Depopulated vena caval homograft: a new venous conduit.
OBJECTIVE
Completion of the Fontan procedure is frequently performed by using an extracardiac conduit between the inferior vena cava and the pulmonary artery. Most centers use a polytetrafluoroethylene graft for the extracardiac conduit, and because re-endothelialization is unlikely, anticoagulation is used for a variable period. This study explores the use of an alternate large-caliber venous conduit.


METHODS
The superior vena cava was replaced in 8 minipigs with either a polytetrafluoroethylene interposition graft (2 pigs) or a depopulated (acellular), cryopreserved superior vena caval homograft (6 pigs). After 6 months, the animals were killed, and the grafts were examined for patency and histology, including immunostaining. No anticoagulation was used.


RESULTS
Polytetrafluoroethylene grafts have a cross-sectional luminal narrowing, ranging from 16% to 40%. Histology showed only partial intimal ingrowth, with excessive subendothelial fibrosis and early calcification. In contrast, the depopulated venous homografts showed minimal luminal narrowing, ranging from 2% to 9%. These grafts were completely repopulated by the recipient with an endothelial lining, which stained positively for factor VIII, and a subendothelial region appropriately recellularized by myofibroblasts, which stained positively for smooth muscle actin and procollagen. There was no evidence of an immune response to the venous homografts, as judged by staining for T-cell surface antigen, CD4, and CD8. Thrombus was not seen in any of the grafts.


CONCLUSIONS
Depopulated, cryopreserved vena caval homografts might be superior conduits for cavopulmonary connection during completion of the Fontan operation by using the extracardiac conduit technique.
Wells
Winfield
W
Department of Cardiothoracic Surgery, Keck School of Medicine, University of Southern California, Los Angeles, CA 90027, USA. wwells@chla.usc.edu
Malas
Mahmoud
M
Baker
Craig J
CJ
Quardt
Susanne M
SM
Barr
Mark L
ML
D000199:Actins / Q000378:metabolism; D000714:Anastomosis, Surgical; D000818:Animals; D000945:Antigens, Differentiation, T-Lymphocyte / Q000378:metabolism; D019917:Blood Vessel Prosthesis Implantation / Q000295:instrumentation; D020099:Coated Materials, Biocompatible / Q000494:pharmacology; D004195:Disease Models, Animal; D004730:Endothelium, Vascular / Q000166:cytology / Q000378:metabolism; D004867:Equipment Design / Q000295:instrumentation; D005169:Factor VIII / Q000378:metabolism; D018729:Fontan Procedure / Q000295:instrumentation; D006098:Granulocytes / Q000378:metabolism; D007150:Immunohistochemistry; D008264:Macrophages / Q000378:metabolism; D008955:Models, Cardiovascular; D009131:Muscle, Smooth, Vascular / Q000166:cytology / Q000378:metabolism; D011138:Polytetrafluoroethylene / Q000494:pharmacology; D013552:Swine; D014184:Transplantation, Homologous; D014683:Vena Cava, Superior / Q000378:metabolism / Q000473:pathology / Q000637:transplantation*
D000199:Actins; D000945:Antigens, Differentiation, T-Lymphocyte; D020099:Coated Materials, Biocompatible; D005169:Factor VIII; D011138:Polytetrafluoroethylene