Transcript Heart transplants

HEART TRANSPLANTS
Steff Chavez
Human Physiology
What is a heart transplant?
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An operation in which a diseased, failing heart is
replaced with a healthier donor heart. (One must
have heart failure)
It is a last resort—preformed when other treatments
and operations have failed to improve a patient’s
condition sufficiently.
A person’s chance of survival is good if appropriate
follow-up care is received.
Heart failure
Heart failure (congestive heart failure)
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Heart cannot meet the body’s demand for blood—it cannot pump
enough blood to meet your body’s needs.
Does not mean the heart is about to stop beating—refers to the
failure to pump sufficiently
Caused by various conditions that, over time, result in a heart that
cannot pump or fill efficiently because it is too weak or stiff.
Can be treated with medications—can provide symptom relief and
help extend life.
Lifestyle changes (exercise, reducing salt in diet, managing stress,
treating depression, losing weight) can improve the quality of life of
someone with heart failure.
To prevent heart failure it is important to control risk factors:
coronary artery disease, high blood pressure, high cholesterol,
diabetes, and obesity.
Types of heart failure
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Left-sided heart failure
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Right-sided hart failure
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Fluid can backup in abdomen, legs, and feet (causes swelling)
Can occur with left-sided heart failure
Systolic heart failure
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Most common
Fluid can backup into lungs
Left ventricle cannot contract properly
Pumping problem
Diastolic heart failure
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Left ventricle cannot relax or fill properly
Filling problem
Most common conditions that can lead
to heart failure a transplant
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Coronary artery disease (most common)
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Cardiomyopathy
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Valvular heart disease
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Congenital heart defect
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Myocardial infarction (heart attack)
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High blood pressure
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Myocarditis (inflammation of heart muscle)
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Cardiac arrhythmias
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Pulmonary hypertension (high blood pressure in lungs’ vessels)
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Alcoholism or drug abuse
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Anemia (low red blood cell count)
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Previously failed heart transplant
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Other diseases: diabetes, hyperthyroidism, hypothyroidism, emphysema, lupus, hemochromatosis (buildup of iron), amyloidosis
(buildup of protein), and sarcoidosos (buildup of inflammatory cells) can contribute
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Acute causes: viruses that attack the heart muscle, severe infections, blood clots, allergic reactions, certain medications
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In children:
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Congenital heart defect
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Cardiomyopathy
Symptoms of heart failure
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Shortness of breath (especially when exerting oneself and laying down)
Fatigue
Weakness
Swelling of ankles, feet, and legs
Rapid/irregular heartbeat
Decreased ability to exercise
Coughing and wheezing (sometimes with bloody phlegm)
Abdomen swelling
Sudden weight gain (from retention of fluids)
Lack of appetite
Nausea
Difficulty concentrating
Reduced alertness
Complications of heart failure
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Kidney damage/failure
 Blood
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flow to kidneys can be reduced
Heart valve damage
 Damage
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from blood and fluid buildup
Liver damage
 Fluid
buildup can put too much pressure on the liver
 Fluid buildup can lead to scarring on liver
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Heart attack and stroke
 Increased
risk
How to diagnose heart failure
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Blood tests
Chest X-rays
ECG (Electrocardiogram)
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Records heart’s electrical activity
Echocardiogram (most important)
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Distinguish between types of heart failure
Assess how well (or not well) the heart is pumping
Measures the ejection fraction: percentage of blood pumped out of the left ventricle
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Healthy ejection fraction: 50% (more than half the blood that fills the left ventricle is pumped out of
the chamber with each beat)
Stress test
Cardiac CT or MRI (computerized tomography or magnetic resonance imaging)
Angiogram (coronary catheterization)
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Helps identify narrowed arteries
Can help assess strength of left ventricle as well as health of heart valves with a
ventriculogram
Medications for heart failure
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Ace inhibitors (Angiotensin-converting enzyme)
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Angiotensin II receptor blockers
Digoxin (digitalis)
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Slow heart rate
Lowers blood pressure
Limit or reverse some heart damage
Diuretics
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Increases strength of muscle contractions in heart
Can slow heartbeat
Beta blockers
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Vasodilator (widens vessels)
Helps lower blood pressure, improve blood flow, decrease heart’s work
Make you pee a lot
Expelling fluid from body so fluid buildup is decreased (especially in lungs)
Aldosterone antagonists
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Diuretic
Help reverse heart scarring which can lengthen lifespan
Surgeries for heart failure
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Coronary bypass surgery
Valve repair/replacement
ICD (implantable cardioverter-defibrillator)
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CRT (cardiac resynchronization therapy)
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Type of pacemaker that sends timed biventricular electrical impulses
LVAD (left ventricular assist device)
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Like a pacemaker
Monitors rhythm
Helps shock heart back to normal rhythm
Can speed heartbeat up if too slow
Help weakened hart pump
Used as an alternative to heart transplant for those who cannot have a transplant
Used for those waiting for heart transplant
Heart transplant
Back to heart transplants
Some history
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First human heart transplant preformed on December 3, 1967
Recipient: 53 year old Lewis Washkansky
Donor: 25 year old Denise Darvall, fatally injured in a car crash
Performed at Groote Schuur Hospital in Cape Town, South Africa
Surgeon: Dr. Christiaan Barnard
First successful heart transplant performed by Norman Shumway at Stanford University on a dog in 1958
Lewis died 18 days later from pneumonia
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Surgeons all over the world willing to try and within 2 years 150 heart transplants were preformed
But 80% of patients died within a year because vulnerable to infections
By 1970, only 18 transplants
Anti-rejection drugs were not as well developed as they are today
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New heart functioned normally
Better developed drugs came in 1970s
In ‘70s, patients started living for up to 5 years
First successful heart transplant in US took place in 1968
First heat-lung transplant in 1981
2007: 2,210 heart transplants preformed in the United States
Risks of a heart transplant
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Rejection of heart
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Artery problems
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Artery walls can thicken, harden
Blood circulation can be difficult (can cause heart attack, heart failure, arrhythmias, or sudden death)
Side effects to medications
Cancer (risk of immunosuppressants)
Infection
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Immune system will attack the foreign object
Patient given immunosuppressants to reduce risk of rejection
25% of recipients show signs and symptoms of rejection even up to a full year after their transplant
Typically rejection can be dealt with by adjusting medications
Biopsies taken every few months to see if heart is being rejected
Immunosuppressants inhibit body’s ability to fight infection
Most transplant patients acquire an infection in the first year and have to be admitted
Bleeding
Blood clots
Breathing problems
Kidney failure
Evaluation process
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Psychological and social evaluations
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Blood tests
Diagnostic tests
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Evaluate overall health
Assess health of lungs
Immunizations
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Stress
Family support
Financial issues
To minimize development of certain infections that could end up
affecting donor heart
If good candidate for transplant, placed on UNOS list
Restrictions
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Not everybody is a viable candidate for a heart
transplant
 Age
65+
 Have some other medical condition that shorten lifespan
 Peripheral artery disease (serious artery blockages in
arms or legs)
 Have had cancer
 Unwilling to maker certain lifestyle changes such as not
drinking, smoking, continuing drug abuse
Donor-recipient matching system
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Medical urgency
Blood type
Antibodies developed by recipient
Size of donor heart
Time spent on waiting list
Heart viability
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Transplant needs to occur within four hours of
heart’s removal from donor
Hearts first offered to transplant centers close by
Hearts come from people who have been declared
brain dead
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common donors: gun shot and car crash victims
 Must be declared brain dead by two physicians
 1-2% of patients who die in hospitals are brain dead
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Donors either already donors or family consents to
donate organs
UNOS
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United Network for Organ Sharing
Manages national transplant waiting list
Manages database of every organ transplant in US
since 1986
Develop policies to best use the limited supply of
organs
OPTN
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Organ Procurement and Transplantation Network
National Organ Transplant Act passed in 1987 by
Congress established OPTN and Scientific Registry
of Transplant Recipients
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stipulated that network be private sector, nonprofit
OPTN is administered by UNOS
The wait
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Can be days, months, years
Average wait: 3-5 years (all organs)
There are not enough hearts for every person who
needs one
People die while waiting
Can be removed temporarily if serious medical
condition develops (infection, stroke)
VADs can be used
Position on list (and waiting times) can
be affected by…
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Blood type
Tissue type
Height and weight of recipient
Size of donated organ
Medical urgency
Time on waiting list
Distance between the recipient, the donor organ,
and the transplant center
The list
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Today as of 6:08 AM:
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2011 for hearts
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Waiting list candidates: 117,257 (all organs)
Active candidates: 74,608
Transplants from January-November 2012: 25,787
Donors from January-November 2012: 12,874
3,461 waiting for a heart transplant
67.8 transplants per 100 wait-list years
http://srtr.transplant.hrsa.gov/annual_reports/2011/pdf/05_he
art_12.pdf
2008: 60% of those waiting for heart transplant underwent
the transplant within the first 12 months of listing
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By 12 months 25% were still waiting, 9.5% had died
The procedure
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Usually lasts about 4 hours
IV line will be started to administer fluids and medications during surgery
Catheter inserted
Anesthesia administered
Incision made from center of chest to abdomen (just above the bellybutton)
Sternum cut in half with a surgical saw
Two halves of sternum separated to expose heart
Pericardium opened
Recipient aorta and pulmonary arteries are not replaced as part of transplant
Tubes will be inserted into chest so that blood can be pumped through body by a heart-lung machine
Once blood is diverted completely into heart lung machine diseased heart will be removed EXCEPT a
recipient ventricle will be left in place (usually the left ventricle)
Donor heart is sewn in to place and vessels connected
Heart lung machine turned off, blood allowed back into heart
Heart shocked to restart heartbeat
Heart will be observed to make sure it is working properly and that no reconnected vessels are leaking
Procedure continued
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Sternum wired back together
Skin sewn back together
Initial incision closed with sutures or surgical staples
Tubes inserted into chest to train any blood or
excess fluids from around the heart
Dressing/bandage applied
Will be in hospital for 7-21 days after procedure
http://www.pbs.org/wgbh/nova/eheart/transplant
wave.html
Some fun pictures…
Heterotopic heart transplant
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“Piggyback transplant”
Attach donor heart to recipients heart
Hearts work together
Donor heart takes stress off of recipient’s heart
Used when recipient’s heart is too weak to function
on its own
Some statistics (United States)
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Roughly 79 transplants take place everyday (all
organs)
More than 28,000 transplants every year (all
organs)
One donor can help 50 people (with all of his/her
organs/parts)
Roughly 18 people die everyday waiting for a
transplant (all organs)
Survival rate in US
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90% after one year
74% after five years
Ethical Issues
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Organ shortage
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enough organs for everyone in need
 Organ shortage most problematic for hearts because a
heart cannot come from a live donor
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The list
 Does
the list determining who gets the next viable heart
do so ethically?
 What is the most important factor?
 Should age play a role?
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Black market (for other organs)
How do we get more donors?
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Persuade more people to become organ donors when
they die
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Go to organdonor.gov to become a donor!
Implement hospital policies and procedures to foster
organ donation
Obtain more organs from victims of brain and cardiac
death
Increase number of live donors
Only 1 in 4 people have indicated that they are donors
on appropriate forms in this country
Age is not a limit for donation!
The future of hearts
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Embryonic stem cells
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Get stem cells to become heart cells
Replace damaged heart tissue
Controversy
“primordial progenitor cells”
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Study at Mass Gen
Cells multiply and diversify into multipotent cardiovascular cell lineages for
several weeks
These cells give rise to production of other cells
These cells present from weeks 11-18 of gestation
These cells are gradually lost
ISL1—differentiation potential being assessed
Regeneration, transplants (especially for myocardium)
Trying to help understand how in development some cells lead to congenital
heart defects
Future continued
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Stimulate heart’s ability to grow new cells
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Cell division believed to be bad for heart b/c can lead to many DNA replication errors
and lead to disruption of electrical system
Growing new organs
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Using body itself to nourish encourage engineered tissue to grow
Growing entire organs is far away but growing structures may not be
Study using intestinal tissue where intestinal tissue was grown. New tissue replaced
diseased tissue.
Bladders and windpipes have been grown
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Windpipe: exact copy made from porous, fibrous plastic that was then seeded in stem cells that
were taken from bone marrow. It was then placed in a type of incubator, then sewn in to the
recipient
Study where rat hearts and lungs were stripped of living cells, leaving the structure
of the organ
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Scaffolds: “compounds that act like mortar to hold cells in their proper place that also play
a major role in how cells are recruited for tissue repair”
Very expensive
Future continued
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Study in zebrafish
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regrow their cardiac tissue
 In 1 week, can repair 20% of its cardiac tissue
 Hopefully, one day, human heart can mend itself
 Key protein: thymosine beta-4 which triggers growth of
epicardium membrane
 Drugs
to help heart mend itself being researched using this
protein
 Goal:
those with diseases can make full recovery
 Goal: make heart transplant surgery unnecessary
because heart can repair damage itself
Sources
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www.nhlbi.nih.gov
www.Nyp.org
www.mayoclinic.com
www.cts.usc.edu
www.heart.org
www.unos.org
www.pbs.org
www.clevelandclinic.org
www.hopkinsmedicine.org
www.nytimes.com
www.ohsu.edu
www.history.com
www.time.com
www.optn.transplant.hrsa.gov/