Deep venous thrombosis of the lower extremity: US evaluation

Relationship of the Novel Scoring System for Lower Extremity Venous Thrombosis with Pulmonary Embolism

RATIONALE AND OBJECTIVE

To develop a new scoring system, the "Lower extremity venous Doppler ultrasound scoring system" (LEVDUS), to predict the diagnosis of pulmonary embolism (PE) localization in patients with deep vein thrombosis (DVT).

METHODS

This single-center retrospective study included 182 patients aged ≥ 18 years. We used scoring according to thrombosis localization and stage in Doppler US. Patients with PE were divided into three categories based on the pulmonary artery (PA) location on CT pulmonary angiography. LEVDUS values were compared according to the PE classification. The threshold value was determined for the diagnosis of PE in the receiver operating characteristics analysis. Factors affecting the diagnosis of PE were evaluated by logistic regression analysis.

RESULTS

A total of 182 patients were included (female patients: 55.5% [101/182]). The median age of the patients was 68 (IQR, 56-77). The rates of DVT and PE were 35.2% (64/182) and 52.7% (96/182), respectively. Although the median LEVDUS and d-dimer values in the subsegmental PE group were higher, LEVDUS was statistically significant but d-dimer was not (p = 0.005 and p = 0.022, respectively). In addition, both LEVDUS and d-dimer median values in the other PE groups were statistically significantly higher than the non-PE group (p < 0.001). The cut-off value for the diagnosis of PE was LEVDUS≥ 2.5. LEVDUS was 1.2-fold higher for the presence of PE.

CONCLUSION

LEVDUS provides useful information in predicting the presence of PE in patients and provides a common diagnostic language between radiologists and emergency or clinic physicians.

Emergency medicine residents' learning curve in diagnosing deep vein thrombosis with 3-point venous point-of-care ultrasound

BACKGROUND

Many cases of deep vein thrombosis (DVT) are diagnosed in the emergency department, and abbreviated lower extremity venous point-of-care ultrasound (POCUS) has already shown an accuracy comparable to that of specialists. This study aimed to identify the learning curve necessary for emergency medicine (EM) residents to achieve expertise-level accuracy in diagnosing DVT through a 3-point lower extremity venous POCUS.

METHODS

This prospective study was conducted at an emergency department between May 2021 and October 2022. Four EM residents underwent a one-hour POCUS training session and performed DVT assessments in participants with DVT symptoms or confirmed pulmonary embolism. POCUS was performed at three proximal lower extremity sites to evaluate the thrombi presence and vein compressibility, with results validated by specialized radiology ultrasound. Cumulative sum (CUSUM) and the Bush and Mosteller models were used to analyze the learning curve, while generalized estimating equations were used to identify factors affecting diagnostic accuracy.

RESULTS

91 POCUS scans were conducted in 49 patients, resulting in 22% DVT confirmed by specialized venous ultrasound. In the CUSUM analysis, all four EM residents attained a 90% success rate at the common femoral vein, whereas only half achieved this rate when all three sites were considered. According to Bush and Mosteller models, 13-18 cases are required to attain 90-95% diagnostic accuracy. After 10-16 cases, the examination time for each resident decreased, and a 20% increase in examiner confidence was linked to a 2.506-fold increase in the DVT diagnosis accuracy.

CONCLUSION

EM residents generally required 13-18 cases for 90-95% DVT diagnostic accuracy, but proficiency varied among individuals, particularly requiring more cases for regions outside the common femoral vein.

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

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

Comparison of clear effect and the complications, and short and mid-term effects between ultrasound-guided and non-guided catheter-directed thrombolysis in the treatment of deep venous thrombosis of lower extremity

Objective

To compare the therapeutic effects of ultrasound-guided and non-guided catheter-directed thrombolysis in the treatment of deep venous thrombosis of lower extremity.

Methods

From August 2015 to April 2016, 60 patients with lower extremity deep venous thrombosis were randomly divided into two groups ( n = 30 for each) to receive catheter-directed thrombolysis. Group A was treated under the ultrasound guidance, while Group B was treated without guidance.

Results

Catheter-directed thrombolysis was successfully performed by only one intubate in Group A but by 5.9 intubates in Group B. It took 15.4 ± 3.2 min in Group A, significantly less than that in Group B (30.8 ± 6.6 min, p < 0.05). The incidences of hematoma were also remarkably different between the two groups (3.33% vs. 26.67%, p = 0.026). No pseudoaneurysm or arteriovenous fistula was found in Group A, but there were two cases of pseudoaneurysm and two cases of arteriovenous fistula in Group B (both 6.67%, p = 0.492). The circumference differences of the affected limb between before and after thrombolysis were 49.47 ± 2.484 mm in Group A, significantly higher than that in Group B (28.40 ± 2.856 mm, p < 0.001). After treatment, the venous unobstructed improvement rates and deep vein patency rate were both better than those in Group B (77 + 2.603% vs. 57.23 + 1.828% and 80% vs. 46.67%, respectively; p < 0.001). There were only three cases of PTS in Group A (10%, 3/30), but there were 11 cases in Group B (36.67%, 11/30).

Conclusion

Ultrasound-guided catheter-directed thrombolysis has advantages, with improvement of venous patency and decrease of the incidence of PTS.

Cardiovascular ultrasonography detection of embolic sources in trauma

Venous thromboembolism (deep vein thrombosis and pulmonary embolism) and bone cement implantation syndrome are major sources of embolic events in trauma patients. In these patients, embolic events due to venous thromboembolism and bone cement implantation syndrome have been detected with cardiac and vascular ultrasonography in the emergency setting, during the perioperative period, and in the intensive care unit. This article discusses the ultrasonography modalities and imaging findings of embolic events related to venous thromboembolism and bone cement implantation syndrome. The aim is to present a short review with exceptional illustrations that can enable physicians to identify sources of emboli in trauma patients with cardiovascular ultrasonography.

Diagnosis of Deep Venous Thrombosis by Duplex Sonography

In a prospective study 90 patients with clinically suggested lower limb deep venous thrombosis (DVT) were examined with duplex ultrasonography (US) prior to venography. No attempts were made to examine the calf veins. Five ultrasound examinations were inconclusive. Thirty-four patients had DVT diagnosed at US with a sensitivity of 97 per cent and a specificity of 96 per cent. Compressibility of the vein as assessed by the real-time image was in the acute phase an easy and fast test for DVT, whereas the Doppler data failed to add to the diagnostic accuracy. Twenty-seven patients with DVT were followed during anticoagulant treatment, but only 16 regained fully compressible veins within the observation period of 3 to 6 months. Duplex sonography was useful in monitoring the changes in vein patency during anticoagulant treatment.

Colour-Coded Duplex Sonography in the Diagnosis of Deep Vein Thrombosis: A Comparison with Phlebography

A total of 50 legs in 34 consecutive patients with clinically suspected deep vein thrombosis (DVT) were evaluated both with colour-coded duplex sonography and phlebography, the tests being performed immediately following each other without the examiner knowing the result of the other procedure. Contrast phlebography was regarded as the standard for diagnosis. All the sonograms were considered to be technically adequate. The overall diagnostic accuracy, taking the leg as a whole from the ilio–femoral segment to the calf, was 92% and the sensitivity 78%. The accuracy in the femoral vein was 92%, sensitivity 64%. In the calf the accuracy was 90% and sensitivity 81%. although no attempt was made to localize or quantify the thrombus. The accuracy of the diagnosis of thrombus was not improved by the use of the colour-coded duplex facility. The main advantage of colour-coded duplex sonography over conventional duplex scanning is the easier identification of the venous system making it faster to perform. It is suggested that colour-coded sonography is a useful primary investigation for patients suspected of DVT or pulmonary embolism, but that about a third of patients will require contrast phlebography if the sonogram is negative or technically inadequate. It is emphasized that phlebography remains the most accurate method currently available for the diagnosis of DVT and using low osmolar contrast media is well tolerated and impressively safe.

Ultrasonic Diagnosis of Iliofemoral Venous Thrombosis: Merits and Disadvantages

Twenty-nine patients with clinical suspicion of iliofemoral venous thrombosis were investigated by duplex-Doppler ultrasound and phlebography. Twenty-two of the patients were proven to have thrombosis in one of the lower limbs by both duplex-Doppler ultrasound and phlebology. Of these, 19 patients had iliofemoral thrombosis. The upper end of the thrombus could be demonstrated with ultrasound in only two patients. It is concluded that duplex-Doppler ultrasound is very reliable for the diagnosis of the thrombotic condition but that for proper determination of the upper end of an iliofemoral thrombosis phlebography is still needed, especially if operative treatment is contemplated.

Considerations for Imaging the Inferior Vena Cava (IVC) with/without IVC Filters

Deep venous thrombosis (DVT), thrombosis of the inferior vena cava, and pulmonary embolism (PE) constitute a continuum that includes venous thromboembolic (VTE) disease. VTE is the third most common cardiovascular disorder that affects all races, ethnicities, gender, and ages. VTE predominantly affects the elderly population, exponentially increasing in incidence with increasing age. Venous thromboembolism is not only a singular event but a chronic disease and has been found to have a rate of recurrence approaching 40% among all patients after 10 years. Whether symptomatic or asymptomatic, once thromboembolism is suspected, objective methods are required for the accurate and confirmatory presence of a thrombus with imaging as the next step in the diagnostic algorithm. Imaging also allows for the determination of the extent of clot burden, clot propagation, occlusive versus nonocclusive thrombus, acute versus chronic thrombus, or in some cases thrombus recurrence versus thrombophlebitis. Vena caval filter placement is, in some instances, required to prevent a significant subsequent VTE event. Placement of these therapeutic devices paradoxically promotes thrombus formation, and other sequelae may arise from the placement of inferior vena cava filters. In this article, the authors provide an overview of available techniques for imaging the vena cava with or without a filter and discuss advantages and drawbacks for each.

Soluble P-selectin for the diagnosis of lower extremity deep venous thrombosis

OBJECTIVE

Although duplex ultrasound is the standard for the diagnosis of lower extremity deep venous thrombosis (LE-DVT), imaging is not always available. The use of D-dimer can exclude (high-sensitivity), but not rule in (low-specificity) LE-DVT. Previously, we demonstrated that soluble P-selectin (sP-sel) in combination with the Wells score, establishes the diagnosis of LE-DVT with a specificity of 96% and a positive predictive value of 100%. In order to validate our previous results, we applied the model to a separate but similar patient cohort. Additionally, we analyzed the role of biomarkers for diagnosing upper extremity DVT (UE-DVT).

METHODS

Between April 2009 and March 2012, all patients presenting for a duplex ultrasound exam with concern of DVT were screened. Demographics, clinical data, D-dimer, sP-sel, C-reactive protein, a disintegrin and metalloproteinase with a thrombospondin type 1 motif, member 13, and von Willebrand factor levels were prospectively collected in 279 patients (234 LE-DVT, 45 UE-DVT). Continuous and categorical variables among patients with DVT were compared with patients without DVT. The diagnostic sensitivity, specificity, positive predictive value, and negative predictive value were then calculated using our previously derived cut points to rule in or exclude DVT.

RESULTS

Among 234 patients evaluated for LE-DVT, 112 (48%) patients had a confirmed LE-DVT with significant differences in all biomarkers. When Wells score ≥2, sP-sel could rule in LE-DVT with a specificity of 97.5% and a positive predictive value of 91%, which was more accurate than Wells score ≥2 and D-dimer (specificity, 65%; positive predictive value, 69%). When Wells score was <2, D-dimer was superior to sP-sel for excluding the diagnosis of LE-DVT (sensitivity, 98%; negative predictive value, 95% vs sensitivity, 91%; negative predictive value, 79%). The use of additional biomarkers did not increase accuracy. Had imaging not been available, we could have correctly ruled in or ruled out LE-DVT in 29% (67/234) of patients. The use of sP-sel in UE-DVT was nondiagnostic.

CONCLUSIONS

We demonstrate that when Wells score ≥2, sP-sel is an excellent biomarker to rule in LE-DVT. Different from our previous study, D-dimer and a Wells score <2 was most sensitive at excluding a diagnosis of LE-DVT. Combined, Wells score, sP-sel, and D-dimer can both rule in and exclude LE-DVT in approximately one-third of patients.

The accuracy of limited B-mode compression technique in diagnosing deep venous thrombosis in lower extremities

BACKGROUND

Deep vein thrombosis (DVT) is prevalent in the emergency departments. Nearly 60% of them may lead to pulmonary embolism. A complete color-flow duplex ultrasound (CFDU), performed by the radiologists, is the most common diagnostic method used to detect DVT. A limited B-mode compression technique (BMCT) can also be useful for the emergency specialists visiting suspicious cases.

OBJECTIVES

The purpose of this study was to compare the sensitivity, specificity, and accuracy of a BMCT done by emergency medicine residents with that of a CFDU in diagnosing the proximal DVT of lower extremities.

METHODS

This prospective study was conducted on 74 patients (41 men and 33 women) presenting with painful and swollen lower limbs in the emergency department of Imam Khomeini Hospital. First, the affected lower extremity was examined by a BMCT carried out by one of the 2 emergency medicine residents. Then, the CFDU was performed by a radiologist blinded to the results of the BMCT. The sensitivity, specificity, and accuracy of the BMCT were compared with that of the CFDU as a gold standard.

RESULTS

The mean age of the patients was 55.16 ± 17.4 years. Positive results were reported in 35 patients (47.3%) using the 2 tests. Compared with CFDU, BMCT had a sensitivity, specificity, accuracy, positive predictive values, and negative predictive values of 100%.

CONCLUSION

These findings suggest that BMCT performed by the emergency medicine specialists to diagnose proximal DVT of lower extremities is not only an acceptable method but also less time-consuming when compared with CFDU.

Imaging presentation of venous thrombosis in patients with cancer

OBJECTIVE

The purpose of this article is to review the imaging of venous thrombosis in patients with cancer.

CONCLUSION

Multiple imaging techniques have the capacity to display thrombosis accurately. The optimal choice is dictated by the location and duration of symptoms and by the availability of imaging techniques. Peripheral and superficial thrombi are best managed with ultrasound, whereas central thrombi require CT or MRI. If CT and MRI are contraindicated, flow studies are appropriate. FDG PET/CT appropriately shows venous thrombosis and might play a prominent role in the future.

Venothromboembolism

This article focuses on the clinical presentation, diagnosis, and management of veno-thromboembolism, including deep venous thrombosis (DVT) and pulmonary embolism (PE), from the perspective of the emergency physician. The discussion is divided into two sections: DVT and PE. Because veno-thromboembolism is a continuum, certain aspects, such as background, incidence, the use of D dimer, and anticoagulation of both DVT and PE, are discussed together. Heavier emphasis is placed on topics germane to the emergency physician, and considerations for special populations are reviewed.

Sonography for Deep Venous Thrombosis

Deep venous thrombosis (DVT) is a one of the most common problems facing the clinician in medicine today. It is often asymptomatic and goes undiagnosed with potentially fatal consequences. Ultrasound has become the "gold standard" in the diagnosis of deep venous thrombosis and with proper attention to technique sensitivity of this test is approximately 97%. An understanding of anatomy, pathophysiology, and risk factors is important. Thrombus formation usually begins beneath a valve leaflet below the knee. Approximately 40% will resolve spontaneously, 40% will become organized, and 20% will propagate. Whether or not a calf vein thrombus is identified, a repeat examination in 7 to 10 days is recommended in patients with risk factors or when deep venous thrombosis is suspected. The three main risk factors for thrombus formation are age greater than 75 years, previous history of deep venous thrombosis, and underlying malignancy. Other diagnostic studies include the contrast venogram, CT or MRI venogram, Tc99m Apcitide study, and the laboratory test D-Dimer. The D-Dimer study is being used more frequently as a screening test with 99% sensitivity in detecting thrombus, whether deep venous thrombosis or pulmonary embolism. However, specificity is only approximately 50% with many conditions leading to false-positive exams. Therefore, a negative examination is useful in avoiding other diagnostic studies, but a positive one may be misleading. Conditions that can lead to a false-positive examination include, but are not limited to diabetes, pregnancy, liver disease, heart conditions, recent surgery, and some gastrointestinal diseases. Like the sonogram, two negative D-Dimer studies a week apart exclude the diagnosis of deep venous thrombosis. Compression sonography with color Doppler remains the best overall test for deep venous thrombosis. It is easy to perform, less expensive than most "high tech" studies, can be performed as a portable examination, and is highly reliable when done properly.

Systematic review and meta-analysis of the diagnostic accuracy of ultrasonography for deep vein thrombosis

BACKGROUND

Ultrasound (US) has largely replaced contrast venography as the definitive diagnostic test for deep vein thrombosis (DVT). We aimed to derive a definitive estimate of the diagnostic accuracy of US for clinically suspected DVT and identify study-level factors that might predict accuracy.

METHODS

We undertook a systematic review, meta-analysis and meta-regression of diagnostic cohort studies that compared US to contrast venography in patients with suspected DVT. We searched Medline, EMBASE, CINAHL, Web of Science, Cochrane Database of Systematic Reviews, Cochrane Controlled Trials Register, Database of Reviews of Effectiveness, the ACP Journal Club, and citation lists (1966 to April 2004). Random effects meta-analysis was used to derive pooled estimates of sensitivity and specificity. Random effects meta-regression was used to identify study-level covariates that predicted diagnostic performance.

RESULTS

We identified 100 cohorts comparing US to venography in patients with suspected DVT. Overall sensitivity for proximal DVT (95% confidence interval) was 94.2% (93.2 to 95.0), for distal DVT was 63.5% (59.8 to 67.0), and specificity was 93.8% (93.1 to 94.4). Duplex US had pooled sensitivity of 96.5% (95.1 to 97.6) for proximal DVT, 71.2% (64.6 to 77.2) for distal DVT and specificity of 94.0% (92.8 to 95.1). Triplex US had pooled sensitivity of 96.4% (94.4 to 97.1%) for proximal DVT, 75.2% (67.7 to 81.6) for distal DVT and specificity of 94.3% (92.5 to 95.8). Compression US alone had pooled sensitivity of 93.8 % (92.0 to 95.3%) for proximal DVT, 56.8% (49.0 to 66.4) for distal DVT and specificity of 97.8% (97.0 to 98.4). Sensitivity was higher in more recently published studies and in cohorts with higher prevalence of DVT and more proximal DVT, and was lower in cohorts that reported interpretation by a radiologist. Specificity was higher in cohorts that excluded patients with previous DVT. No studies were identified that compared repeat US to venography in all patients. Repeat US appears to have a positive yield of 1.3%, with 89% of these being confirmed by venography.

CONCLUSION

Combined colour-doppler US techniques have optimal sensitivity, while compression US has optimal specificity for DVT. However, all estimates are subject to substantial unexplained heterogeneity. The role of repeat scanning is very uncertain and based upon limited data.

Augmentation in Lower Extremity Sonography for the Detection of Deep Venous Thrombosis

OBJECTIVE

The purpose of our study was to evaluate the usefulness of venous flow augmentation with duplex sonography in the evaluation of deep venous thrombus of the lower extremities.

CONCLUSION

The augmentation component of the lower extremity sonogram rarely provides additional information in the diagnosis of deep venous thrombus. In our large series, no deep venous thromboses were discovered with augmentation. Factors such as the lack of usefulness and patient discomfort may justify removal of augmentation from the routine study. However, augmentation should still be applied as a diagnostic tool in difficult or uncertain cases.

The incidence of deep vein thrombosis in elderly Chinese suffering hip fracture is low without prophylaxis: a prospective study using serial duplex ultrasound

PURPOSE

To investigate the incidence of deep vein thrombosis (DVT) among elderly Hong Kong Chinese patients suffering from acute hip fracture and to analyse the risk factors associated with DVT.

METHODS

A total of 100 consecutive Chinese hip fracture patients with a mean age of 80 years were investigated serially using duplex ultrasound scans preoperatively and at 1 week, 3 to 6 weeks, and 3 months postoperatively. No chemoprophylaxis or prophylaxis against DVT was given.

RESULTS

95 patients completed 3 duplex scans during hospitalisation; 5 (5.3%) of them were found to have developed DVT over the ilio-femoral venous segment. Of the 90 patients who had no DVT, 73 were reassessed 3 months after operation; one of them was found to have developed calf DVT. Older patients, chairbound or dependent patients, and patients living in institutions carried a higher risk of developing DVT.

CONCLUSION

This prospective study shows that the incidence of DVT developing after acute hip fracture in Chinese geriatric patients was low. We therefore do not recommend routine chemoprophylaxis for elderly patients with hip fracture.

Ultrasound diagnosis of deep venous thrombosis

The ultrasound diagnosis of deep venous thrombosis by an emergency physician is occurring with increased frequency. The examination is simple to perform and, when combined with a clinical pretest probability or D-dimer, can aid in the rapid disposition ofa patient with lower extremity pain and swelling. The technique and findings of the limited lower extremity ultrasound and the data to support its use in the emergency department are discussed.

Sonography and venography of the lower extremities for diagnosing deep vein thrombosis in symptomatic patients

The purpose of this study was to investigate the efficacy of sonography and the frequency of indeterminate sonographic examinations in the evaluation of patients with suspected lower extremity deep vein thrombosis (DVT). We prospectively evaluated 136 symptomatic patients (157 extremities) with suspected DVT using sonography and contrast-enhanced venography (n=106 patients, 115 extremities). Using venography as the reference standard for diagnosing DVT, the sensitivity and specificity of sonography was 92.8% and 98%, respectively, yielding an accuracy of 96.8%. The frequency of indeterminate examinations for calf DVT was 32.4%. One (0.7%) fatal pulmonary embolus occurred in our patients. The pulmonary embolism (PE) rate was 1.6% after lower extremity sonography with negative results. Sonography is highly accurate in detecting lower extremity DVT in symptomatic patients. Because of the high frequency of indeterminate studies in the calf and the associated possible risk of pulmonary emboli, we urge radiologists exercise additional caution when evaluating symptomatic patients with clinically suspected lower extremity DVT.

Randomized prospective study comparing routine versus selective use of sonography of the complete calf in patients with suspected deep venous thrombosis

OBJECTIVE

We compared patient outcomes using two protocols: one routinely and the other selectively evaluating the calves completely during sonographic assessment of the lower extremities in patients with suspected deep venous thrombosis.

SUBJECTS AND METHODS

In this randomized prospective study, patients were assigned to two groups. In one group, the deep calf veins were routinely evaluated in their entirety, and in the other group the calf was not evaluated unless the patient had symptoms or physical signs in the calf, in which case only the areas of symptoms or physical signs were evaluated. Patients were followed up for 3 months by medical record review, physician surveys, and telephone calls. An adverse outcome was a propagated deep venous thrombosis into the thigh or a pulmonary embolus. Examination times were recorded when possible.

RESULTS

Of the 235 patients in the group in which the deep calf veins were routinely evaluated, we saw no adverse outcomes (0.0%; 97.5% one-sided confidence interval [CI], 0.6-1.6%). Of the 261 patients in the group in which the calf was only evaluated if there were signs or symptoms, we saw two adverse outcomes (0.8%; 95% CI, 0.1-2.7%).

CONCLUSION

We found no significant difference in adverse outcomes in patients undergoing a protocol in which the deep calf veins were routinely evaluated or a protocol in which the calf was evaluated only if physical signs or symptoms were present.

Radiologic study of injection drug use complications

The complications of injection drug use (IDU) can lead to a wide variety of clinical problems that range from complications localized to the injection site to more disseminated disease. The radiologic workup of these problems uses multiple modalities, depending on the location and type of problem to be investigated. This article discusses and illustrates some of the local and disseminated complications that can occur after IDU.

CT of pulmonary thromboembolic disease

A good quality CT pulmonary angiogram has a high accuracy rate for the evaluation of pulmonary embolism. Investigators have reported that the subsegmental emboli can be missed; however, visualization of smaller arterial branches, and therefore, detection of small emboli may improve with the availability of multidetector scanners. Some of the advantages of using CT for pulmonary embolism compared with lung scintigraphy include: (1) direct visualization of emboli on CT, (2) evaluation of lung parenchyma and mediastinum, which may provide an alternate diagnosis, and (3) capability to acquire CT venogram without additional contrast with "one-stop examination" for evaluation of thromboembolic disease.

The diagnosis of lower extremity deep venous thrombosis

The diagnosis of lower extremity deep venous thrombosis (DVT) is critical to emergency physicians because of the risk of pulmonary embolism. This article reviews the diagnostic modalities available for patients with suspected lower extremity DVT. The use of compression ultrasonography and the recent advances in the D-dimer assays are emphasized. A clinical algorithm that utilizes a non invasive approach to this potentially life threatening disease is presented.

Surgeon-performed ultrasound imaging in acute surgical disorders

As the role of the general surgeon continues to evolve, the surgeon's use of ultrasound imaging will surely influence practice patterns, particularly for the evaluation of patients in the acute setting. With the use of real-time imaging, the surgeon receives "instantaneous" information to augment the physical examination, to narrow the differential diagnosis, or to initiate an intervention. With select ultrasound examinations, the surgeon can rapidly evaluate adult and pediatric patients with an acute abdomen, especially those patients who are hypotensive. In the hands of the surgeon, this noninvasive, bedside tool can assess more accurately the presence, depth, and extent of an abscess, confirm complete aspiration, or diagnose wound dehiscence before it is apparent on physical examination. Ultrasound imaging is so accurate for the diagnosis of pyloric stenosis that it has essentially replaced the upper gastrointestinal series in most institutions. The surgeon's use of ultrasound imaging to detect a pleural effusion has virtually supplanted the lateral decubitus radiograph. Furthermore, an ultrasound-guided thoracentesis not only facilitates the procedure but improves its safety. As surgeons become more facile with ultrasound imaging, it is anticipated that other uses will develop to further enhance its value for the assessment of patients in the acute setting.

Duplicated popliteal and superficial femoral veins: incidence and potential significance

BACKGROUND

Duplication of the popliteal and superficial femoral veins (PV, SFV) is a normal variant previously reported in up to 25% of limbs. Little clinical significance, however, has been attributed to this apparently common anomaly. The present study was designed to determine the incidence of duplications in individuals presenting for venous incompetence studies, and whether their presence could, in theory, act as a predisposing factor to deep venous thrombosis (DVT) formation.

METHODS

Duplex ultrasound examinations were performed in which venous duplications were actively searched for and recorded. The diameters of both limbs of any duplicated system and the single vessel immediately distal to it were recorded. Using these measurements, the changes in total cross-sectional area (CSA) associated with these anomalies were calculated. In addition, with the knowledge that the volume flow rate must remain constant, the velocity changes associated with such systems were calculated.

RESULTS

A total of 248 limbs from 177 patients was scanned. Duplications were found in 39 (15.7%) of these limbs. Of these, 30 limbs (77%) involved only the SFV, seven (18%) involved both the SFV and PV, and two (5%) involved only the PV. Short-segment SFV duplications were used to calculate the percentage change in total CSA and therefore blood flow velocities. Of the 13 (33%) suitable for such calculations, and calculating for each individual duplicated system, a mean increase in the vessel's total CSA of 42%, which corresponded to a theoretical decrease in blood flow velocity of 36%, was found.

CONCLUSION

The present study confirms the significantly high incidence of duplications of the PV and SFV and raises the possibility of the potential for DVT formation secondary to changes in flow velocities.

Calf sonography for detecting deep venous thrombosis in symptomatic patients: experience and review of the literature

PURPOSE

We determined the accuracy of sonography in the detection of isolated calf deep venous thrombosis (DVT) and the rate of indeterminate ultrasound examinations in patients with physical signs or symptoms suggestive of DVT.

METHODS

We reviewed the medical literature (MEDLINE) to determine the accuracy of sonography and the frequency of indeterminate studies in detecting isolated calf DVT in patients with physical signs or symptoms suggestive of DVT. A meta-analysis was used to derive summary measures of sensitivity, specificity, and accuracy from studies in which 5 or more isolated calf DVT were identified. Frequencies of indeterminate examinations were recorded for studies in which these data were provided, and we pooled these results with our own data for 196 patients.

RESULTS

The meta-analysis revealed that sonography correctly identified isolated calf DVT in 49 of 53 extremities (sensitivity, 92.5%; 95% confidence interval, 81.8-97.9%) and correctly identified the absence of calf DVT in 157 of 159 extremities (specificity, 98.7%; 95% confidence interval, 95.5-99. 9%), yielding an accuracy of 97.2% (95% confidence interval, 93.9-99. 0%) for ultrasound examinations considered diagnostic. However, when evaluating our patient population and the literature, we found a substantial number of indeterminate studies (overall rate of 54.6% in 463 extremities), with a wide variation in the reported frequency of indeterminate studies (9.3-82.7%).

CONCLUSIONS

Sonography is highly accurate in detecting isolated calf DVT in symptomatic patients, but indeterminate studies occur frequently, with a wide range of reported rates. Each ultrasound laboratory should evaluate its own rate of indeterminate studies.

Imaging evaluation of suspected pulmonary embolism

Venous thromboembolism (VTE) is a common disorder that is difficult to diagnose clinically but carries significant morbidity and mortality if untreated. Additionally, although demonstrated to be of benefit in cases of proven deep vein thrombosis (DVT) and pulmonary embolism (PE), anticoagulation therapy is not without risk. Because the clinical exam is known to be unreliable for the detection of both DVT and PE, many imaging modalities have been used in the diagnostic imaging algorithm for the detection of VTE, including chest radiography, ventilation/perfusion (V/Q) scintigraphy, pulmonary angiography, and recently, spiral computed tomography (CT) and magnetic resonance imaging (MRI). Chest radiographic findings in acute PE include focal oligemia, vascular enlargement, atelectasis, pleural effusions, and air space opacities representing pulmonary hemorrhage or infarction. The chest radiograph can occasionally be suggestive of PE but is more often nonspecifically abnormal. The main use of the chest radiograph in the evaluation of suspected PE is to exclude entities that may simulate PE and to assist in the interpretation of V/Q scintigraphy. Lower extremity venous compression ultrasonography (CU) is both sensitive and specific for the diagnosis of femoropopliteal DVT, and the value of negative CU results has been established in outcomes studies. However, the reliability of CU for the detection of isolated calf vein thrombosis is not well established, and the clinical significance of such thrombi is debatable. Additional methods such as color and spectral Doppler analysis are also useful in the diagnostic evaluation of DVT but are best considered as adjuncts to the conventional CU examination rather than as primary diagnostic modalities themselves. Compression ultrasonography and Doppler techniques are useful in the evaluation of suspected upper extremity DVT; spectral Doppler waveform analysis is particularly useful to assess for the patency of veins that cannot be directly visualized and compressed with conventional gray-scale sonography. V/Q scintigraphy has been the initial modality obtained in patients suspected of PE for a number of years. Although many studies have investigated the role of V/Q scintigraphy in the evaluation of VTE, the Prospective Investigation of Pulmonary Embolism Diagnosis (PIOPED) study has provided the most useful information regarding the utility of V/Q scintigraphy in this setting. A high probability scan interpretation is sufficient justification to institute anticoagulation, and a normal perfusion scan effectively excludes the diagnosis of PE. A normal/near normal scan interpretation also carries a sufficiently low prevalence of angiographically proven PE to withhold anticoagulation. Although the prevalence of PE in the setting of low probability scan interpretations is low and several outcomes studies have demonstrated a benign course in untreated patients with low probability scan results, patients with inadequate cardiopulmonary reserve do not necessarily have good outcomes. Such patients deserve more aggressive evaluation. Patients with intermediate probability scan results have a 20% to 40% prevalence of angiographically proven PE and thus require further investigation. The radionuclide investigation of DVT includes such techniques as radionuclide venography and thrombus-avid scintigraphy. Although these methods have not been as thoroughly evaluated as CU, studies thus far have indicated encouraging results, and further investigations are warranted. Pulmonary angiography has been the gold standard for the diagnosis of PE for decades. Studies have indicated that angiography has probably been underutilized by referring physicians for the evaluation of suspected PE, likely because of the perception of significant morbidity and mortality associated with the procedure. (ABSTRACT TRUNCATED)

Exclusion and diagnosis of deep vein thrombosis by a rapid ELISA D-dimer test, compression ultrasonography, and a simple clinical model

The classical clinical signs of deep vein thrombosis (DVT) are unspecific and may be found in several other conditions besides DVT. Therefore, patients suspicious of DVT are subjected to elaborate invasive or noninvasive evidence-based procedures that actually confirm DVT in only 20% to 30% of patients in this setting. However, simple laboratory tests and noninvasive strategies to exclude and diagnose DVT are becoming available in the clinical emergency setting of outpatients. In the presented literature, a sound basis is provided for quantifying clinical judgment for the diagnosis of acute proximal DVT. The number of positive clinical findings at time of first suspicion of DVT appears to correlate directly with the probability of acute proximal DVT. The modified clinical model of Landefeld and Wells for DVT allows reasonable accurate classification of patients into low, moderate, and high probability for suffering DVT. The rapid automated enzyme-linked immunoabsorbant assay (ELISA) VIDAS D-dimer presently available can be rapidly performed in daily practice and emergency situations and is accurate to a high degree, especially in ruling out ongoing venous thromboembolic processes. The sequential use of the rapid ELISA VIDAS D-dimer test and compression ultrasonography in a well-designed clinical setting using a simple clinical model predicts a significant improvement due to a high sensitivity near 100% for the exclusion and diagnosis of DVT in the majority of outpatients with suspect DVT. A prospective decision analysis management study is proposed to exclude and diagnose DVT based on the rapid ELISA VIDAS D-dimer test and compression ultrasonography within the context of a ready-to-use simple clinical model. The proposed simple model of a rational diagnosis of deep vein thrombosis (RADIA DVT) has to be tested in a large multicenter study of more than 1,000 outpatients with suspected DVT. This model would be less expensive, easy to perform, and likely yield a significant simplification and improvement of highly accurate evidence-based exclusion or diagnosis of DVT on the basis of which clear-cut indications of anticoagulation could be appropriately initiated or safely withheld.

Diagnostic role of ED ultrasound in deep venous thrombosis and pulmonary embolism

Proximal deep venous thrombosis (DVT), which may lead to pulmonary embolism (PE), is one of the serious and underrecognized causes of lower extremity pain and swelling. The diagnosis of DVT requires a confirmatory objective test because clinical signs and symptoms are unreliable. Assessment of thigh vein compressibility with real-time ultrasound is an accurate test for DVT that may be performed rapidly at the bedside. Although unproven, we propose that wider use of this test in the emergency department by emergency physicians might increase the diagnosis of DVT, prevent PE, and reduce utilization of other more costly and invasive diagnostic tests. Evaluation of DVT by compression ultrasound may also be incorporated in the diagnostic workup of suspected PE. In the case of a nondiagnostic ventilation/perfusion scan, demonstration of proximal DVT by ultrasound represents a likely source of PE and an indication for anticoagulation, eliminating the need for pulmonary angiography. In the critically ill patient whose presentation is consistent with massive PE, one rapid approach to the diagnosis may be to combine transthoracic echocardiography with lower extremity ultrasound.

Doppler respiratory patterns in the femoral veins with pelvic vein obstruction

An appropriate Doppler response to valsalva in the common femoral veins has been described previously as excluding a more proximal venous obstruction. We describe our experience in three patients in whom an appropriate response to valsalva did not exclude a more proximal pelvic venous obstruction. Dampening of the Doppler waveforms on the affected side when compared with the opposite limb led to the diagnosis of proximal venous obstruction.

Clinically important pulmonary emboli: does calf vein US alter outcomes?

PURPOSE

To assess whether calf imaging is necessary to identify patients at risk for developing clinically important pulmonary emboli (PE) or propagation of calf deep venous thrombosis (DVT) when the initial thigh ultrasonographic (US) scan is negative for DVT.

MATERIALS AND METHODS

The authors retrospectively evaluated the radiology reports from 283 patients (168 female and 115 male patients; mean age, 55.7 years; age range, 1-93 years) in whom US was performed to rule out lower extremity DVT. In all patients, the initial thigh examination was negative for DVT. All patients were classified as to the reason for the examination, risk factors for DVT (including recent surgery), whether they received anticoagulation therapy, and findings on calf US scans. Adverse outcomes were considered a clinically important PE or DVT in the thigh.

RESULTS

Only 1.1% of patients (95% CI = 0.2%, 3.1%) had adverse outcomes. Adverse outcomes occurred only in postsurgical patients (P = .028) and were not related to the presence or absence of calf DVT or method of treatment.

CONCLUSION

US of the calf is unnecessary at initial evaluation to identify patients at risk of clinically important PE or propagation of DVT into the thigh.

Developments in diagnosis and classification of venous disorders: non-invasive diagnosis

PURPOSE

This review examines the many techniques that have been used for the non-invasive diagnosis of acute and chronic venous disease and was conducted by members of the Committee on Research of the American Venous Forum. It proposes to identify those techniques with the greatest clinical potential, to suggest algorithms for the clinical application of non-invasive techniques in the identification of acute deep venous thrombosis and chronic venous insufficiency, and to identify areas of deficient knowledge and potential areas for future research initiatives.

METHODS

Review of pertinent clinical and research material.

RESULTS

Impedance plethysmography and ultrasonic imaging are the primary non-invasive tools used in the diagnosis of acute deep venous thrombosis. At present, ultrasonic imaging techniques are recommended on the basis of greater diagnostic accuracy in recent comparative clinical trials. Data would suggest that serial evaluation should probably be viewed as the preferred option for symptomatic patients with a negative initial examination and the presence of risk factors or physical findings suggesting a proximal deep venous obstruction/thrombosis. Chronic venous disease is the result of valvular incompetence, with or without associated venous obstruction. Duplex imaging can be used to determine the location and extent of reflux; however, there are reported procedural variations in the performance and interpretation of such studies. Recent innovations in air plethysmography may provide a means of quantifying volume changes, and permit an objective characterization of venous reflux and calf pump efficiency.

CONCLUSIONS

There are still significant questions that need to be answered by well-designed research initiatives. Research applications that incorporate non-invasive diagnostic techniques may involve the diagnosis, treatment and natural history of acute deep venous obstruction/thrombosis and chronic venous insufficiency, assessment prior to and following venous reconstruction, and the basic science aspects of acute and chronic venous disease. At present, a lack of common standards is, by far, the greatest impediment to an organized research approach to venous disease.

Diagnosis of deep venous thrombosis of the lower limbs: it is premature to introduce ultrasound as a routine method

Ultrasound is sometimes employed as an alternative technique to phlebography in the diagnosis of deep venous thromboses (DVT). To evaluate the efficacy of ultrasound, 74 patients suspected of DVT in the lower limbs were examined with both ultrasound and phlebography. The results indicate that positive reports following ultrasound examination are reliable but that negative reports are not very dependable. The authors urge, therefore, a degree of caution before ultrasound is introduced as a routine method in hospital care.

Ultrasound screening for deep venous thrombosis after total knee arthroplasty. 2-year reassessment

The efficacy of ultrasound compared with ascending venography for the detection of deep venous thrombosis immediately after total knee arthroplasty was assessed after a 2-year interval. One hundred thirty-seven patients were eligible for the study; however, 31 patients received only one of the screening methods and a color Doppler examination was inconclusive in six patients. Therefore, 100 patients had a Doppler examination and a venogram. Overall, the sensitivity of ultrasound was 85%, the specificity 97%, the positive predictive value 85%, the negative predictive value 97%, and the accuracy 95%. The sensitivity in the calf was 83%, in the popliteal vein 86%, and in the femoral vein 100%. Two years ago, the initial assessment of ultrasound for the detection of deep venous thrombosis after surgery in patients who had total joint arthroplasty revealed a 75% sensitivity, 99% specificity, 91% positive predictive value, 97% negative predictive value, and 97% accuracy. The sensitivity in the calf was 83%; the sensitivity in the popliteal vein was 40%; and the sensitivity in the femoral vein was 50%. After 2 years of using this screening test with one technician and one radiologist, an improvement with this noninvasive technique was shown. However, it was found that Doppler imaging is not as sensitive as venography for detecting calf thrombi. Any imaging technique should be validated by each institution to determine the validity of the instrument and the learning curve of the technician administering the examination.

Diagnostic management of venous thromboembolism

The accuracy of diagnostic methods for the diagnosis of deep vein thrombosis and pulmonary embolism in symptomatic patients is critically reviewed. In addition, the safety of withholding anticoagulant therapy from patients with suspected deep vein thrombosis or pulmonary embolism in whom the qualified diagnostic strategy was normal is evaluated by determining the frequency of venous thromboembolic complications during 3 months of follow-up. It is shown that the currently used available diagnostic techniques for deep vein thrombosis are all able to identify the majority of patients who indeed have venous thrombosis. However, as result of its accuracy and practical advantages, compression ultrasound is the test of choice in the evaluation of symptomatic patients. Patients with a normal test outcome should be re-tested to detect the small proportion of patients with proximally extending calf vein thrombosis. In the strategy of repeated diagnostic testing, impedance plethysmography could be used as an alternative to ultrasonography. To obtain a reduction in repeat tests various diagnostic strategies have been evaluated and it was shown that these strategies, using non-invasive tests, can be as accurate and safe as the invasive reference strategy. The safeties of the various strategies were very similar; however, important differences were observed with respect to the practical implementation of the various diagnostic strategies. Simplification of the repeated testing strategy by using a D-dimer assay and/or a clinical decision rule seems to be promising. The reference standard for the diagnosis of pulmonary embolism remains pulmonary angiography. Several strategies based on non-invasive diagnostic methods have been evaluated for their safety and complexability. Perfusion-ventilation lung scanning is the most thoroughly evaluated non-invasive technique so far. It seems safe to withhold anticoagulant therapy in patients suspected of pulmonary embolism with a normal perfusion lung scan result; however, further testing is needed in the case of a non-diagnostic perfusion-ventilation lung scan result. At this moment angiography is the method of choice in this category of patients. D-dimer assays, clinical decision rules and ultrasound examinations of the legs seem to have a high potential to limit the need for angiography. Also, spiral computerized tomography and magnetic resonance imaging are promising techniques, but their role in the diagnostic management of pulmonary embolism is still uncertain.

Diagnosis of acute lower limb deep venous thrombosis with ultrasound: trends and controversies

Acute deep venous thrombosis of the lower limb is a common and threatening condition whose clinical diagnosis is known to be unreliable. Sonography has gradually superseded venography as the primary diagnostic procedure. A review of the medical literature shows that sonography offers a high level of sensitivity and specificity in symptomatic patients but suffers from a lack of sensitivity at the calf level and in asymptomatic patients. Technologic progress, as well as increased operator experience, may improve sensitivity. Nevertheless, several critical issues remain unresolved, such as the significance of free-floating thrombi, the usefulness of calf and bilateral examination, the criteria that are essential to the diagnosis, the risk of compression sonography, and sonography's role in the direct detection of venous emboli.

Fate of free flap microanastomosis distal to the zone of injury in lower extremity trauma

The decision to perform free flap microanastomosis to clearly uninjured vessels proximal to the zone of injury for lower extremity reconstruction must be weighed against the anatomic and technical difficulties of performing such an anastomosis. Preserved blood flow through vessels traversing the zone of injury has been shown. The records of all patients who underwent lower extremity reconstruction with microvascular free flaps at NYU Medical Center and Bellevue Hospital Center from January 1979 through August 1995 were reviewed. Patients with free flap microanastomoses distal to the zone of injury were compared with those with proximally based anastomoses. The group of patients was subdivided further into acute (1-21 days), subacute (22-60 days), and chronic (greater than 60 days) reconstruction groups. Of 451 microvascular free flaps, 35 were performed with recipient vessels distal to the zone of injury. Time interval from injury to coverage ranged from 24 hours to 57 years. Of 35 distally based flaps, 33 (94 percent) were successful and 5 required reoperation (14 percent). There was a similar incidence of thrombotic complications throughout all after-injury phases. Of 416 free flaps performed with microanastomoses to vessels proximal to the zone of injury, 388 (93 percent) were successful and 62 (15 percent) required reoperation. There was no significant difference (p > 0.05) in outcome between distal and proximal anastomoses and no significant difference (p > 0.05) in rates of reoperation. Timing of operation after injury had no bearing on outcome. Distally based microvascular free flaps anastomoses may be technically less difficult with rates of survival equal to those of proximally based flaps. The consideration and use of microanastomoses distal to the zone of injury are encouraged in selected patients.

Duplex scanning in the postoperative surveillance of patients undergoing total hip arthroplasty

Color flow duplex imaging is a well-established method for the diagnosis of deep vein thrombosis in symptomatic patients; however, the sensitivity and specificity of duplex scanning compared with venography in high-risk asymptomatic patients are not known. Consecutive patients undergoing total hip arthroplasty who consented to have bilateral venography on days 8 to 12 were included in this prospective study. One hundred and fifty-one venograms were finally obtained in 78 patients. All duplex scanning was performed with the Ultramark 9 ATL (Advanced Technology Laboratories) by one investigator. In the beginning of the study, the first 44 legs, only the femoropopliteal segment was tested and the result was based on B-mode compression; the sensitivity for the duplex was 56% (5/9), and the specificity, 94% (33/35). In the next 107 legs, the addition of color to our criteria improved the sensitivity of the duplex scan from 55% to 93% (13/14) for the femoropopliteal segment and the specificity from 94% to 99% (92/93). For the calf segment, in the same 107 legs, using the color facility of the duplex, the sensitivity and specificity were 79% (15/19) and 97% (85/88), respectively. The color facility of new-generation machines makes duplex scanning reliable for the detection of proximal deep vein thrombosis, even in asymptomatic high-risk patients. For the detection of calf deep vein thrombosis, however, more experience is needed. A larger study is necessary to confirm these preliminary data.