Polymeric endoaortic paving: Mechanical, thermoforming, and degradation properties of polycaprolactone/polyurethane blends for cardiovascular applications

Abstract

Polymeric endoaortic paving (PEAP) is a process by which a polymer is endovascularly delivered and thermoformed to coat or “pave” the lumen of the aorta. This method may offer an improvement to conventional endoaortic therapy in allowing conformal graft application with reduced risk of endoleak and customization to complex patient geometries. Polycaprolactone (PCL)/polyurethane (PU) blends of various blend ratios were assessed as a potential material for PEAP by characterizing their mechanical, thermoforming, and degradation properties. Biaxial tension testing revealed that the blends' stiffness is similar to that of aortic tissue, is higher for blends with more PCL content, and may be affected by thermoforming and degradation. Tubes of blends were able to maintain a higher diameter increase after thermoforming at higher PCL content and higher heating temperatures; 50/50 blend tubes heated to 55°C were able to maintain 90% of the diameter increase applied. Delamination forces of the blends ranged from 41 to 235 N/m2. In a Pseudomonas lipase solution, the 50/50 blend had a 94% lower degradation rate than pure PCL, and the 10/90 blend exhibited no degradation. These results indicate that PEAP, consisting of a PCL/PU blend, may be useful in developing the next generation of endoaortic therapy.

Segmented linear shape memory polyurethanes with thermoreversible Diels-Alder coupling: Effects of polycaprolactone molecular weight and diisocyanate type

“…Due to their outstanding properties, PUs are widely used in automotive (instrument panel, belt, seals), electric/electronic (cable jacketing, mobile phones), transportation (conveyor belt, tyres), footwear (shoe and shoe sole), medical (catheters) fields, sporting goods, leisure articles (grips) etc. [3][4][5][6][7][8]. Linear PUs are traditionally produced by reacting diisocyanates (hard segments), long-chain diols of polyesters and/or polyethers (soft segments) and with short-chain diols (socalled chain extenders).…”

Effects of transforming growth factor-beta-1 neutralizing antibody and transforming growth factor-beta-3 on the development of tracheal stenosis

“…Thus, this polymer can be used in various medical practices. [14,15] Polycaprolactone is a deformable polymer and its biodegradation occurs slowly over a long period of time. It is also widely biocompatible, [16] which is the main reason we chose it for our current study.…”

Wall Stress Reduction in Abdominal Aortic Aneurysms as a Result of Polymeric Endoaortic Paving

“…3 Blends of PCL (MW 70,000, Fisher Scientific, NC9498824) and PU (Lubrizol, Tecoflex Ò SG-80A) were made by dissolving them in chloroform, yielding 10/90 and 50/50 ratios (wt% PCL/PU). Sheets were fabricated via solvent casting.…”

“…1,19,21,29 Testing in our laboratory revealed that PCL/PU blends are thermoformable at 55°C, resistant to biodegradation, and have mechanical properties that can be controlled by varying PCL/ PU ratios. 3 In order for PEAP to prevent AAA rupture and provide a viable option to treat AAA, it must reduce aneurysm wall stress at least as effectively as stentgrafts. Various computational techniques have been used to estimate stresses in AAA, some of which include finite element modeling (FEM), 10,13 coupled fluid-structure interaction simulations (FSI), 22,26 and more recently porohyperelastic modeling.…”

“…3 While PEAP placement could be patient specific (i.e., its geometry could follow that of the patient's aortic lumen precisely), we chose to simulate cylindrically shaped PEAP delivery here. This was done in order to remove the effects of PEAP geometry (except thickness) in comparing our device to that of a stent-graft.…”