Lipid uptake in expanded polytetrafluoroethylene vascular grafts

Vermette, Patrick; Thibault, Jules; Laroche, Gaétan

doi:10.1016/s0741-5214(98)70140-5

Cited by 8 publications

(9 citation statements)

References 20 publications

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“…16,17 In light of this study, we examined the lipid retention on ePTFE vascular grafts exposed to a phospholipid suspension as a function of various flow conditions. 18 Findings from this study indicated that the lipid uptake depended on the transmural pressure and the time of exposure to the model fluid.…”

Section: Introductionmentioning

confidence: 71%

“…Lipid uptake on the luminal and external surface of an ePTFE microporous vascular prosthesis exposed to a phospholipid suspension under various flow conditions was analyzed and reported elsewhere. 18 It was demonstrated that the lipids rapidly permeated the prosthesis to gradually agglomerate within the prosthesis wall, thereby inhibiting the further passage of lipids through the membrane. In light of this, the present study focused on examining the lipid sorption across an ePTFE prosthesis wall.…”

Section: Discussionmentioning

confidence: 99%

“…In light of the previous article, we may also postulate that the lipid permeation of the prosthesis wall was magnified by the regularly spaced perforations along the prosthesis structure that channeled preferential pathways of lipid advection. 18 While in the past the prosthesis wall was considered structurally homogeneous based on its macroscopic properties, it is true that heterogeneity in the membrane's structural properties was observed at different microscopic scale. It is, therefore, evident that solute transport in a porous medium is eventually affected by the geometric irregularity of the pores.…”

Section: Discussionmentioning

confidence: 99%

“…30 Second, following the lipid adsorption, it was further possible to observe the germination of lipid deposits. 18 Once a layer of lipid particles had formed on the polymer, its surface became a de facto filter medium. The deposited and agglomerated lipids, in fact, created an additional resistance to the fluid permeation.…”

Section: Discussionmentioning

confidence: 99%

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Lipid uptake across the wall of an expanded polytetrafluoroethylene vascular graft

Vermette

Thibault

Lévesque³

et al. 1999

J. Biomed. Mater. Res.

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Previous studies have shown that vascular grafts were prone to inducing an atherosclerosis-like phenomenon, thus possibly jeopardizing their performance. Furthermore, lipid retention, observed in most synthetic arterial prostheses explanted from humans, appears to have an important role in the progression of this atherosclerotic process, therefore hindering the healing process and neo-intima formation of these synthetic conduits. The current study examined lipid concentration profiles across prosthesis membranes exposed to lipid dispersion under various transmural pressures, flow rates, and durations of exposure. It was demonstrated that the lipids rapidly permeated the prosthesis membrane, as lipid advection increased to a maximum, then steadily decreased until the membrane became completely impermeable to the fluid. The concentration of lipids within the grafts was monitored using FT-IR microspectroscopy, then correlated as a function of time in order to evaluate the mass transfer coefficients and lipid saturation concentration. Lipid sorption, as a function of time, was described by a mechanism taking into account two first-order kinetic models. The lipids were first rapidly adsorbed onto the Teflon(R), potentially influenced by the strong affinity of these lipids for the highly hydrophobic polytetrafluoroethylene polymer. This affinity then enhanced the germination of the lipid deposits that filled in the prosthesis wall. For lipid retention as a function of the transmural pressure and flow rate, no clear tendency was established.

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Section: Introductionmentioning

confidence: 71%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

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Lipid uptake across the wall of an expanded polytetrafluoroethylene vascular graft

Vermette

Thibault

Lévesque³

et al. 1999

J. Biomed. Mater. Res.

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“…A 3% (wt/wt) lipid suspension was obtained by mixing appropriate amounts of phosphatidylcholine (PC) from fresh frozen egg yolk (P‐9671, Sigma Chemical Co., St. Louis, MO, U.S.A.) in double‐distilled deionized water. This particular lipid concentration was chosen because the viscosity of the dispersion closely matched that of blood in similar flow conditions (24), and it provided a good signal in the subsequent FTIR analysis. In fact, even if the 3% concentration was higher than that observed in whole human blood (25), obtaining a good signal from the FTIR spectroscopy was an essential condition, as the focus of this procedure was to detect lipid transport through the prosthesis wall.…”

Section: Methodsmentioning

confidence: 99%

Modeling Lipid Uptake in Expanded Polytetrafluoroethylene Vascular Prostheses and Its Effects on Mechanical Properties

Vermette¹,

Fiset²,

Guidoin

et al. 2000

Artificial Organs

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The radial transport across the wall of expanded polytetrafluoroethylene (ePTFE) arterial prostheses has a significant effect on lipid uptake observed in prostheses implanted in humans, which has been postulated to be one of the causes associated with implant failure. The goal of this study was to stimulate radial transport on a lipidic dispersion across the wall of an ePTFE prosthesis and investigate its effects on the circumferential mechanical properties of the prosthesis. An in vitro model was developed to simulate the lipidic radial transport across the wall. Lipids contained in a phosphatidylcholine dispersion were used as the transported molecules. Lipid concentration profiles were obtained after exposing commercial ePTFE prostheses to various transmural pressure and/or lipidic concentration gradients. Phospholipids gradually accumulated up to the external reinforcing wrap of the prosthesis, which clearly acted as a rigid barrier against lipid infiltration. Tensile tests performed on the virgin samples showed that the wrap was much more rigid than the microporous part of the prosthesis. After the lipid simulation, the rigidity of the wrap decreased with respect to what was observed for the virgin prosthesis. Finally, some clinical implications of this phenomena are discussed.

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Silk fibroin for vascular regeneration

Wang

Liu

Fan

2015

Microscopy Res & Technique

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Cardiovascular disease is the primary cause of morbidity and mortality in today's world. Due to the lack of healthy autologous vessels, more tissue-engineered blood vessels are needed to repair or replace the damaged arteries. Biomaterials play an indispensable role in creating a living neovessel with biological responses. Silk fibroin produced by silkworms possesses good cytocompatibility, tailorable biodegradability, suitable mechanical properties, and minimal inflammatory reactions. In addition, regenerated silk fibroin solutions can be processed into various forms of scaffolds such as films, fibers, tubes, and porous sponges. These features make silk fibroin a promising biomaterial for small-diameter vascular grafts. The present article focuses on the applications of silk fibroin for vascular regeneration. A brief overview of the properties of silk fibroin is provided, following which the current research status and future directions of the main types of silk fibroin scaffolds for vascular regeneration are reviewed and discussed. Microsc. Res. Tech. 80:280-290, 2017. © 2015 Wiley Periodicals, Inc.

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Lipid uptake in expanded polytetrafluoroethylene vascular grafts

Abstract: The occurrence of the membrane permeability may be associated with the dilatation and plastic deformation of the prosthesis. Lipid uptake occurs in ePTFE grafts after an aggressive kinetic process.

Cited by 8 publications

References 20 publications

Lipid uptake across the wall of an expanded polytetrafluoroethylene vascular graft

Lipid uptake across the wall of an expanded polytetrafluoroethylene vascular graft

Modeling Lipid Uptake in Expanded Polytetrafluoroethylene Vascular Prostheses and Its Effects on Mechanical Properties

Silk fibroin for vascular regeneration

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