A new study finds that an experimental device implanted in the heart can relieve the chest pain of heart disease in people who aren't candidates for stents or surgery.

Instead of opening up a blood vessel, the novel device narrows it.

It's called the Reducer, and it restricts the flow of blood leaving the heart, causing blood to back up into areas of the heart muscle that aren't getting enough nourishment, which relieves the angina.

In a small test published in the New England Journal of Medicine, more than a third of 52 angina patients found major relief six months after the reducer was implanted, compared to 15 percent of 52 volunteers who underwent a fake implantation procedure.

In an editorial, Drs. Christopher Granger of the Duke Clinical Research Institute in Durham, North Carolina, and Bernard Gersh of the Mayo Clinic in Rochester, Minnesota, said that if the results are confirmed in larger trials, the technique "may be a welcome and needed addition to the options to improve the quality of life of patients with refractory angina."

All the patients had previously failed to get relief with drug therapy. Most had already been treated with stents or bypass surgery.

"These patients have chest pain in every minor physical activity and they don't have any other options for treatment," the study’s senior author Dr. Shmuel Banai of the Tel Aviv Medical Center in Israel told Reuters Health. "I had a patient who had angina with minimal effort. Today he is an instructor of classical dance. It really makes a difference. It may not prolong life, but it really improves quality of life."

But that example may not be typical.

Overall, there was no significant improvement in the amount of time that device recipients could exercise, a key yardstick for measuring the debilitating effects of angina. In the device group, exercise time, which averaged 7 minutes 21 seconds before implantation, increased by only 59 seconds. In the control group, it rose by just 4 seconds.

The device is made of stainless steel mesh, like early stents. But in this case, once expanded in the blood vessel the device assumes the shape of an hour glass.

Eventually, tissue from the wall of the blood vessel grows over the mesh, leaving only a narrow passage in the center. That shape constricts the flow of blood leaving the heart muscle..

"Right after implantation, nothing happens," said Banai. "If you ask the patient two or three weeks after implantation, he doesn't see any improvement. Then, after a month or six weeks, after the mesh is covered with tissue, there is a pressure gradient. Then it becomes beneficial and improves symptoms."

"This is a simple procedure. Implantation takes 10 to 20 minutes. The patient goes home the same day. A month or two after implantation, their quality of life is markedly improved," he said.

Success was judged by a four-point scale of angina symptoms that assessed whether the degree to which a person's physical activity was limited because of chest pain. While only 15 percent of those getting fake surgery improved by 2 points on the scale, 35 percent of the reducer recipients did.

When success was measured by an improvement of 1 point, 71 percent of the people who got the device improved versus 42 percent in the fake-treatment group.

A high rate of success in the sham treatment group was expected, Banai said.

"These chronic, no-option patients are very eager to believe they feel better, and some of that is in the brain," he said. "We anticipated about 30 percent (improvement with sham therapy). We got more than 40 percent, which is a bit surprising. Yet despite this huge placebo effect, the fact that the study was positive was amazing. This means the device is really effective."

The study was financed by Neovasc Inc., which makes the device. It has been approved for use in the European Union but is not yet for sale. It has not been approved by the U.S. Food and Drug Administration.

Dr. Elliott Antman, a senior physician in the Cardiovascular Division of the Brigham and Women's Hospital in Boston who was not connected with the study, advised caution.

"It is important to realize that the results of this small study are preliminary and depend heavily on the subjective report of relief of discomfort by the study subjects." he told Reuters Health in an email.

Before thinking about using the device in patients, Antman said, doctors need to know more about how it works and its longterm safety.