HIFU (High-Intensity Focused Ultrasound) for the treatment of varicose veins

What is HIFU treatment for varicose veins?

HIFU stands for high-intensity focused ultrasound. It is a technology that concentrates ultrasound energy on a very small area beneath the skin.

In the treatment of varicose veins, this energy is directed at the wall of a superficial vein that is not functioning properly. The localised heating causes a controlled thermal lesion, causing the vein to contract and close.

Blood is no longer retained in the leg. As it ceases to flow through the treated vein, it is redistributed to other veins that are still functioning properly.

From a medical point of view, HIFU is a form of extracorporeal thermal ablation. The term ‘extracorporeal’ indicates that the energy is applied from outside the body, without inserting a fibre, a catheter or a substance into the vein.

Some commercial platforms have been developed specifically to apply this technology to venous disease. SONOVEIN® is one such device, but the treatment should be understood as a medical technique — focussed ultrasound for venous closure — rather than as a specific brand.

Is it an established technique?

HIFU has a growing body of clinical experience, but does not yet have the same level of evidence as endovenous laser therapy, radiofrequency ablation or sclerotherapy.

Early clinical studies described the technique as a new and potentially useful procedure for closing veins without percutaneous access.

Subsequent observational studies have reported favourable outcomes in selected patients, including a retrospective study published in 2025 on patients treated between 2020 and 2024. However, a retrospective study does not offer the same degree of certainty as a randomised controlled trial.

New observational series with prospective follow-up have also been published, thereby expanding the available information. HIFU should therefore be regarded as an innovative option for selected patients, rather than a universal substitute for established endovenous techniques.

Preparation before the procedure

Preparation is usually straightforward, although it depends on the patient’s characteristics and the centre’s protocol. Before treatment, the patient’s medical history, allergies, history of thrombosis and regular medication are reviewed. Anticoagulants, antiplatelet agents and other medicines must not be stopped without medical advice.

The team may ask the patient to wear comfortable clothing and not to apply any creams to the area to be treated. They will also explain whether the patient needs to fast beforehand, whether pain relief or sedation will be administered, and whether it is advisable to be accompanied.

How is it carried out?

The procedure is usually carried out on an outpatient basis, under continuous ultrasound guidance.

1. Locating the vein

The patient is positioned in the most suitable way to visualise the vein. The specialist performs a Doppler ultrasound scan and confirms the vein’s course, depth and the points where energy will be applied.

2. Treatment planning

Small segments of the venous wall are selected on the ultrasound image. The planning must take into account the distance from the skin, nerves and other structures. If the vein changes position, the treatment site must be adjusted before the energy is applied.

3. Application of ultrasound

The transducer is placed on the skin and emits focused ultrasound waves towards the selected point. Each application is brief, but the procedure may require multiple pulses distributed along the length of the vein. For this reason, the total duration depends on the length being treated, the anatomy and the number of points required.

4. Check and mobilisation

After treating the intended segment, the specialist examines the vein using ultrasound. The patient usually gets up and walks after the procedure, provided their clinical condition allows it.

Is anaesthesia required?

HIFU does not routinely require general anaesthesia, but this does not mean that it can always be performed without measures to manage discomfort.

During each application, heat, pressure or localised pain may be felt. The intensity varies depending on the depth of the vein, the energy required and individual sensitivity. The team may use analgesia, local anaesthesia, light sedation or other comfort measures, depending on the protocol and the characteristics of the treatment.

The need for pain management does not make the technique invasive. The main difference is that no catheter is inserted into the vein.

How long does the treatment take?

There is no set duration. The time depends on the length of the vein, the number of points to be treated, their depth and the ease of maintaining an accurate ultrasound image.

As the energy is applied point by point, some sessions may take longer than certain endovenous treatments. It is therefore not appropriate to promise that the procedure will always be completed in under an hour.

What results can be expected?

The primary aim is to achieve closure of the selected vein or venous segment. Available studies have reported favourable closure rates in selected patients, although the results should not be interpreted as an individual guarantee. Furthermore, the variety of protocols, anatomical variations and study designs makes it difficult to directly compare HIFU with more established techniques such as thermal ablation.

Improvement in symptoms such as heaviness, pain or swelling depends on whether they are related to the reflux being treated. Not all leg discomfort has a venous cause. Muscular, joint, neurological or lymphatic problems may also be present.

Closure does not mean that all visible varicose veins will disappear immediately. Some branches may diminish over time, whilst others may require additional treatment.

How does ultrasound affect the vein?

The equipment combines real-time ultrasound imaging with a system that emits focused ultrasound waves.

The ultrasound scan allows the vein to be visualised and its position monitored throughout the procedure. Using this image, the specialist selects small treatment points along the length of the vein.

The ultrasound waves pass through the skin and concentrate their energy on the vein wall. A controlled increase in temperature occurs at the focal point, whilst the tissues outside this area receive much less energy.

The treatment is carried out point by point. After each application, the position of the vein is checked before moving on to the next segment.

The aim is not to ‘dissolve’ the vein immediately, but to bring about its gradual closure. Over the following weeks, the body initiates a process of transformation and reduction of the treated vessel.

Is this the same HIFU used in aesthetic medicine?

No. Although both treatments use focused ultrasound, the aim and depth of application are different.

In aesthetic medicine, HIFU is mainly used to heat specific layers of the skin and stimulate changes in the tissues, such as collagen production.

In venous treatment, the energy is directed towards the wall of an insufficient vein located beneath the skin. The aim is to close the vessel and reduce venous reflux.

The equipment used, the ultrasound planning and the training required also differ. Vein treatment must be carried out by a team with experience in venous disease, vascular ultrasound and ablation procedures.

What problem does it aim to correct?

The veins in the legs contain small valves that help blood flow upwards towards the heart. When these valves fail to close properly, some of the blood flows back towards the feet due to the force of gravity. This backward flow is known as venous reflux.

The sustained increase in pressure can cause the veins to dilate and lead to the development of varicose veins, heaviness, pain, itching, cramps or swelling. In more advanced stages, skin changes or venous ulcers may develop.

HIFU does not treat just any visible vein. Its aim is to close a segment of vein that is contributing to the reflux and venous disease.

In which cases might it be considered?

Focalised ultrasound treatment may be considered for people with insufficient superficial veins that can be localised and safely accessed from the outside.

Published studies have mainly included patients with symptomatic venous disease and reflux confirmed by ultrasound. The available experience focuses on veins and leakage points selected on the basis of their anatomy, rather than on any type of varicose vein.

It may be of interest when one wishes to avoid a venipuncture or the insertion of a catheter, provided that the course and depth of the vein allow the energy to be applied safely.

It may also be considered when there are anatomical difficulties in using an endovenous technique. However, the fact that it does not require a catheter does not mean that it is automatically the best option. The indication depends on the anatomy, the type of reflux, the team’s experience and the available alternatives.

How do you know if it is the right treatment?

The key test is venous Doppler ultrasound. This scan allows the veins to be visualised, the direction of blood flow to be assessed and the presence of reflux to be checked. It also shows the diameter, depth and course of the vein.

In medical contexts, it may also be referred to as a duplex scan or Doppler ultrasound. In this factsheet, the term ‘venous Doppler ultrasound’ is primarily used, as it is the most recognisable term for someone without medical training.

To assess a HIFU treatment, the ultrasound scan must determine whether the vein is at a suitable distance from the skin and other structures. The energy must not be directed towards an area where there is a high risk of thermal injury.

The specialist also reviews the patient’s history of thrombosis, associated conditions, mobility, medication and previous venous treatments.

Therefore, patient selection does not depend solely on the size of the varicose veins. Two people with veins that look similar may require different treatments.

Is the result permanent?

The aim is to achieve sustained closure of the treated vein, but we cannot speak of a permanent result in all patients. As with other techniques, the vein may not close completely, may partially reopen, or may develop new pathways for blood flow.

Furthermore, venous insufficiency may progress and affect other veins over time. The appearance of new varicose veins does not necessarily mean that the procedure was carried out incorrectly. It may simply reflect the natural progression of venous disease.

Risks and possible side effects

Although it does not require incisions or catheter access, HIFU is not without side effects or complications.

After the procedure, tenderness, a sensation of heat, redness or localised swelling may occur. Some people may experience discomfort along the treated vein.

Small bruises may also occur, although the technique does not involve puncturing the vein. These may be related to the pressure exerted on the tissues, to superficial blood vessels or to complementary procedures.

As heat is applied from the outside, there is a risk of thermal injury to the skin or nearby tissues. Ultrasound planning and precise control of the energy output are essential to minimise this risk.

If the vein runs close to a nerve, irritation, pain, tingling or altered sensation may occur. There may also be inflammation of a superficial vein, incomplete closure or subsequent reopening.

Thrombotic complications appear to be rare in the available studies, but cannot be ruled out entirely. Individual risk assessment remains necessary. The studies published to date are mainly observational and do not allow all risks to be quantified with the same precision as techniques with a longer track record.

What is the recovery like?

As there is no incision and no catheter is inserted, many people are able to walk and resume light daily activities after treatment. However, recovery is not the same in every case. It may depend on the area treated, the level of pain, the degree of inflammation and whether other procedures have been carried out.

During the first few days

You may experience tenderness, tightness or a hardened area along the vein. Walking is usually recommended, whilst remaining immobile for many hours does not generally offer any benefits.

Returning to work

Returning to work depends on the type of work and any discomfort. Office-based work can usually be resumed sooner than a job that requires standing for long periods, lifting heavy objects or physical exertion.

Exercise and daily life

The medical team will advise when you can resume vigorous exercise, high-impact sports, saunas or very hot baths. Driving should be postponed if you have taken sedatives or if you are in pain that prevents you from braking safely in an emergency.

Compression

The need to wear compression stockings may vary depending on the treatment protocol, the duration of treatment and the presence of other varicose veins. It should not be assumed that all patients will require the same regimen.

Follow-up

Follow-up allows us to check whether the vein has closed and whether healing is progressing as expected. Doppler ultrasound can be used to examine the treated segment, detect incomplete closure and rule out complications. It also allows us to assess whether any varicose branches remain that may require sclerotherapy or another procedure.

Given that long-term evidence is still more limited than that for established techniques, clinical and ultrasound follow-up is particularly important.

HIFU, laser, radiofrequency or sclerotherapy: what’s the difference?

All four techniques can close veins, but they do so using different mechanisms.

HIFU: Applies focused ultrasound from outside the skin. It does not require a catheter to be inserted into the vein.

Endovenous laser: A fibre is inserted into the vein and light energy is applied, which is converted into heat.

Radiofrequency: A catheter is inserted and the vein wall is heated in a controlled manner.

Sclerotherapy: Injects a liquid or foam substance that produces a controlled reaction in the vessel wall.

Laser and radiofrequency treatments have a longer track record of clinical experience and are more widely supported in current recommendations for many cases of insufficient saphenous veins. NICE recognises endothermic ablation as a standard option for trunk reflux, and European guidelines extensively cover endovenous thermal techniques.

HIFU offers the distinct advantage of avoiding intravascular access, but has less comparative evidence and may require more time to treat the vein end-to-end. The least invasive technique is not necessarily the best for everyone. The choice depends on the anatomy, safety, the team’s experience, the available evidence and the patient’s informed preferences.

Situations requiring special consideration

During pregnancy, interventional treatments for varicose veins are usually postponed except in exceptional circumstances. People taking anticoagulants or antiplatelet agents require individualised planning. These medicines must not be discontinued without medical supervision.

A history of thrombosis necessitates a careful assessment of the deep venous system and the risk of further complications. People with severely reduced mobility, arterial disease, sensory disturbances or veins situated very close to the skin or nerve structures also require specific assessment.

When to seek a follow-up consultation after treatment

Moderate tenderness, a sensation of warmth or localised swelling may be part of the initial recovery process. These symptoms should gradually subside.

You should contact the healthcare team if the pain increases, the redness spreads, a skin lesion appears, the leg swells more than expected, or a persistent change in sensation develops.

Seek urgent medical attention if you experience:

• Sudden difficulty breathing.

• Chest pain.

• Coughing up blood.

• Sudden and severe swelling of a leg.

• Severe pain in the calf accompanied by swelling.

• Loss of strength or sensation.

• Fainting or severe dizziness.

Which specialists are involved

The assessment must be led by a specialist in Angiology and Vascular Surgery with experience in venous disease and ablation procedures.

At our hospital, we have a Varicose Vein Unit, which forms part of the Department of Angiology and Vascular Surgery and specialises in the diagnosis and treatment of venous diseases. The Unit carries out an individualised clinical and ultrasound assessment to determine which treatment may be most appropriate in each case.

Among the available options is treatment using high-intensity focused ultrasound (HIFU), which is indicated for certain patients and carried out under ultrasound guidance, without the need for incisions or the insertion of catheters into the vein.

Doppler ultrasound plays a central role in the planning and performance of the procedure, as well as in subsequent follow-up, as it allows for a precise assessment of the anatomy and function of the venous system.

Nursing staff are involved in preparation, post-treatment care, mobilisation and providing the necessary advice following treatment. For people with ulcers or advanced venous disease, care can be coordinated with other specialists where necessary.

Frequently Asked Questions

Is a needle or catheter inserted?

The energy is applied from the outside and there is no need to insert a catheter into the vein. Needles may be used to administer pain relief, local anaesthesia or sedation if the protocol requires it.

Is it the same as cosmetic HIFU?

No. Cosmetic HIFU acts on the layers of the skin and superficial tissues. Venous HIFU is directed at the wall of an incompetent vein under ultrasound guidance.

Can you treat any saphenous vein?

No. The depth, diameter, course and proximity to the skin or nerves determine whether the vein can be treated safely.

Does it hurt?

It may cause heat, pressure or localised pain during treatment. The experience varies, and various measures can be taken to improve comfort.

How long does it last?

The duration depends on the length of the vein and the number of areas to be treated. There is no set time for all patients.

Might more than one session be necessary?

Yes. It may be necessary to complete the treatment if a segment remains open or if other veins are affected.

Do varicose veins disappear straight away?

No. The treated vein needs time to close and shrink. Some visible branches may remain and require a different technique.

Could the vein open up again?

Yes. Incomplete closure or partial reopening may occur, as is the case with other venous treatments.

Is it more highly recommended than laser treatment or radiofrequency?

Not as a general rule. HIFU may be useful in selected patients, but laser and radiofrequency treatments have a longer track record of clinical use and are supported by more long-term evidence.