UCSF study shows that drug administered during heart procedures preserves blood flow into the heart

By Maureen McInaney on November 13, 2000

A drug commonly used during invasive heart procedures not only helps maintain
blood flow through the large blood vessels that have been enlarged during the
procedure by balloons and metal tubes, but also preserves blood flow through
the smaller blood vessels downstream that may become blocked by debris. This
helps to restore much needed oxygen supply directly to heart muscle, according
to C. Michael Gibson, MD, UCSF chief of interventional cardiology, director of
the Core Angiographic Laboratory at UCSF and lead author of the study.

Gibson presented the results at the American Heart Association in New Orleans,
Louisiana,  on Sunday, November 12.

“During invasive heart procedures many small blood clots may be released during
the placement of a tube or stent in the artery, and these small clots may in
turn float downstream and block the small vessels or capillaries that supply
blood to the heart muscle itself.  In order to prevent irreversible injury to
the heart that can occur following stenting, it is critical that this complex
network of very small blood vessels that supply oxygen to the heart muscle
remain intact,” explained Gibson.  “Our study clearly demonstrates that use of
the drug eptifibatide at the time of stent placement helps preserve the
integrity of the microvasculature and blood flow into the heart muscle.”

Eptifibatide (Integrilin) blocks the receptors on platelets, components in the
blood that are responsible for coagulation. This reduces clot formation that
can lead to heart attack or death, said Gibson. Use of eptifibatide
significantly improved the ability of the heart to speed up its blood flow in
large arteries by 39 percent when compared with placebo. It improved the speed
at which blood entered the microvasculature in the heart muscle by 84 percent
compared to placebo, explained Gibson. Improving the entry of blood into the
heart muscle preserves blood supply to the previously oxygen-starved heart
muscle in patients undergoing angioplasty, he said.

Nearly 600,000 angioplasty procedures are performed in the United States each
year.  The procedure is used to stretch the walls of narrowed blood vessels in
the heart that limit the supply of oxygen to heart muscle.  More than six out
of ten procedures involve the placement of intracoronary stents, metal mesh
structures that hold the heart arteries open after the procedure. Although
angioplasty and intracoronary stenting are generally successful at restoring
blood flow and preventing the collapse of the artery, the use of a stent into
the artery wall can result in the clumping of platelets and the development of
blood clots.  A clot can obstruct blood flow through both large and small
arteries.

Investigators evaluated angiograms of 65 patients taken before and after stent
placement to determine the extent of and speed of blood flow through the
network of very small blood vessels that supply oxygen to the heart muscle.
With computer assisted analysis, investigators were able to measure how bright
the heart muscle became (due to a surge of dye indicating increased blood flow
to the microvasculature) after use of the eptifibatide.

Co-investigators in the study were David Cohen, MD, assistant professor of
medicine, Harvard University and James E. Tcheng, MD, associate professor of
medicine, Duke University.

Integrilin was developed and is marketed in the United States by COR
Therapeutics, Inc., South San Francisco and Key Pharmaceuticals, Inc.,
Kenilworth, New Jersey. Both companies funded the study.