Vascular Prostheses: The Need for Standards—Historical and Surgical Perspectives

Wesolow, Adam

doi:10.1520/stp33296s

Cited by 9 publications

(3 citation statements)

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“…There are distinctive advantages to the use of pigs in that they share similar anatomic and physiologic characteristics with humans particularly pertaining to the cardiac and vascular systems 25 . Classic animal experimental data reported by Wesolowski 18 on growing pigs weighing 20-39 kg formed the benchmark for graft research as implantation data of three months in growing pigs in terms of healing patterns and characteristics were noted to be equivalent to three years in man. Hence, we chose pigs as the animal model in addition to the fact that preclinical trial of the standard uncoated graft was also successfully completed in pigs.…”

Section: Discussionmentioning

confidence: 99%

“…Three groups were assigned explantation to study healing characteristics at 2, 12 and 26 wk with six animals each as test and three each as control. Weslowski's experiments showed that healing pattern in pigs over three months was equivalent to three years in man 18 . In addition, large animal like pig posed significant supportive and financial impact, limiting the number.…”

Section: Methodsmentioning

confidence: 99%

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Preclinical evaluation of hydrogel sealed fluropassivated indigenous vascular prosthesis

Unnikrishnan

Umashankar

Viswanathan

et al. 2017

Indian Journal of Medical Research

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Background & objectives: Polyethylene terephthalate (PET) graft, designed and developed at our institute for vascular reconstruction, is porous to promote optimal incorporation and neointima formation, requiring pre-clotting or biomodification by sealing the pores before implantation. The objective of this study was to characterize, test and perform preclinical evaluation of hydrogel (alginate dialdehyde cross-linked gelatin) sealed fluoropassivated PET vascular prosthesis in pig model, so as to avoid pre-clotting, for its safety and efficacy before employing the indigenous and less expensive graft for clinical use. Methods: Hydrogel sealed, fluoropassivated PET vascular prosthesis were tested for haemocompatibility and toxicity followed by small animal toxicology tests and in vivo experiments in pigs receiving implantation at thoracic aorta. All 33 animals received test as well as control grafts with a plan for phased explantation at 2, 12 and 26 weeks. All animals underwent completion angiogram at the end of procedure as well as before graft explantation. Results: Haemocompatibility tests for haemolysis and toxicity tests showed no adverse events in tested mice and rabbits. Completion angiogram showed intact anastamosis and patent graft in each animal in post-operative period and at explantation. Gross and histopathological examination showed well-encapsulated grafts, clean glistening neointima and no evidence of thrombus in both test and control grafts. Interpretation & conclusions: Hydrogel sealed, fluoropassivated PET vascular prosthesis was found non-toxic, haemocompatible and remained patent in in vivo studies at planned intervals.

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Section: Discussionmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Preclinical evaluation of hydrogel sealed fluropassivated indigenous vascular prosthesis

Unnikrishnan

Umashankar

Viswanathan

et al. 2017

Indian Journal of Medical Research

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“…Classic animal experimental data reported by Adam Wesolowski delineated pigs as the most suitable model for in vivo experiments10. His original work on growing pigs weighing 20-39 kg formed the benchmark for graft research as implantation data of three months in growing pigs in terms of healing patterns and characteristics were noted to be equivalent to three years in man.…”

Section: Discussionmentioning

confidence: 99%

The making of indigenous vascular prosthesis

Unnikrishnan

Viswanathan

Balasubramaniam³

et al. 2016

Indian Journal of Medical Research

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Background & objectives:Vascular illnesses are on the rise in India, due to increase in lifestyle diseases and demographic transition, requiring intervention to save life, organ or limbs using vascular prosthesis. The aim of this study was to develop indigenous large diameter vascular graft for treatment of patients with vascular pathologies.Methods:The South India Textile Research Association, at Coimbatore, Tamil Nadu, India, developed seamless woven polyester (Polyethylene terephthalate) graft at its research wing. Further characterization and testing followed by clinical trials were conducted at Sree Chitra Tirunal Institute for Medical Sciences and Technology, Thiruvananthapuram, Kerala, India. Fifteen in vivo experiments were carried out in 1992-1994 in pigs as animal model. Controlled (phase I) clinical trial in ten patients was performed along with control graft. Thereafter, phase II trial involved 22 patients who underwent multi-centre clinical trial in four centres across India.Results:Laboratory testing showed that polyester graft was non-toxic, non-leeching and non-haemolytic with preserved long-term quality, further confirming in pigs by implanting in thoracic aorta, comparable to control Dacron grafts. Perigraft incorporation and smooth neointima formation which are prime features of excellent healing characteristics, were noted at explantation at planned intervals. Subsequently in the phase I and II clinical trials, all patients had excellent recovery without mortality or device-related adverse events. Patients receiving the test graft were followed up for 10 and 5 years, respectively. Serial clinical, duplex scans and CT angiograms performed periodically confirmed excellent graft performance.Interpretation & conclusions:Indigenously developed Chitra vascular graft was comparable to commercially available Dacron graft, ready for clinical use at affordable cost to patients as against costly imported grafts.

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Porosity of porcine small‐intestinal submucosa for use as a vascular graft

Hiles

Badylak

Geddes

et al. 1993

J. Biomed. Mater. Res.

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The porosity of a vascular graft material has been suggested as a major factor affecting the rate and degree of neovascularization of newly implanted grafts, with higher porosities generally associated with better performance. The objective of this study was to determine the water porosity of a new vascular graft material, small-intestinal submucosa (SIS), and to compare the values to those reported for other common vascular graft materials. In addition, the porosity of SIS was investigated with respect to applied pressure and applied uniaxial tension. Both rectangular, flat specimens and tubular specimens of SIS were subjected to static water pressure, and water was collected as it passed through the SIS material. SIS has a typical porosity of 0.52 mL/min.cm-2 at an applied pressure of 120 mm Hg. Although porosity appeared to be unaffected by uniaxial tension, it increased in proportion to applied pressure at a rate of 4.8 x 10(-3) mL/min.cm-2/mm Hg. These low porosity values and the past success of SIS as a vascular graft material suggest that high-porosity materials are not required for implant success.

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Vascular Prostheses: The Need for Standards—Historical and Surgical Perspectives

Cited by 9 publications

References 0 publications

Preclinical evaluation of hydrogel sealed fluropassivated indigenous vascular prosthesis

Preclinical evaluation of hydrogel sealed fluropassivated indigenous vascular prosthesis

The making of indigenous vascular prosthesis

Porosity of porcine small‐intestinal submucosa for use as a vascular graft

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