DOCTOR'S VIEW ARCHIVE
Heart Disease & Stroke - Progress Through
Research
Gene therapy designed to grow new blood vessels in the heart
muscle led the list of the top 10 research advances in heart disease
and stroke compiled by the American Heart Association. The list,
first created in 1996, recognizes achievements in basic and clinical
research that may have the most impact on the prevention and
treatment of cardiovascular disease.
The most recent edition of the list is as follows:
- Gene therapy to create a "natural" bypass around blockage
- New drugs to prevent clots causing heart attacks and strokes
- Relationship between inflammation and heart attacks
- Detection of unstable plaques in vessels by imaging technology
- Heart cells recover thanks to left ventricular assist device
- Tobacco's effects from fewer than 10 cigarettes a day
- Impact of diet and exercise on blood cholesterol levels
- Education of people with heart symptoms to go to the emergency
room
- Epidemic of cardiovascular disease and stroke
- Nobel Prize for discovery of nitric oxide (which relaxes blood
vessels).
This list was issued at the end of 1999 by the American Heart
Association and is based upon developments reported during 1998. We
will comment upon each of these ten advances:
1. Gene therapy to create a "natural" bypass to circumvent
plaques obstructing the heart's blood vessels.
People with heart disease may be routinely treated in the future
by a genetically engineered technique that induces the growth of new
blood vessels. The new vessels would help restore blood flow to the
hearts of people whose arteries are obstructed by plaques. By
impeding blood flow, these obstructions can cause severe chest pain
(angina) and heart attacks.
Scientists reported that they had used a human growth factor
called FGF-1 (fibroblast growth factor-1), obtained through genetic
engineering, to induce the growth of new blood vessels in 20 patients
with heart disease. In their three-year follow-up study of the
patients, the scientists reported that the treatment resulted in a
two to three times more blood flow to the heart.
Another growth factor called VEGF (vascular endothelial growth
factor) also appears capable of inducing new blood vessel growth for
the heart. Gene therapy may thus become an important part of the
treatment of heart disease.
2. New drugs to prevent clots causing heart attacks and
strokes.
Drugs called platelet blockers (or, more formally, IIb/IIIa
receptor blockers) were found to keep blood platelets from clumping
and forming blood clots that can trigger a
heart attack or stroke. In
this regard they are like aspirin. However, the platelet blockers --
eptifibatide (brand name: Integrilin), tirofiban (Aggrastatin) and
abciximab (ReoPro) -- are more potent than aspirin. And they are
administered intravenously (IV).
To test the usefulness of the platelet inhibitor drugs, a total of
about 32,000 heart patients received a platelet blocker as part of
their treatment for a heart attack or severe chest pain. Some
individuals received only the
platelet blockers while others were treated with a platelet blocker
plus angioplasty -- a procedure that uses a balloon-tipped catheter
to restore blood flow in the blood vessel. Those who received the
platelet blockers had a 30 percent reduced risk of all-cause death
than those who did not receive the drugs. The individuals who
particularly benefited from the drugs were those who also were
treated with angioplasty. In these individuals the drug was
administered just as the coronary arteries were being opened by
inflation of the balloon-tipped catheters used for the procedure.
3. Relationship between inflammation and heart attacks.
It is recommended that people at elevated risk for heart attack
and stroke take aspirin because it helps prevent the blood clots that
can cause heart attacks and strokes. Aspirin, however, may have
another benefit for people at high risk for heart attacks and stroke.
Aspirin is an anti-inflammatory drug, and research suggests that the
body's inflammatory response may play a role in cardiovascular
disease.
The area of the blood vessel where an obstructive plaque develops
can become inflamed. The inflammatory response may not be localized
to the blood vessel wall in that area. It also can occur throughout
the bloodstream. This systemic inflammation may explain the
development of blood clots on top of relatively stable plaques.
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