Biochemistry Prolonged Preservation of the Heart Prior to Transplantation
Biochemistry - Prolonged Preservation of the Heart Prior to TransplantationPicture this. A man is involved in a severe car crash in
Florida which has left him brain-dead with no hope for any
kind of recovery. The majority of his vital organs are
still functional and the man has designated that his organs
be donated to a needy person upon his untimely death.
Meanwhile, upon checking with the donor registry board, it
is discovered that the best match for receiving the heart of
the Florida man is a male in Oregon who is in desperate need
of a heart transplant. Without the transplant, the man will
most certainly die within 48 hours. The second man’s
tissues match up perfectly with the brain-dead man’s in
Florida. This seems like an excellent opportunity for a
heart transplant. However, a transplant is currently not a
viable option for the Oregon man since he is separated by
such a vast geographic distance from the organ. Scientists
and doctors are currently only able to keep a donor heart
viable for four hours before the tissues become irreversibly
damaged. Because of this preservation restriction, the
donor heart is ultimately given to someone whose tissues do
not match up as well, so there is a greatly increased chance
for rejection of the organ by the recipient. As far as the
man in Oregon goes, he will probably not receive a donor
heart before his own expires.
Currently, when a heart is being prepared for
transplantation, it is simply submerged in an isotonic
saline ice bath in an attempt to stop all metabolic activity
of that heart. This cold submersion technique is adequate
for only four hours. However, if the heart is perfused with
the proper media, it can remain viable for up to 24 hours.
The technique of perfusion is based on intrinsically simple
principles. What occurs is a physician carefully excises
the heart from the donor. He then accurately trims the
vessels of the heart so they can be easily attached to the
perfusion apparatus. After trimming, a cannula is inserted
into the superior vena cava. Through this cannula, the
preservation media can be pumped in.
What if this scenario were different? What if doctors were
able to preserve the donor heart and keep it viable outside
the body for up to 24 hours instead of only four hours? If
this were possible, the heart in Florida could have been
transported across the country to Oregon where the perfect
recipient waited. The biochemical composition of the
preservation media for hearts during the transplant delay is
drastically important for prolonging the viability of the
organ. If a media can be developed that could preserve the
heart for longer periods of time, many...
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