Coil embolisation in the cath lab: a Cath Lab 101 guide
Reviewed by Rodnie Oro, cath lab charge nurse · Last reviewed: October 2026 · Education only, not medical advice
Coil embolisation in one minute
What it is: blocking an unwanted blood vessel or abnormal connection by placing small metal coils through a catheter; the coils trigger a clot that seals it.
Who it is for: people with abnormal connections such as collateral vessels, fistulas, some congenital heart conditions, or a bleeding vessel.
Main risks: bruising at the access site, a coil moving out of place, blocking the wrong vessel and, rarely, vessel injury.
Usually: under local or general anaesthetic, 1–2 hours.
On this page: What is coil embolisation? · Who is it for? · When is it done? · Step by step · Recovery · Risks · Kit list · First time in the lab? · FAQ
What is coil embolisation?
Embolisation means deliberately blocking a blood vessel. Coils are tiny springs of metal, often with fibres, that curl up when pushed out of a catheter.
- a catheter is guided to the vessel that needs closing
- coils are pushed out one by one until the vessel is packed
- a clot forms around them and the vessel seals
In cardiology it is used, for example, for coronary fistulas, collateral vessels in congenital heart disease, or abnormal connections in the lungs.
New to the acronyms? See the Cath Lab Abbreviations A–Z.
Who is it for?
It may be considered for people with:
- coronary artery fistulas
- unwanted collateral vessels in congenital heart disease
- abnormal lung artery-to-vein connections
- some bleeding vessels
The decision is made by your heart team, who will talk through the reasons, the alternatives and the risks with you.
When is it done?
It can be planned in advance or done urgently. Before it, you usually have:
- blood tests, including kidney function and blood count
- an ECG, and often an echo or other scan
- a review of your medicines, especially blood thinners and diabetes medicines, as per centre protocol
- a chance to ask questions and give consent
Step by step
1. Getting ready
You lie on the X-ray table. Children and some adults have a general anaesthetic; others have local anaesthetic with or without sedation, as per centre protocol.
2. Access
A sheath is placed in the femoral artery or vein, depending on the vessel being treated, sizes per device and operator. Heparin is given as per centre protocol.
3. Coiling
- A. Map. Angiograms show the vessel to be closed.
- B. Microcatheter. A small catheter is placed in the target vessel.
- C. Coils. Coils are pushed out and packed; each is checked before release.
- D. Check. Angiograms confirm the vessel is closed.
4. Finishing
The catheters and sheath are removed and the site closed with pressure.
Recovery and aftercare
- First hours: checks of the access site and observations, as per centre protocol.
- Going home: often the same or next day.
- Activity: avoid heavy lifting for a few days.
- Follow-up: a scan or clinic visit to check the vessel stays closed.
Call 999 if you have chest pain, breathlessness, fainting, signs of a stroke, or heavy bleeding or swelling at the access site.
Risks and complications
Your team will explain the risks that apply to you. Possible problems include:
- bruising or bleeding at the access site
- a coil moving to the wrong place (it can usually be retrieved)
- blocking a normal vessel nearby
- incomplete closure needing a repeat procedure
- vessel injury or, rarely, stroke
Cath lab kit list (printable)
Barts example kit list
An example from one UK centre, written generically. Every lab has its own protocol, and sizes and doses vary.
- arterial or venous sheath, size per device and operator
- diagnostic and guide catheters, per operator
- microcatheter and guidewires, per operator
- coils, sizes and types per device and operator
- snare for retrieval, per operator
- heparin, as per centre protocol
Procedural steps (Barts example)
- Access; angiogram to map the vessel
- Microcatheter to the target
- Coils deployed; position checked before release
- Repeat until packed
- Final angiogram; sheath out
First time in the cath lab?
đź’ˇ First-time tip
- Log every coil. Record size, type and number.
- Snare ready. Have a snare on standby.
- Size matters. Coil sizes are chosen per vessel; hand the right one.
- Final pictures. Confirm closure before finishing.
FAQ
Do the coils stay in forever?
Yes. They are permanent.
Will they set off airport scanners?
Unlikely; ask for a device card.
Can I have an MRI?
Usually yes; check with your team.
Related Cath Lab 101 guides
Sources
All checked on 10 October 2026. Each page's own date is shown where it gives one.
- Baumgartner H, et al. 2020 ESC Guidelines for the management of adult congenital heart disease. Eur Heart J 2021;42(6):563–645. PubMed 32860028
- StatPearls (NCBI Bookshelf), search: coil embolization. ncbi.nlm.nih.gov/books
Disclaimer
Education only. This page is for general education for healthcare students, cath lab staff and curious readers. It isn't medical advice and doesn't replace advice from your own doctor, heart team or local unit protocols. Equipment and medicines are described generically. No product or manufacturer is recommended. If you think someone is having a heart emergency, call 999.
Disclosure: I work in the medical device industry. This page is independent education and isn't sponsored or reviewed by any company.
All diagrams on this page are original illustrations created for rodnieoro.com.
