Videographic assessment of the embolic characteristics of three polymeric compounds: ethylene vinyl alcohol, cellulose acetate, and liquid urethane.
OBJECTIVE
Aneurysms have been clinically and experimentally treated with various surgical and endovascular methods, including endovascular polymer instillation. Additional tools may help to identify advantages and disadvantages of polymeric aneurysm treatment. We assessed the value of high-resolution videography to compare in vitro embolization characteristics of ethylene vinyl alcohol copolymer (VIN), cellulose acetate polymer (ACE), and urethane copolymer (UCO).


METHODS
In a "neck-up" glass aneurysm model, solutions of 8% and 12% VIN, 8% and 12% ACE, and 8% UCO were introduced through a microcatheter into a xanthan gum solution at three flow rates: full physiological (62 cm/s), half physiological, and flow arrest. Each formulation was then introduced into a "neck-down" aneurysm model at flow arrest, for a total of 20 experiments. Results were tabulated for six different categories: outflow tail formation, inflow-zone polymer-mass deformation, inflow-zone migration, detachment tail formation, adherent mass pullout, and conjectural net effect.


RESULTS
Of the 20 experiments, nine had unacceptable results because of potential clinical complications. The results were unacceptable in four of eight VIN experiments, four of eight ACE experiments, and one of four UCO experiments. VIN performance was more dependent on flow arrest than the more viscous ACE. The growth of the ACE solutions was most circumferential, with balloonlike growth characteristics, little inflow-zone effects, and fewer outflow tails than seen with VIN. All compounds had the potential for partial catheter adhesion and catheter-adhesing tails. UCO had the highest percentage of favorable results and the lowest percentage of unfavorable results.


CONCLUSIONS
Videographic analysis allows detailed assessment of the dynamic embolization characteristics of polymers, revealing potential advantages of compounds such as UCO.
Norbash
A M
AM
Department of Neuroradiology, Brigham and Women's Hospital, Boston, MA 02115, USA.
Singer
R J
RJ
D002482:Cellulose / Q000031:analogs & derivatives / Q000627:therapeutic use*; D004621:Embolization, Therapeutic / Q000379:methods*; D008955:Models, Cardiovascular; D011108:Polymers; D011145:Polyvinyls / Q000627:therapeutic use*; D012212:Rheology; D014520:Urethane / Q000627:therapeutic use*; D014743:Videotape Recording; D014783:Viscosity
D011108:Polymers; D011145:Polyvinyls; C020320:ethylene-vinyl alcohol copolymer; D014520:Urethane; C005062:acetylcellulose; D002482:Cellulose