In vivo observations on arterial micrografts.

Few investigations have been made to date on the in vivo behavior of blood vessel grafts. An experimental model is described which permits continuous monitoring of grafted arteries both by gross examination and by in vivo microscopy. Allografts and autografts of the central ear arteries of rabbits, 0.5 mm in diameter and 10 mm in length, were transplanted in rabbit ears and subsequently enclosed with transparent plastic discs on each surface of the ear in place of the reflected skin. Allograft segments showed decreased vasomotor activity by about 3 weeks after grafting, whereas the recipient arteries and autograft segments retained their activity. Reduced activity of allograft segments was confirmed by their poor responses to vasoactive drugs. Many allografts thrombosed due to immune reaction between 3 and 8 weeks after grafting. Allografts that survived this episode went on functioning as efficient conduits of blood for many months thereafter.