Negative Compression Ultrasonography Research Articles

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

BackgroundDeep vein thrombosis (DVT) is common in pregnancy, yet data are limited on the best diagnostic strategies in pregnant patients suspected of DVT. ObjectivesWe conducted a prospective cohort study to evaluate the rate of symptomatic DVT in the 90 days after a negative whole-leg compression ultrasound (CUS) in pregnant women presenting with DVT symptoms. MethodsIn this prospective cohort study, we enrolled pregnant patients suspected of DVT between 2011 and 2019 who were referred to the vascular imaging laboratory at a tertiary care center and had anticoagulation held after a negative whole-leg CUS. Primary outcome was objectively confirmed DVT or pulmonary embolism or death due to venous thromboembolism (VTE). ResultsWhole-leg CUS yielded normal results in 186 patients (97.9%) and identified DVT in 4 (2.1%). The mean age was 30 and 164 were White. Among the 186 patients with a negative, initial whole-leg CUS who did not receive anticoagulation, there were 2 DVT events identified over the 90-day follow-up period, for an overall rate of 1.1% (95% CI: 0.2-3.4%). The study was terminated before full planned accrual for administrative reasons. ConclusionThe rate of symptomatic DVT is low in pregnant patients who have a single, negative whole-leg CUS and did not receive anticoagulation. Adequately powered studies should prospectively assess whole-leg CUS in a larger population alone and in combination with pre-test probability scores and/or D-dimer to determine its role in the evaluation of suspected DVT in pregnancy.

Asymptomatic and symptomatic deep venous thrombosis in hospitalized acutely ill medical patients: risk factors and therapeutic implications

BackgroundAcutely ill medical patients experience deep venous thrombosis (DVT) during the hospitalization, however the time course of DVT is still unclear.ObjectivesTo evaluate risk factors in acutely ill hospitalized medical patients for proximal asymptomatic DVT (ADVT) and symptomatic DVT (SDVT) at admission and discharge.Patients/MethodsIn this prospective observational study, consecutive acutely ill medical patients (hospitalized mainly for acute medical disease as infections, neoplasm, anemia, heart failure) underwent compression ultrasonography (CUS) of proximal lower limb veins within 48 h from admission and at discharge to diagnose ADVT and SDVT. Covid-19 patients, anticoagulant therapy, surgical procedures, acute SDVT, and acute pulmonary embolism, were exclusion criteria. Biographical characteristics at hospitalization, D-Dimer (assessed by ELISA)) and DD-improve score.ResultsOf 2,100 patients (1002 females, 998 males, age 71 ± 16 years) 58 (2.7%) had proximal ADVT at admission. Logistic regression analysis showed that age, and active cancer were independently associated with ADVT at admission. The median length of hospitalization was 10 days [interquartile range: 6–15]. During the hospital stay, 6 patients (0.3%) with a negative CUS at admission experienced DVT (2 SDVT and 4 ADVT). In the subgroup of patients (n = 1118), in whom D-dimer was measured at admission, D-Dimer and IMPROVE-DD score were associated with ADVT at admission (n = 37) and with all DVT (n = 42) at discharge. ROC curve defined an IMPROVE-DD score of 2.5 as the optimal cut-off for discriminating patients with and without thrombotic events.ConclusionsWe provide evidence of early development of ADVT in unselected acutely ill medical patients suggesting the need of investigating patients by CUS immediately after hospital admission (within 48 h). Advanced age, active cancer, known thrombophilia and increased IMPROVE-DD score may identify patients at risk. The benefit of anticoagulation needs to be investigated in patients with these specific risk factors and negative CUS at admission.Trial registrationNCT03157843.

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

AbstractGuidelines 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.

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

BackgroundCompression 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.ObjectivesThis systematic review and meta-analysis aimed to summarize and compare the diagnostic accuracy of single limited, serial limited, and whole-leg CUS for DVT.MethodsMEDLINE, Embase, and CENTRAL were searched from January 1st, 1989 to July 23rd, 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.ResultsForty 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.ConclusionsThe 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.

Low Rate of Intrahospital Deep Venous Thrombosis in Acutely Ill Medical Patients: Results From the AURELIO Study

ObjectiveTo evaluate the effect of hospitalization on deep venous thrombosis (DVT) rate by the cumulative incidence of DVT in the proximal venous tract of the lower limbs at admission and discharge. MethodsThe AURELIO (rAte of venoUs thRombosis in acutEly iLl patIents hOspitalized in internal medicine wards) multicenter observational study was carried out in hospital-university internal medicine wards including consecutive acutely ill medical patients. Patients underwent compression ultrasonography (CUS) of proximal lower limb veins at admission and discharge. The occurrence of DVT was the primary end point of the study. ResultsAmong 1340 patients, 26 (1.9%; 95% CI, 1.3%-2.8%) had asymptomatic DVT at admission and were excluded. During the follow-up, 144 patients were excluded because of hospitalization less than 5 days. The remaining 1170 patients underwent a CUS at discharge. Two hundred fifty (21%) underwent prophylaxis with parenteral anticoagulants; the remaining 920 (79%) were not treated with anticoagulants. The mean length of hospitalization was 13±8 days. Compared with patients without prophylaxis, those treated with parenteral anticoagulants had a higher incidence of active cancer, heart and respiratory failure, pneumonia, renal failure, previous venous thromboembolism, reduced mobility, and elderly age. During the hospital stay, 3 patients with a negative CUS at admission experienced DVT in the proximal tract (0.025%, rate of 1 per 5017 patient-days); 2 of them were in prophylaxis with parenteral anticoagulants. ConclusionWe provide evidence that in the real world acutely ill medical patients display more than 90% (1.9%) asymptomatic DVT at admission, whereas the intrahospital DVT occurrence is very low. This suggests a novel diagnostic workup and a careful reanalysis of anticoagulant prophylaxis.

Safe Exclusion of Deep Vein Thrombosis by a Rapid Sensitive ELISA D-dimer and Compression Ultrasonography in 1330 Outpatients With Suspected DVT

Of 1330 outpatients with suspected deep vein thrombosis (DVT), a normal enzyme-linked immunosorbent assay (ELISA) d-dimer (VIDAS) of <500 ng/mL was true negative in 382 of 384 and false negative in compression ultrasonography (CUS) in 2, indicating a sensitivity of 99.52% and a negative predictive value (NPV) of 99.48%, with a specificity of 36% irrespective of clinical score. In 1059 outpatients with no DVT, the CUS was positive for the alternative diagnoses (AD): Bakers cyst, muscle hematoma, or old DVT in 62 (5.8%); superficial vein thrombosis without DVT in 78 (7.4%), and leg edema or varices in 17%. A second CUS in 641 patients was positive in 26 (4.0%), indicating an NPV of 96% after a first negative CUS. The NPV of the combination of a negative first CUS and a ELISA d-dimer test <1000 ng/mL was 99.1% at a specificity of 66.9%. As this strategy is cost effective by reduction in the need to repeat CUS by 67%, we designed a novel algorithm for the safe exclusion and diagnosis of DVT and AD for subsequent evaluation in a large prospective study.

Single whole‐leg compression ultrasound for exclusion of deep vein thrombosis in symptomatic ambulatory patients: a prospective observational cohort study

International guidance has recently recommended serial proximal compression ultrasound (CUS) as first line imaging for suspected deep vein thrombosis (DVT). Single whole-leg CUS is a routine alternative diagnostic strategy that can reduce repeated attendances and identify alternative pathology. We conducted a prospective observational cohort study. Consecutive ambulatory, adult patients with suspected DVT and negative or inconclusive whole-leg CUS had anticoagulation withheld and were followed for 3months. The primary outcome was a predefined clinically relevant adverse event rate. Secondary outcomes included technical failure, alternative diagnoses and all cause mortality. 212 patients agreed to participate and completed follow up. One patient was subsequently diagnosed with an isolated distal DVT. The adverse event rate was thus 1/212, 0·47% (95% confidence interval [CI] 0·08-2·62). Technical imaging failure occurred in 11·3% of cases (95% CI 7·7-16·3). Several potential predictors of an inconclusive result were identified on multivariate analysis. 150 (70·8%) patients were provided with a documented alternative diagnosis. Patients who have anticoagulation withheld following a negative or inconclusive whole-leg CUS for suspected DVT have a low rate of adverse events. Technical failure remains an issue: several factors were significantly associated with inconclusive results and may warrant an alternative diagnostic approach.

SINGLE WHOLE-LEG COMPRESSION ULTRASOUND FOR EXCLUSION OF DEEP VEIN THROMBOSIS IN SYMPTOMATIC AMBULATORY PATIENTS: A PROSPECTIVE OBSERVATIONAL COHORT STUDY

Objectives & BackgroundInternational guidance has recently recommended serial proximal compression ultrasound (CUS) as first line imaging for suspected deep vein thrombosis (DVT). Limitations with this strategy include attrition, lack of...

Unusual deep vein thrombosis sites: magnetic resonance venography in patients with negative compression ultrasound and symptomatic pulmonary embolism

To evaluate the clinical characteristics of patients with pulmonary embolism (PE), negative compression ultrasound (CUS) of the lower limbs and detection of unusual deep vein thrombosis (DVT) sites by means of magnetic resonance (MR) venography. A retrospective data analysis of PE patients hospitalized at our institution from April 2009 to 2011. From April 2009 to 2011, a total of 762 PE patients were treated at our institution. In 169 of these patients CUS for DVT was negative. In these patients MR venography was performed for further evaluation. We found venous thrombosis at unusual sites in 12 of these patients. Due to free floating thrombus masses and fear of life-threatening PE progression we inserted an inferior vena cava filter in three of these 12 patients. The leading venous thromboembolism risk factor in our patients was immobilization (5 patients, 41.7%). We conclude that especially in patients with PE and negative CUS of the lower limbs a thrombosis of the pelvic veins should be considered in case of symptoms for venous thrombosis in this area. Further diagnostic work-up with MR venography should be scheduled in these patients especially in patients with risk factor immobilization as therapeutic consequences might occur.

Risk of Deep Vein Thrombosis Following a Single Negative Whole-Leg Compression Ultrasound

In patients with suspected lower extremity deep vein thrombosis (DVT), compression ultrasound (CUS) is typically the initial test to confirm or exclude DVT. Patients with an initial negative CUS result often require repeat CUS after 5 to 7 days. Whole-leg CUS may exclude proximal and distal DVT in a single evaluation. To determine the risk of venous thromboembolism after withholding anticoagulation in patients with suspected lower extremity DVT following a single negative whole-leg CUS result. MEDLINE, EMBASE, CINAHL, LILACS, Cochrane, and Health Technology Assessments databases were searched for articles published from January 1970 through November 2009. Supplemental searches were performed of Internet resources, reference lists, and by contacting content experts. Included studies were randomized controlled trials and prospective cohort studies of patients with suspected DVT and a negative whole-leg CUS result who did not receive anticoagulant therapy, and were followed up at least 90 days for venous thromboembolism events. Two authors independently reviewed and extracted data regarding a single positive or negative whole-leg CUS result, occurrence of venous thromboembolism during follow-up, and study quality. Seven studies were included totaling 4731 patients with negative whole-leg CUS examinations who did not receive anticoagulation. Of these, up to 647 patients (13.7%) had active cancer and up to 725 patients (15.3%) recently underwent a major surgery. Most participants were identified from an ambulatory setting. Venous thromboembolism or suspected venous thromboembolism-related death occurred in 34 patients (0.7%), including 11 patients with distal DVT (32.4%); 7 patients with proximal DVT (20.6%); 7 patients with nonfatal pulmonary emboli (20.6%); and 9 patients (26.5%) who died, possibly related to venous thromboembolism. Using a random-effects model with inverse variance weighting, the combined venous thromboembolism event rate at 3 months was 0.57% (95% confidence interval, 0.25%-0.89%). Withholding anticoagulation following a single negative whole-leg CUS result was associated with a low risk of venous thromboembolism during 3-month follow-up.

Predicting Deep Venous Thrombosis in Pregnancy: Out in “LEFt” Field?

In the nonpregnant general population, deep venous thrombosis (DVT) can be excluded at the initial presentation not only by clinical assessment and review of risk factors, but also by the clinician's assessment of probability using subjective criteria or prediction rules. Because of the absence of a validated prediction rule for diagnosing DVT during pregnancy, diagnosis in pregnant patients depends largely on the use of compression ultrasonography, the diagnostic reference standard that establishes the presence or absence of DVT. The aim of this cross-sectional study was to investigate the predictive accuracy of clinicians' subjective assessment of the probability of DVT in women with suspected DVT and to identify useful objective prediction variables. The participants were 194 unselected pregnant women with suspected first DVT. Potential study patients were identified by clinicians during the initial examination when the clinical assessment was consistent with DVT, and led to consultation with thrombosis experts who obtained informed consent for participation in the study. Before compression ultrasonography testing, the experts examined each study patient and categorized their pretest probability of DVT based on subjective criteria as low, moderate, or high. The sensitivity, specificity, negative predictive value, and likelihood ratios of the clinicians' subjective pretest probability were calculated. Patients defined as DVT positive had abnormal diagnostic compression ultrasonography results at the initial presentation or during serial testing, or had symptomatic DVT or pulmonary embolism on follow-up. Patients with negative compression ultrasonography at presentation and no venous thromboembolism on follow-up were defined as DVT negative. DVT was diagnosed in 17 women (8.8%). The prevalence of DVT in patients with low pretest probability (two-third of patients) was 1.5% (2/131), with a 95% confidence interval of 0.4% to 5.4% (P < 0.001). The prevalence among those with moderate or high pretest probability was considerably higher, 24.6% (15/61), with a 95% confidence interval of 15.5% to 36.7% (P < 0.001). Multivariate analysis identified 3 independent variables that were highly predictive of DVT in pregnant women: left leg symptoms, difference in calf circumference of 2 cm or more, and presentation during the first trimester of pregnancy. DVT was unlikely in the absence of all 3 variables, and its probability increased substantially if 1 or more was present. These findings demonstrate that probability of DVT in pregnant women with suspected DVT may be assessed with use of 3 easily determined objective variables. The data show that DVT is very unlikely with a very low pretest probability.

Safety of Excluding Suspected Deep Vein Thrombosis with a Single Whole-Leg Compression Ultrasound: Systematic Review and Meta-Analysis.

Abstract 243 Background:In patients with suspected lower extremity deep vein thrombosis (DVT), compression ultrasonography (CUS) is typically used as the initial test to confirm or exclude DVT. Patients with a negative CUS and either a moderate-to-high probability and/or a positive D-dimer usually require repeat CUS testing after 5–7 days to exclude proximal propagation of distal DVT, reducing diagnostic efficiency. Whole-leg compression ultrasound may safely exclude proximal and distal DVT in a single evaluation. Purpose:To assess the safety of withholding anticoagulation in patients presenting with suspected lower extremity DVT following a single negative whole-leg CUS. Methods:MEDLINE, EMBASE, CINAHL, LILACS, Cochrane, Health Technology Assessments databases were searched from January 1970 to April 2009 without language restrictions. This search was supplemented by reviewing Google, Google Scholar, clinicaltrials.gov, meeting abstracts, conference proceedings, reference lists, and by contacting content experts. Study Selection and Data Extraction:Randomized controlled trials and prospective cohort studies of patients with suspected DVT with a negative whole-leg CUS, not treated with anticoagulation, and followed at least 90 days for occurrence of venous thromboembolism (VTE). Studies required objective confirmation of VTE events during follow-up. Two authors independently reviewed articles and extracted data. Results:Six studies were included totaling 4,229 patients with negative whole-leg CUS exams and not receiving anticoagulation. VTE or suspected VTE-related death occurred within the follow-up period in 24 (0.6%) patients. Of these 24 events, 9 (37.5%) were distal DVT, 7 (29.2%) were proximal DVT, 6 (25.0%) were non-fatal pulmonary embolism, and 2 (8.3%) were deaths, possibly related to VTE. Combined VTE event rate at 3 months was 0.46% (95% CI 0.22, 0.70). Limitations:Pretest probability assessment was not available for all analyzed patients. Conclusions:Withholding anticoagulation in patients with suspected DVT based on a single whole-leg CUS is associated with a low risk of VTE (0.46%) during 3 months of follow-up. This strategy represents a safe and efficient alternative to serial CUS testing in patients with suspected DVT. Disclosures:No relevant conflicts of interest to declare.

Predicting Deep Venous Thrombosis in Pregnancy: Out in “LEFt” Field?

Clinicians' assessment of pretest probability, based on subjective criteria or prediction rules, is central to the diagnosis of deep venous thrombosis (DVT). Pretest probability assessment for DVT diagnosis has never been evaluated in pregnant women. To evaluate the accuracy of clinicians' subjective assessment of pretest probability for DVT diagnosis and identify prediction variables that could be used for pretest probability assessment in pregnant women with suspected DVT. A cross-sectional study conducted over 7 years (March 2000 to April 2007). 5 university-affiliated, tertiary care centers in Canada. 194 unselected pregnant women with suspected first DVT. Diagnosis of DVT was established with abnormal compression ultrasonography at presentation or on serial imaging. Pretest probability by subjective assessment was recorded by thrombosis experts for each patient before knowledge of results. The sensitivity, specificity, negative predictive value, and likelihood ratios of subjective pretest probability assessment and their corresponding 95% CIs were calculated on the basis of the diagnosis of DVT. Patients were DVT positive if they had diagnostic compression ultrasonography at initial or serial testing or symptomatic venous thromboembolism on follow-up. Patients were DVT negative if they had negative compression ultrasonography at presentation and no venous thromboembolism on follow-up. A prediction rule for assessing DVT was derived, and an internal validation study was done to explore its performance. The prevalence of DVT was 8.8%. Clinicians' subjective assessment of pretest probability categorized patients into 2 groups: low pretest probability (two thirds of patients) with a low prevalence of DVT (1.5% [95% CI, 0.4% to 5.4%]) and a negative predictive value of 98.5% (CI, 94.6% to 99.6%), and nonlow pretest probability with a higher prevalence of DVT (24.6% [CI, 15.5% to 36.7%]). Three variables (symptoms in the left leg [L], calf circumference difference > or = 2 cm [E], and first trimester presentation [Ft]) were highly predictive of DVT in pregnant patients. Few outcomes occurred. Altogether, 17 events were diagnosed during the study. The prediction rule derived should be validated on an independent sample before applying it to clinical practice. Subjective assessment of pretest probability seems to exclude DVT when the pretest probability is low. Moreover, 3 objective variables ("LEFt") may improve the accuracy of the diagnosis of DVT in pregnancy. Prospective validation studies are needed. Heart and Stroke Foundation of Ontario.

Safety of ruling out acute pulmonary embolism by normal computed tomography pulmonary angiography in patients with an indication for computed tomography: systematic review and meta-analysis.

Several outcome studies have ruled out acute pulmonary embolism (PE) by normal computed tomography pulmonary angiography (CTPA). We performed a meta-analysis in order to determine the safety of this strategy in a specific group of patients with a strict indication for CTPA, that is, 'likely' or 'high' clinical probability for PE, an elevated D-dimer concentration, or both. Studies that ruled out PE by normal CTPA, with or without subsequent normal bilateral compression ultrasonography (CUS), in patients with a strict indication for CTPA, were searched for in Medline, EMBASE, Web of Science and the Cochrane dataset. The primary endpoint was the occurrence of (fatal) venous thromboembolism (VTE) in a 3-month follow-up period. Three studies were identified that excluded PE by CTPA alone (2020 patients), and three studies that performed additional CUS of the legs after normal CTPA (1069 patients). The pooled incidence of VTE at 3 months was 1.2% [95% confidence interval (CI) 0.8-1.8] based on a normal CTPA result as a sole test, and 1.1% (95% CI 0.6-2.0) based on normal CTPA and negative CUS findings, resulting in negative predictive values of 98.8% (95% CI 98.2-99.2) and 98.9% (95% CI 98.0-99.4), respectively. This compares favorably with the VTE failure rate after normal pulmonary angiography (1.7%, 95% CI 1.0-2.7). The risk of fatal PE did not differ between the diagnostic strategies (0.6% vs. 0.5%). A normal CTPA result alone can safely exclude PE in all patients in whom CTPA is required to rule out this disease. There is no need for additional ultrasonography to rule out VTE in these patients.

A Negative D-dimer Excludes Recurrent Deep Vein Thrombosis: Results of a Multicentre Management Study.

The high frequency of residual radiologic abnormalities after initial deep vein thrombosis (DVT) makes management of patients with suspected recurrence difficult. D-dimer (DD) and serial compression ultrasonography (CUS) of the proximal veins have a high sensitivity and negative predictive value (NPV) in suspected first DVT. We hypothesized that it would be safe to withhold anticoagulation in patients with suspected recurrence who had a negative sensitive DD or negative serial CUS when DD testing was positive. In a multicentre prospective cohort study, patients underwent DD testing with an immunoturbidometric assay (MDA DD). If the DD was negative (<0.5 ug fibrinogen equivalent units [FEU]/mL), patients had no further testing. If the DD was positive, CUS was performed and, if normal, repeated after 1–3 and 7–10 days. Patients with a positive DD and abnormal CUS at presentation were managed as per their treating physician. Patients were followed for 3 months to detect venous thromboembolism (VTE) and suspected VTE were adjudicated centrally. Of the 504 patients enrolled in this study, 14 were subsequently deemed ineligible and 2 patients were lost to follow-up. The overall prevalence of confirmed recurrent DVT at presentation or during follow-up was 17%. 230 patients had a negative DD at presentation and, of the 227 evaluable patients, 4 had definite confirmed VTE (NPV of DD = 98%; 95% Confidence Interval [CI], 96–99%). Of the 135 patients with a positive DD and normal initial CUS, serial CUS was negative in 129 cases. Of these patients, 3 had definite VTE during follow-up (NPV of serial CUS in patients with positive DD = 98%; 95% CI, 93–99%). These results suggest that a negative MDA DD result excludes clinically significant recurrent DVT and that anticoagulants can also be safely withheld in patients with negative serial CUS, even if their DD is positive. This simple diagnostic approach can be used to safely manage approximately 70% of patients with suspected recurrent DVT.

Diagnosis of pulmonary embolism in hospitalised patients: retrospective survey of an institutional standard

The aim of the present study was to assess the safety and implementation of a diagnostic strategy in hospitalised patients with suspected acute pulmonary embolism (PE). A diagnostic strategy was established and implemented in a general hospital. A retrospective cohort study, including 400 consecutive in-patients, was performed in order to assess the appropriateness of the diagnostic management and the incidence of symptomatic venous thromboembolic events (VTE) during follow-up. PE was confirmed in 116 (29%) patients. The incremental value of adding compression ultrasonography (CUS) to multidetector-row computed tomography (MDCT) for the diagnosis of PE was 8.6%. PE was appropriately excluded in 169 (42%) patients due to a normal lung scan (n = 34), a negative MDCT providing an alternative diagnosis (n = 94), and a negative MDCT and CUS (n = 41). During follow-up, VTE occurred in 3.5% patients. The almost unique cause of inappropriate management was the absence of further work-up after a MDCT-negative result for PE providing no alternative diagnosis (n = 115). Inappropriate management was associated with a nonsignificant increased risk of VTE (7.2%). A frontline diagnostic work-up based on pulmonary multidetector-row computed tomography associated with a compression ultrasonography of the leg veins is effective and more sensitive than pulmonary multidetector-row computed tomography alone in ruling out pulmonary embolism.

Is it worth diagnosing and treating distal deep vein thrombosis? No.

The standard diagnostic approach to suspected deep vein thrombosis (DVT) is serial lower limb compression ultrasound (CUS) of proximal veins. Although it only assesses the proximal veins, withholding anticoagulant treatment in patients with a negative CUS on day 1 and after 1 week has been proved safe. In particular, studies evaluating CUS limited to the proximal veins showed a good safety profile with a pooled estimate of the 3-month thromboembolic rate of 0.6% (95% CI, 0.4-0.9%) in non-anticoagulated patients. However, performing two lower limbs CUS is cumbersome and expensive. Recently, studies using a unique complete (proximal and distal) CUS showed a similar pooled estimate of the 3-month thromboembolic rate (0.3%; 95% CI, 0.1-0.6%) but distal DVTs accounted for as many as 50% of all diagnosed DVTs in those series. Comparing these studies may suggest that systematically searching for calf DVTs potentially doubles the number of patients given anticoagulant therapy and entails a risk of over-treatment. Admittedly, performing calf CUS is highly useful in diagnosing other conditions such as popliteal cyst, hematoma or muscle rupture. Performing a CUS limited to the popliteal site in the presence of calf pain may be not well accepted by the patient. However, the advantage of calf CUS in diagnosing venous thromboembolism appears to be at the least debatable. Data suggesting that anticoagulation is indicated for distal DVT are limited, and realizing systematic distal CUS entails a risk of over-treatment. There is an urgent need for randomized trials assessing the usefulness of anticoagulant treatment in distal DVT.

Different Accuracies of Rapid Enzyme-Linked Immunosorbent, Turbidimetric, and Agglutination D-Dimer Assays for Thrombosis Exclusion: Impact on Diagnostic Work-Ups of Outpatients with Suspected Deep Vein Thrombosis and Pulmonary Embolism

The requirement for a safe diagnostic strategy should be based on an overall posttest incidence of venous thromboembolism (VTE) of less than 1%, with a negative predictive value of more than 99 to 100% during 3-month follow-up. Compression ultrasonography (CUS) and spiral computed tomography (CT) currently are the methods of choice to confirm or rule out deep venous thrombosis (DVT) and pulmonary embolism (PE), respectively. CUS has a negative predictive value (NPV) of 97 to 98%, indicating the need to improve the diagnostic work-up of patients with suspected DVT by clinical score assessment and D-dimer testing. Spiral CT as a stand-alone method detects all clinically relevant PEs and a large number of alternative diagnoses. It rules out PE with a NPV of 98 to 99%. Spiral CT is expensive, emphasizing the need to improve the diagnostic work-up of patients with suspected PE by the use of clinical score assessment and D-dimer testing. Clinical score assessment for DVT and PE has not safely ruled out VTE in multicenter studies and in routine daily practices. Modification of the Wells clinical score assessment for DVT by elimination of the "minus 2 points" for alternative diagnosis will improve the reproducibility of the clinical score assessment. The combination of a first negative CUS and a negative SimpliRed or an enzyme-linked immunosorbent assay (ELISA) VIDAS D-dimer of < 1,000 ng/mL safely exclude DVT (NPV > 99%) irrespective of clinical score assessment and without the need to repeat CUS in approximately 60 to 70% of patients. The rapid quantitative and qualitative agglutination D-dimer assays for the exclusion of VTE are not sensitive enough as stand-alone tests and should be used in combination with clinical score assessment. A normal rapid ELISA VIDAS D-dimer test as a stand-alone test safely excludes DVT and PE, with a NPV of 99 to 100%, irrespective of clinical score, without the need of CUS or spiral CT. The combined strategy of a rapid ELISA VIDAS D-dimer followed by objective testing with CUS for DVT and by spiral CT for PE will reduce the need for noninvasive imaging techniques by 40 to 50%.

Clinical relevance of distal deep vein thrombosis

The standard diagnostic approach of suspected deep vein thrombosis (DVT) is serial lower limb compression ultrasound (CUS) of proximal veins. Although it only assesses the proximal veins, withholding anticoagulant treatment in patients with a negative CUS on day one and after one week has been proven to be safe. However, in many centres, distal DVT is systematically screened for and treated by anticoagulants. The objectives of the review were 1) to evaluate the rate of extension of distal DVTs to proximal veins 2) to compare the safety of proximal limited CUS versus single complete CUS. We performed a MEDLINE search covering the period from January 1983 to January 2005 by using the key-words "calf vein thrombosis", "distal thrombosis" and "compression ultrasonography". English, German and French language original studies were retrieved. Moreover, references of retrieved articles were screened in order to detect missed pertinent articles. We pooled data of management studies where proximal or complete (i.e. proximal and distal) CUS were used, respectively. Studies evaluating CUS limited to the proximal veins showed a good safety profile with a pooled estimate of the 3-month thromboembolic rate of 0.6% (95% CI: 0.4-0.9%) in patients in whom anticoagulation was withheld. Studies using proximal and distal CUS showed a similar pooled estimate of the 3-month thromboembolic rate (0.4%, 95% CI: 0.1-0.6%) but distal DVT accounted for as many as 50% of all diagnosed DVTs in those series. Therefore, searching for distal DVT potentially doubles the number of patients given anticoagulant therapy and entails a risk of over-treatment. Data suggesting that anticoagulation is indicated for distal DVT are limited, and realizing distal CUS entails a risk of over-treatment. There is an urgent need for randomised trials assessing the usefulness of anticoagulant treatment in distal DVT.

Screening for Deep Vein Thrombosis and Pulmonary Embolism in Outpatients with Suspected DVT or PE by the Sequential Use of Clinical Score: A Sensitive Quantitative D-Dimer Test and Noninvasive Diagnostic Tools

The requirement for a safe diagnostic strategy should be based on an overall posttest incidence of venous thromboembolism (VTE) of less than 1% during 3-month follow-up. The negative predictive value (NPV) during 3 months of follow-up is 98.1 to 99% after a normal venogram, 97 to 98% after a normal compression ultrasonography (CUS), and > 99% after serial CUS testing. Serial CUS testing is safe but 100 CUS must be repeated to find one or two CUS positive for deep vein thrombosis (DVT), which is not cost-effective and indicates the need to improve the diagnostic workup of DVT by the use of clinical score assessment and D-dimer testing. The NPV varies from 97.6 to 99.4% for low clinical score followed by a negative SimpiRED test, indicating the need for a first CUS. The NPV is 98.4 to 99.3% for a normal rapid enzyme-linked immunosorbent assay (ELISA) VIDAS D-dimer test result (< 500 ng/mL) irrespective of clinical score. The NPV is more than 99% for a negative CUS followed by either a negative SimpiRED test or an ELISA VIDAS test result of < 1000 ng/mL without the need to repeat a second CUS within 1 week. The sequential use of a sensitive, rapid ELISA D-dimer and clinical score assessment will safely reduce the need for CUS testing by 40 to 60%. Large prospective outcome studies demonstrate that with one negative examination with complete duplex color ultrasonography (CCUS) of the proximal and distal veins of the affected leg with suspected DVT, it is safe to withhold anticoagulant treatment, with a negative predictive value of 99.5%. This may indicates that CCUS is equal to serial CUS or the combined use of clinical score, D-dimer testing, and CUS. Pulmonary angiography is the gold standard for segmental pulmonary embolism (PE) but not for subsegmental PE. A normal perfusion lung scan and a normal rapid ELISA VIDAS D-dimer test safely excludes PE. Helical spiral computed tomography (CT) detects all clinically relevant PE and a large number of alternative diagnoses in symptomatic patients with suspected PE and can replace both the ventilation perfusion scan and pulmonary angiography to safely rule in PE and to rule out PE with an NPV of > 99%. The combination of clinical assessment, a rapid ELISA VIDAS D-dimer, followed by CUS will reduce the need for helical spiral CT by 40 to 50%.