Mechanical properties of completely autologous human tissue engineered blood vessels compared to human saphenous vein and mammary artery

Abstract

We have previously reported the initial clinical feasibility with our small diameter tissue engineered blood vessel (TEBV). Here we present in vitro results of the mechanical properties of the TEBVs of the first 25 patients enrolled in an arterio-venous (A-V) shunt safety trial, and compare these properties with those of risk-matched human vein and artery. TEBV average burst pressures (3490 ± 892 mmHg, n = 230) were higher than native saphenous vein (SV) (1599 ± 877 mmHg, n = 7), and not significantly different from native internal mammary artery (IMA) (3196 ± 1264 mmHg, n = 16). Suture retention strength for the TEBVs (152 ± 50 gmf) was also not significantly different than IMA (138 ± 50 gmf). Compliance for the TEBVs prior to implantation (3.4 ± 1.6%/100 mmHg) was lower than IMA (11.5 ± 3.9%/100 mmHg). By 6 months post-implant, the TEBV compliance (8.8 ± 4.2%/100 mmHg, n = 5) had increased to values comparable to IMA, and showed no evidence of dilation or aneurysm formation. With clinical time points beyond 21 months as an A–V shunt without intervention, the mechanical tests and subsequent lot release criteria reported here would seem appropriate minimum standards for clinical use of tissue engineered vessels.