The Journal of Thoracic and Cardiovascular Surgery, Vol 100, 769-776, Copyright © 1990 by The American Association for Thoracic Surgery and The Western Thoracic Surgical Association
Long-term evaluation of a new selectively biodegradable vascular graft coated with polyethylene oxide-polylactic acid for right ventricular conduit. An experimental study
G Uretzky, Y Appelbaum, H Younes, R Udassin, P Nataf, E Baccioglu, G Pizof, JB Borman and D Cohn
Joseph Lunenfeld Cardiac Surgery Research Center, Hadassah University Hospital, Jerusalem, Israel.
Low-porosity woven Dacron grafts have been used extensively as an
extracardiac conduit in the surgical treatment of congenital and acquired
heart diseases involving total heparinization. Caution is still warranted
in their use, however, because of long-term complications, including
calcification and development of obstructive fibrous peel. In contrast,
high-porosity grafts offer much better tissue anchorage and healing but
cannot be used under heparinization. We have developed a compound vascular
prosthesis in which a knitted Dacron graft is coated with a polymeric
biodegradable sealant. Polyethylene oxide-polylactic acid-segmented
copolymers comprised the degradable component of the graft. In vitro
studies showed that the coated prosthesis exhibited a highly flexible
elastomer-like mechanical response. The prostheses were completely
watertight, and significant degradation started after 1 week, with
absorption completed after 3 weeks. Seven woven and six knitted
polyethylene oxide-polylactic acid- coated Dacron grafts used as
extracordiac conduits (16 mm), connecting the right ventricle and the
pulmonary artery were implanted in dogs. The dogs were killed after 12 to
18 months, and the results are reported. Scanning electron microscopy
examination showed peel detachment and nonhomogenous intimal surface with
fenestrations in the woven graft group, but complete healing and
incorporation of the pseudointima with homogenous, thin lining of the
luminal surface in the polyethylene oxide-polylactic acid-coated group.
Histologic studies indicated much superior healing and anchorage of the
periprosthetic tissue and the pseudointima in the polyethylene
oxide-polylactic acid- coated grafts. The biodegradable polymer was fully
degraded and exhibited a complete incorporation of the compound vascular
prosthesis. This study indicates the superior healing properties of these
selectively biodegradable grafts, which might increase long-term patency
and decrease complications of right ventricular conduits.
