We have previously reported 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 (3,490 +/− 892 mmHg, n=230) were higher than native saphenous vein (SV) (1,599 +/− 877 mmHg, n=7), and not significantly different than native internal mammary artery (IMA) (3,196 +/− 1,264 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.

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Background-The aim of this study was to use serial intravascular ultrasound (IVUS) to evaluate the long-term effect of stent-based 7-hexanoyltaxol (QP2, a taxane analogue) delivery on neointimal tissue growth within the stent and on vessel dimensions at the adjacent reference segments. Methods and Results-Serial IVUS analyses (immediately after intervention and at follow-up at 8.3 months) were performed in 15 native coronary lesions treated with the QuaDS-QP2 stent. IVUS measurements were performed at 8 cross-sections in each target segment (4 cross-sections within the stent and 2 cross-sections in each reference segment). At baseline, no significant plaque protrusion or thrombus was detected in the target segment. Mild incomplete stent apposition and edge dissection were observed in one and two cases, respectively. Percent expansion of the stent (minimum stent area/average reference lumen area) was 96.0Ϯ21.7%. At follow-up, mean neointimal area within the stent was 1.2Ϯ1.3 mm 2 , and mean cross-sectional narrowing (neointimal area/stent area) was 13.6Ϯ14.9%. At the vessel segments immediately adjacent to the stent, a significant increase in plaque area (1.9Ϯ2.6 mm 2 , Pϭ0.001) was observed, but vessel area remained unchanged. However, no patients showed clinically significant in-stent or edge restenosis (diameter stenosis Ն50%) during the follow-up period. Conclusions-The first human experience with the new drug-delivery stent showed a minimal amount of neointimal proliferation in the stented segment. Late lumen loss at the reference sites adjacent to the stent was acceptable and predominantly due to plaque proliferation.