When you need an experienced catheter development and manufacturing team to support your microcatheter program, Midwest Interventional Systems is your turn-key solution. We leverage our design and development expertise in microcatheters, along with our strategic relationships with key component vendors to produce microcatheters with industry leading performance while maintaining thin wall construction and tight tolerances. By utilizing our experience, our clients are able to get to market faster and within budget.

By defining the design outputs at the beginning of our program

  • Torque response
  • Pushability
  • Bend radius and kink radius
  • Dimensional specifications

These outputs are driven by the anatomy, approach, and device or therapeutic to be delivered. We have direct experience in designing and developing microcatheter systems, which include:

  • Cerebral embolization and aneurysm coiling delivery systems
  • Cerebral angioplasty and stenting delivery systems
  • Embolic protection systems
  • Clot retrieval devices
  • Vascular snares
  • Wire support microcatheters

Once the desired functional requirements are determined for your catheter system, our design engineers begin designing the components of the delivery system to achieve the desired outputs.

Microcatheter Design Process


Mandrel and processing aid selection is critical in microcatheter design. Depending on the design requirements for the inner lumen of the microcatheter, there are several features that must be considered:

  • Thermal properties during reflow/lamination
  • Geometry considerations - mandrel grooving, radius considerations, tapered mandrels
  • Surface treatments
  • Coatings
  • Radial compression


The next component MIS evaluates in the design process is the liner material for the main lumen of the catheter. Liners are lubricious material that line the inner diameter of lumens to reduce frictional forces from passing other instruments, catheters, devices. There are a number of options for liner material to incorporate into the delivery system, and they ultimately depend on the application. Common liner materials typically consist of:

  • Film cast or ram extruded and etched PTFE
  • FEP, etched
  • Standard thermoplastic extrusions with lubricious additives
  • Polyimide

Liner thicknesses for microcatheters can vary, but we have experience in working with liners that have a single wall thickness of 0.0005”.


The next layer to a microcatheter delivery system is typically a reinforcement layer. The reinforcement layer plays a critical role in the overall device torquability, achievable bend angles and bend diameters, kink resistance, and pushability. Depending on the application of the device, performance requirements, and other interacting devices, MIS engineers have a plethora of options in their catheter reinforcement toolbox, including, but not limited to:

Braid Reinforcement

  • Round and flat wire
  • Single, dual, tri, & quad start wire
  • Variable pitch braiding
  • Braid pattern and number of carriers
  • Material: 304 & 316 Stainless steel, nitinol, tungsten, UHMWPE, etc.

Wire thicknesses as low as 0.0005”.

Coil Reinforcement

  • Round and flat wire
  • Clockwise and counterclockwise winding
  • Single or multilayered
  • Variable pitch coiling
  • Material: 304 & 316 Stainless steel, nitinol, tungsten, UHMWPE, etc.

Braid/Coil Hybrid

  • Braided and coiled hybrid designs are commonplace in microcatheter design. A proximal braided portion provides pushability and torquability, while a coiled distal section allows for a tighter bend radius to be achieved while minimizing lumen ovalization. Important system considerations need to be taken into account, particularly at the junction of the braid and coil segments, and our experienced team can provide guidance in these areas.


The final layer in constructing a microcatheter is the jacket, or medical extrusion. The extrusions provide coverage over the reinforcement layer of the catheter and are also critical to the device torqueability, flexibility, compression and elongation resistance. MIS will help in developing a number of specifications surrounding these jackets, which include:

  • Material selection – Polyamides, thermoplastic elastomers (TPEs), and thermoplastic urethanes (TPUs)
  • Selective durometer placement and material transition considerations
  • Catheter distal tip forming
  • Hydrophilic coating

Contact us today to discuss how we can help determine the optimal approach to design your microcatheter, and partnering with you on the development of your delivery system.

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