Technology

Weaving technology

Specially adapted weaving looms

Knitting technology

VASCUTEK manufactures Köper knitted grafts for excellent dilatation resistance.

The unique, patented knitted structure, produced by this technology results in yarns being arranged perpendicular to each other on the inner surface of the graft, more similar to a woven rather than a conventionally knitted structure.

This innovative configuration preserves all the advantages of a knitted material, such as  absence of fraying, no need for cautery and soft handling, along with the added benefit of  dilatation resistance. 3,4,5

The GelsoftTM Plus Köper knitted structure provides enhanced strength and radial stability4,6. When used for Thin Wall grafts and patches, the inherent strength has allowed a reduction in thickness of the product. This provides superb handling, particularly useful in peripheral procedures. In all cases, the balanced, stable fabric structure provides excellent suture retention6, facilitating rapid anastomosis.

Unique Köper knitted structure with woven configuration (SEM)
The Köper knitted structure features yarns arranged perpendicular to each other on the inner surface. 

Increased radial stability (graph)
The Köper knitted structure displays superior dilatation resistance to conventional knitted grafts3.

Sealant technology

VASCUTEK sealed products feature a unique patented modified mammalian gelatin impregnation with many years of clinical experience worldwide. These products are 100% porosity tested by VASCUTEK.

The impregnation also demonstrates a number of other significant features, in addition to its primary function as a sealant. Unlike other sealants, it hydrolyses over a period of 14 days by a non-enzymatic mechanism that does not elicit a prolonged inflammatory response 2,3. This degradation profile allows unimpaired tissue incorporation into the matrix of the graft 4.

 

Low Thrombogenicity / Heparin Bonding*

Gelatin has been shown to have a low thrombogenicity4,5. Under test conditions, sealed polyester attracts fewer platelets than non-impregnated polyester 6 and collagen sealed polyester7. It also passively absorbs heparin* (achieved with a simple soaking technique) providing short-term high local concentration at the surface of the material. This gives additional active thromboresistance during the critical post-operative period that is particularly useful in low flow situations8.

Heparin bonding to VASCUTEK unique gelatin has CE dossier approval 15

Antibiotic Bonding*

VASCUTEK gelatin has been shown to be the ideal sealant for ionically bonding to the antibiotic Rifampicin* 9. This technique may be used in order to minimise the incidence of postoperative graft infection 10. The simple bonding procedure is particularly useful in high-risk cases 10,11, including the replacement of infected grafts 12, where the rifampicin-gelatin combination will survive arterial pressure and flow 13. VASCUTEK Rifampicin* bonded grafts have been shown to be significantly more resistant to bacteremic infection than silver/collagen coated grafts 14.

Rifampicin* bonding to VASCUTEK unique gelatin has CE dossier approval 15 and is backed by over 35 publications and 10 years' experience. Publications on request.

*Please Note: The Rifampicin loading procedure is subject to local regulatory approval and has not been approved in the United States of America, Canada or Singapore

Fluoropassiv™ Technology

This is a novel, patented technology whereby the surface of each fibre within a macroporous polyester matrix is totally covered by fluoropolymer molecules.

The surface of each fibre within a macroporous polyester matrix is totally covered by fluoropolymer molecules. The process ensures that the fluoropolymer molecules bond with the polyester giving an interpenetrating molecular network at the interface between the two polymers.

The thinness of the covering (less than 10 nanometres) does not allow it to be seen using mainstream technology - this can however be achieved by using Secondary Ion Mass Spectroscopy (SIMS). The  output from the SIMS instrument visualises the presence of fluorine atoms over the total surface, providing evidence of a completely fluoropassivated structure. The result is a new biomaterial - the first macroporous fluoropolymer.

In vitro, in vivo and ex vivo studies3,4,5 on platelet deposition confirm that the Fluoropassiv™ biomaterial exhibits significantly reduced thrombogenicity compared to polyester and ePTFE. Improved healing is evidenced in animal models by more complete pseudointimal development and vasa vasorum6,7, formation. A thin pseudointima has been noted with extensive coverage by endothelium even in the mid portion of long thoracoabdominal grafts. Fluoropassivation is used in the production of Thin Wall peripheral grafts and carotid patches.

No clinical data is available which evaluates the long-term impact of the fluoropassivated surface modification treatment. (Claims based on animal and laboratory data available from VASCUTEK Ltd).

Product availability subject to regulatory approval.

ePTFE technology

VASCUTEK utilises the very latest state of the art computer controlled manufacturing and monitoring systems in its ePTFE production facility.

These systems ensure that an exacting level of consistency and quality of product is achieved. 

ePTFE Quality Control Procedures

Quality and consistency are paramount at every stage of ePTFE production. From raw material checks to finished goods, VASCUTEK’s Quality Assurance Programme guarantees production excellence.

To ensure our finished products meet their exacting design specifications, we remove multiple samples from each production batch and test these to destruction. The remainder of the batch is held in quarantine.

The testing schedule includes the following:

  • Longitudinal tensile strength
  • Suture retention (straight & oblique)
  • Differential scanning calorimetery (DSC)
  • Wall thickness measurements
  • Internal diameter measurements
  • Radial burst strength
  • Peel strength (externally reinforced products)
  • Peel strength (wrapped products)

Only after the samples have passed ALL tests, will the remainder of the batch be released for sale.

If the products fail to meet the design specification for ANY of the tests – the whole batch will be rejected and destroyed.

References

1. U.S. Patent No: 5732572

2. European Patent No: 691829

3. Guidoin R, et al. 
In vitro and in vivo studies of a polyester arterial prosthesis with a warp-knitted sharkskin structure. 
Journal of Biomedical Materials Research (1997) 35, 459-472

4. Walker D, et al. 
Novel structure for a polyester vascular prosthesis with improved mechanical properties. 
Society for Biomaterials, March 1995

5. Goëau-Brissonnière O et al 
Can knitting effect dilation of polyester bifurcated prosthesis? A randomised study with the use of helical computed tomographic scanning.
Journal of Vascular Surgery (2000) 31,157-163

6. Data on file, VASCUTEK Ltd

1. U.S. Patent No: 4,747,848

2. Vohra R, et al. 
Sealed versus unsealed knitted Dacron® prosthesis: A comparison of the acute phase protein response. 
Annals of Vasc Surg. (1987) I: 548-551

3. Jonas R A, et al. 
Unsatisfactory clinical experience with a collagen-sealed knitted Dacron® extracardiac conduit. 
J Cardiac Surg. (1987), Vol 2, No 2, 257-264

4. Harasaki H. et al. 
Blood-blood pump surface interaction. 
Ch 9 Biocompatible Polymers, Metals and Composites, ed. M. Szycher, Technomic (1983)

5. Gloviczki P. et al. 
Experimental evaluation of bleeding complications, thrombogenicity and neointimal characteristics of prosthetic patch materials used for carotid angioplasty. 
Cardiovascular Surgery (1996), Vol. 4, No 6, 746-752

6. Drury J.K. et al.
Experimental and clinical experience with a gelatin impregnated Dacron® prosthesis. 
Ann. Vascular Surgery (1987), 542-547

7. Safepharm report on thrombogenicity (Data available on request)

8. Data on file at VASCUTEK Ltd.

9. Ashton T. et al
Antibiotic loading of vascular grafts
16th Annual Meeting of the Society for Biomaterials, May 1990, Charleston, USA

10. Strachan C.J.L. et al. 
The clinical use of an antibiotic-bonded graft. 
Eur J Vasc Surg (1991), 5, 627-632

11. Strachan C.J.L. et al.
Prosthetic graft infection
Critical Ischaemia (1993), Vol 2. No 3, 5-16

12. Naylor A R et al. 
Treatment of major aortic graft infection: preliminary experience with total graft excision and in situ replacement with a rifampicin bonded prosthesis. 
Eur J Vasc Endovasc Surg. (1995), 9, 252-256

13. Braithwaite B.D. et al
Early results of a randomized trial of rifampicin-bonded dacron grafts for extra-anataomic vascular reconstruction
British Journal of Surgery 1998; 85; 1378-1381

14. Goëau-Brissonnière, Olivier et al
Comparison of the resistance to infection of rifampicin bonded gelatin-sealed and silver/collagen-coated polyester prostheses.
J Vasc Surg 2002; 35; 1260-1263

15. Rinsing of Gelatin Sealed Prostheses with Rifampicin and/or Heparin BSI EQ# 10020927

3. Ashton T. et al. 
Platelet thrombogenic response to polyester can be passivated by fluoropolymer surface treatment. 
European Society for Biomaterials, (1995)

4. Rhee R. et al. 
Experimental evaluation of bleeding complications, thrombogenicity, and neonintimal characteristics of prosthetic patch materials used for carotid angioplasty.
Cardiovascular Surgery, (1996). Vol.4, No.6, 746-752

5. Chinn J.A. et al.
Blood & tissue compatibility of modified polyester: thrombosis, inflammation and healing. 
J. Biomed. Mat.Res.(1998), Vol. 39, 130-140

6. Curti T. et al. 
Biocompatibility of the new Fluoropassiv™ vascular prosthesis- ultrastructure analysis
Giornale Italiano di Chirurgia Vascolare (1994), Vol.1, No.1-2, 27-30

7. Guidon R. et al. 
The benefits of fluoropassivation of polyester arterial prosthesis as observed in a canine model. 
American Society for Artificial Internal Organs, (1994), Vol 40, No. 3, M870-879