Current vascular allograft procurement, cryopreservation and transplantation techniques in the Czech Republic

Abstract

Background. Vascular allotransplantations are performed worldwide in selected patients suffering from vascular prosthesis infection or critical limb ischemia. Either fresh or cryopreserved vascular allograft may be used. Objectives. In various points, we address several aspects (allograft procurement, cryopreservation and transplantation technique) of the program of vascular allotransplantations in the Czech Republic. Materials and methods. Vascular grafts retrieval has been done within multiorgan harvests using no-touch technique. Very short time of cold ischemia is achieved due to close cooperation with Tissue Establishment where the following processing of cryopreservation is performed. Meeting all necessary quality criteria is a prerequisity for releasing grafts for clinical application. Standardized thawing protocol and surgical handling aims to minimize microfractures before implantation. Results. Based on experimental and clinical work, the first validation of cryopreserved arterial and venous grafts for clinical use was performed between 2011 and 2013 in the Czech Republic. The developement of storage of vascular tissue in banks was stimulated in 2000-2010 by the issue of EU directives and national harmonized norms, aimed at assurance of high quality and safety of cells and tissues used for transplantations in humans. Conclusions. There are several crucial moments affecting final quality, including graft retrieval within a multiorgan harvest, short ischemic time, cryopreservation, and thawing technique used. The recommended surgical handling during implantation may also affect results and graft-related complications.

Current vascular allograft procurement, cryopreservation and transplantation techniques in the Asan Medical Center Tissue Bank

“…Any change in the institutional SOP should be approved by the MFDS. All tissue banks over the world have their own SOP [1,2]. The AMC Tissue Bank has undergone audit annually by the MFDS since 2005.…”

“…They include the iliac artery and vein, femoral artery and vein, inferior vena cava, aorta, greater saphenous vein, and other sizable arteries and veins. These vascular allografts are cryopreserved at the tissue banks [1,2].…”

The Effect of Different Thawing Rates on Cryopreserved Human Iliac Arteries Allograft’s Structural Damage and Mechanical Properties

“…After the packaging was completed, the bag was placed into a metal cassette and cooled at a controlled rate of -1°C/min from +17°C to -90°C, 5 K/min till -150°C in a programmable freezer Kryo 10/16 (Planer Biomed, UK). Stored in a vapor phase of liquid nitrogen in a container Kryo-CE 10 K (Taylor –Wharton, USA) equipped with automatic filling, and continuous registration of the temperature and liquid nitrogen levels at -194°C [ 7 ]. The grafts were thawed after the 1- to 4-year period of storage.…”

Influence of the new standardized clinical cryopreservation/slow thawing protocol on immunogenicity of arterial allografts in rats

“…cryoprotectant was removed gradually in tapered dilutions. According to our clinical protocol, the cassetes with cryopreserved grafts are thawed in a normal refrigerator within 2 hours and they are stored thereafter in the pre-cooled conservation solution until implantation [8].…”

“…Both solid organ and cold-stored arterial transplantation programs are governed by the same legislation and managed by the "Transplantation Coordination Centre of the Czech Republic". Therefore, the cold-stored arteries obtained during multi-organ recovery from braindead donors are stored in organ conservation solutions and must be transplanted to the patient included in the special "waiting list" within 48 hours after recovery [8].…”