Selecting the right microcatheter for coiling or liquid embolic delivery is a foundational decision in endovascular aneurysm and vascular malformation treatment, since the catheter's handling characteristics directly influence how precisely an operator can deliver embolic material. This guide reviews how microcatheters function in these two delivery contexts and what design factors matter for each.
Why Does Microcatheter Selection Matter for Embolic Delivery?
Both coil and liquid embolic delivery require the microcatheter tip to be positioned precisely at the target site — typically within an aneurysm sac or at the nidus of a vascular malformation — before embolic material is introduced. Because these targets are often located in distal, tortuous intracranial vessels, the microcatheter must balance several competing mechanical demands:
- Sufficient flexibility to navigate small, curved vessels without straightening them
- Adequate pushability and torque response to reach the target reliably
- A lumen and tip design compatible with the specific embolic material being used
- Stable positioning during embolic delivery, since catheter movement during infusion can affect placement accuracy
How Do Coiling Microcatheters Work?
For aneurysm coiling, a microcatheter is navigated into the aneurysm sac itself, and detachable coils are advanced through the catheter lumen and released to gradually fill the sac. The microcatheter tip position is critical throughout the procedure, since coils are typically deployed in a specific sequence to build a stable framework before finer coils are added.
Catheter shapeability — the ability of the distal segment to be steam-shaped by the operator to match aneurysm neck geometry — is a commonly used technique to improve stability of the catheter tip within the sac during coil delivery.
How Do Liquid Embolic Delivery Microcatheters Differ?
Liquid embolic agents, such as ethylene vinyl alcohol copolymer (EVOH) formulations, are typically dissolved in dimethyl sulfoxide (DMSO) as a delivery solvent. This introduces an additional requirement: the microcatheter must be chemically compatible with DMSO, since some catheter materials can be damaged by prolonged DMSO contact.
Catheters designed for liquid embolic delivery are typically constructed with DMSO-compatible materials throughout the catheter shaft and hub, and some are designed with "flow-directed" characteristics that use blood flow to help advance the catheter tip into small, distal vessels feeding a malformation.
Because liquid embolic agents polymerize on contact with blood or ionic solutions, controlled, steady injection technique and catheter tip stability are especially important to avoid unintended reflux or premature polymerization within the catheter lumen.
What Are General Considerations for Physicians?
Device selection depends on the specific procedure, target anatomy, and embolic material planned. All embolization and coiling procedures carry inherent risks, including vessel injury, non-target embolization, or incomplete treatment, and suitability is determined by the treating physician based on imaging and clinical assessment. Physicians should always consult the official Instructions for Use (IFU) for complete compatibility and technique information specific to each device and embolic agent.
Frequently Asked Questions
Can the same microcatheter be used for both coiling and liquid embolics?
Some microcatheter platforms offer variants suited to either application, but compatibility depends on the specific catheter's material construction, particularly for DMSO compatibility with liquid embolic agents. Always confirm compatibility against the official IFU before use.
Why is DMSO compatibility specifically important?
DMSO is commonly used as a solvent for certain liquid embolic agents, and some catheter materials can degrade with prolonged DMSO exposure. Using a catheter not rated for DMSO compatibility with these agents could compromise catheter integrity during the procedure.
What role does catheter tip shaping play in coiling procedures?
Steam-shaping the distal catheter tip is a widely used technique to help the catheter conform to aneurysm neck anatomy, which can improve stability during coil deployment. This is performed by the treating physician based on pre-procedural imaging.
Related INVAMED Resources
- Neurovascular Interventions — INVAMED's neurovascular microcatheter and embolization device portfolio
- MicroCATH Neurovascular Catheter Family: Overview — general design and intended use of the MicroCATH lineup
- Contact INVAMED — request technical information about neurovascular microcatheters
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.