Every year, hundreds of thousands of people are implanted with heart stents to relieve chest pain.
But now, a study published this month in the medical journal Lancet is casting doubt on the practice, suggesting that stents are useless for the majority of these patients.
A heart stent is implanted in a blocked artery during a procedure called cardiac angioplasty. Once in place, the small, wire tubes act like scaffolds to keep the artery open. Some heart stents are coated with drugs to prevent the artery from re-narrowing.
Stents are often used to treat people who are having a heart attack. The devices are proven life savers in these cases.
More frequently, however, stents are implanted in patients with blocked arteries who experience chest pain, a condition called angina. The devices may also be used to unblock arteries in people who have no pain at all.
The Lancet study was conducted by researchers at the Imperial College London, and involved 200 patients with a severely blocked coronary artery and chest pain acute enough to limit physical activity.
For six weeks, all subjects were treated with medications – aspirin, statins, and a blood pressure drug – to reduce their risk of heart attack. They also received medications that relieve chest pain.
The patients then underwent angioplasty. But only half were implanted with a heart stent. Doctors merely pulled the catheter out without inserting a stent in the remaining patients.
Neither the patients nor the researchers conducting the study knew who had received a stent.
As expected, the placement of a heart stent greatly improved blood flow in blocked arteries.
But six weeks later, both groups reported that they were experiencing less chest pain. And both showed improvement on treadmill tests. According to the authors of the study, there was no real difference between the groups.
The findings have sent shock waves through the medical community.
“It’s a very humbling study for someone who puts in stents,” Dr. Brahmajee K. Nallamothu, an interventional cardiologist at the University of Michigan, told The New York Times.
“I think this is a game-changer,” Dr. Rita Redberg, a researcher and cardiologist at the University of California, San Francisco, told the Minneapolis Star Tribune, “I think we have some real explaining to do.”
The unnecessary use of stents can have serious health consequences for some patients.
Just days ago, for example, the U.S. Food & Drug Administration (FDA) warned that Abbot Vascular, Inc.’s Absorb G1 BVS System may expose patients to an increased risk of blood clots and adverse cardiac events.
The Absorb G1 BVS System was only cleared by the agency in July 2016, and was the first and only fully dissolving, drug-eluting stent ever approved to treat patients with coronary artery disease.
The FDA began investigating the BVS system in March, after interim results of the ABSORB III clinical trial showed an 11% rate of major adverse cardiac events (e.g., cardiac death, heart attack, or the need for an additional procedure to re-open the treated heart vessel) in patients receiving an Absorb stent at two years compared with 7.9% in patients treated with Abbott’s drug-eluting, metal XIENCE stent.
The clinical trial also showed a 1.9% rate of developing blood clots within the Absorb stent versus 0.8% within the XIENCE stent at 2 years.
The FDA updated its warning late last month, after ABSORB III results through three years continued to show an increased rate of major adverse cardiac events and BVS scaffold thrombosis in patients receiving the Absorb GT1 BVX System, when compared to patients treated with the XIENCE stent.
Abbott Vascular ended worldwide sales of the Absorb GT1 BVX System in September. However, the company maintained that the move was made for commercial reasons rather than safety concerns.