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The aorta, the heart’s
main artery, is like a major fuel pipeline. Both are
conduits that feed a vital element into smaller supply
lines. And if the artery or the pipeline ruptures, there
can be life-threatening consequences.
An aneurysm occurs when
an area of the aorta’s wall weakens and balloons
out (see drawing below) past its normal size. If the
aneurysm occurs near the heart, it is called a thoracic
(chest) aortic aneurysm; however, aneurysms can also
develop in other parts of the body, such as the abdomen
and the brain. Thoracic aortic aneurysms are relatively
uncommon; most aneurysms–about 75 percent–occur
in the abdomen.
The danger with an aneurysm
is two fold:
- 1. An enlarged aorta
may compress the neighboring structures, and causing
symptoms. For example tracheal compression causing
difficulty in breathing and pain due to nerve compression
or compression of the blood vessels and their blockage.
- 2. More importantly,
with little warning, the aneurysm could rupture and
cause excessive bleeding and shock. If not treated
immediately, a ruptured thoracic aortic aneurysm is
fatal. A person with an unruptured aneurysm might
not feel any symptoms; other times, there is pain
in the back and shoulders, hoarseness, and a dry cough.
A ruptured aneurysm, however, brings on sharp, excruciating
chest pain.
“Ideally, we’re
able to identify an aneurysm before it ruptures through
an echocardiogram, computed tomography or magnetic resonance
imaging scans, or chest X-ray so we can map a strategy
for repair,” says Dr. Ahmad Rajaii Khorasani,
a cardiac surgeon at University Hospital. “These
are complex operations designed to eliminate the danger
of rupture while ensuring the safe distribution of blood
to the rest of the body. Once an anuerysm ruptures,
it’s a true surgical emergency.”
In theory, aneurysm repair
is simple: replace the damaged section of aorta with
a graft of special surgical woven material. In practice,
these open-heart operations are extremely complicated,
depending on where the aneurysm is located. (See
“Where the Aorta Travels.”) For example,
a repair near the heart might also require replacement
of the aortic valve. There’s also the possibility
of complications. “The aorta is the trunk of the
circulatory tree,” says Dr. Khorasani. “The
techniques used in these operations have the potential
to affect every organ system in the body.”
What’s important
is that the surgeon is experienced in performing these
very specialized procedures and knows when–and
when not to–operate especially when the aneurysm
is small. Sometimes it’s in the patient’s
best interest to initially treat the condition with
medicine, such as beta blockers, which can enable the
heart to beat with less force, or antihypertensives
to lower blood pressure.”
Dr. Rajaii Khorasani
has the expertise, from his training, practice and years
of innovative and problem oriented research in the area
of prevention of stroke and paralysis, two disastrous
complications associated with thoracic and thoracoabdominal
aortic surgery. Since January of this year, he has managed
about 10 cases, a high number considering that this
condition is very uncommon. His innovative technique
of perfusion of the brain and spinal cord blood vessels
have been effective in avoiding these complications.
Another potentially fatal
condition of the heart’s main artery is aortic
dissection. “Aortic dissection can be compared
to the treads of a tire peeling apart,” says Dr.
Khorasani. “The inner layers of the aorta tear,
leaving only an outermost, very thin layer. Blood forces
its way between the layers, which can lead to heart
attack or stroke.”
As with thoracic aortic
aneurysm, the symptoms of aortic dissection can be gradual
and subtle until the situation is severe; then, there
is typically sharp pain in the back or below the breast
bone. In some cases of dissection, early treatment with
antihypertensives or beta blockers may be best. But
in other cases, dissection requires emergency surgery.
Click
here for a more detailed explanation of how the aorta
works.
A thoracic aortic aneurysm
can occur for a variety of reasons, says Dr. Khorasani,
including atherosclerosis, a build up of plaque commonly
referred to as hardening of the arteries, and more rarely,
untreated syphilis. Hypertension, atherosclerosis, or
an injury to the chest can all lead to aortic dissection;
sometimes dissection occurs in an aortic aneurysm. Women
who are pregnant or have Turner’s syndrome, a
chromosomal disorder, are also predisposed to aortic
dissection.
But one group of people
at high risk for both thoracic aneurysm and dissection
are those who have Marfan syndrome, a rare, inherited
condition involving the body’s connective tissue.
People with Marfan syndrome
are typically tall and thin; their arm span often exceeds
their height. Abraham Lincoln, for example, is believed
to have had the syndrome. They may also have scoliosis
(curvature of the spine) and visual problems such as
nearsightedness or detached retina. But the most severe
ramifications of Marfan syndrome involve the heart.
“Because their
connective tissue isn’t formed properly, the aorta
in Marfan syndrome patients can progressively widen,
making it more susceptible to becoming an aneurysm,”
says Dr. Khorasani, who has treated many Marfan patients.
“The layers within the aorta are also more fragile
and subject to tear, resulting in aortic dissection.”
“It is quite possible
for a person, seemingly in good health, to be unaware
he or she has Marfan syndrome well into adulthood, until
an aneurysm or dissection occurs,” he continues.
“Obviously, our first priority is that patient,
but we also are concerned about that person’s
blood relatives, who might also unknowingly have Marfan
syndrome. It is very important that these family members
be examined and evaluated for the syndrome.”
When an aneurysm or dissection
is diagnosed in the early stage, the better the possibility
exists for a positive outcome. “Sometimes it is
tempting for people to dismiss mild chest pain as nothing
serious,” says Dr. Khorasani. “But especially
for those with Marfan syndrome or a history of atherosclerosis,
waiting too long to seek help can have serious consequences.”
For more
information about cardiovascular services and treatments,
call the New Jersey Cardiovascular Institute at (973)
972-5742 or visit our Web site at: www.theuniversityhospital.com/njci
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