The making of indigenous vascular prosthesis

Abstract

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.

Preclinical evaluation of hydrogel sealed fluropassivated indigenous vascular prosthesis

“…Test graft appeared clean, with excellent aesthetic appearance. Burst strength, suture retention, conformability were already reported for the indigenous vascular prosthesis 12 .…”

“…The test graft was found to be well incorporated in perigraft capsule, both anastomosis intact with no thrombus and clean and lustrous neointima at explantation comparing well with widely used control graft. Since thrombogenicity is inversely proportional to quality of neointima 12 , long-term graft patency will also be higher when the neointima is well formed.…”

“…Porosity was 200±50 cc/min/cm 2 of normal saline at 120 mmHg. Extensively tested at our laboratory, implanted in pigs as animal models, graft completed implantation in controlled as well as multi-centric studies for 10 and 5 years, respectively with excellent results 12 .…”

“…Physical characteristics : Laboratory tests including burst strength, suture retention, fraying at edges, conformability and suturability, already tested in standard test grafts, were performed 12 .…”

Vascular Surgery in India – the Challenge and the Promise

“…The same model has been used by state and central governments to increase access to health care. This is coupled with incentives for domestic manufacturing of medical devices including vascular grafts 9 and endovascular equipment to reduce costs. The Government also aims to provide free healthcare to nearly 500 million people through Pradhan Mantri Jan Aarogya Yojana.…”