Study on water permeability of vascular grafts and its testing equipment

Abstract

Event Abstract Back to Event Study on water permeability of vascular grafts and its testing equipment Guoping Guan1, Rui Xu1, Gaotian Shen1, Xingyou Hu1 and Lu Wang1 1 Donghua University, College of Textiles, China Water permeability of vascular grafts is an important evaluation index of the wall structure, because whether a vascular graft should be proclotted before implantation depends on the water permeability. According to ISO 7198, water permeability of vascular grafts should be measured under 120mmHg for continuous 10 minutes, expressed as mL/min·cm2. The water permeability includes two types, water permeability and integral water permeability [1]. In the present work, we firstly designed and established an installation for testing water permeability and integral water permeability of vascular grafts under 120mmHg (Fig.1) [2]. The results showed that several factors influence the water permeability significantly, such as porosity, pore size and its distribution [3]. Furthermore, hydrophilicity of vascular grafts has a key influence on the water permeability, hydrophobic vascular grafts have a lower water permeability [4]. Fig.1 Schematic drawing of the static testing installation Blood pressure is a pulsatile pressure, and is different in various sites of body. Therefore, in order to measure the water permeability of vascular grafts with diverse diameters, we designed and developed an equipment which could test the water permeability under diverse pressure values, from 0 to 30 kPa (from 0 to 225mmHg) (Fig.2) [5],[6]. The testing pressure could thus be determined by the diameter of the vascular graft and the implantation site, instead of the constant 120mmHg. Moreover, the equipment could provide a pulsatile pressure within diverse pressure ranges. The results showed that the water permeability increased with the increase of the pressure. Fig.2 Image of the dynamic testing equipment In summary, the equipment developed in the present work could objectively evaluate the water permeability of vascular grafts and indirectly reflect the features of the wall, such as pore size, pores distribution and interconnectivity. Both water permeability and integral water permeability could be measured not only under 120mmHg, but also under diverse pressure ranges with a pulsatile. Therefore, the deviation between the results in a lab and the required value in clinic has been decreased significantly. Most importantly, it provides a possibility for establishing a quantitative relationship between water permeability and blood permeability, and it will hopefully give a specific value to a surgeon for judging the necessity of proclotting a vascular graft. This work was funded by NSFC (No.31100682, No.81371648),“111 project” （ B07024 ）, the Fundamental Research Funds of Central Universities (No. 2232015A3-02), Innovation Program of Shanghai Municipal Education Commission(No.ZX201503000017).