Polymeric embolization coil of bilayered polyvinyl alcohol strand for therapeutic vascular occlusion: a feasibility study in canine experimental vascular models.

Abstract

PURPOSE:

To investigate the feasibility of polyvinyl alcohol (PVA) polymer coil as a new endovascular embolic agent and to gauge the related histologic response in a canine vascular model.

MATERIALS AND METHODS:

PVA polymer coil was fabricated by cross-linking PVA and tantalum particles. Basic properties were then studied in vitro via swelling ratio and bending diameter. Normal renal segmental arteries and wide-necked aneurysms of carotid sidewalls served as canine vascular models. Endovascular PVA coil embolization of normal renal segmental arteries (N = 20) and carotid aneurysms (N = 8) was performed under fluoroscopic guidance in 10 dogs. Degree of occlusion was assessed immediately and at 4 weeks after embolization by conventional and computed tomographic angiography. Histologic features were also graded at acute (day 1, six segmental arteries and four aneurysms) and chronic phases (week 4, 14 segmental arteries and four aneurysms) after embolization to assess inflammation, organization of thrombus, and neointimal proliferation.

RESULTS:

Swelling ratio declined as concentrations of cross-linking agent increased. Mean bending diameters were 2.05 mm (range, 0.86-6.25 mm) in water at 37 °C and 2.29 mm (range, 0.94-6.38 mm) in canine blood samples at 37 °C. Occlusion of normal renal segmental arteries was sustained (complete occlusion at day 1, n = 20; at week 4, n = 14), whereas immediate outcomes in carotid aneurysms (day 1, complete occlusion, n = 5; residual neck only, n = 3) were not sustained (week 4, complete occlusion, n = 1; minor recanalization, n = 1; major recanalization, n = 2). At week 4, chronic inflammatory cells predominated, with progressive organization of thrombus and fibrocellular ingrowth. All aneurysms bore full neointimal linings on the coil mass in the chronic phase.

CONCLUSIONS:

Vascular occlusion by PVA polymer coil proved superior in normal renal segmental arteries and feasible in surgically constructed carotid aneurysms (with packing densities ≥ 30%), constituting acceptable radiologic feasibility and histologic response.

• Authors: Seung Chai Jung, Seung Hong Choi, Hye Rim Cho, Tae Hoon Lee, Tae Yang Kim, Woowon Jeong, Kyehan Rhee, Jae Young Jho, Jae Hyoung Kim, Moon Hee Han
• Journal: Journal of vascular and interventional radiology : JVIR (J Vasc Interv Radiol) Vol. 26 Issue 1 Pg. 117-23 (Jan 2015) ISSN: 1535-7732 [Electronic] United States
• PMID: 25454653 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
• Copyright: Copyright © 2015 SIR. Published by Elsevier Inc. All rights reserved.

Chemical References

• Polyvinyl Alcohol

Topics

• Animals
• Arterial Occlusive Diseases (diagnostic imaging, therapy)
• Carotid Arteries (diagnostic imaging)
• Chemoembolization, Therapeutic
• Disease Models, Animal
• Dogs
• Feasibility Studies
• Polyvinyl Alcohol (administration & dosage)
• Renal Artery (diagnostic imaging)
• Tomography, X-Ray Computed