TUESDAY, July 25, 2006 (HealthDay News) -- Inserting a stent to open the main artery to the brain may help to reduce depression associated with a condition called carotid stenosis, a new Austrian study suggests.
But experts differ about whether the beneficial effect had a purely physical cause -- better blood flow to the brain -- or whether there was a strong psychological factor involved.
The Austrian physician who led the study leans toward a physical explanation. "Our findings suggest that opening the carotid artery and restoring blood flow to the brain via a minimally invasive technique under local anesthesia is associated with significant reduction in depressive symptoms," Dr. Wolfgang Mlekusch, a specialist in clinical angiography and internal medicine at Vienna General Hospital and Medical School, said in a statement.
Mlekusch was lead author of the report that was published in the August issue of the journal Radiology.
But Dr. Michael M. Dake, chairman of the department of radiology at the University of Virginia, said the psychological element can't be ruled out.
Someone who has been told that his or her carotid artery -- the main vessel delivering blood to the brain -- is narrowed is likely to be more depressed than average because they're facing an increased risk of stroke, Dake said. "Many people in our society feel that a stroke is worse than death. It's not surprising for a person who has a disease that significantly narrows the arteries is depressed, as opposed to having something that affects the legs," he explained.
The Austrian researchers compared 143 patients with carotid stenosis -- severely narrowed carotid arteries -- with 102 patients who had peripheral arterial disease (PAD), which is narrowed vessels in the leg. All took a standard test for symptoms of depression, and one-third of those with narrowed carotid arteries had symptoms of depression, compared to 16.7 percent of those with PAD.
Four weeks after both groups underwent the artery-opening procedures, 13 percent of those treated for PAD were depressed, compared to 9.8 percent of those who had stents implanted to improve carotid blood flow.
It's possible that improved blood flow relieved the carotid-stenosis patients' depression, Dake said. But there's also the "halo effect" that some patients experience that must be considered, he said: "I went though the operation and didn't have a stroke."
But the physical effect can't be ruled out, Dake said. "This is intriguing work that needs to be followed up," he said.
Recent studies have described a condition called "vascular depression," a set of depressive disorders that may be caused by conditions that restrict blood flow to the brain. There are debates about the psychological components of those conditions.
One fact that bolsters the physical explanation was that the Austrian researchers tested a small group of carotid stenting patients several months later and found that the improvement in depressive symptoms persisted, Dake said. But the evidence falls short of convincing, he said.
"The fact is that these people had more depression than those in the control group, for whatever reasons," Dake said. "After treatment, they had significant improvement. I'm not sure it is an either-or explanation. One challenge of the future is to tease out what is the major contributor to this state."
Benjamin Mast, associate professor of psychological and brain sciences at the University of Louisville, said that challenge might be met with a trial that had a different comparison group.
"An appropriate group would be people who are waiting for stenting," Mast said. "As it is, it is difficult to say that stenting leads to relief of depression."
Mast added that one slight flaw in the study was that the measurement of depression was made just three days before stenting was done. "It would be helpful to know how stable that depression was," he said.
The American Heart Association has more on carotid stenosis.