVT. Clinical characteristics and laboratory results, including D-dimer level, were compared between patients with and without DVT. Independent risk factors for DVT were investigated using multivariable analysis. Similar analysis was performed to identify factors associated with elevated D-dimer level (> 0.5 mg/dl) in acute ischemic stroke patients.

Results

During the study period, 289 patients were enrolled, and 38 (13.1%) showed DVT. Female sex (OR = 2.579, 95% CI = 1.224–5.432; p = 0.013) and a high National Institutes of Health Stroke Scale (NIHSS) score (OR = 1.191 95% CI = 1.095–1.294; p = 0.005) were independently associated with the presence of DVT, although D-dimer level was not. Stroke mechanism, especially cardioembolic stroke (OR = 3.777, 95% CI = 1.532–9.313; p = 0.004; reference: large artery atherosclerosis), NIHSS score (OR = 1.087, 95% CI = 1.002–1.179; p = 0.001) and thrombolysis (OR = 12.360, 95% CI 2.456–62.213; p = 0.002) were independently associated with elevated abnormal D-dimer levels.

Conclusion

The severity of ischemic stroke, but not the D-dimer level, was associated with the presence of DVT in Asian ischemic stroke patients. D-dimer level was influenced by the stroke mechanism. LEUS in patients with severe neurological deficit, rather than screening with D-dimer, may be more beneficial for diagnosing DVT in Asian patients with acute ischemic stroke.

Diagnosis of deep vein thrombosis

Deep vein thrombosis (DVT) is part of the clinical spectrum of venous thromboembolism disease (VTE), whose estimated annual incidence rate is 1-2 episodes per 1000 individuals and represents the third leading cause of cardiovascular mortality in developed countries. Establishing an accurate diagnosis of DVT is essential for preventing acute complications (such as pulmonary embolism) and chronic complications associated with post-thrombotic syndrome. Currently, there are well-established diagnostic algorithms for lower extremity DVT, which include clinical probability models that help establish the risk of experiencing the disease based on the patients' history, clinical findings, D dimer measurements, fibrin degradation product tests with a high negative predictive value and imaging tests to confirm the diagnosis. Venous compression ultrasonography is currently the technique of choice because it is a non-invasive, easy-to-administer test that can make serial evaluations. There is much accumulated evidence that DVT can be safely ruled out in patients with a low or intermediate clinical probability and a negative D dimer (<500 ng/mL) without performing additional examinations. The consensus is not as clear about the need for a proximal or complete examination of the entire extremity. Other techniques may also be employed, such as magnetic resonance venography and venous phase computed axial tomography, although these should not be a substitute for compression ultrasonography as the initial diagnostic test. There are other special circumstances in which the diagnosis is more problematic and there are no diagnostic algorithms as consolidated, such as DVT during pregnancy, diagnosing rethrombosis and DVT that affects the upper extremities.

Deep Venous Thrombosis in a Patient with a Moderate Pretest Probability and a Negative D-Dimer Test: A Review of the Diagnostic Algorithms

Modern diagnostic strategies of venous thromboembolism (VTE) have been developed. In this review, the diagnostic algorithms for deep-vein thrombosis (DVT) and their parameters are discussed individually in the context of reporting a case of DVT in a 43-year-old Caucasian female with a moderate pretest probability stratified by Wells’ score and a negative high quality D-dimer test. The patient was on treatment with Xarelto (rivaroxaban), 20 mg PO daily at the time of presentation. The diagnosis was verified through a complete lower limb ultrasound (US). This case highlights the diagnostic challenges and pitfalls of the current algorithms, especially those seen in a subgroup of patients such as patients with cancer, pregnancy, recurrent VTE or are on anticoagulation therapy at the time of presentation. The diagnosis of DVT is less plausible in a patient who is on anticoagulation therapy, but physicians should be aware of such a possibility. Physicians should also know in advance the numerous clinically relevant limitations of D-dimer testing before interpreting the results. Unifying the current diagnostic strategies, modifying the current Wells’ score and using the protocol of a whole-leg compression US instead of the limited US protocol are among the several cautious suggestions that have been proposed based on this review to possibly decrease the incidence of missed DVT.

Case Report and Management of Discovery of Lower Extremity Venous Thrombosis on Musculoskeletal Ultrasound

Despite the increasing availability of ultrasound in the ambulatory setting, there has yet to be an established consensus on what constitutes proper diagnosis of a deep vein thrombosis (DVT) using point-of-care ultrasound (POCUS) as well as proper management if one is suspected using this modality. This case report presents the discovery of non-compressible veins during a musculoskeletal (MSK) POCUS examination for a calf injury and explores the current standard of care for the appropriate subsequent steps in the diagnosis and management of suspected lower-extremity (LE) DVT using MSK POCUS.

Predictive Factors of Deep Vein Thrombosis in Gynecologic Cancer Survivors with Lower Extremity Edema: A Single-Center and Retrospective Study

This study was conducted to examine predictive factors of deep vein thrombosis (DVT) in gynecologic cancer survivors with lower extremity edema (LEE). In the current single-center, retrospective study, there was a total of 315 eligible patients, including 80 patients with DVT and 235 without DVT. They were therefore divided into two groups: the DVT group (n = 80) and the non-DVT group (n = 235). Then, baseline and clinical characteristics of the patients were compared between the two groups. In our study, distant organ metastasis, advanced stage, lymphadectomy, and amount of intraoperative blood loss had a positive predictive value for the occurrence of DVT in gynecologic cancer survivors presenting LEE. In conclusion, our results indicate that it is necessary to consider the possibility of LEE arising from DVT in gynecologic cancer survivors with advanced-stage cancer, distant organ metastasis, lymphadectomy, and intraoperative blood loss over 1500 mL.

Diagnostic accuracy of three ultrasonography strategies for deep vein thrombosis of the lower extremity: A systematic review and meta-analysis

Background

Compression ultrasonography (CUS) is the first-line imaging test in the diagnostic management of suspected deep vein thrombosis (DVT) of the lower extremity. Three CUS strategies are used in clinical practice. However, their relative diagnostic accuracy is uncertain.

Objectives

This systematic review and meta-analysis aimed to summarize and compare the diagnostic accuracy of single limited, serial limited, and whole-leg CUS for DVT.

Methods

MEDLINE, Embase, and CENTRAL were searched from January 1^st, 1989 to July 23^rd, 2019 for studies assessing at least one of the CUS strategies in adults with suspected DVT of the lower extremity, using clinical follow-up for venous thromboembolism or contrast venography as the reference standard. Study selection, data extraction, and risk of bias assessment were performed in duplicate by independent authors. A bivariate random-effects model was used to compute diagnostic accuracy summary estimates.

Results

Forty studies (n = 21,250) were included. The venous thromboembolic event rate after a negative CUS (failure rate) of single limited (1.4%; 95% CI, 0.83–2.5), serial limited (1.9%; 95% CI, 1.4–2.5), and whole-leg CUS (1.0%; 95% CI, 0.6–1.6) did not differ significantly. The proportion of positive results was lower with single limited CUS, as was DVT prevalence in this group.

Conclusions

The failure rates of single limited, serial limited, and whole-leg CUS for DVT appeared to be quite comparable. The relative failure rate of single limited CUS remains uncertain, as the DVT prevalence was lower in these studies. Therefore, this CUS strategy may only be safe in a selected group of low-risk patients. Preference for one of the strategies may be based on pretest probability assessment, feasibility, expertise, and perceived clinical relevance of isolated distal DVT.

Research quality in the study of mechanical methods of deep vein thrombosis prophylaxis

There is a lack of good-quality recent clinical data to support the use of mechanical methods to prevent deep vein thrombosis. Recommendations and meta-analyses have to rely on old data from evaluations of devices that are no longer available, with diagnostic methods that are obsolete. The aim of this narrative review is to examine the reasons why better recent evidence is not available, and how this will affect innovation in mechanical deep vein thrombosis prophylaxis. Analysis of recent published trials shows great variability in techniques and technologies, which complicates evaluation of the effectiveness of properties of intermittent pneumatic compression, graduated compression stockings, and electrical stimulation devices. Negative controlled trials have become difficult to conduct, and low rates of deep vein thrombosis have left many comparative trials of devices underpowered. There is a risk that if new approaches to enable clinical research are not developed that technological advancement of mechanical prophylaxis will be inhibited.

Can emergency physicians perform extended compression ultrasound for the diagnosis of lower extremity deep vein thrombosis?

BACKGROUND

Current point-of-care ultrasound protocols in the evaluation of lower extremity deep vein thrombosis (DVT) can miss isolated femoral vein clots. Extended compression ultrasound (ECUS) includes evaluation of the femoral vein from the femoral vein/deep femoral vein bifurcation to the adductor canal. Our objective is to determine if emergency physicians (EPs) can learn ECUS for lower extremity DVT evaluation after a focused training session.

METHODS

Prospective study at an urban academic center. Participants with varied ultrasound experience received instruction in ECUS prior to evaluation. Two live models with varied levels of difficult sonographic anatomy were intentionally chosen for the evaluation. Each participant scanned both models. Pre- and post-study surveys were completed.

RESULTS

A total of 96 ultrasound examinations were performed by 48 participants (11 attendings and 37 residents). Participants' assessment scores averaged 95.8% (95% CI 93.3%-98.3%) on the easier anatomy live model and averaged 92.3% (95% CI 88.4%-96.2%) on the difficult anatomy model. There were no statistically significant differences between attendings and residents. On the model with easier anatomy, all but 1 participant identified and compressed the proximal femoral vein successfully, and all participants identified and compressed the mid and distal femoral vein. With the difficult anatomy, 97.9% (95% CI 93.8%-102%) identified and compressed the proximal femoral vein, whereas 93.8% (95% CI 86.9%-100.6%) identified and compressed the mid femoral vein, and 91.7% (95% CI 83.9%-99.5%) identified and compressed the distal femoral vein.

CONCLUSION

EPs at our institution were able to perform ECUS with good reproducibility after a focused training session.

Global guidelines trends and controversies in lower limb venous and lymphatic disease: Narrative literature revision and experts' opinions following the vWINter international meeting in Phlebology, Lymphology & Aesthetics, 23-25 January 2019

Guidelines are fundamental in addressing everyday clinical indications and in reporting the current evidence-based data of related scientific investigations. At the same time, a spatial and temporal issue can limit their value. Indeed, variability in the recommendations can be found both among the same nation different scientific societies and among different nations/continents. On the other side, Garcia already published in 2014 data showing how, after three years in average, one out of five recommendations gets outdated (Martinez Garcia LM, Sanabria AJ, Garcia Alvarez E, et al. The validity of recommendations from clinical guidelines: a survival analysis. CMAJ 2014;186(16):1211–1219). The present document reports a narrative literature revision on the major international recommendations in lower limb venous and lymphatic disease management, focusing on the different countries’ guidelines, trends and controversies from all the continents, while identifying new evidence-based data potentially influencing future guidelines. World renowned experts’ opinions are also provided. The document has been written following the recorded round tables scientific discussions held at the vWINter international meeting (22–26 January 2019; Cortina d’Ampezzo, Italy) and the pre- and post-meeting literature search performed by the leading experts.

Point of care ultrasound in thoracic malignancy

Ultrasonography is a safe, efficient and cost-effective mode of imaging that can assist clinicians with important treatment decisions and provide procedural guidance. Today, point of care ultrasound plays an essential role in the assessment of benign and malignant conditions of chest, both in the outpatient and inpatient setting. Small, ultra-portable, affordable units can now be carried in the coat pocket. Advanced lung cancer, metastatic diseases to the lungs or thoracic malignancies can present with pleural effusion, pulmonary edema, post-obstructive pneumonia, or ascites that can be assessed by the clinician with ultrasound. It can be used to evaluate the extent of thoracic tumors beyond the parenchyma to the parietal pleura or chest wall, assess cervical, supraclavicular lymphadenopathy prior to fine needle aspiration or to determine venous thromboembolism (VTE) associated with malignancy. Thoracic ultrasound is currently being practiced by the pulmonologists, thoracic surgeons and intensivists to provide guidance during placement of pleural catheters, chest tubes or to evaluate the pleural cavity before thoracoscopy. Point of care ultrasound can improve efficiency in procedures by decreasing complications, increasing success and reducing financial strain on the health care system.

Assessment of deep venous thrombosis in the lower extremity in Behçet's syndrome: MR venography versus Doppler ultrasonography

Lower extremity venous thrombosis (DVT) is the most common vascular manifestation of Behçet's syndrome (BS). Currently, Doppler ultrasonography (USG) is the most commonly preferred imaging modality in the diagnosis and follow-up of patients with acute and chronic DVT. Magnetic resonance (MR) venography, a quick and a non-invasive imaging modality, is successfully used to detect DVT in various settings. We had been unaware of studies with MR venography in BS. The aim of this study is to compare the diagnostic value of true fast imaging with steady-state precession magnetic resonance (True-FISP MR) venography and Doppler USG in the assessment of chronic DVT among patients with BS. 28 BS patients with chronic lower extremity DVT were studied. Common femoral (CFV) and femoral vein (FV) on both right and left sides were examined for the presence of thrombosis, recanalisation, collaterals and reflux. There are findings of chronic DVT in all Doppler USG images of 28 patients (45 of 56 FV and 35 of 56 CFV), while MR venography detects chronic thrombotic changes in 26/28 (93%) patients (43 of 52 FV and 28 of 52 CFV). Collateral veins are detected in 19 patients (19/28) with MR venography, whereas they are present in only 7 (7/28) with USG (P = 0.003). Furthermore, patients with severe post-thrombotic syndrome are more likely to have collateral formation on the MR compared to those without (12/14 vs 7/14; P = 0.043). Among patients with BS, MR venography might be an alternative or additional method to detect chronic thrombosis in the lower extremities.

Asymptomatic "breakthrough" thrombosis and anticoagulant "failure": Keep calm and carry on

Despite therapeutic anticoagulation, patients with venous thromboembolism (VTE) not uncommonly present with findings of progressive thrombosis, sometimes within the first several weeks of treatment. While the prevailing strategy in these scenarios is to assume the current anticoagulant is ineffective and to switch to a different drug class, this practice may be unnecessary. Numerous trials of heparins and vitamin K antagonists for VTE have demonstrated that asymptomatic thrombus propagation despite therapeutic anticoagulation is common. While similar, serial imaging studies after initial VTE have not been replicated in trials of the direct oral anticoagulants, we reason that asymptomatic thrombus propagation detected within the first month of VTE diagnosis can be managed with continuation of the current anticoagulant strategy and close follow‐up for worsening or recurrent symptoms.

It's Not All Deep Vein Thrombosis: Sonography of the Painful Lower Extremity With Multimodality Correlation

The purpose of this pictorial essay is to review different etiologies for lower extremity pain encountered on lower extremity venous sonography including acute deep venous thrombosis, chronic postthrombotic change, central venous disease, common arterial pathologies, and nonvascular abnormalities.

The Role of Serial Ultrasounds in Diagnosing Suspected Deep Venous Thrombosis

Venous thromboembolisms (VTE), which include deep venous thrombosis (DVT) and pulmonary embolism (PE), are a major cause of morbidity and mortality in the United States and globally. This often underdiagnosed medical condition has many known risk factors including pregnancy, malignancy, immobility, exogenous estrogen use, and hereditary factors. A significant portion of emergency department visits involves ruling out these diseases.

This case presents a woman with unilateral leg pain and swelling who initially had a negative emergency room workup including a negative lower extremity Doppler study. Upon a repeat visit, she was found to have extensive deep venous thrombosis and was diagnosed with B-cell lymphoma. This case highlights the importance of having patients return for repeat imaging if Dopplers are negative in the initial encounter.

Ultrasound elastography is useful to distinguish acute and chronic deep vein thrombosis

Essentials Ultrasound elastography uses tissue deformation to assess the relative quantification of its elasticity. Compression and duplex ultrasonography may be unable to correctly determine the thrombus age. Ultrasound elastography may be useful to distinguish between acute and chronic deep vein thrombosis. The exact determination of the thrombus age could have both therapeutic and prognostic implications. BACKGROUND: Background Ultrasound elastography (UE) imaging is a novel sonographic technique that is commonly employed for relative quantification of tissue elasticity. Its applicability to venous thromboembolic events has not yet been fully established; in particular, it is unclear whether this technique may be useful in determining the age of deep vein thrombosis (DVT). Thus, the aim of this study was to assess the role of UE in distinguishing acute from chronic DVT. Methods Consecutive patients with a first unprovoked acute and chronic (3 months old) DVT of the lower limbs were analyzed. Patients with recurrent DVT or with a suspected recurrence were excluded. The mean elasticity index (EI) values of acute and chronic popliteal and femoral vein thrombosis were compared. The accuracy of the EI in distinguishing acute from chronic DVT was also assessed by measuring the sensitivity, specificity, positive and negative predictive values, and likelihood ratios. Results One-hundred and forty-nine patients (mean age 63.9 years, standard deviation 13.6; 73 males) with acute and chronic DVT were included. The mean EI of acute femoral DVT was higher than that of chronic femoral DVT (5.09 versus 2.46), and the mean EI of acute popliteal DVT was higher than that of chronic popliteal DVT (4.96 versus 2.48). An EI value of > 4 resulted in a sensitivity of 98.9% (95% confidence interval [CI] 93.3-99.9), a specificity of 99.1% (95% CI 94.8-99.9), a positive predictive value of 91.1% (95% CI 77.9-97.1), a negative predictive value of 98.6% (95% CI 91.3-99.9), a positive likelihood ratio of 13.23 (95% CI 93-653) and a negative likelihood ratio of 0.001 (95% CI 0.008-0.05) for acute DVT. Conclusions UE appears to be a promising technique for distinguishing between acute and chronic DVT. Larger prospective studies are warranted to confirm our preliminary findings.