Endovenous Thermal Ablation of Saphenous and Perforating Veins




Historical Background


Venous valve anatomy was first described in the 1500s, but with the exception of compression wraps, treatment for chronic venous disease (CVD) was not considered until several centuries later. Trendelenburg described saphenous vein ligation in 1891 as a treatment of varicose veins, but it was soon recognized to be associated with a high recurrence rate. Ligation and stripping of the entire saphenous vein became a mainstay of therapy in the twentieth century, but this method was later modified to selective stripping of the upper portion of the great saphenous vein to reduce of the risk of neuralgia observed with vein stripping below the knee.


Sclerotherapy, or chemical ablation of the saphenous vein, was described over the past 2 centuries, but the safety profile of ablative chemical agents was not considered acceptable until the 1960s. The application of ultrasound guidance proved to be a useful adjunct, but the success rates of chemical ablation remained suboptimal with a high risk of recanalization. In the late 1990s endovenous thermal ablation was first described using radiofrequency (RF) energy, and soon thereafter endovenous laser treatment was developed.




Indications


The types and stages of CVDs have been defined by a classification system composed of four components: clinical stage (1-6), etiology (primary, secondary, or congenital), anatomy (deep, superficial, or perforator system), and pathophysiology (reflux, obstruction, or both), known by the acronym CEAP ( Fig. 60-1 ). Another scoring system that has gained popularity is the venous clinical severity score, which assigns a score to various clinical attributes, such as pain, varicose veins, edema, skin changes, use of compression, and ulceration. Such scoring systems can be helpful in evaluating outcomes and disease progression.




Figure 60-1


The classification of venous disease using CEAP system. A , Stage C1: Telangiectasia and reticular veins. B , Stage C2: Varicosities. C , Stage C3: Edema. Stage C4: Skin changes, including eczema and pigmentation ( D ) or lipodermatosclerosis and atrophie blanche ( E ). Stage C5: Preulcerative ( F ) or healed ( G ) ulcer. H , Stage C6: Active ulceration.


Varicose veins may be associated with distinct pattern of clinical findings, categorized into six clinical stages (C1-C6) in the CEAP classification system. Early symptoms (C1) are mild and include aching, tiredness, heaviness, or throbbing while upright without overt varicosities. Conservative measures such as support hose at 20 to 30 or 30 to 40 mm Hg of external compression often alleviate early symptoms. As the degree of venous hypertension increases, enlarging varicosities can cause local discomfort. Pain, cramping, or restless leg symptoms at night, as well as itching, can be associated with venous disease. Numbness or sharp or radiating pain are not usually attributable to venous insufficiency. Varicose veins (C2) are often associated with one or multiple sources of reflux and may be symptomatic, progressive, or of cosmetic concern. Although edema (C3) may result from CVD, other causes, including lymphedema, lipedema, medication effects, pulmonary, cardiac, renal, hepatic, endocrine, or sleep apnea, should be excluded. Venous stasis skin changes (C4) in the gaiter distribution, including pigmentation, eczema, lipodermatosclerosis, inflammation, and ulceration, are associated with multiple sources of reflux with or without obstruction. Skin changes are an indication for treatment of superficial venous reflux, if present. Skin ulceration (C5-C6) requires compression and local wound care, which should precede treatment of CVD. Surgical stripping of the great saphenous vein has decreased ulcer recurrence, but multiple sources of reflux, including superficial, perforator veins, and deep venous reflux, may be present.


Treatment should always begin with conservative measures, including compression therapy, exercise, weight loss, and intermittent elevation. Continued signs or symptoms of progressive venous insufficiency consistent with CEAP C2 to C6 venous disease are indications for endovenous or surgical treatment. A history of superficial vein thrombosis (SVT) does not preclude endovenous treatment. Both thermal and chemical ablation techniques can be used to treat recanalized refluxing veins after SVT.


Absolute contraindications to endovenous thermal ablation of saphenous and perforating veins include an inability to ambulate, the presence of arteriovenous malformation or uncompensated deep venous obstruction with poorly developed collaterals, pregnancy, and allergic reaction local anesthetic. Relative contraindications include the presence of superficial veins that lie within 1 cm of the skin, because a risk of skin burn exists. This can be prevented by injecting tumescent anesthesia to increase the depth of the vein to greater than 1 cm from the skin. If the vein is immediately subdermal, alternatives to thermal ablation should be considered given the risk of a phlebitic reaction, prolonged pain, and skin changes with retraction or pigmentation. Likewise, tortuous veins may increase the difficulty of advancing the catheter. Aneurysmal vein segments or larger vein diameters (>25 mm), as well as short refluxing vein segments (<3 cm long) and veins with small diameters (<3 mm) may be best treated with other approaches.




Preoperative Preparation





  • Ultrasound evaluation. Duplex evaluation of the superficial venous system should be performed in the upright position ( Fig. 60-2 ). All major leg veins should be evaluated in B mode for compressibility, wall thickness, and the presence of internal echoes. Axial veins should be described with regard to diameters, depths, length within the fascia, degree of tortuosity, and communications with perforators or other enlarged tributaries. Perforators are assessed for diameter at the fascia level, location, and the presence of reflux with the patient seated and dangling the leg. Augmentation of venous flow with distal compression cuffs or manual squeeze of the calf are used with color flow Doppler waveform analysis of each refluxing vein.




    Figure 60-2


    Duplex ultrasound examination of venous reflux. A , Patient is in the standing position, and reflux is induced with rapid cuff inflation. B , Flow is measured proximally over the veins using Doppler waveform analysis. After cuff deflation, reversal of flow for more than 0.5 seconds is consistent with reflux within the vein segment.



  • Preoperative vein assessment. The target vein is mapped by ultrasound and marked, and diameters and depths are measured. Major tributaries; large refluxing perforators; tortuous, partially occluded, and aneurysmal segments; and refluxing duplicate veins should be noted using a marker pen. Entry sites are selected where the vein is superficial, but ablation is halted proximal to the entry point to prevent skin burn or phlebitis. Preprocedure photographs are helpful for documentation ( Fig. 60-3 ).




    Figure 60-3


    Preoperative marking of the varicose veins. Before the endovenous thermal ablation, the refluxing vein segments should be carefully mapped by ultrasound and marked percutaneously. Diameters, depths, aneurysmal segments, and partially occluded or tortuous segments should be indicated, as well as communication with tributaries or perforating veins. This information is used to plan the treatment of each segment of the target vein to use the minimal effective amount of energy and decrease the risk of complication.



  • Assessment of thrombotic risk. Evaluation of personal or family history of thrombosis should be conducted, and those at increased risk of thrombosis should be assessed for an inherited thrombophilia. Endovenous ablation can be performed while on warfarin, and low-molecular-weight heparin can be administered perioperatively to those patients at increased risk.



  • Medications and compression. An oral benzodiazepine and an antibiotic are prescribed 1 and 2 hours before the procedure, respectively. If indicated, low-molecular-weight heparin is also administered 1 to 2 hours before the procedure. A 30 to 40 mm Hg thigh-high stocking with an open toe and a waist attachment should be available and applied immediately after the procedure.





Pitfalls and Danger Points





  • Bruising and hematoma



  • Superficial phlebitis



  • Deep vein thrombosis



  • Thrombus extension to deep vein junction



  • Thermal skin injury



  • Paresthesia



  • Recanalization



  • Neovascularization





Endovascular Strategy


Deep and Perforating Veins


The perforator veins connect the superficial and deep venous system and have unidirectional valves. A clinically significant source of reflux may be present if the valves are incompetent and the perforator is greater than 3.5 mm in diameter. However, perforator incompetence may resolve after treatment of superficial venous insufficiency alone.


Great Saphenous Veins


The great saphenous vein begins anterior to the medial malleolus of the ankle, travels up the medial thigh, and terminates at the saphenofemoral junction (SFJ) at or below the inguinal ligament and medial to the femoral artery ( Fig. 60-4 ). Anterior and posterior accessory saphenous veins may be present and may be a source of concurrent or recurrent varicosities after treatment of the great saphenous vein.




Figure 60-4


Lower extremity venous anatomy. The great saphenous vein travels up the medial aspect of the leg from the ankle to the saphenofemoral junction (SPJ). Major tributaries or accessory saphenous veins are variable at the junction and can include the anterior accessory great saphenous vein and the posterior accessory great saphenous vein. The small saphenous vein starts at the lateral ankle and travels up the posterior calf. It can extend above the popliteal fossa into the posterior thigh vein or can communicate medially with the great saphenous vein as the intersaphenous vein. The SPJ is usually at or above the popliteal fossa, where the vein enters the deep popliteal vein. The anatomy of this junction is highly variable, and connections from the muscular veins in the popliteal fossa must be preserved when performing ablation of the small saphenous vein.


Small Saphenous Veins


The small saphenous vein begins at the lateral aspect of the foot, continues over the Achilles tendon, and runs up the posterior calf to the saphenopopliteal junction (SPJ) within 10 cm of the popliteal fossa ( Fig. 60-4 ). The anatomy of the small saphenous vein is highly variable and commonly duplicate. A cranial or posterior thigh extension can continue from the small saphenous vein up the posterior thigh, emptying into the femoral vein. The intersaphenous vein, previously known as the “vein of Giacomini,” can communicate from the small saphenous vein in the popliteal fossa to the medial thigh great saphenous vein. Refluxing perforators are found in the popliteal fossa, often lateral and superior to the SPJ, which must be carefully distinguished from small saphenous vein reflux. Gastrocnemius and soleus veins are deep to the muscular fascia but can be mistaken for the small saphenous vein by inexperienced ultrasound technicians. The saphenous veins are identified outside the muscular fascia and beneath the saphenous fascia. The administration of tumescent anesthesia is facilitated by injecting into this saphenous compartment.


Superficial Tributaries


Tributaries or varicosities consist of an interconnecting network of subcutaneous veins communicating with the main saphenous trunks and are best treated with phlebectomy. Significantly, ultrasound can be used to evaluate whether tributaries are associated with refluxing axial veins or enlarged incompetent perforators that require treatment.


Proximal Pelvic Veins


Medial labial and thigh varicosities may be associated with pelvic venous insufficiency and abdominal wall and suprapubic varicosities related to a proximal source of obstruction. Varicosities in these areas should not be treated without assessment of proximal iliac and vena cava anatomy.


Smaller Veins


Reticular veins are flat, blue, and less than 3 mm in diameter, whereas spider veins are more superficial, present as red or purple dermal veins, and are less than 1 mm in diameter. These veins are not suitable for endovenous thermal ablation but are amenable to cosmetic sclerotherapy. A flare or confluence of spider veins at the medial ankle and foot (corona phlebectatica) may indicate deep or perforator vein insufficiency.

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Mar 13, 2019 | Posted by in VASCULAR SURGERY | Comments Off on Endovenous Thermal Ablation of Saphenous and Perforating Veins
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