March 10, 2000

Peripheral artery study seeks increased blood flow

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Nuclear Medicine Technologist Chris Smith administers a bone-density screen to patient Judy Bloeser. (photo by Dana Johnson)

Peripheral artery study seeks increased blood flow

Vanderbilt University Medical Center investigators are studying an angiogenesis drug's ability to improve blood flow in the legs of patients with peripheral artery disease.

The condition results from the buildup of plaque in the blood vessels. By using an agent that promotes angiogenesis, or the growth of new blood vessels, researchers hope to bypass the clog and improve blood flow.

The drug currently being tested is called recombinant fibroblast growth factor 2 (rFGF-2), a key protein that promotes the formation of new blood vessels.

Approximately six to eight million Americans suffer from peripheral artery disease and many are unable to walk more than a few steps without pain and cramps in the legs.

The disease is similar to coronary artery disease in that it blocks blood flow, but different in the way in which it can be treated. Beta-blockers, which slow down the beating of the heart muscle so it needs less oxygen, are not an option for patients who can’t walk due to insufficient blood flow to the leg muscles. In addition, another method to reduce plaque buildup in the arteries — exercise — is not an option for patients who can't walk.

“The blood flow is decreased because of plaque that forms in the vessel wall. Currently, the most effective therapies are mechanical therapies. These include balloon angioplasty to open the arteries, stent placement to keep the arteries open, or bypass surgery,” said Dr. Raul Guzman, assistant professor of Surgery.

In animal models, it has been shown that rFGF-2 promotes blood vessel growth in the area to which it is applied and not to the entire vascular system.

“At this point, we can’t inject rFGF-2 into the bloodstream through a vein, so the trial requires a procedure to inject it into an artery of the leg,” said Guzman.

Study participants will be divided into three groups who will all receive an injection at the beginning of the trial and again after 30 days. The first group will receive rFGF-2 for both injections. The second group will receive rFGF-2 for the first injection and placebo for the second. The third group will receive placebo for both injections.

Researchers will study the drug's efficacy and whether a second dose is necessary to sustain the angiogenic effect.

“What we will actually measure is a patients' ability to walk without pain" said Guzman.

To qualify for the study, patients must be over 40 years old, have significant peripheral artery disease, limited walking ability, and have been medically stable over the last four months.

“Currently, these are the patients we feel can benefit most from this therapy, although once this trial is completed, we hope to try this treatment on patients with more advanced forms of the disease."

Patients must not have had cancer in the last 10 years or a history of diabetic retinopathy, a proliferation of cells in the eye that can cause blindness.

“All of our patients will undergo a thorough medical exam and cancer screening prior to enrollment in the trial "said Guzman.

“We know that these patients are at high risk for heart attack and stroke. We hope that in addition to helping our patients walk farther, we will allow them to reduce their overall risk of vascular disease by increasing their ability to exercise.”

For more information about the trial, please contact Elizabeth Card at 343-4257.