Duplex ultrasound (DUS) examination is based on a combination of ultrasound imaging and pulsed wave Doppler with which information can be obtained on both the anatomy and the hemodynamic features of the venous system. Additional color flow imaging is routinely employed to quicken and improve DUS accuracy.1
Ultrasound for the evaluation of deep vein thrombosis (DVT)
The annual incidence of a first episode of symptomatic DVT in the adult population ranges from 50 to 100 per 100,000 population.8 Risk factors for VTE, such as older age, malignancy, inflammatory disorders, and inherited thrombophilia, are associated with higher risk of VTE.49 Sixty percent of all VTE events occur in patients aged > 65 years.50 Deep vein thrombosis of the lower extremities can be associated with significant morbidity and may progress to pulmonary embolism and post thrombotic syndrome. Early diagnosis and treatment are important to minimize the risk of these complications.3
Karande et al12 conducted a review of advanced imaging in acute and chronic deep vein thrombosis. Deep venous thrombosis affecting the extremities is a common clinical problem. Prompt imaging aids in rapid diagnosis and adequate treatment. Deep venous thrombosis is a major cause of morbidity and mortality all over the world. It commonly occurs in the lower extremity and is associated with life threatening complication of PE referred together as VTE. The main cause of DVT is stasis of the blood flow.
Venous ultrasonography is the first-line imaging test when DVT is suspected.3-7 Ultrasonography findings in the presence of DVT include venous non-compressibility, direct thrombus visualization with venous dilation, and abnormal spectral and color Doppler blood flow.3,4
One study evaluated the diagnostic accuracy of various ultrasonography methods in the emergency room. Both 2-point and 3-point point-of-care compression ultrasound (POCUS) techniques showed excellent performance for the diagnosis of DVT.9
Bhatt et al3 and Kraaijpoel et al5 conducted two systematic reviews that were similar in their focus, study population and yielded similar results. The sensitivity and specificity for three different ultrasound techniques (limited compression ultrasound [CUS] serial ultrasound, and whole leg CUS) were above 90%. They share the same strength of evaluation on US in DVT in a large patient population. Weaknesses: the gold standard varied across studies, older studies using venography and newer studies using clinical follow-up. The authors also pointed out the large heterogeneity across studies including different DVT prevalence, experience of the ultrasonographers and ultrasonography technology.
Ortel et al documented the evidence-based guidelines from the American Society of Hematology (ASH) for management of venous thromboembolism and treatment of deep vein thrombosis and pulmonary embolism. For patients with unprovoked deep vein thrombosis and/or pulmonary embolism, the ASH guideline panel suggests against routine use of prognostic scores, D-dimer testing, or ultrasound to detect residual vein thrombosis to guide the duration of anticoagulation.23 Follow-up US can be obtained in patients with known venous thrombosis on therapy and who undergo a clinical change and where a change in thrombus burden will alter treatment.2,14
DVT could be asymptomatic, is usually unilateral and is clinically suspected in patients presenting with acute-onset pain, swelling, erythema and/or warmth of the lower extremity involved.3,10 The American Institute of Ultrasound in Medicine (AIUM) published a paper with practice parameters for the performance of point-of-care ultrasound examinations. Limitations of the point-of-care examination of the lower extremity are body habitus and the inability to identify key anatomic points. Any uncertainty in the examination should prompt a full lower extremity Doppler examination. The main limitation of the point-of-care examination is its operator dependency. The operator must be knowledgeable in its clinical use and be appropriately trained in image acquisition and in interpretation of the findings.2
Both clinical evaluation and objective tests are required to make a diagnosis of VTE. Wells score is a validated clinical decision rule to estimate the pretest probability for acute DVT in ambulatory settings. It is intended to be combined with ultrasound or D-dimer for suspected cases. The score ranges from less than two (low risk) to above two (intermediate/high risk) and is combined with D-dimer determination.4,6,7,13
Venous US should be performed in the investigation of confirmed PE.2,6,10,14
Currently recommendations are mostly based on the efficiency and safety of the individual strategies and society guidelines, as randomized controlled trials (RCTs) with direct comparisons between strategies are scarce. From a practical point of view, a single diagnostic examination may be preferred over a serial approach as the latter implies that the patient must return for a second examination when the first examination was negative for DVT. However, performing whole-leg CUS may not always be feasible, for example at the emergency department with limited time to examine the patient or when CUS is performed at the bedside by less experienced ultrasonographers.3 The only recent RCTs are addressing performance of point-of-care US, a rapidly evolving field due to technological advances of US and wide adoption by non-radiologists.3,5
In summary, the body of peer-reviewed literature concerning peripheral venous ultrasound to diagnose deep vein thrombosis is sufficient to establish the analytic validity, clinical validity, and clinical utility of this test in the Medicare population.
US for the evaluation of chronic venous insufficiency (CVI) and chronic venous disease (CVD)
In the United States, approximately 25% of adult people are impacted by CVD. Several diagnostic and treatment modalities have been implemented over the past decade. Prospective, randomized studies comparing a hand-held Doppler (HHD) examination with DUS examination have not been performed since DUS examination became the standard of care in the 1980s. However, the studies in this current systematic review do confirm that DUS examination provides more objective, reproducible information for treatment and is more useful regarding the location of superficial reflux, the extent of the reflux, the size of the refluxing vein throughout its course, the depth of the entire vein, and whether it is above or below the superficial fascia.51
Farah et al51 conducted a systematic review that included DUS examination to diagnose saphenous vein incompetence in patients with varicose veins. They only included two old comparative observational studies that included 110 patients (151 limbs), a mean age of 45.5 years. The primary outcomes were the incompetence of the saphenofemoral junction (SFJ), sapheno-popliteal junction, great saphenous vein, which was defined as (retrograde flow in the great saphenous vein of >500 ms). The evidence supports duplex scanning for evaluation of patients with varicose veins and confirms that high ligation and stripping (HL/S) resulted in similar long-term saphenous vein closure rates as endovenous laser ablation (EVLA) and in better rates than radiofrequency ablation and ultrasound-guided foam schlerotherapy (UGFS). Thermal interventions were associated with inferior general quality of life scores than nonthermal interventions, but had a lower risk of recurrent incompetence than UGFS. The quality of evidence was rated as B due to small sample size, however we believe that it should have been rated C as there were no randomized controlled studies included in the analysis.
Chronic venous insufficiency is a common but underdiagnosed cause of leg pain and swelling, and it is frequently associated with varicose veins. The effects of CVI can cause changes in the skin and subcutaneous tissues, such as edema, hyperpigmentation, and lipodermatosclerosis. It is a consequence of the dysfunction of the valve of the veins, associated with an impaired circulation of blood in the leg veins. The most accurate exam is a venous duplex ultrasound scan, that provides an accurate image of the vein, so that any blockage caused by blood clots or improper vein valve function can be detected. Clinical signs/symptoms can include pain and edema of the lower extremities, venous stasis ulcers, aching, itching, lipodermatosclerosis, and skin pigmentation. Duplex scanning of the lower extremities is recommended as a first line diagnostic test in all patients with chronic venous insufficiency. Venous duplex imaging is currently the most common technique used to confirm the diagnosis of CVI and assess its etiology and anatomy and is highly recommended in the Clinical Practice Guidelines (CPG) of the Society of Vascular Surgery and American Venous Forum of 2011. Duplex ultrasonography is a simple, noninvasive, painless, and readily available modality that can assess the anatomy and physiology of the lower extremity venous system.1,15,16,17,18
The American Institute of Ultrasound in Medicine (AIUM), The American College of Radiology (ACR), the Society for Pediatric Radiology (SPR), and the Society of Radiologists in Ultrasound (SRU) and the Society for Vascular Ultrasound (SVU) published papers with performance guidelines that support lower extremity venous duplex ultrasound is an appropriate evaluation of varicose veins.2,14,16,52
In summary, the body of peer-reviewed literature concerning peripheral venous ultrasound to diagnose chronic venous insufficiency and chronic venous disease is sufficient to establish the analytic validity, clinical validity, and clinical utility of this test in the Medicare population.
Preoperative US Examinations
The venous DUS study provides data not only on reflux time and the size of each superficial vein, but also anatomic location, helping to differentiate between a duplicated superficial truncal vein and an accessory vein, as well as the depth and extent of the reflux. In addition, a DUS examination can identify perforating veins along the path of the truncal vein. All this additional information may have important therapeutic implications.51
Advantages of extremity venous Duplex US are that it is readily available, quick, cost effective, noninvasive, devoid of ionizing radiation, lacks need for intravenous contrast and can be portable for critically ill patients prone for developing DVT.12
The AIUM published a practice guideline that recommended peripheral venous ultrasound examinations for venous mapping before surgical procedures.2,14
Limitations include operator dependency, technical difficulties and decreased sensitivity in patients with obesity, edema, tenderness, recent hip or knee arthroplasty, cast, overlying bandages and immobilization devices. It also has limitations in patients who had previous DVT and have new symptoms shortly after treatment.12
The ACR-SPR-SRU guidelines indicate that venous US is intended for use by health care providers. Diagnostic ultrasound examinations should be performed only when there is an appropriate clinical indication.53 They recommend a permanent record of the ultrasound examination and its interpretation.14 All diagnostic ultrasound examinations should be supervised and interpreted by trained and qualified physicians.53
Linni et al21 conducted a prospective randomized trial to study the effect of preoperative duplex vein mapping (DVM) of the great saphenous vein (GSV) prior to cardiac bypass surgery. The study found that preoperative DVM in patients undergoing infrainguinal bypass surgery does not speed up surgery, shorten incisions, avoid technical errors, or improve bypass patency. However, preoperative DVM and marking of the ipsilateral GSV does avoid unnecessary surgical exploration and an intraoperative change of surgical strategy, which leads to a significant reduction of postoperative major surgical site infections (SSIs) and consecutive readmissions. The method should become standard technique in the preoperative diagnostic setting of patients undergoing infrainguinal bypass grafting. Routine DVM should be recommended for infrainguinal bypass surgery. The study found that preoperative DVM significantly avoids unnecessary surgical exploration, development of major SSI, and reduces frequency of readmissions for SSI treatment.
Media et al22 performed a systematic literature review to evaluate the effect of preoperative ultrasound mapping of the saphenous vein on leg wound complications after coronary artery bypass surgery. A systematic literature search was conducted in PubMed, Cochrane, and Embase databases. Extraction of relevant data was performed including study characteristics, patient characteristics, and all reported outcomes. Ultrasonography for preoperative vein mapping has been used to assess and determine the anatomical course of the long saphenous vein (LSV), thereby facilitating rapid and accurate location of the vein during surgery. Furthermore, preoperative vein mapping has been suggested to be of value in patients whose veins are not evident by physical examination due to edema, multiple varicosities, or complex saphenous vein anatomy. Thus, unnecessary incisions can be avoided reducing complications at incision sites and wound healing disturbances. The primary outcome was occurrence of leg wound complications following harvest of the saphenous vein. The secondary outcome was additional leg incision, leg incision length, and harvest time. Of 4,514 papers screened in this systematic review, 36 papers underwent full-text assessment with final inclusion of five studies: three observational studies, and two randomized trials. The two RCTs showed no effects of preoperative ultrasound. Data from the three non-randomized studies was pooled in a meta-analysis, which suggested a significant reduction in the risk of harvest wound complications by ultrasound mapping prior to surgery (RR 0.32; 95%CI = [0.19–0.55]). The findings indicate that preoperative vein mapping leads to a better preoperative qualitative assessment of the LSV thus possibly reducing harvest site infection, incision lengths, the need for additional incisions, and harvesting times as compared to blind leg incision.
In summary, the body of peer-reviewed literature concerning peripheral venous ultrasound for preoperative examination prior to bypass surgery is sufficient to establish the analytic validity, clinical validity, and clinical utility of this test in the Medicare population.
Post-procedure assessment of venous ablation
Healy et al19 conducted a systematic review and meta-analysis to determine the incidence of thrombotic events following GSV endovenous thermal ablation (EVTA). Eligible studies were RCTs and case series that included at least 100 patients who underwent GSV EVTA (laser ablation or radiofrequency ablation [RFA]) with duplex ultrasound (DUS within 30 days). The systematic review focused on the complications of endovenous heat induced thrombosis (EHIT), DVT, and PE. There were 52 studies analyzed (16,398 patients). A total of 731 records were selected after screening. Regarding study participants, females outnumbered males and the mean age of participants in the studies ranged from 38 years to 61 years. The timing of the first DUS ranged from one day to one month. Considerable variation regarding the timing of postprocedural DUS was noted. Forty-two of the included studies in this review reported that the first postprocedural DUS took place within one week. The optimal timing of post-procedural DUS for the most efficient and accurate detection of EHIT remains unclear but may become apparent as understanding of the natural history of EHIT improves.
In an author manuscript, Itoga et al20 reviewed data in the Truven Health Marketscan Database, a comprehensive national private insurance claims database, to identify patients who underwent RFA or laser ablation (LA). The authors sought to describe the risk factors for, and incidence of DVT after RFA and LA. Despite the relative safety of these techniques, LA and RFA may cause EHIT which can cause the clot to extend or propagate leading to DVT. In rare cases LA and RFA procedures may also lead to PE. A total of 256,999 patients underwent 433,286 ablation procedures: 192,195 (44.4%) RFA and 241,091 LA. Of these, 8,203 (1.9%) had a newly diagnosed DVT within seven days and 13,347 (3.1%) within 30-days of the procedure. Lower extremity ablation procedures were included if they had a follow-up duplex ultrasound within 30 days of an ablation procedure. The incidence of newly diagnosed DVT within 30-days of an ablation procedure was 3.2%. The risk for DVT decreased in recent years and LA was associated with an 18% decreased risk compared to RFA. Results suggest that the timing postoperative screening might affect reports of thromboembolic complications. Currently, guidelines recommend routine duplex ultrasound within two to three days of surgery to screen for thromboembolic complications; others recommend screening within a week of surgery.
In summary, the body of peer-reviewed literature concerning peripheral venous ultrasound for post procedure assessment following venous ablation is sufficient to establish the analytic validity, clinical validity, and clinical utility of this test in the Medicare population.
Post Procedure Assessment of Venous Ablation
Shutze et al42 conducted a retrospective observational study of patients that underwent EVLA in the outpatient setting. Their hypothesis was that the incidence of EHIT depends on the laser wavelength used in EVLA of the saphenous veins. There were 1,439 veins ablated in 1,109 patients. Patients may develop postablation thrombosis of the common femoral vein after EVLA or RFA of the GSV. It can also occur in the popliteal vein after treatment of the small saphenous vein (SSV). This type of venous thrombosis has been termed EHIT to differentiate it from DVT because it has a different etiology, ultrasound characteristic, and course. Postoperatively, patients were placed in compression bandages or stockings. Ultrasound was done immediately and again approximately one week following the procedure to confirm the absence of thrombus in the adjacent deep vein system. The authors concluded that laser wavelength has a more significant effect on EHIT than the amount of energy delivered – linear endovenous energy density (LEED). A higher LEED is associated with higher closure rates. LEED and laser wavelength are independent factors.
Ryer et al43 conducted a retrospective observational study to evaluate patients that underwent endothermal ablation of the GSV. Endothermal ablation of the GSV is associated with a small but definite risk of EHIT extending into the common femoral vein. Follow-up duplex ultrasound imaging to detect EHIT after ETA is considered standard of care, although the exact timing of duplex ultrasound imaging to detect EHIT after ETA remains unclear. The authors hypothesized that an additional duplex ultrasound assessment one week after ETA would not identify a significant number of patients with EHIT and would significantly increase health care costs. Once the vein was treated, patients were placed in a compressive dressing. All patients (n=842) underwent preoperative and at least one postoperative ultrasound assessment on clinic day one, and 662 patients (79%) underwent a second delayed duplex ultrasound scan one week later. In the study of 842 consecutive GSV ETAs, the authors identified 43 with EHIT requiring anticoagulation. Of the 43 patients with EHIT, 20 (47%) were found on the initial ultrasound assessment performed 24 hours postprocedure, but 19 patients (44%) with EHIT were found on ultrasound assessment one week later. The authors concluded that a significant number of EHIT cases involving the common femoral vein are not identified with a single day 1 postprocedural duplex examination. Delayed duplex ultrasound scanning after GSV ETA comes with associated health care costs but does yield a significant number of patients with progression to EHIT.
In summary, the submitted literature submitted by the provider supported that post procedure assessment with venous ultrasound can be performed one week following a vein ablation procedure. The literature supports removing the 72 hour guideline.
Performance of Multiple Non-invasive Studies on the Same Encounter or Same Day
Ten publications were informational guides or articles that did not support the performance of multiple non-invasive studies on the same day. The informational guides discussed vascular anatomy, duplex ultrasound mechanics, patient information, chronic venous disease, peripheral artery disease, treatment of varicose veins, ankle-brachial index, deep vein thrombosis, and other diagnostic tests such as venography.30,32,33,34,35,36,37,38,39,40
Two publications were guidelines that had no new information to support the performance of multiple non-invasive studies on the same day or had outdated information. The guidelines included a patient guide for the venous ultrasound procedure and clinical recommendations for physicians for the diagnosis and treatment of peripheral artery disease.28,31
One publication was a single-center retrospective study that analyzed patients with type 2 diabetes mellitus who concurrently underwent ankle-brachial index (ABI) testing and carotid intima-media thickness (CIMT) measurements and color Doppler ultrasonography.48
One publication was a practice guideline from the American College of Cardiology (ACC) and the American Heart Association (AHA) to provide recommendations applicable to patients with or at risk of developing cardiovascular disease. The guideline included clinical assessment, diagnostic testing, screening, medical therapy, structured exercise therapy, and other treatments for peripheral arterial disease (PAD).27
One publication was a cross-sectional study that evaluated the use of a handheld doppler to obtain ABI to evaluate for PAD. The study was conducted greater than 10 years ago.46
One publication was a systematic review and evidence report that reviewed the evidence on the benefits and harm of screening for PAD using the ABI. The publication did not evaluate utilization, indications, or benefits of the venous ultrasound for diagnosis of vascular abnormalities.26
One publication was a review article that evaluated the basic scanning techniques of color and pulsed-wave Doppler US for the lower extremity arteries and the spectral analysis of normal and stenotic arteries on pulsed-wave Doppler US.29
One publication was a longitudinal observational study to evaluate the association between large-vessel PAD with mortality due to coronary heart disease, cardiovascular disease, and all causes. The study was performed in 1992 and does not support current evidence.41
Leng et al44 published a cohort study with 1,592 subjects that aimed to determine whether low ankle pressure ABI was associated with an increased risk of cardiovascular events and death and whether the prediction of such events could be improved by including this index. The study was published in 1996 and is too outdated to be used as a source of evidence-based practice.
Nicolaides45 published a consensus document that provides an explanation of the various methods available for the investigation of CVI of the lower limbs, with an outline of their history, usefulness, and limitations. The document describes several methods that can be used to perform duplex scanning for the diagnosis of deep vein thrombosis. The authors conclude that there is no one test that can give all the answers needed but do not specify the timeline of testing or the use of noninvasive venous testing together on the same day.45
AbuRahma et al47 published a retrospective review that analyzed the resting ABI in the diagnosis of symptomatic PAD. The conclusions of the study suggest that further testing may be needed for patients with PAD than just ABI, toe-brachial index (TBI), or doppler US testing. It does not suggest or recommend against multiple tests in one day, lower and upper extremity testing at the same time (minus ABI use), and it excluded patients with arterial occlusive disease.
In summary, the literature submitted by the provider included information on the symptoms, diagnosis, and treatment of PAD and venous thromboembolic disease. The literature lacked any strong or current evidence to support the performance of multiple non-invasive studies on the same day. There is no literature to support the use of peripheral venous ultrasound studies with arterial studies on the same day.
Our literature search supports the use of ultrasound venous studies in the evaluation of the following clinical scenarios: deep venous thrombosis, chronic venous insufficiency, preoperative vein mapping and post procedure assessment of venous ablation. Systematic reviews, clinical guidelines and RCTs support the use of venous ultrasound as the standard test to identify irregularities in blood flow in the venous system. There is a paucity of new RCTs in the literature.