Embolization coils are small, tightly wound metallic devices used by interventional radiologists to block blood flow within a targeted blood vessel or aneurysm. Understanding how do embolization coils work can help patients feel more informed before a scheduled procedure. This guide walks through the basic mechanism, materials, and delivery process behind coil embolization in plain language.
What Are Embolization Coils Made Of?
Embolization coils are commonly manufactured from platinum alloys because platinum is biocompatible, flexible, and highly visible under fluoroscopic imaging. For example, INVAMED's Spider coil platform uses a platinum-tungsten (92/8%) alloy, which combines platinum's compatibility and radiopacity with added structural strength. Coils are available in a range of diameters, such as 2–30 mm, to accommodate different vessel sizes and clinical needs.
Many coils also feature synthetic fibers woven into the metal framework. These fibers are intended to increase surface area within the vessel, which can help promote the body's natural clotting process once the coil is in place.
How Do Embolization Coils Create Blockage?
The basic mechanism behind coil embolization involves two complementary effects:
- Mechanical occlusion — the coiled shape is designed to fill the internal space of a vessel or aneurysm sac, physically obstructing blood flow
- Thrombogenic effect — the coil surface and any incorporated fibers are intended to encourage platelets and clotting factors to accumulate, forming a stable clot that reinforces the blockage over time
Together, these effects are designed to achieve durable occlusion of the targeted vessel, although outcomes vary based on vessel anatomy, flow characteristics, and the number of coils used.
How Are Coils Delivered Into the Body?
Coils are delivered through a microcatheter that has already been navigated to the target site using imaging guidance. Physicians typically advance the coil through the catheter using a pusher wire until it reaches the intended location, where it naturally coils into its pre-shaped configuration.
Some coil systems are described as "pushable," meaning the coil is advanced and released without a separate detachment mechanism, while others are "detachable," allowing the physician to reposition or fully seat the coil before mechanically releasing it. The choice between these approaches depends on the clinical scenario and physician preference.
Why Might Multiple Coils Be Used?
In many procedures, more than one coil is placed to achieve what is known as adequate packing density, meaning enough coil material fills the vessel or aneurysm to promote stable, lasting occlusion. Physicians assess packing progress using live imaging throughout the procedure, adjusting the number and size of coils as needed for the specific anatomy involved.
Frequently Asked Questions
Are embolization coils permanent?
Embolization coils are generally intended to remain in place permanently once deployed, as they are designed to promote long-term vessel occlusion. Your physician can explain the expected long-term plan specific to your condition.
Do embolization coils set off metal detectors?
Coils are typically small and made of biocompatible metals; patients should discuss any concerns about medical devices and travel or security screening with their treating physician.
Is coil placement painful?
Embolization procedures are usually performed with sedation or anesthesia, so patients typically do not feel the coil placement itself. Your care team can describe what sensations, if any, to expect during your specific procedure.
Related INVAMED Resources
- Embolization Products — INVAMED's embolization coil and plug portfolio
- Neurovascular Interventions — related catheter-based delivery technologies
- Contact INVAMED — request further product information
Medical Disclaimer: This article is provided for general informational and educational purposes only and does not constitute medical advice, diagnosis, or treatment recommendation. It is not a substitute for consultation with a qualified healthcare professional. Product indications, availability, and regulatory status vary by country. Always refer to the official Instructions for Use (IFU) and consult a licensed physician for guidance specific to your situation. INVAMED devices are intended for use by trained healthcare professionals.