NIH-Funded
Trial Allows Emory Researchers to Study Treatment Options for Diabetics
with Coronary Artery Disease
Coronary artery
disease (CAD) is a major complication and the leading cause of premature
death among people with diabetes, according to both the American Diabetes
Association and the American College of Cardiology. So why is there
such a strong association between the two conditions? And are medical
therapies now being provided for people who suffer from both conditions
adequate? Emory University researchers have recently begun a new study
to address these questions.
"For some time now, medical
literature has suggested that high insulin levels are associated with
abnormal blood vessel structure and function," says Suzanne Gebhart,
M.D., professor of medicine in the division of endocrinology, Emory
University School of Medicine and co-investigator of this study. "Insulin
promotes growth of endothelial cells, cells which line blood vessels.
Extra insulin in the body could mean extra cell growth in the blood
vessels. This, in turn, may cause atherosclerosis (hardening of the
arteries) and lead to the progression of coronary artery disease. However,
elevated blood sugar as a result of too little insulin is clearly harmful,
as well," Dr. Gebhart explains.
Funded by the National Institutes
of Health (NIH), this new multi-center, multi-million dollar trial,
called Bypass Angioplasty Revascularization Investigation 2 Diabetes
or BARI 2D, will enroll participants who have previously been diagnosed
with both CAD and Type 2 diabetes. Type 2 diabetes is described as a
condition where the body develops a resistance to insulin even though
the pancreas may continue to manufacture insulin. Nationwide, 4800 participants
will be enrolled.
Participants in this five-year
study will be randomly selected by computer to receive a treatment for
CAD and a treatment for Type 2 diabetes. In the CAD treatment arm of
the study, participants will be randomized to receive angioplasty and
medical therapy, bypass surgery and medical therapy or medical therapy
alone. In the diabetes treatment arm, participants will randomly receive
insulin promoting drugs, which increase insulin, or insulin sensitizing
drugs, which enhance a person's own insulin.
"At any time during the study,
participants who need a more aggressive treatment for their heart disease
may cross over to angioplasty or bypass surgery," says John Douglas,
M.D., professor of medicine in the division or cardiology, Emory University
School of Medicine and co-investigator of the trial. "No one will be
denied necessary therapy because they've been selected for one group
over another."
A previous BARI 1 (Bypass
Angioplasty Revascularization Investigation 1) study showed that diabetics
with CAD who underwent either angioplasty or bypass surgery did not
fare as well as non-diabetes who underwent the same procedures. But
the reasons why were unclear. "As a result of the BARI 1 study, our
focus now is on the diabetic population with coronary artery disease,"
Dr. Gebhart states. "Since little research has been done on the connection
between insulin and coronary artery disease, we hope the BARI 2D study
will help us pinpoint why the outcomes of diabetics following intervention
seem to be worse."
Coronary artery disease in the
diabetic population is frequently silent and deadly. "CAD screening is
so important in diabetics since it often goes unrecognized," Dr. Douglas
points out. "Because diabetics' nerves are often affected by the disease,
they have less sensation of pain and may be less likely to recognize chest
pain – an important indicator of heart disease."
Participants must first undergo
a stress test to determine if they qualify for this trial. Those who
have positive stress test results will then undergo a heart catheterization
to find out if they have a blocked or narrowed artery. Once selected
to participate in the trial, participants will receive regular cardiology
exams. Every month for the first six months of the trial, participants
will also be seen by the endocrinology staff with the aim of achieving
optimal management of their diabetes. Afterwards, they will be followed
every three months for the duration of the trial.
Recruitment is underway for
this study. Participants must be 25 years of age or older, with Type
2 diabetes and stable CAD. Those who have had angioplasty longer than
one year ago can enroll in this trial, as can participants who have
undergone previous bypass surgery. Participants in this study must also
be willing to turn certain aspects of their medical management over
to Emory doctors throughout the duration of this study, since endocrinologists
and cardiologists involved in this study must be BARI 2D certified.
For more information or to find out if you are eligible for this trial,
please contact Emory Health Connection at (404) 778-7777.
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