Resumen de In vitro development and evaluation of a polyacrylic acid–silicone device intended for gradual occlusion of portosystemic shunts in dogs and cats

Mandy L. Wallace, Gary W. Ellison, Christopher Batich, J. Brad Case, Stanley E. Kim

• In vitro development and evaluation of a polyacrylic acid–silicone device intended for gradual occlusion of portosystemic shunts in dogs and cats Mandy L. Wallace, DVM, MS; Gary W. Ellison, DVM, MS; Christopher Batich, PhD; J. Brad Case, DVM, MS; Stanley E. Kim, BVSC, MS Department of Clinical Sciences, College of Veterinary Medicine, University of Florida, Gainesville, FL 32610. (Wallace, Ellison, Case, Kim); Department of Materials Science and Engineering, College of Engineering, University of Florida, Gainesville, FL 32611. (Batich) Address correspondence to Dr. Wallace (wallaceml@ufl.edu).

  OBJECTIVE To develop a device intended for gradual venous occlusion over 4 to 6 weeks.

  SAMPLE Silicone tubing filled with various inorganic salt and polyacrylic acid (PAA) formulations and mounted within a polypropylene or polyether ether ketone (PEEK) outer ring.

  PROCEDURES 15 polypropylene prototype rings were initially filled with 1 of 5 formulations and placed in PBSS. In a second test, 10 polypropylene and 7 PEEK prototype rings were filled with 1 formulation and placed in PBSS. In a third test, 2 formulations were loaded into 6 PEEK rings each, placed in physiologic solution, and incubated. In all tests, ring luminal diameter, outer diameter, and luminal area were measured over 6 weeks.

  RESULTS In the first test, 2 formulations had the greatest changes in luminal area and diameter, and 1 of those had a greater linear swell rate than the other had. In the second test, 6 of 7 PEEK rings and 6 of 10 polypropylene rings closed to a luminal diamater < 1 mm within 6 weeks. Polypropylene rings had a greater increase in outer diameter than did PEEK rings between 4.5 and 6 weeks. In the third test, 11 of 12 PEEK rings gradually closed to a luminal diameter < 1 mm within 6 weeks.

  CONCLUSIONS AND CLINICAL RELEVANCE A PAA and inorganic salt formulation in a prototype silicone and polymer ring resulted in gradual occlusion over 4 to 6 weeks in vitro. Prototype PEEK rings provided more reliable closure than did polypropylene rings.