Effects of balloon dilatation on ePTFE structural characteristics

Abstract

The search for less invasive treatments for cardiovascular disease has lead to the development of endovascular stent grafts, metallic and alloy stents surrounded by prosthetic vascular graft material. Introduced intravascularly, the deployment of stent grafts requires balloon dilatation of the device which results in expansion of the stent along with the vascular graft material. We hypothesized that balloon dilatation of stent grafts would alter the physical structure of the prosthetic graft material. In this study, noncompliant angioplasty balloons were used to dilate expanded polytetrafluoroethylene (ePTFE), a material commonly used for endovascular stent-graft technology. The maximal outer diameter (inflated balloon within the lumen) and the recoiled outer diameter (balloon removed) of two types of ePTFE, 3-mm inside diameter (i.d.) thin wall (30-micron internodal distance) and 4-mm i.d. standard wall (30-micron internodal distance), were measured to compare material recoil. Following balloon dilatation, ePTFE samples were prepared for scanning electron microscopic examination and the following parameters were measured: wall thickness, internodal distance, nodal width, interfiber distance, and fiber width. Following primary dilatation, both types of ePTFE recoiled approximately 20% regardless of inflated balloon diameter. However, following eight repetitive balloon dilatations, recoil decreased to approximately 10%. Scanning electron microscopic analysis revealed variations in internodal distance and significant decreases in wall thickness, nodal thickness, and interfiber distance. Fiber width was significantly decreased following dilatation of 3 mm, but not 4 mm ePTFE. Our data support our initial hypothesis that balloon dilatation alters the structure of ePTFE.

Evaluation of an aqueous drainage glaucoma device constructed of ePTFE

“…3,5 The basis for these differences is thought to involve not only polymer chemistry, but also polymer architecture and manufacturer processing. 3,4,6,7 Our efforts have been directed at developing an improved aqueous drainage device using an alternative biomaterial and design. In this article, we report the use of expanded polytetrafluoroethylene (ePTFE) in a unique aqueous shunt.…”

Application of dual Willis covered stents in the management of large fusiform carotid aneurysms in a canine model

“…Possible causes of endoleaks after covered stent deployment include incomplete occlusion of the aneurysm orifice, discordance in the diameters of the PA at the two points where the stent is to be deployed, aneurysms located at an acutely angled vessel segment, a tear in the graft, and retrograde flow from a collateral vessel. [15][16][17] In the present study, the FAs were created in straight vessels without acute angles, so we speculated that the main cause of the endoleaks was that the dilated vessel wall provided insufficient support for the stent. One effective method for solving the problem was to use more than one stent, as our results demonstrate.…”

A tissue‐engineered aneurysm model for evaluation of endovascular devices

“…Expanded polytetrafluoroethylene vascular grafts were used based on the ability to balloon dilate ePTFE, 25 thereby generating aneurysmal scaffolds. These grafts also provide a tubular, porous structure for the adherence and bioreactor culture of stromal vascular fraction cells.…”