Diagnostic Evaluation in patients with Venous Leg Ulcer : What is needed to plan venous intervention ?

Iram Naz1, Bhagwan Satiani2* 1Consultant Vascular Surgeon, Aga Khan University, Karachi 2Department of Surgery, Division of Vascular Diseases & Surgery, Associate Director FAME; Director Faculty Leadership Institute Medical Director Vascular Labs St# 700 376 W. 10th Avenue, Columbus, OH 43210 The Ohio State University College of Medicine Columbus, Ohio 43210 American Journal of Cardiovascular and Thoracic Surgery Open Access Review Article


Introduction
VLU is defined as an open skin lesion of the leg or foot that occurs in an area affected by venous hypertension.[1].It has been estimated that approximately 2.5 million people suffer from Chronic Venous Insufficiency (CVI) in the United States, and of those, about 20% develop a venous ulcer [2].The economic impact is substantial too.A recent study examined a cohort of patients with non-healing VLU (CEAP6) who presented to a wound clinic [3].The mean total cost of treating VLU was $ 15,732.Inpatient admission for infected ulcer markedly increased costs ($ 33,629).By contrast, VLU treated with surgical intervention of the superficial venous system did not significantly increase total cost over that of patients receiving best medical therapy ($ 11,960 vs. $ 12,304), but significantly reduced recurrence rate (34% vs. 5%) [3].Both reflux and obstruction accounts for pathophysiologic mechanism of VLU, and leads to venous hypertension.Obstruction from secondary venous disease and venous reflux including Post Thrombotic Syndrome (PTS) are associated with a much more rapid progression of disease and a higher rate of venous ulceration, as compared to primary venous disease [4][5][6].Detailed history and physical examination is recommended as the first step in the approach to a patient assess the reflux with the pulsed Doppler component of duplex scanner.Some vascular labs prefer to test for reflux in the supine position.A reflux time that is > 0.5sec in duration is abnormal and indicates valvular insufficiency at that level [Figure 3].Some experts suggest using a greater degree of reflux (> 1 second) for the deep system versus 0.5 seconds for the superficial venous system.One study found velocity and peak flow at the peak of reflux correlated better with clinical severity as compared to the reflux time [12].

Other test for detecting reflux
Air Plethysmography (APG): APG is a noninvasive physiological test that measure volume changes in the limb in response to postural changes and muscular activity.APG cannot precisely localize sites of venous reflux, and provides, primarily an overall estimate of venous function and monitor overall venous hemodynamics.The test is performed in some vascular laboratories as a research tool or by clinicians who perform large numbers of venous procedures as a means to assess the hemodynamic results of venous interventions [13].

Photoplethysmography (PPG):
PPG can be used to assess overall venous hemodynamics [14].Unlike DUS, it cannot accurately identify the location of reflux.To perform the test, a light emitting diode is placed over the medial ankle region.Transmitted light is reflected back to the PPG diode with the intensity of the reflection indicative of the red cell content of the subcutaneous tissue.After establishing a baseline, the patient is asked to perform tiptoe maneuvers or sequential dorsiflexion and plantar flexion of the ankle 10 times.These maneuvers serve to empty the subcutaneous veins and the PPG recording decreases.In the presence of reflux, veins fill more quickly.A venous refill

Diagnostic Evaluation in patients with Venous Leg Ulcer: What is needed to plan venous intervention?
Copyright: © 2016 Satiani et al.
time less than 20sec indicate venous reflux.Although typically performed in a vascular laboratory, hand-held PPG devices are available and may be used as screening tool for Chronic Venous Insufficiency (CVI) [15].

Imaging the deep venous system
Much has improved with regard to management for deep vein obstruction (DVO) over the past two decades [16].It is important to identify chronic DVO in patients with CVI.Additionally, moderate to severe post-thrombotic syndrome (PTS) negatively affects patients on a daily basis, with a reported lower quality of life related to this disease especially recurrent venous ulceration [17].It has been shown that patients' quality of life suffering from PTS can be improved with interventional treatment [18].Imaging modalities mentioned beloware primarily used to assist in patient evaluation, treatment planning, and confirmation of clinical suspicion of severity to predict the treatment outcome.One recent study reported how different levels of obstruction (caval, iliocaval, iliofemoral, femoral) have shown different outcomes after recanalization, stenting, and selected cases endophlebectomy [18].DUS: B-mode imaging is the noninvasive test to assess the compressibility of the veins.Normal veins collapses with the application of pressure using the probe [Figure 5] but thrombosed veins do not collapse.Doppler examination of common femoral vein (CFV) waveform can be used to predict proximal obstruction.CFV waveform should be phasic and vary with respiration.If blunted or flat waveform with respiration is found, a more proximal Deep Vein Thrombosis (DVT) should be suspected [19].In Chronic Venous Obstruction (CVO), specific attention should be paid to insufficiency of deep vein below the inguinal ligament, post thrombotic changes [Figure 5], and iliac obstruction.Pelvic and groin collaterals, non-reversibility of compression with augmentation, and an increased velocity ratio > 2.5 are also valuable in identifying chronic obstruction [20].
Other tests: Other imaging modalities such as conventional venography, CT Venography (CTV), and Magnetic Resonance Venography (MRV) are considered when DUS is inconclusive or not possible.

CTV:
In some institutions, CTV is used.When evaluating the ilio-caval segments, external compression or chronic venous obstruction should be reported.
MRV: MRV when available can provide an excellent overview of chronic vein changes in the leg, pelvis, and abdomen.DVT changes, external compression, chronic obstruction, collateral pathways, and/or flow redistribution can all be visualized.Dynamic imaging can show inflow and outflow of the pelvis vasculature [21].It is currently used in combination with DUS to plan deep vein interventions in some centers in United States.

Contrast venography:
Ascending venography is the classic, but rarely needed, "gold standard" for diagnosing deep venous thrombosis.It provides an objective anatomic and hemodynamic evaluation of the venous system [7].In patients, already debilitated with severe symptoms coupled with disadvantages mentioned earlier, this is used only rarely and in centers where noninvasive imaging is not available.

Conclusion
Currently, acute deep venous thrombosis is managed with anticoagulation by a variety of specialties and inconsistent guidelines.Sometimes PTS results because in a large number of patients the natural history of thrombi results in sufficient valvular damage to lead to CVI.Other times the anticoagulation or thrombolysis is inadequate sometimes leaving patients with severe PTS and recurrent VLU.There are ongoing trials on acute DVT and CVO interventional treatment outcomes [22][23].Once data is finalized, then incorporating them in current clinical practice guidelines coupled with awareness to providers will hopefully reduce suffering and the economic burden from VLU.Until then, properly performed noninvasive testing i.e.DUS as initial test of choice alone in experienced hands or/and when DUS is inconclusive, then MRV/CTV has potential to delineate underlying pathology and location of problem better.This will help plan venous interventions and improve outcomes of patients presenting with VLU in the future.

Figure 1 :
Figure 1: Color Doppler image of the groin in Normal individual.The common femoral artery (CFA), common femoral vein (CFV) and great saphenous vein (GSV) can be visualized, medial to Common femoral artery.

Figure 2 :
Figure 2: Color Doppler image of common femoral vein.Spectral analysis depicting respiratory phasicity (arrow) (A) and augmentation of flow (arrow) (B) with augmentation maneuvers.

Figure 3 :
Figure 3: DUS imaging of great saphenous vein in distal thigh.B-mode imaging & spectral analysis shows patent vein with reflux time of > 1 second (arrow).

Figure 4 :
Figure 4: B-mode imaging of common femoral vein in groin showing uncompressed image (left) compressibility of normal vein (right).