Copyright © 1998 Nando.net
Copyright © 1998 The Associated Press
ATLANTA (March 30, 1998 4:19 p.m. EST http://www.nando.net) -- For the
first time, doctors have shown that injections of a genetically engineered
hormone can help people with bad hearts grow their own bypasses -- an
approach that could someday offer an alternative to surgery and angioplasty.
The hormone, which occurs naturally in the body, triggers the heart to
sprout tiny vessels to carry blood around blockages that cause angina pain.
The results of the first experimental use, released Monday, showed that the
treatment eased angina in 13 of the 15 people treated.
The results are considered very preliminary, and the doctors caution that
much more testing will be needed to know precisely how well it works.
Nevertheless, Dr. Timothy D. Henry of the University of Minnesota, who
directed the study, said, "We are excited by this. It is a unique approach
to treating coronary artery disease."
About 1 million Americans a year undergo either bypass or angioplasty. A
bypass involves grafting tiny pieces of blood vessel onto the heart to
shuttle blood around blocked sections of artery. Angioplasty uses a tiny
balloon, threaded into the heart, to squeeze open narrowed passages
temporarily.
If all goes as the researchers hope, natural proteins called growth factors
could offer a new alternative, especially for those who have already failed
the standard approaches or cannot be helped by them.
In this experiment, doctors injected genetically engineered vascular
endothelial growth factor, or VEGF. The protein is made by Genentech Inc.,
which paid for the experiment.
All of the men and women had serious chest pain and could not be treated by
angioplasty or bypass surgery.
Among those helped was a man in his early 50s who had already had two
bypasses and two angioplasties, yet was still crippled by angina. The
growth hormone appeared to relieve his condition almost completely.
Henry said the man told him that "the only side effect was that he had to
go back to work."
Doctors performed angiograms -- X-ray movies of the heart arteries -- on
seven of the patients. Five of them showed significant growth of tiny blood
vessels the width of a hair. Others tests indicted that the patients' heart
tissue was getting more oxygen.
Henry described the results at a meeting in Atlanta of the American College
of Cardiology.
"This absolutely looks promising," said Dr. Judith L. Swain of Stanford
University. "This is a technology that's here."
Dr. Michael Mann of Harvard Medical School called the research "a critical
and bold step that sets the stage for larger studies" to answer whether
this approach truly works.
Those answers could come from a follow-up study, scheduled to begin next
month at 25 hospitals, where doctors will test VEGF on 400 patients. The
treatment is not available except in such carefully controlled studies.
The body naturally responds to VEGF to stimulate the growth of new blood
vessels in tissue that is starved of oxygen -- as the heart is in coronary
artery disease.
The researchers injected VEGF directly into the heart arteries while they
performed angiograms. Henry said 30 other patients have been given simple
injections of the hormone into veins, and the results of that experiment
are not yet known.
Last month, a team from Fulda Medical Center in Germany reported
experimental use of a similar protein, called fibroblast growth factor, on
20 patients. The patients were given the protein during bypass surgery.
They improved, but it was unclear how much was due to the growth factor.
Other researchers are experimentally giving bypass patients the gene that
carries manufacturing instructions for VEGF. The idea is to trigger the
heart to make more of the protein on its own.
The results of these experiments on the heart have not been released.
However, this approach has shown promise when used on people with clogged
leg arteries that could have led to amputations.
By DANIEL Q. HANEY, AP Medical Editor