Venous · IR Playbook

Image-Guided Sclerotherapy of Low-Flow Venous and Venolymphatic Malformations (VM/VLM sclerotherapy)

Image-guided percutaneous sclerotherapy is the first-line treatment for symptomatic low-flow venous (VM) and combined venolymphatic (VLM) malformations, delivering a chemical sclerosant directly into the dysplastic channels through a needle placed under ultrasound and fluoroscopic guidance. The mechanism is deliberate destruction of the abnormal endothelium, producing thrombosis, an acute inflammatory phase and subsequent fibrotic contraction of the lesion — which is why stagnant intralesional flow (long sclerosant dwell time) predicts response, and why rapid drainage into a normal vein predicts both treatment failure and systemic sclerosant escape. Reported outcomes with bleomycin-polidocanol foam include mean lesion volume reduction of approximately 78% with symptom relief in the majority of patients after staged sessions. The headline risks are skin necrosis and, agent-dependent, systemic toxicity — ethanol carrying the highest risk of cardiopulmonary collapse and nerve injury.

Learning objectives

Select patients in whom sclerotherapy rather than surgery or observation is indicated, using MRI flow characterisation and symptom burden
Identify the venous drainage pattern on direct-puncture phlebography and modify sclerosant volume, concentration and outflow control accordingly
Choose between bleomycin, polidocanol, sodium tetradecyl sulfate, doxycycline and ethanol on the basis of lesion type, location and toxicity ceiling
Recognise localized intravascular coagulopathy preoperatively and manage it before and after sclerotherapy
Recognise and manage skin necrosis, nerve injury and haemoglobinuria in the periprocedural window

Indications

Pain, swelling or heaviness from a venous or venolymphatic malformation not controlled by compression garments and analgesia
Functional impairment such as restricted joint movement, limb-length discrepancy of the affected segment, or interference with mastication or speech
Recurrent intralesional thrombosis with phlebolith formation causing episodic pain
Recurrent bleeding or lymphorrhoea from mucosal or cutaneous vesicles in a venolymphatic lesion
Cosmetic deformity causing significant psychosocial morbidity
Preoperative volume reduction to make a subsequent surgical resection feasible or less haemorrhagic
Recurrent infection of a macrocystic lymphatic component

Absolute contraindications

High-flow arteriovenous malformation misdiagnosed as low-flow lesion
Active infection of the malformation or overlying skin
Known severe hypersensitivity to the intended sclerosant
Pre-existing significant pulmonary fibrosis or interstitial lung disease when bleomycin is the intended agent

Relative contraindications

Uncorrected localized intravascular coagulopathy with hypofibrinogenaemia
Right-to-left cardiac shunt, which permits paradoxical passage of foam or particulate thrombus
Lesion intimately encasing a major motor nerve, where ethanol is contraindicated and lower-toxicity agents with reduced volume should be used
Extensive lesion in which the volume required would exceed the safe dose of any single agent in one session, favouring a staged strategy
Renal impairment when large-volume ethanol with expected haemoglobinuria is planned

Equipment

High-frequency linear ultrasound transducer, 7-15 MHz, with colour Doppler and sterile probe cover
21G or 22G needles; 20G intravenous cannula for larger channels; butterfly needles for small superficial lesions
Fluoroscopy or DSA unit for direct-puncture phlebography
Non-ionic iodinated contrast medium for phlebography
Bleomycin vials for reconstitution, dose calculated at 0.5-1 mg/kg with a 15 mg per-session ceiling
Polidocanol 1-3% or sodium tetradecyl sulfate 1-3% for foam preparation
Two 5 or 10 mL syringes and a three-way stopcock for Tessari foam preparation, or a commercial foam kit
Doxycycline 100 mg vials reconstituted to 10 mg/mL for macrocystic lymphatic components
5 Fr pigtail drainage catheter and 0.035 inch guidewire for large macrocysts requiring staged instillation
Absolute ethanol with radiopaque additive, reserved for refractory lesions and used with invasive haemodynamic monitoring
Pneumatic tourniquet or elastic bandage for outflow control in limb lesions
Compression garment for the treated segment

Procedure steps

Position the patient so that the lesion is dependent, which distends the channels and makes puncture easier. Scan the whole lesion and mark the symptomatic compartment and a safe puncture window on the skin.Pearl: Placing the limb dependent for a few minutes before draping increases lesion volume and makes an otherwise collapsed compartment targetable.
Prepare the field widely and secure anaesthetic monitoring. If ethanol is planned, ensure invasive arterial pressure monitoring and, for large-volume cases, pulmonary artery pressure monitoring with a vasodilator available.
Advance a 21G needle along the long axis of the target compartment under continuous ultrasound visualisation, angling obliquely rather than perpendicularly in superficial lesions. Confirm intralesional position by free aspiration of dark venous blood, or of straw-coloured or chylous fluid from a lymphatic cyst.Pearl: Aspiration of dark non-pulsatile blood that flows freely without a syringe plunger pulled hard confirms a capacious venous space rather than a punctured normal vein.
Hand-inject dilute contrast under fluoroscopy or DSA and record the fill pattern and drainage. Watch three things: the volume of contrast the compartment accepts before it is full, whether contrast remains stagnant, and whether it drains rapidly into a named deep vein. The compartment volume accepted defines the sclerosant volume you will use; the drainage pattern defines whether outflow control is needed.Pearl: The volume of contrast required to opacify the compartment is the most reliable guide to sclerosant volume; injecting a preset volume without this step overfills the lesion.
If phlebography shows rapid antegrade escape, apply a pneumatic tourniquet proximal to a limb lesion, or direct manual compression over the draining vein, and repeat the contrast injection. Proceed only when the repeat run shows contrast retained within the lesion for several seconds.
Aspirate the opacified blood or cyst fluid to near-collapse before delivering the sclerosant. This removes the diluting volume so that the agent contacts endothelium at full concentration, and it creates space so that the injected volume does not raise intralesional pressure and force sclerosant into the drainage pathway.Pearl: For a macrocyst exceeding about 30 mL, exchange for a 5 Fr pigtail catheter so that doxycycline can be instilled, dwelled for approximately four hours, drained and repeated on subsequent days without repuncture.
For a venous compartment, prepare foam by the Tessari method, passing liquid sclerosant and air between two syringes through a three-way stopcock in a one-to-four liquid-to-gas ratio for approximately twenty passes. Foam displaces blood and maintains endothelial contact far better than liquid, which is why foam is standard for venous compartments. Bleomycin may be mixed into the polidocanol foam within the same preparation.Pearl: Bleomycin-polidocanol foam combines the endothelial detergent effect of polidocanol with the antiproliferative effect of bleomycin and causes markedly less post-procedural swelling than ethanol, which matters most in the head and neck.
Inject slowly under fluoroscopy or ultrasound, watching the foam or opacified agent reproduce the contrast fill pattern seen on phlebography. Stop when the compartment is filled to the volume the phlebogram defined, when the agent begins to escape into the draining vein, or when the maximum permitted dose for the agent is reached, whichever comes first. Never chase an incompletely filled lesion with extra volume in the same session.
Keep the tourniquet or compression in place for the agent-specific dwell time, typically several minutes for foam. Release compression gradually rather than abruptly so that any residual free sclerosant is not delivered as a bolus into the systemic circulation.
Reposition the needle to an adjacent compartment and repeat phlebography and injection, tracking the cumulative dose against the session ceiling. Stop the session when the ceiling is reached even if lesion remains; the remainder is treated at the next stage.
Remove the needle, apply firm local compression for several minutes to prevent tracking of sclerosant along the needle path, and apply a compression garment or bandage to the treated segment.
Inspect the overlying skin for blanching or dusky discoloration, which indicates dermal sclerosant and predicts necrosis, and document distal pulses and motor and sensory function against the pre-procedural baseline. Both findings change immediate postoperative management.

Complications

Skin necrosis and ulceration
Airway or orbital compromise from post-procedural swelling
Nerve injury
Cardiopulmonary collapse and pulmonary hypertension after ethanol
Haemoglobinuria and acute kidney injury
Post-sclerotherapy pain and swelling
Localized intravascular coagulopathy exacerbation and bleeding
Flagellate hyperpigmentation after bleomycin
Bleomycin pulmonary toxicity
Infection of the treated malformation

Exam pearls

Venous malformations are ISSVA slow-flow malformations of ectatic endothelium-lined channels with deficient smooth muscle; they distend with dependency and Valsalva and thrombose to form phleboliths, which are the pathognomonic radiographic sign.
Elevated D-dimer with low fibrinogen in a patient with an extensive vascular malformation indicates localized intravascular coagulopathy, not disseminated intravascular coagulation; platelet count is typically normal or only mildly reduced, which is the discriminating feature from Kasabach-Merritt phenomenon.
Bleomycin for intralesional sclerotherapy is dosed at 0.5 to 1 mg/kg to a maximum of 15 mg per session; no case of pulmonary fibrosis has been reported from intralesional use in vascular malformations, but the cumulative lifetime total is still recorded because of the oncological ceiling of 400 mg.
Absolute ethanol total dose in a single session should not exceed approximately 1 mL/kg, and cardiopulmonary complications have been described at absolute doses around 0.24 mL/kg given rapidly, making injection rate as important as total volume.
Macrocystic lymphatic malformations respond well to aspiration and doxycycline at 10 mg/mL, whereas microcystic lymphatic disease responds poorly to any sclerosant and is the component that drives referral for sirolimus.
Foam is preferred to liquid sclerosant in venous compartments because it displaces blood and maintains endothelial contact; the Tessari method uses a one-to-four liquid-to-gas ratio passed approximately twenty times between two syringes.

Viva questions

You puncture a calf malformation and the phlebogram shows immediate drainage into the popliteal vein. Why does this change your plan, and what do you do?: Rapid outflow both washes the sclerosant away before it can injure endothelium, causing treatment failure, and exports it systemically, risking pulmonary embolism or cardiopulmonary collapse. Apply a proximal tourniquet or manual compression and repeat the run; if outflow is still uncontrolled, coil-occlude the dominant draining vein, reduce foam volume, and abandon any plan to use ethanol.
Why is bleomycin often preferred over ethanol for a floor-of-mouth malformation, even though ethanol is more potent?: The limiting factor in that anatomical site is post-procedural swelling into a space that cannot expand, which threatens the airway. Bleomycin-polidocanol foam produces markedly less inflammatory swelling than ethanol, so the reduced potency is an acceptable trade for a manageable airway.
A patient with an extensive thigh venous malformation has D-dimer of 8 mg/L and fibrinogen of 1.2 g/L. What is happening and how does it alter management?: This is localized intravascular coagulopathy from chronic stasis and consumption within the malformation. Proceeding risks significant periprocedural bleeding and severe pain. Defer, start low molecular weight heparin for 10-14 days before and after treatment, and correct fibrinogen before the session.
Why do you aspirate the compartment before injecting sclerosant rather than simply injecting into the blood-filled lesion?: Residual blood dilutes the agent and buffers it from the endothelium, and the added volume raises intralesional pressure and forces sclerosant into the drainage pathway. Aspiration to collapse maximises effective concentration at the endothelial surface and keeps the agent contained.
The skin blanches midway through injection of a superficial forearm lesion. What has happened and what do you do next?: Sclerosant has entered the dermis or subdermal plexus, usually because the needle was angled too perpendicularly in a superficial lesion. Stop injecting immediately, withdraw the needle deeper, do not treat that compartment further in this session, and dress the area with anticipation of blistering and possible ulceration.
Your MRI shows a mixed lesion with a large septated cyst and a diffuse infiltrative T2-bright component. How do you counsel the patient about expected response?: The macrocystic component should respond well to aspiration and doxycycline, but the diffuse infiltrative component is microcystic lymphatic disease, which responds poorly to sclerotherapy. Counsel that the discrete swelling will improve substantially while the diffuse infiltration may not, and raise sirolimus or surgical options for the latter.
How much bleomycin can you give in one session, and what governs that number?: 0.5 to 1 mg/kg to a maximum of 15 mg. The ceiling is set to limit systemic absorption and cumulative exposure, since bleomycin pulmonary toxicity is dose-dependent; the practical consequence is that extensive lesions must be treated in staged sessions rather than in one sitting.
Six weeks after ethanol sclerotherapy a patient has persistent foot drop. What is the immediate diagnostic priority?: Distinguish direct ethanol neurotoxicity, which is not reversible surgically, from a compressive haematoma or tense post-procedural swelling, which is. Image urgently with ultrasound or MRI; decompress if compression is demonstrated, otherwise manage expectantly with physiotherapy and neurophysiological follow-up, as partial deficits often improve over months.