It is mainly used to restore or establish new blood flow channels to maintain or improve blood circulation in a certain part of tissues or organs, when vascular segment defects are caused by trauma or excision for some reasons, or when the length of vascular pedicle used for vascular anastomosis or organ transplantation is insufficient, or when arterial embolism or lymphatic obstruction occurs? Bridging? Vascular transplantation is needed in the case of circulatory bypass.