The common practice of inserting a stent to repair a narrowed artery has no benefit over standard medical care in treating stable coronary artery disease, according to a new review of randomized controlled trials published on Monday.
Stable coronary artery disease is the type of heart ailment that causes angina, or chest pain, after physical exercise or emotional stress but generally not at other times. The review did not include studies of the emergency use of stents for heart attacks.
Stent implantation involves a procedure called percutaneous coronary intervention, or P.C.I., in which a surgeon inserts a mesh tube made of metal into an artery that has become narrowed by accumulated plaque. The tube, threaded through an artery in the leg or arm, expands to hold the artery open at the point where blood flow is restricted.
Some of these devices, called drug-eluting stents, are coated with medicine that helps to keep the artery open. The cost of the procedure varies from about $30,000 to $50,000, and more than one million are performed every year in the United States.
The procedure has certain risks. According to Dr. David L. Brown, an author of the analysis, the risk for death is about one in a thousand, and complications can include stroke, heart attack, bleeding, kidney damage and serious allergic reactions. But those events are rare, and the review did not detect any increased risk in P.C.I. compared with medical treatment.
Despite the widespread popularity of the procedure, previous studies have reached mixed conclusions as to whether stents are effective for treatment of stable coronary artery disease.
The researchers reviewed eight randomized trials comparing P.C.I. with standard medical care. Combining data from all the studies, the researchers found that prescribing beta blockers, ACE inhibitors, statins and daily aspirin — now standard for treatment of stable coronary artery disease — was just as effective as stent implantation for prevention of chest pain, heart attack, the need for a future P.C.I. and death.
More than half of patients with stable coronary artery disease are now implanted with stents without even trying drug treatment, Dr. Brown said. The reason, he believes, is financial.
“In many hospitals, the cardiac service line generates 40 percent of the total hospital revenue, so there’s incredible pressure to do more procedures,” he said.
“When you put in a stent, everyone is happy — the hospital is making more money, the doctor is making more money — everybody is happier except the health care system as a whole, which is paying more money for no better results.”
Dr. Allan Schwartz, chief of cardiology at Columbia, who was not involved in the study, said that the analysis reinforced what was already known — that treatment with medicine first is usually the best approach.
“I agree with the conclusions,” he said, “but they shouldn’t be oversimplified. Cardiac disease is complicated, and there are lot of factors that go into assessing who should and shouldn’t be treated with stenting.” Sometimes a stent is indicated even in patients with stable coronary artery disease, he said — for example, when the medicine doesn’t work or has intolerable side effects.
Two recent meta-analyses showed an advantage for P.C.I. But those reviews considered patients enrolled in the 1980s and 1990s when balloon angioplasty without stents was the predominant form of surgical intervention, and when medical therapy generally did not include statins, ACE inhibitors and other drugs that are now standard in medical treatment.
This review, published in The Archives of Internal Medicine, included only prospective randomized trials that compared P.C.I. and medical therapy with medical therapy alone. There were 7,229 patients in all, half randomized to P.C.I. and half to medicine alone. More than 70 percent of the surgical patients received stents, and the studies followed patients for an average of more than four years
.Death rates were 8.9 percent with P.C.I. and 9.1 percent with medical treatment. Rates for nonfatal heart attacks were 8.9 percent for those who got stents and 8.1 percent for those on medicine alone.

P.C.I. was eventually performed on 30.7 percent of patients who got only medicine, but a second P.C.I. was required for 21.4 percent of those who got stents. None of these differences was statistically significant.
Dr. Harlan Krumholz, a cardiologist and professor of medicine at Yale who was not involved in the study, said that the findings hold a lesson for doctors treating heart patients. “When people are making decisions, it’s important to disclose to them that this procedure — outside of an emergency — is not known to be lifesaving or to prevent heart attacks,” he said. “The vast majority of people who have this procedure have the expectation that it will help them live longer. That belief is out of alignment with the evidence.”
Some theories suggest that stenting reduces mortality by improving blood flow or stabilizing plaques that can break away and cause blood clots, but the researchers found nothing to support those ideas.
Angina is often the symptom that convinces doctors and patients that medical therapy is not enough and that a stent is required. But in this analysis, 29 percent of people who had P.C.I. still had angina, compared with 33 percent of those on medicine, an insignificant difference.
These results support the current concept of coronary artery disease, the authors wrote — that it is a systemic inflammatory disease of the arteries that cannot be successfully treated by surgical intervention at a particular site on one artery.
According to Dr. Brown, a professor of medicine at Stony Brook University, many doctors cannot accept this. Instead, he said, “interventional cardiologists use the analogy of a pipe blocked in a house — it’s a terrible analogy, but patients accept it. It’s simplistic and erroneous.”