How does heart transplant surgery work? - Roni Shanoada
Your heart beats more
than 100,000 times a day.
In just a minute, it pumps over five
liters of blood throughout your body.
But unlike skin and bones, the heart
has a limited ability to repair itself.
So if this organ is severely damaged,
there’s often only one medical solution:
replacing it.
Today, nearly 3,500 heart transplants
are performed each year
in a complex and intricate procedure
with no room for error.
The process begins
by testing potential recipients
to ensure they’re healthy enough
for this demanding operation.
Doctors are especially concerned with
identifying immunocompromising illnesses
or any other conditions that could
compromise a patient's chance of survival.
The next step is to match an eligible
recipient with a heart donor.
Donors are often comatose patients
with no chance of being resuscitated
or victims of a fatal event
whose hearts are still healthy.
In both cases, these patients need
to be registered as an organ donor
or have their families give consent.
And even when a heart is available,
surgeons can’t just pair any donor
with any recipient.
The recipient’s immune system will view
a transplanted heart
as a foreign organism
that must be attacked.
So doctors need to match recipients
with donors that share their blood type
and have similar antigens.
If a match can be made,
the surgery can begin.
Once the donor's heart is
confirmed to be healthy,
the organ is immersed in an ice slush
and injected with a solution
to induce cardiac arrest.
These treatments stop the heart
from pumping
to ensure it can be removed cleanly.
Surgeons then place the organ
in a mix of cold saline
and preservation solution.
This is when the clock starts.
Disconnected from its blood supply,
the heart’s cells start taking on damage
from lack of oxygen.
The organ will only remain viable
outside the body for a few hours,
so it needs to reach its recipient
as fast as possible.
Once the heart arrives, the recipient
is put under general anesthesia.
The surgeon makes an incision
down the length of the chest,
cutting through the breastbone
to separate the rib cage
and expose the heart.
To keep blood flowing
while they remove the damaged organ,
surgeons use a cardiopulmonary
bypass machine.
This takes over the heart's job,
generating enough force to push blood
through the patient's circulatory system.
After the old heart is removed,
the surgeon begins sewing
the donor heart into place.
This is an incredibly precise process,
where each blood vessel and artery
must be carefully attached to avoid leaks.
The procedure can last several hours,
potentially longer if there’s scar tissue
from previous surgeries.
Once it’s finished,
the bypass machine is turned off
and blood is allowed
to flow into the aorta.
Doctors carefully monitor the new heart
to ensure it’s beating on its own
before sewing the recipient back up.
Even after the procedure is complete,
there's still work to be done.
Surgeons are unable to directly
connect the heart
to the recipient’s nervous system,
and it can take years for the body
to fully innervate the new organ.
During this period, the transplanted organ
has a higher resting heart rate
and risk of stroke, making exercise
difficult and dangerous.
And since it’s incredibly rare
to find a perfect match
between donor and recipient,
the immune system will also
have some response to the new heart.
Immunosuppressive drugs can help
manage the risk of rejection,
but they also leave patients open
to contracting dangerous infections.
It requires constant monitoring
and testing to balance these two concerns.
Despite these challenges, about 70%
of heart transplant recipients survive
for at least five years
after the operation,
and just over 20% live another 20 years.
So when this procedure is successful,
it's truly lifesaving.
Unfortunately, people in developing
countries are often unable
to access this surgery,
and many viable hearts can’t be donated
due to legal and regulatory issues.
Thousands of people remain
on waiting lists,
and many are never able
to find a suitable donor.
