Feb. 8, 2000
EECP strikes back against angina
By Mike Falcon
With Dr. Jonathan M. Sackier, medical adviser
A Doctor In Your House.com
A unique non-invasive heart disease therapy called Enhanced
External Counterpulsation (EECP) may help make the following
scenario historical fiction ...
You lift your laughing baby grandchild above your head so
she can "walk" upside down on the ceiling.
Suddenly an excruciating pain drives its claws into your chest
and drops you to your knees. You fold like an accordion onto the
floor, struggling in agony to catch your breath. The pressure is
so intense, it feels like a car is parked on top of your heart.
Can you get to the phone and dial 911 without having a full-on
heart attack? Or to the bathroom medicine cabinet for a
nitroglycerine capsule?
Can you even get to your feet?
You lie there paralyzed with fear, praying that the pain will
pass. . .
Angina pectoris
Words can only go so far in describing the pain of an acute
attack of angina pectoris. The real thing is an experience no
one wants to have.
But last year 6.2 million Americans were stricken with the
condition. Another 7 million suffered myocardial infarctions -
acute heart attacks - the result of a cessation or restriction
of blood supply to the heart, causing the heart muscle to die.
Inadequate blood supply to the heart in both angina and
myocardial infarctions - known as ischemia - is caused by
blockages or narrowing in the two major coronary arteries that
supply the heart with vital blood. These restrictions result
from fatty deposits building up on the arterial walls. Excessive
dietary fat, lack of exercise, smoking, and genetics may all
contribute to the disease.
Two major surgical interventions are frequently performed to
restore blood flow to the heart:
 Angioplasties use
balloons that expand and open narrowed or closed arteries.
Coronary bypasses
reroute the arteries around the restricted vessels.
In 2-4% of cases, coronary artery bypass surgery is necessary
immediately following angioplasty.
Repeat cardiac customers = EECP candidates
But in 20-30% of angioplasties, the coronary arteries are
obstructed again with six months. Arterial deposits may continue
to build after a bypass as well. "The blockages often keep
coming back, or new ones develop," notes Dr. Rohit R.Arora,
director of surgical cardio care services and associate
professor of medicine at Columbia-Presbyterian Medical Center in
New York. "These 'refractory' patients will make up 10-20% of
who we will see in the next few years." That percentage is
expected to increase over the next decade as a swell of baby
boomers enter their 60s.
"A patient who's had two or three bypasses - or five or six
angioplasties - never plans to have repeat invasive procedures,
but we're seeing them more and more now," says Dr. Tony M. Chou,
director of the adult cardiac catheterization laboratory and
associate professor at the University of California, San
Francisco. "This was unexpected when these procedures were
initiated."
Refractory angina patients are increasingly elderly, have less
chance of successful operations, and a greater risk of
complications and death. The morbidity for first-time
angioplasty is between 1-2%, and 3-5% of patients actually have
heart attacks during the procedure. "Depending on risk factors
such as age and overall health, that figure virtually doubles
for those who need the operation repeated," says Chou.
While genetic factors may play a part in arteries clogging
again, the chief culprit is the patient's lifestyle and diet.
"After the first operation, we frequently see a sudden change in
behaviors," says Chou. "They stop smoking. They cut down
saturated fat in their diets. They exercise regularly. But after
4-8 weeks, the pain of what they went through begins to fade,
and the old, habituated behaviors often return. Five to 10 years
later, we see the same areas blocked or obstructed, and we're
faced with repeating the operation."
Eventually angioplasties become less and less effective. The
arteries seem as if they have a memory and begin to narrow again
almost immediately. Because no suitable material is left for
bypasses, patients are no longer viable surgery candidates. "All
that's left is medication, which usually tries to dilate the
arteries to their maximum," explains Chou. "But they don't
reduce the obstruction."
"These patients, along with others whose risk factors make them
poor candidates for surgical intervention - or those who simple
elect to delay it - are the primary candidates for EECP at this
time," notes Chou.
How EECP works
EECP relieves or reduces angina by increasing the amount of
blood that reaches the heart through collateral blood vessels.
These tiny conduits usually are relatively inactive, but EECP
gradually opens them up. The enlarged vessels can usually
transport enough oxygen-rich blood to allow the patient to
resume normal activities and exercise, as well as reduce or
eliminate the use of nitroglycerin or other medications. They
may develop into permanent alternative pathways for significant
blood to reach the heart.
The simple theory behind EECP is based on collateral blood flow
research. When the heart is deprived of oxygen, the collaterals
begin to dilate in an attempt to provide the heart with more
blood. But because the vessels are so small, they can't
accommodate enough blood for heart function to continue. Also,
the collaterals initially will allow significant flow only so
long as arterial flow is critically restricted.
In effect, EECP "fools" the collateral mechanism by creating
additional pressure when the heart relaxes, prompting the
collaterals to remain dilated.
Large cuffs placed on the outsides of upper and lower legs
compress and move more blood through the collaterals during the
relaxation phase. The cuff contractions are electronically timed
so that at the precise moment the heart relaxes, the cuffs
compress - the "counter" in counterpulse.
When the heart contracts to move blood through the arteries in
the usual fashion, the cuff compression releases instantly, and
resumes in milliseconds. Over a period of time, as the
collaterals become more accustomed to their new task, they
develop the capacity to handle greater blood supply.
EECP was developed at Harvard and MIT in the 1950s, but the
technologies to make the system work were not sufficiently
refined until the early 1990s. Original models used huge
hydraulic pumps to move liquid in and out of the cuffs, but it
proved impossible to reliably time contractions and releases to
the 80-120 heartbeats per minute usually seen.
Pneumatic pumps and complex electronic processors that precisely
monitor heartbeats and changing respiratory rates proved to be
the answer. In 1995, the FDA cleared EECP for therapeutic use.
EECP treatment
The initial course of outpatient treatment takes an hour a day,
five days a week, for 4-7 weeks. Patients with very extensive
damage may require treatment over an extended period. Although
the procedure is somewhat forceful due to the nearly
instantaneous increase and decrease of pressure, it's painless.
Patients usually bring a book to read or listen to portable CD
players during their treatments.
Between 4,000-5,000 patients have been treated with EECP in the
past five years at about 160 sites in the USA. Two thousand
participate in a registry that details their histories and
progress. In China, where the EECP machines are manufactured, as
many as 10,000 units are in use.
In addition to treating angina, the EECP apparatus can be used
for some neurological and retinal diseases where increased blood
and oxygen flow may be of value. EECP may also have applications
in sports, particularly in events where additional oxygen can
increase performance.
Results have been extremely encouraging. About 70% of patients
demonstrate improved corollary blood flow to ischemic portions
of the heart. Typically, a patient experiences a decrease in
chest pain. Some report no further angina episodes at all. Many
are able to reduce their need for nitroglycerin or other
medications. Others may no longer require any medication.
But it's the improvements in the quality of life that are the
foremost achievements for successful EECP patients. They can
leave the house, exercise, or go on vacation without the nagging
fear of an attack.
They can even help the baby walk on the ceiling upside down.
For more information about EECP, check out: below.
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