Diagnostic evaluation of lower extremity chronic venous disease

INTRODUCTION — Clinical manifestations such as edema, varicose veins, skin changes, and venous ulceration are often indicative of chronic venous disease of the lower extremities. However, additional imaging or other tests might be needed to localize the anatomic distribution of the culprit veins (eg, deep versus superficial, infrainguinal versus more proximal venous disease) and its pathology (reflux, obstruction, or reflux and obstruction).

Findings on imaging and diagnostic testing are used to correlate the patient's symptoms, but in some cases, a patient may have findings of venous reflux or venous obstruction on duplex ultrasound examination but may not experience symptoms if the disease is mild. On the other hand, a patient may present with symptoms that mimic venous disease but have test findings that are negative because symptoms are due to another etiology. Thus, it is always important to correlate the findings of venous testing with clinical symptoms to confirm that it is causal.

The diagnostic tests available to evaluate the patient with suspected chronic venous disease are reviewed here. The pathophysiology, clinical manifestations, and treatment of this disorder are discussed separately.

●(See "Overview of lower extremity chronic venous disease".)

●(See "Pathophysiology of chronic venous disease" and "Clinical manifestations of lower extremity chronic venous disease".)

●(See "Approach to treating symptomatic superficial venous insufficiency" and "Evaluation and management of chronic venous insufficiency including venous leg ulcer".)

APPROACH TO VENOUS EVALUATION — Chronic venous disease is a spectrum that can present asymptomatically with some small spider veins, telangiectasias, and varicose veins, or with symptomatic larger varicose veins, venous edema, skin changes, and venous leg ulcers (VLU). History taking and physical examination, including observing the patient in a standing position with bare legs and without shoes, are important aspects of the initial assessment. The history and physical examination help to differentiate systemic causes of venous hypertension (eg, heart failure), mechanical and anatomic factors (eg, obesity, calf weakness, dependent edema), or other disease states that mimic chronic venous diseases. Details of approach to history taking and physical examination are discussed in detail elsewhere. (See "Clinical manifestations of lower extremity chronic venous disease" and "Overview of lower extremity chronic venous disease", section on 'Differential diagnosis'.)

Initial evaluation using duplex ultrasound — For most patients with symptoms and signs of chronic venous disease, duplex ultrasound is the initial diagnostic study to evaluate for the presence of venous obstruction (eg, thrombus) or venous reflux in the lower extremities [1]. Because it is reproducible, noninvasive, and inexpensive, duplex has essentially replaced venography for the initial evaluation of most lower extremity venous disorders [2-4]. (See 'Venous duplex ultrasound' below.)

Duplex ultrasound is generally not necessary prior to treating telangiectasias, reticular veins, or small varicose veins that are not associated with other limb symptoms (eg, swelling, aching, heaviness). (See "Injection sclerotherapy techniques for the treatment of telangiectasias, reticular veins, and small varicose veins" and "Laser and light therapy of lower extremity telangiectasias, reticular veins, and small varicose veins".)

Venous duplex ultrasonography should be performed in the following clinical situations:

●For patients with symptoms and a clinical history and physical examination that support a diagnosis of venous obstruction or venous reflux. (See "Clinical manifestations of lower extremity chronic venous disease".)

●For patients with VLUs. (See "Evaluation and management of chronic venous insufficiency including venous leg ulcer".)

●For patients with history of deep venous thrombosis who present with persistent leg symptoms (ie, post-thrombotic syndrome). (See "Post-thrombotic (postphlebitic) syndrome".)

●When the cause of leg swelling is undetermined. (See "Clinical manifestations and evaluation of edema in adults", section on 'Clinical manifestations and evaluation'.)

Venous duplex ultrasound is also helpful for planning venous ablation. Understanding the distribution and severity of superficial venous reflux is essential. Duplex ultrasound may also be used to evaluate for reflux in perforating veins in patients with persistent venous ulcers or symptomatic varicose veins following treatment of superficial veins. (See "Approach to treating symptomatic superficial venous insufficiency" and "Evaluation and management of chronic venous insufficiency including venous leg ulcer", section on 'Venous intervention'.)

Advanced venous imaging — Advanced venous imaging (computed tomography [CT] venography, magnetic resonance [MR] venography, catheter-based venography) may be obtained when there is suspicion for iliocaval venous obstruction based upon history and physical examination or demonstration of continuous or pulsatile flow in the common femoral (ie, absence of respiratory variation) on ultrasound. (See 'Identifying venous obstruction' below.)

History and clinical features suggestive of iliocaval venous obstruction or compression include:

●Prior venous thromboembolism (VTE; ie, post-thrombotic syndrome)

●Recurrent VTE

●Symptoms and a history and physical examination that support a diagnosis of May-Thurner syndrome (See "May-Thurner syndrome".)

●Possible compression from pelvic or retroperitoneal tumor

For suspicion of a hemodynamically significant venous stenosis or obstruction on CT or MR venogram, catheter-based venography with intravascular ultrasound is obtained, if the patient is a candidate for endovenous treatment. (See "Overview of iliocaval venous obstruction".)

When to obtain arterial testing — Patients with chronic venous disease and VLU may have concurrent arterial disease; ulcers with a mixed etiology where there is both arterial ischemia and venous congestion are important to identify. Patients with weak or absent pulses, symptoms (eg, claudication) or risk factors (eg, smoking, diabetes) for peripheral artery disease (PAD), or ulcers in locations not consistent with a typical venous ulcer should undergo screening for PAD using the ankle-brachial index (ABI). Purely venous ulcers are most often located medially in the ankle region (picture 1) and are never found above the knee, and only rarely on the foot. (See "Clinical assessment of chronic wounds", section on 'Differentiation of chronic ulcers'.)

To evaluate lower extremity arterial flow, the ABI is a useful tool, and is the initial test in patients with ulceration(s) and delayed VLU healing or other clinical features consistent with PAD. An ABI ≤0.9 indicates the presence of arterial occlusion, which is commonly related to PAD. For patients in whom ABI determination may be too painful or difficult to obtain (eg, chronic venous ulcer), additional noninvasive studies (eg, toe pressures, duplex ultrasound) can be obtained.(See "Noninvasive diagnosis of upper and lower extremity arterial disease", section on 'Ankle-brachial index'.)

Concurrent arterial disease may affect treatment. As an example, compression therapy, which is the standard treatment for venous ulceration, needs to be used with caution in the presence of significant arterial occlusive disease [5]. (See "Compression therapy for the treatment of chronic venous insufficiency", section on 'Contraindications'.)

Other studies — Other noninvasive tests are available to assess the presence and severity of venous reflux; however, these are not routinely used in clinical practice. These are sometimes used for research purposes or may be done to evaluate proximal venous obstruction in some patients.

●Air plethysmography – Air plethysmography (APG) is a noninvasive physiologic examination that measures relative volume changes in the limb in response to postural changes and muscular activity. APG measures pressure changes in the cuff (figure 1), which are translatable to volume changes within the leg [6-9]. The venous volume is measured and used to calculate a venous filling index. APG primarily provides an overall assessment of venous function but cannot localize sites of venous reflux. It can be used to monitor overall venous hemodynamics. Changes in APG correlate well with duplex and clinical severity of disease in cross-sectional studies, but there are few studies using APG to predict which patients are most likely to have complications (eg, venous ulcer recurrence) [10,11].

●Photoplethysmography – Photoplethysmography (PPG) can also be used to assess overall venous hemodynamics. PPG is sensitive but nonspecific for the diagnosis of venous insufficiency, and, like APG, it cannot localize reflux [12]. To perform the test, a light-emitting diode is placed over the medial ankle region. After establishing a baseline, the patient is asked to perform 10 tiptoe maneuvers, or to sequentially perform dorsiflexion and plantarflexion of the ankle 10 times to empty the subcutaneous veins, and the PPG recording decreases from the baseline value. As the veins refill passively, the PPG recording rises back to the baseline value. In the presence of venous reflux, the veins refill more quickly. A venous refill time <20 seconds indicates venous reflux. If an abnormal reflux time is normalized with the application of a superficial tourniquet, isolated superficial reflux is present. If the venous refill time does not normalize, either deep venous reflux or a combination of superficial and deep venous reflux is present.

VENOUS DUPLEX ULTRASOUND — Venous duplex ultrasound allows functional, anatomic, and dynamic evaluation of the status of the venous system of the involved extremity. Lower extremity duplex ultrasound examination is performed to evaluate for venous obstruction and venous reflux. Venous obstruction is identified by looking at vessel compressibility, while venous reflux is identified by examining the duration of retrograde or reversed flow in the veins using augmentation maneuvers.

Principles of venous duplex — Duplex ultrasound identifies blood vessels and the presence and direction of blood flow, and is used to detect venous obstruction (absence of venous flow) and its anatomic location, and presence of venous reflux [4,13-18]:

●In B-mode, a real-time ultrasound transducer encased in a probe rapidly and automatically sweeps an ultrasound beam over the area to be imaged, constructing an image from the reflected wave [15]. B-mode can identify blood vessels and changes within the vessel wall, as well as other anatomic structures that can produce lower extremity swelling and other symptoms such as popliteal (Baker) cyst, hematoma, arterial aneurysm, and other soft tissue masses [19,20]. (See "Popliteal (Baker's) cyst" and "Popliteal artery aneurysm".)

●Doppler imaging detects relative motion between the source of the signal and the reflector of the signal. The sources of the reflected signals in peripheral vascular studies are the red blood cells moving in the vessels. Flow analysis can be performed by listening to the audible signal or by recording the spectral analysis of the signal. An analysis of the spectral display then determines the flow velocity, direction, and characteristics of flow (laminar versus turbulent). (See "Noninvasive diagnosis of upper and lower extremity arterial disease", section on 'Duplex ultrasound'.)

Identifying venous obstruction — For detecting venous obstruction, B-mode imaging assesses the compressibility of the vein. Normal veins collapse with the application of pressure using the ultrasound probe. If there is complete obstruction of the vein, the vein will not collapse at all. However, if there is partial obstruction due to the thrombus or partial recanalization, the vein will collapse partially. In addition, color Doppler is used to assess vessel patency by examining the color fill of the vein being examined.

Duplex examination of the lower extremity can also be used to predict if there is more proximal obstruction, such as iliac vein stenosis, by evaluating the common femoral vein waveforms, which should be phasic and vary with respiration. If the waveform is blunted or flat without respiratory variation, more proximal venous obstruction should be suspected [5]. Venous duplex imaging above the inguinal ligament varies depending on the patient's body habitus and advanced venous imaging (eg, CT or MR venography, catheter-based venography) may be necessary to evaluate for iliocaval venous obstruction [20-24]. (See 'Advanced venous imaging' above.)

Identifying venous reflux — To detect reflux, the patient is usually examined in a steep reverse Trendelenburg or upright and non-weight-bearing position [25,26]. Augmentation maneuvers are performed to elicit reflux. Augmentation can be achieved either by asking the patient to bear down (ie, Valsalva maneuver) or by the sonographer performing a calf squeeze or by using a blood pressure cuff rapidly inflated and deflated. The venous valve closure time is known as the reflux time, and this represents the flow going the opposite direction of physiologic normal venous flow. The reflux time is obtained while acquiring the Doppler spectral waveforms and interpreting color flow orientation (table 1) [25].

SOCIETY GUIDELINE LINKS — Links to society and government-sponsored guidelines from selected countries and regions around the world are provided separately. (See "Society guideline links: Chronic venous disorders".)

INFORMATION FOR PATIENTS — UpToDate offers two types of patient education materials, "The Basics" and "Beyond the Basics." The Basics patient education pieces are written in plain language, at the 5^th to 6^th grade reading level, and they answer the four or five key questions a patient might have about a given condition. These articles are best for patients who want a general overview and who prefer short, easy-to-read materials. Beyond the Basics patient education pieces are longer, more sophisticated, and more detailed. These articles are written at the 10^th to 12^th grade reading level and are best for patients who want in-depth information and are comfortable with some medical jargon.

Here are the patient education articles that are relevant to this topic. We encourage you to print or e-mail these topics to your patients. (You can also locate patient education articles on a variety of subjects by searching on “patient info” and the keyword(s) of interest.)

●Basics topics (see "Patient education: Varicose veins and other vein disease in the legs (The Basics)")

●Beyond the Basics topics (see "Patient education: Lower extremity chronic venous disease (Beyond the Basics)")

SUMMARY AND RECOMMENDATIONS

●Chronic venous disease – Lower extremity chronic venous disease can generally be diagnosed clinically based on manifestations such as lower extremity pain and edema, varicose veins, skin changes, and venous ulceration; however, objective testing evaluation is necessary to confirm a venous pathology as the cause of symptoms, determine the etiology (reflux, or obstruction, or both reflux and obstruction), localize the anatomic site and level of disease, or identify concurrent peripheral artery disease (PAD). (See 'Introduction' above.)

●Duplex ultrasonography – Duplex ultrasonography, combining B-mode real-time imaging and Doppler flow assessment, is the initial imaging study of choice for the diagnosis of venous obstruction (eg, thrombosis, venous stenosis) and is also used to identify venous reflux. Duplex ultrasound examination may not be necessary for patients who present with asymptomatic spider veins, telangiectasia, or small varicose veins. (See 'Approach to venous evaluation' above and 'Venous duplex ultrasound' above.)

•Indications – Duplex ultrasonography should be performed in the following clinical situations:

-If a clinical diagnosis of venous obstruction of valvular insufficiency (reflux) cannot be established but symptoms are strongly suggestive

-In cases of leg swelling where the cause is undetermined

-In cases of venous leg ulcers (VLUs)

-Persistent lower extremity symptoms in patients with history of deep vein thrombosis (ie, post-thrombotic syndrome)

•Venous obstruction – For detecting venous obstruction, B-mode imaging assesses compressibility. Normal veins collapse with the application of pressure using the ultrasound probe; thrombosed veins do not collapse. Venous patency can also be assessed by examining Doppler color fill. Iliocaval venous obstruction is inferred by blunted or flat common femoral venous waveforms that are without respiratory variation. (See 'Identifying venous obstruction' above.)

•Venous reflux – For detecting venous reflux, the duration of retrograde or reversed venous flow with augmentation maneuvers is determined. The accepted normal values for reflux time vary by anatomic site (table 1). (See 'Identifying venous reflux' above.)

●Advanced venous imaging – For patients in whom iliocaval venous obstruction is suspected based on clinical features or findings on ultrasound, venography (CT, MR, or catheter-based, intravascular ultrasound) might be obtained to further define venous disease or to plan intervention. (See 'Advanced venous imaging' above.)

●Identifying concurrent PAD – Ulcers with mixed venous and arterial components are important to identify, as treatment options for the ulcer are impacted. Patients with weak or absent pulses, symptoms (eg, claudication) or risk factors for PAD (eg, smoking, diabetes), or ulcers with delayed healing or in locations not consistent with a typical venous ulcer should undergo screening for PAD using the ankle-brachial index (ABI). (See 'When to obtain arterial testing' above.)

ACKNOWLEDGMENT — The UpToDate editorial staff acknowledges Patrick C Alguire, MD, FACP, who contributed to earlier versions of this topic review.