A new study says heart stents don’t make much difference in easing chest pains, but a number of cardiology experts say the research is flawed.
Stents, which are as ubiquitous for chest pain as pumpkin pie is for Thanksgiving, have gotten a bad rap lately.
The findings fly in the face of decades of use.
These tiny wire cages are crucial when used to open arteries in people who’ve experienced heart attacks.
Stents also are used in those who experience pain while performing certain activities, such as climbing stairs.
Others have no pain, just a blockage that is treated with a stent.
Stenting is big business in this country. Heart disease is the leading killer of Americans, and the use of stents is part of treatment in practically every hospital.
More than 500,000 heart patients worldwide have stents inserted each year to relieve chest pain, according to The New York Times.
Several companies — including Boston Scientific, Medtronic, and Abbott Laboratories — sell the devices.
Inserting one costs from $11,000 to $41,000 at hospitals in the United States.
Into this established treatment paradigm comes a study that finds no significant difference in pain relief between those given a stent and those undergoing a placebo-type procedure.
“These results are surprising,” Dr. Sidney C. Smith Jr., MACC, FAHA, FACP, FESC, a professor of medicine at University of North Carolina, a clinician at the UNC Center for Heart and Vascular Center Care, and a past president of both the American Heart Association and the World Heart Federation, told Healthline.
The study merits some consideration, he said, but as it was for a small number of patients, “We should look at the data carefully.”
The study was a double-blind, randomized controlled trial at five sites in the United Kingdom.
It started with 200 patients, with 105 patients receiving a stent and 95 in the placebo group. Six weeks later, both groups were subjected to treadmill tests.
Smith said the subject merited further study because it raised questions he couldn’t answer.
“Did some of the participants have small-vessel disease?” he wondered, since the study parameters were based on having a large blocked vessel.
“How many women were included in the study?” Smith wanted to know. “Women tend to get heart disease later than men.”
He added that diabetes could have affected the results. He was also interested in the link between hypertension and test results.
All study participants were first treated for six weeks with drugs to reduce the risk of a heart attack.
The drugs included aspirin, a statin, and a blood pressure drug as well as medications that relieve chest pain by slowing the heart or opening blood vessels.
Dr. Farhan J. Khawaja, a cardiologist with the Orlando Health Heart Institute Cardiology Group in Florida, told Healthline that he found the study interesting, but the choice of participants was a weakness.
“They had a select population, not the people we traditionally treat in cardiac care,” he said. “We deal with sicker people. These were patients who were [already] stable. That’s a difference.
“Patients with only one blocked vessel were included in the study,” he added. “They didn’t look at microvascular arteries.”
Khawaja qualified his comments by noting it was a “well-designed study that was very nice overall.”
He wouldn’t see the same results, Khawaja thought, because his patients are in poorer health. He’d like to see the study replicated elsewhere, but foresaw questions in the United States.
“Guidelines in the U.S. would not necessarily support intervention” at this level, he said.
Every cardiologist contacted by Healthline found something wanting in the study’s methodology.
Dr. Samir Kapadia, the section head of invasive and interventional cardiology at the Cleveland Clinic, had a number of questions.
“Don’t say stenting doesn’t work. It does,” Kapadia asserted.
He thought the study’s test of subjects was misleading. The patients were given a treadmill test six weeks after the procedure.
“They wanted to see if there was any difference after six weeks. Their goal was to find a difference of 30 seconds,” he said.
Standard endurance tests involve brief periods on the treadmill with the intensity increasing. “You [patients] are instructed to do as much as you can,” Kapadia explained. “The idea is not to test exercise tolerance but heart capacity.
“To add 30 seconds is very difficult because you are already going at a fast pace,” he said.
The researchers did find small difference between the group that received the shunts and the group that didn’t.
The problem was that the difference wasn’t statistically significant, which Kapadia attributed in part to the small number of participants.
As an additional complication, eight people in the placebo group ended up having stents inserted.
Kapadia plans to write a letter to the Lancet detailing his critique.
For now, his advice is succinct: “Ignore this study. Trust your doctor and don’t be afraid.”