Radiology - Venous Sinus Stenting for Idiopathic Intracranial Hypertension

What is Idiopathic Intracranial Hypertension (IIH)?

IIH is an increase in the pressure of cerebrospinal fluid (CSF) that nourishes the brain. Patients with IIH may present with a range of symptoms like headaches, ringing sounds in your ear and, more importantly a progressive loss of vision.

The cause of IIH is poorly understood. One suspected cause of IIH is from a narrowing of the veins that drain blood from the brain. The narrowing of these veins can increase the pressure in the venous system which means CSF is not easy absorbed. This can lead to an increase of CSF and a build-up of pressure.

What is Venous Sinus Stenting?

Venous sinus stenting involves placing a stent (small metal tube) into the narrowed vein. This stent allows for an easier passage of blood through the vein without resistance. This aims to lower the blood pressure in the vein, which means more CSF can be absorbed. The stents placed are permanent and will stay inside the vein.

How effective is Venous sinus stenting?

Venous sinus stenting is a relatively new technique and is only being performed in a small number of specialist hospitals. As this procedure is new, we have not yet seen any long terms effects from this treatment.

From the current evidence available, the treatment was found to show improvement in 8 out 10 patients in some or all of their symptoms.
 
It is very difficult to predict who will improve from Venous sinus stenting prior to the procedure. The evidence shows the procedure is more likely to improve your symptoms related to your eyes rather than your headaches. of symptoms is seen more with visual problems than headaches.

Who will perform the endovascular treatment?

A specially trained doctor- Interventional Neuroradiologist or Interventional Neurovascular surgeon will perform the procedure. The team helping to complete the procedure consists of anaesthetists, ODPs, interventional nurses and radiographers, who are all highly trained in helping to make you feel at ease.

Where will the procedure take place?

The procedure is undertaken in Interventional Radiology. The procedure will take place in a specialist theatre which uses X-rays to help the doctors perform the procedure.

How long will it take?

The treatment time is variable and usually takes between 2-3 hours. The treatment is often broken down into two parts, which tend to be done on the same day-

Part 1 - The team will take pictures and pressure measurements of the arteries and veins in your head. This is completed awake under local anaesthetic.

Part 2 - If the team think that the pictures and measurements are suitable you will be put under a general anaesthetic. From here the team will place the venous sinus stent.

What preparation is there for my treatment?

Before your procedure you will need a pre-operation outpatient appointment. This will help us to assess your medical condition and ensure your safety whilst you are being treated.

The doctors may prescribe you some blood thinning medication before your procedure. It is important that you follow these instructions carefully and contact the department if you are not sure about the doses or when to take the medication.

On the day of your treatment, you will be asked to fast (not eat or drink) from midnight on the day of your appointment. If you require a small drink, sips of water are permitted up to 2 hours before your appointment. However, eating and drinking on the day of your appointment can cause delays and even cancellations.

If you are taking regular medication these should be taken as normal with a small amount of water, unless it has been specified in your appointment letter. Please bring a list of your current medications with you.

You will need to attend to the area specified on your admissions letter on the day of your appointment. Prior to your procedure a member of staff will take clinical observations (blood pressure, oxygen saturations etc.) and complete a safety checklist. At this time, a small blood test may be performed. It is important that you tell the staff of any allergies you may have, as well as mentioning if you have diabetes, asthma or any heart problems.

It is important for us to know if there is any chance you could be pregnant. If you are female the staff may also complete a pregnancy test- this is routine for all operations.

It is also important to let us know if you have had any allergic reactions to x-ray dye (contrast) before, as this is used during your procedure.
 
The Interventional Neuroradiologist and anaesthetist performing the procedure will visit you to explain the benefits of the procedure and any associated risks. They will then ask you to sign your consent form again and answer any questions that you may have about your procedure.

Before you are taken to the Interventional Radiology department you will be asked to change into a hospital gown and remove any jewellery or hair pieces that you are wearing. It is advisable not to bring valuables into the department for your procedure.

It is important to remember that the department treats emergency patients, which can cause postponements. The department will always try to limit this possibility and will keep you informed of any emergency situations that could affect your treatment.

What happens during my procedure?

Once you arrive in the Interventional department an anaesthetist will greet you and will complete final safety checks. From here you will be taken to complete part one of your procedure, which is done awake with local anaesthetic.

Part 1 - Taking pictures and measurements

You will then be taken into the Interventional Radiology room where the treatment is completed. This is a specialised theatre which contains two X-ray machines, which will help guide treatment.

To ensure that the procedure is kept sterile your groin will be cleaned and you will be covered with sterile covers to reduce the chance of any infections. The Interventional Neuroradiologist will access your blood supply via your groin and a catheter will be guided through the blood vessels until it reaches the arteries and veins within the head.
 
Contrast dye is then injected through the catheter whilst the x- ray machines collect images. The anatomy will be examined in detail to ensure that the sizes are fully known. Pressure measurements will also be collected at the same time. These measurements will help to show if there is a build-up of CSF, which are causing your symptoms. Once these images and measurements have been examined the Neuroradiologist can decide on whether a venous stent is the correct treatment choice.

Part 2 - Venous sinus stenting

If it is decided that you are having treatment, you will be taken back into the anaesthetic room and have a general anaesthetic so that you are asleep for the remained of the treatment.

When you are asleep you will be taken back into the Interventional room and the procedure completed.

This involves using a catheter to reach the narrowed part within the vein in your brain. From here a small metal stent (artificial tube) can be placed across the narrowing to stretch it open permanently.

Once all the treatment is complete the Interventional Neuroradiologist will remove the equipment and insert a closure device into the vessel within your groin. This will ensure the site is closed which will prevent bleeding. From here you will normally be woken from your general anaesthetic and be transferred to recovery, before going to your ward.

What happens after the procedure?

After your treatment you will be taken to a ward overnight where you can be closely monitored, whilst here it is important to rest. You will have to lie flat for 6 hours after your procedure, to ensure the entry site has healed. During this time, you will have regular clinical observations performed. After you go home you will not be able to do any this time heavy lifting or strenuous activity as this can increase the risk of bleeding.

Will I get a follow-up?

Standard follow up appointments will be completed with the IIH team. If you require further imaging and treatment, this will be discussed with your referring consultant. If you have had stenting treatment you will need to stay on blood thinning medication- this must be strictly followed.

After treatment there are no restrictions to driving if your vision is within the standards of the DVLA.

Are there any potential risks?

Venous sinus stenting treatment will not be completed unless the benefits outweigh the risks. This will have been discussed with your Neuroradiologist or Neurosurgeon before you agreed to the treatment.

• Radiation - This procedure uses x-rays to help the specialist doctors perform the measuring and stenting. The doctors are specially trained in using x-rays and will only use them when needed. There is a risk that after the procedure you may have a small patch of hair loss (on your scalp), this will be temporary and will grow back
• Allergic Reaction - Occasionally some patients have an allergic reaction to contrast dye. This is normally minor and would result in a skin rash or nausea. The team looking after you are trained to detect any reactions, but it is vital that any allergies are noted by the medical professionals looking after your care
• Kidney Function - Contrast can affect the kidneys due to the way it is broken down within the body. If you have poor renal function the doctor may prescribe some fluids and a blood test, which will help monitor your kidney function
• Bleeding/Bruising - As the procedure involves making a small puncture to the artery, there is normally a small amount of bruising to the site. Occasionally the bleeding around the site may continue if this occurs further treatment may be required
• Infection - There is minimal chance of infection, as the procedure is completed in sterile conditions. If an infection around the site did occur, antibiotics would be prescribed
• Serious Complications - The main risk during the procedure is bleeding from the veins. This, however, is not very common. If this does happen, it can be life threatening and may require open surgery to relieve the pressure on the brain from the bleeding. This may lead to permanent disability of the arms/legs and also weakness, loss of vision and difficulty with speech. In the most severe cases there is a risk to life
• Treatment with venous sinus stenting means taking blood thinning medication. There is a small risk that the stent may become blocked by a blood clot. If this happens it may lead to bleeding in the brain and a stroke. This may require a further procedure to unblock or open the stent

All these risks will be discussed with you and you will have chance to ask any questions about your procedure before having it.

What if I decide not to have the procedure done?

If you decide not to go ahead with your endovascular treatment after you have discussed any queries or questions with the radiologist, the department will notify your referring consultant. From here the referring consultant can discuss any further surgical options for treatment and imaging with you.

If you are Diabetic

If you are diabetic, please contact the Diabetes Centre on 0161 212 2095 between 8.30am and 12noon or as soon as you receive this appointment and ask to speak to a diabetes specialist nurse.

Failure to follow this advice may result in your appointment being cancelled.

What if I cannot attend for my appointment?

If you have any questions about your examination or cannot make the appointment, please telephone the helpline on- 0161 206 2044 or 2404, Monday to Friday 8.30 am to 4.00 pm.

If you are not able to telephone, please contact us via email on booking.radiology@nca.nhs.uk

Please include your name, address, date of birth and hospital number (if known) on all correspondence.

Please help us to cut our waiting lists. If you need to cancel or change your appointment, call us as soon as you can, so that we can give it to another patient.

Interpreters

If you need an interpreter for your examination and/or procedure (either verbal, non-English language or non-verbal, e.g. British Sign Language, Makaton etc.), please call the department so that we can try to arrange this. or there is information about interpretation services on the back page of our leaflets.

I need an ambulance; how do I arrange this?

If you need an ambulance there are contact details on your appointment letter.

Please inform the department, using the contact details in this leaflet, if you are arriving by ambulance.

Other sources of information

Your questions should have been answered by this leaflet but remember that this is only a starting point for discussion about your treatment with the doctors looking after you.

Make sure you are satisfied that you have received enough information about the procedure before you sign the consent form.

Further information regarding the examination can be found on the Internet

NHSUK, 13/01/2017, NHS Choices, Angiography
https://www.nhs.uk/conditions/angiography/

Brain and Spine foundations, 03/2017, Angiogram of the Brain
https://www.brainandspine.org.uk/angiogram-brain

Society of Interventional Radiology, 2017, Tiny incision, big result
www.sirweb.org

If you require further help and information about this procedure, please contact the Angiography Suite, Salford Royal Hospital, Stott Lane, Salford, M6 8HD on 0161 206 5091.