The Journal of Thoracic and Cardiovascular Surgery, Vol 88, 208-216, Copyright © 1984 by The American Association for Thoracic Surgery and The Western Thoracic Surgical Association
Implications of late morphology of Braunwald-Cutter mitral heart valve prostheses
FJ Schoen, SH Goodenough, MI Ionescu and NS Braunwald
Interrelationships among silicone poppet wear, cloth wear, and tissue
ingrowth were investigated in 14 retrieved Braunwald-Cutter heart valve
prostheses following implantation of 37 to 118 (mean 83) months. Six aortic
valves (mean 81 months) had severe cloth and poppet wear. In three the
poppet had escaped. The lesser wear of the strut covering on the eight
mitral valves (mean 84, range 37 to 108 months) was generally functionally
insignificant. Mean decrease in mitral poppet diameter was 0.4% (range 0%
to 1.5%), in contrast to a mean of 5.8% for aortic poppets. Histologic
examination of the cloth/tissue complex demonstrated well-collagenized
tissue ingrowth in areas of intact fabric with focal endothelial lining.
Functionally trivial calcific deposits were often noted deep in the tissue
coating, adjacent to cloth fibers or the strut metal. These results suggest
that the mitral Braunwald-Cutter prosthesis need not be electively replaced
without specific indication. A model is presented which explains the
favorable clinical course demonstrated for mitral recipients and provides a
rationale for the disparate clinicopathological behavior of mitral and
aortic Braunwald-Cutter prostheses. Although inconsequential in this
setting, the focal microcalcification noted in all mitral prostheses
implanted for more than 72 months may have implications for the development
of clinical cardiac assist devices for long-term application.
