A shape memory foam material developed at a weapons laboratory is the foundation of a lifesaving medical device that is now available to the public thanks to technology transfer.  

Blood flow through diseased or damaged vessels puts patients at an increased risk of stroke, severe pain, uncontrolled bleeding, and even death.

The IMPEDE® Embolization Plug, incorporating a foam technology developed at Lawrence Livermore National Laboratory (LLNL), provides a physical barrier to obstruct or reduce the rate of blood flow, reducing the risk of complications.  

The foam plug, made of a polyurethane shaped memory polymer (SMP) initially intended for weapons applications, is crimped to fit into any diagnostic catheter for easy delivery into a diseased blood vessel. Within minutes of delivery, the SMP foam expands to divert blood flow away from the diseased vessel and toward healthy vessels.  

The foam plug is less likely than metal plugs or coils to tear through blood vessel walls and is easier to navigate through the vascular system, because of the material’s compliant nature. Unlike metal devices, the foam plug degrades over time and is replaced with the patient’s natural connective tissue and collagen, all without long-term inflammation or toxicity. 

The foam plug is porous, giving it more surface area than non-porous embolization devices. Preclinical studies indicate that this difference leads to improved long-term healing using the foam plug, and a lower likelihood that re-treatment — which has associated risks — will be needed.  

Unlike metal devices, the foam plug degrades over time and is replaced with the patient’s natural connective tissue and collagen, all without long-term inflammation or toxicity. 

Clinically, more than 200 patients have been treated successfully with the device for conditions such as pulmonary arteriovenous malformations, tumor resection, and pelvic congestion syndrome. No patients reported adverse effects.  

Complementary to the IMPEDE® Embolization Plug, the IMPEDE-FX device is also available for use when embolization of blood vessel regions with larger lengths and diameters is needed. The IMPEDE® Embolization Plug received 501(k) clearance from the US Food and Drug Administration (FDA) in 2018, and the IMPEDE®-FX received FDA 501(k) clearance in 2019. 

Established medical device companies previously reviewed LLNL’s SMP technology but were unwilling to deviate from the industry standard of metal-based occlusion devices. Driven by a belief in the technology, the principal investigator (PI) of the project, Duncan Maitland, left LLNL in 2007 to join the faculty of Texas A&M University and create a start-up, now known as Shape Memory Medical Inc., to develop vascular occlusion devices using the novel foam technology. 

This type of PI transfer can typically create problems related to intellectual property (IP) for both the past and present institutions. To avoid such issues, an inter-institutional agreement developed by LLNL’s Innovation and Partnerships Office gave Texas A&M access to a significant portfolio of background IP for the polymer material and provided LLNL with access to future IP. Technology transfer agreements related to commercialization of the product were also executed between LLNL and Shape Memory Medical, which is now based in Santa Clara, California.