A nitinol "U-Clip" versus sutured arteriovenous anastomosis: local tissue response and intimal hyperplasia development in a sheep model

R L Varcoe; A B P Teo; M H Pelletier; Y Yu; J L Yang; P J Crowe; W R Walsh

doi:10.1016/j.ejvs.2014.12.025

A nitinol "U-Clip" versus sutured arteriovenous anastomosis: local tissue response and intimal hyperplasia development in a sheep model

Eur J Vasc Endovasc Surg. 2015 Mar;49(3):344-52. doi: 10.1016/j.ejvs.2014.12.025. Epub 2015 Jan 24.

Authors

R L Varcoe¹, A B P Teo², M H Pelletier³, Y Yu³, J L Yang⁴, P J Crowe³, W R Walsh³

Affiliations

¹ Department of Surgery, Prince of Wales Hospital, Sydney, Australia; Surgical and Orthopaedic Research Laboratories, Prince of Wales Clinical School, Faculty of Medicine, Sydney, Australia; The University of New South Wales, Sydney, Australia; The Vascular Institute, Prince of Wales Hospital, Sydney, Australia. Electronic address: r.varcoe@unsw.edu.au.
² Department of Surgery, Prince of Wales Hospital, Sydney, Australia; Surgical and Orthopaedic Research Laboratories, Prince of Wales Clinical School, Faculty of Medicine, Sydney, Australia.
³ Department of Surgery, Prince of Wales Hospital, Sydney, Australia; Surgical and Orthopaedic Research Laboratories, Prince of Wales Clinical School, Faculty of Medicine, Sydney, Australia; The University of New South Wales, Sydney, Australia.
⁴ Department of Surgery, Prince of Wales Hospital, Sydney, Australia; Surgical and Orthopaedic Research Laboratories, Prince of Wales Clinical School, Faculty of Medicine, Sydney, Australia; The University of New South Wales, Sydney, Australia; Adult Cancer Program, Lowy Cancer Research Centre, Faculty of Medicine, University of New South Wales, Sydney, Australia.

PMID: 25631458
DOI: 10.1016/j.ejvs.2014.12.025

Abstract

Objectives: This study sought to compare the local tissue response and subsequent volume of intimal hyperplasia (IH) that develops throughout the maturation of an arteriovenous fistula created using continuous/interrupted polypropylene with that of a novel, metal-alloy, penetrating anastomotic clip device.

Materials and methods: Forty-six fistulae were created in 23 sheep under a paired design using the nitinol U-Clip (n = 23) in one hind limb and continuous (n = 20) or interrupted (n = 3) polypropylene suture for the other. Animals were killed at 4 (n = 3), 14 (n = 3), 28 (n = 10), 42 (n = 3), and 180 (n = 4) days. Histological sections were evaluated for quantitative histology and immunohistochemistry.

Results: Compared with continuous polypropylene, U-Clip specimens demonstrated less intima-media area per unit length (IMA/L), proliferating cells, and tissue necrosis at all time points (MANOVA, F = 9.8-24.1, all p ≤ .005; observed power >82%). Specifically, values of IMA/L were reduced by 5% (p = .97), 37% (p = .02), 33% (p < .01), 9% (p = .42), and 14% (p = .22) at the time points of 4, 14, 28, 42, and 180 days respectively. Proliferating cells were reduced by 75% (p < .01), 72% (p = .03), 76% (p = .03), 27% (p = .31), and 60% (p = .01) and tissue necrosis by 67% (p < .01), 58% (p = .02), 40% (p = .33), 21% (p = .43), 77% (p = .11). In a 28-day comparison between U-Clip and interrupted polypropylene the U-Clip group demonstrated a 4% (p = .65) reduction in IMA/L, 74% (p < .01) in proliferating cells and 49% (p < .05) in tissue necrosis.

Conclusions: These results provide evidence of reduced local tissue necrosis, proliferating cells, and IH, favouring arteriovenous fistulae created using the U-Clip anastomotic device over conventional polypropylene suture techniques most evident over the first 4 weeks.

Keywords: Arteriovenous fistula; Haemodialysis vascular access; Intimal hyperplasia; Vascular anastomotic clip.

Publication types

Comparative Study

MeSH terms

Alloys*
Animals
Arteriovenous Shunt, Surgical* / adverse effects
Arteriovenous Shunt, Surgical* / instrumentation
Arteriovenous Shunt, Surgical* / methods
Cell Proliferation
Equipment Design
Femoral Artery / pathology
Femoral Artery / surgery*
Femoral Vein / pathology
Femoral Vein / surgery*
Hindlimb
Hyperplasia
Models, Animal
Muscle, Skeletal / blood supply*
Necrosis
Neointima*
Polypropylenes
Sheep
Surgical Instruments*
Suture Techniques* / adverse effects
Suture Techniques* / instrumentation
Sutures
Time Factors

Substances

Alloys
Polypropylenes
nitinol