Successful Implantation of a Long “Biotube” Vascular Graft for the Bypass Surgery in Critical Limb Ischemia (Cli) in a Goat Model

Abstract

Introduction - There is no superior artificial graft comparable to autologous vein, which can function as a small-diameter graft even under the knee in bypass surgery for critical limb ischemia (CLI). On the other hand, in-body tissue architecture (iBTA) proposed by us can prepare autologous collagenous tubular tissues, called Biotubes, by using a patient's body as a bioreactor. Its process is simple and safe, just subcutaneously embedding a mold for about 2 months. The Biotube has sufficient pressure resistance to arterial pressure and has long-term patency in a canine model. In this study, a small-diameter long Biotube was prepared and the possibility as an alternative vascular graft for bypass in CLI was examined using a goat model. Methods - Disk-like molds (ca. 8 cm in diameter) having spiral cylinder were embedded in goats subcutaneously for 2 months (1 in photos). Biotubes with diameter of 4 mm, length of 50 cm, and wall thickness of 1.5 mm were obtained after removing the mold harvested (2 in photos). The Biotubes were stored in an alcoholic solution at room temperature before implantation. After washing with a saline solution the Biotubes were interposed in carotid arteries of goats to prepare a bypass model (3 in photos). Follow up was performed with Doppler echo and angiography. Results - Completely autologous collagenous Biotubes without living cells were autonomically formed in the molds. After bypassing them to the goat carotid artery, pulsatile flow could be confirmed through palpation or Doppler echo over the entire length. Angiography revealed that all Biotubes were patent without blood leakage, aneurysm, or stenosis. Conclusion - By only subcutaneous embedding the mold, a small-diameter long Biotube could be prepared autonomically. The Biotubes showed excellent vascular performance as bypass grafts and can be considered useful for CLI patients.