Article Text

Original research
A novel self-expanding shape memory polymer coil for intracranial aneurysm embolization: 1 year follow-up in Chile
  1. Daniel Echeverría1,2,
  2. Rodrigo Rivera1,2,
  3. Pablo Giacaman3,
  4. Juan Gabriel Sordo1,2,
  5. Martín Einersen3,4,
  6. Lautaro Badilla1,2
  1. 1Neuroradiology, Instituto de Neurocirugía Dr Alfonso Asenjo, Santiago, Chile
  2. 2Department of Radiology, Universidad de Valparaíso, Valparaíso, Chile
  3. 3Neurovascular Unit, Imaging Service, Hospital Clínico Regional Guillermo Grant Benavente, Concepción, Chile
  4. 4Faculty of Medicine, Department of Specialties (Imaging), Universidad de Concepción, Concepción, Chile
  1. Correspondence to Dr Daniel Echeverría, Neuroradiology Department, Instituto de Neurocirugía Dr. Asenjo, José Manuel Infante 553, Providencia, Santiago, Chile; dannyechev{at}


Background Aneurysm recurrence remains a challenge when coiling cerebral aneurysms. Development of next generation coils has focused on accelerating thrombus maturation and increasing coil packing density. Ultra low density shape memory polymer is a novel embolic material designed for this purpose. The polymer is crimped over a platinum–tungsten coil for catheter delivery and self-expands to a predefined volume on contact with blood.

Methods This prospective study in humans evaluated aneurysms 5–16 mm (inclusive) in diameter that were indicated for endovascular coil embolization. At least 70% coil volume was required to be shape memory polymer coils. Patients were followed-up according to standard of care for 12 months.

Results Nine patients (89% women, mean age 55.8±11.7 years) were treated with shape memory polymer coils and completed 12 months of follow-up. Aneurysms were all unruptured and were in the ophthalmic segment of the internal carotid artery (n=7), posterior communicating artery, and anterior cerebral artery A1–A2 segment. Aneurysms were a mean of 7.8±2.9 mm in diameter (range 5.2–14.9 mm). The mean packing density based on unexpanded polymer was 17±6%. Packing density based on expanded polymer was 43±13%. At 12 months, no recurrence had occurred, and a Raymond–Roy occlusion classification of 1 (n=5) or 2 (n=4) was observed. No serious adverse events related to the study device occurred over the 12 months after the procedure.

Conclusions Shape memory polymer coils were safe and effective in treating intracranial aneurysms over 12 months in this first study in human subjects.

  • Aneurysm
  • Coil
  • Artery
  • Device

Data availability statement

No data are available.

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Data availability statement

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  • Contributors Conception and design: DE and RR. Acquisition of the data: all authors. Analysis and interpretation of the data: all authors. Drafting the manuscript: DE. Critically revising the manuscript: all authors. Reviewing submitted version of manuscript: all authors. DE accepts full responsibility for the work and/or the conduct of the study, had access to the data, controlled the decision to publish, and acts as guarantor.

  • Funding The study was sponsored by Shape Memory Medical.

  • Competing interests DE is a consultant for Shape Memory Medical.

  • Provenance and peer review Not commissioned; externally peer reviewed.

  • Supplemental material This content has been supplied by the author(s). It has not been vetted by BMJ Publishing Group Limited (BMJ) and may not have been peer-reviewed. Any opinions or recommendations discussed are solely those of the author(s) and are not endorsed by BMJ. BMJ disclaims all liability and responsibility arising from any reliance placed on the content. Where the content includes any translated material, BMJ does not warrant the accuracy and reliability of the translations (including but not limited to local regulations, clinical guidelines, terminology, drug names and drug dosages), and is not responsible for any error and/or omissions arising from translation and adaptation or otherwise.