Stent Procedures May Be Unnecessary In Some Heart Cases

March 10, 1999

NEW ORLEANS -- A new analysis by Duke University Medical Center researchers indicates that 1 in 12 implants of tiny tubes called stents to hold open newly unclogged arteries in patients with symptomatic coronary artery disease may be unnecessary.

The arteries were unclogged by an angioplasty procedure in which a tiny balloon is inflated at the site of arterial blockage, pushing the blocking plaque aside and restoring blood flow to the heart. Stents are mesh tubes used to hold arteries open after angioplasty.

The Duke study pooled the results of seven different angioplasty trials and looked at more than 5,000 angioplasty patients. The researchers found that approximately 8 percent to 18 percent of stent implants did not appear to be necessary, especially for men whose vessels had shorter atherosclerotic lesions not involving the top of the artery that feeds the left side of the heart. According to the analysis, a simple angioplasty to clear the blockage appears to work as well as implanting a stent.

"In 1998, more than 500,000 people received stents, and our data suggest that one in 12 may not have required them," said Duke cardiologist Dr. Warren Cantor. "Based on an estimated cost of $1,500 for each stent, the U.S. health care system could potentially save more than $60 million."

Cantor prepared the results of his analysis for presentation Tuesday at the annual scientific sessions of the American College of Cardiology.

The cardiologists looked at those patients who obtained 'stent-like results' from the angioplasty without having had a stent implanted. For the researchers, this meant that the degree of narrowing that persisted after balloon inflation was less than 30 percent without any residual tear in the vessel.

As a part of the study, the researchers also surveyed 133 interventional cardiologists from around the world about how they would define stent-like results, based on visual and radiographic data. As expected, there was a wide variety of opinions, with 45 percent of cardiologists saying that for them, a 10 percent residual narrowing represented stent-like results.

"Only 1 percent of the patients in our study achieved the 10 percent level, which indicates to us that 10 percent is not a practical definition," Cantor said. "On the other hand, we found that a 30 percent or less residual narrowing was associated with a favorable clinical outcome."

Before the advent of stents, up to one-third of all patients who received an angioplasty needed another angioplasty or a bypass operation after six months because the artery would become blocked again, a process known as restenosis. Since the introduction of stents in the United States less than 10 years ago, the restenosis rate has been nearly cut in half.

According to Cantor, about 80 percent of all angioplasty procedures in many institutions now include the placement of a stent.

While stents have markedly reduced the rate of restenosis, Cantor said stents have their own drawbacks. When restenosis does occur, it is more widely diffused along the artery, making it harder to treat. Also, there is a slight (1 percent) risk of clot formation, which could lead to a heart attack

In a typical procedure, the stent is implanted in the artery after the balloon has opened it up. However, it is becoming increasing common for cardiologists to automatically implant the stent before seeing if the balloon achieved the desired effect, according to Duke cardiologist Dr. Magnus Ohman, the study's senior researcher.

"This a very controversial topic, without much scientific data on either side," Ohman said. "This evidence suggests that we can achieve reasonable results with the balloon alone in a certain group of patients. We can always reserve the excellent stent technology for those patients who really need it, and there are many of them, and reduce health care expenditures at the same time."

Ohman added that since this is a retrospective database analysis, the next step is to validate the results in a prospective trial.

The researchers analyzed data from 5,143 patients who received balloon angioplasty and looked at what happened six months later. Of those patients, 18 percent achieved a stent-like result.

Of all the factors that led to stent-like results that were studied, only three were statistically significant: gender, location of the blockage, and the size of the blockage. While the last two factors didn't surprise the researchers, the first did.

"For the men with stent-like results, 17 percent needed repeat revascularization procedures at six months," Cantor said. "For the women, however, 28 percent required repeat revascularization. While we don't know the reason for this difference, it could have do with the fact that, on average, women's vessels are smaller."

At the opposite end of the spectrum would be women who had medium to long blockages.

"For this group, 46 percent needed revascularization at six months," Cantor said. "So, even if someone in this group had a stent-like result after balloon angioplasty, we should still put in a stent."

Looking at the group of patients as a whole, of the 18 percent who achieved stent-like results, 45 percent had all three of the favorable characteristics: gender, size and location of blockage. This represents about 42,000 patients, or 8 to 9 percent of all angioplasty procedures performed, Cantor said.

"The beauty of this study is that it shows we can achieve the best of both worlds -- providing the highest quality of care in a cost-effective manner," Ohman said.

The study was supported by the Duke Clinical Research Institute, as well as the Royal College of Physicians and Surgeons of Canada. Joining Cantor and Ohman in the analysis were Nancy Wilderman, Dr. Michael Sketch, Dr. Eric Peterson, Dr. James Zidar, Dr. James Tcheng and Dr. Robert Califf.
-end-
Note to editors: A graphic showing angioplasty and stent in a clogged artery is available on the web at http://ed-media.mc.duke.edu/aved/avart/angio.htm.



Duke University Medical Center

Related Angioplasty Articles from Brightsurf:

Ticagrelor was not superior to clopidogrel to reduce heart attack risk during angioplasty
A new study found the rate of heart attack and severe complications before, during or soon after elective surgery to open a blocked artery was similar between patients treated with clopidogrel and those who received the more potent antiplatelet medication ticagrelor.

Study finds significant variability in doctors' angioplasty death rates
Some doctors have higher or lower than expected death rates from coronary angioplasty procedures, also known as percutaneous coronary intervention (PCI); however, doctors should not be judged solely on the rate of patients who die from the procedure.

Beta-blockers following angioplasty show little benefit for some older patients
Following coronary angioplasty, beta-blockers did not significantly improve mortality rates or reduce the number of future cardiovascular incidents for older patients with stable angina but no history of heart attack or heart failure, according to a study published today in the JACC: Cardiovascular Interventions.

Sleep disorders may predict heart events after angioplasty
People who have had procedures to open blocked heart arteries after acute coronary syndrome (ACS) may have a higher risk of death, heart failure, heart attack and stroke if they have sleep disorders, such as sleep apnea, compared to those who don't.

Reasons for hospital-level variations in bleeding post-angioplasty are unclear
The use of bleeding avoidance strategies has only a modest effect on the variation in bleeding rates post-angioplasty among hospitals performing this procedure, leaving about 70 percent of the causes for this variation unexplained, according to a study published today in JACC: Cardiovascular Interventions.

US prediction models for kidney injury following angioplasty hold up in Japan
Models developed by the American College of Cardiology NCDR CathPCI Registry to predict the likelihood of angioplasty patients developing acute kidney injury and acute kidney injury requiring dialysis have proven to be effective among patients in Japan.

IV beta blockers before angioplasty are safe, but offer no clinical benefit
Giving intravenous beta blockers before performing a coronary angioplasty in patients who had experienced the deadliest form of heart attack -- ST-segment elevation myocardial infarction (STEMI) -- was safe but did not reduce heart attack severity or improve blood flow from the heart's main pumping chamber, according to research presented at the American College of Cardiology's 65th Annual Scientific Session.

Life-threatening bowel ischemia can often be treated by balloon angioplasty
Acute mesenteric ischemia (AMI) can be successfully treated with endovascular therapy such as balloon angioplasty, according to research from the University of Eastern Finland.

Radial access used less than femoral approach for emergency angioplasty
Although using the radial artery as the access point for angioplasty has been linked to reduced bleeding compared to use of the femoral artery, only a small number of high-risk heart attack patients who undergo rescue angioplasty -- emergency procedures following failed therapy with clot-busting drugs -- are treated by radial access, according to a study published today in the Journal of the American College of Cardiology: Cardiovascular Interventions.

Use of rarely appropriate angioplasty procedures declined sharply
The number of angioplasty procedures classified as rarely appropriate declined sharply between 2010 and 2014, as did the number of those performed on patients with non-acute conditions, according to a study published today in the Journal of the American Medical Association and simultaneously presented at a meeting of the American Heart Association in Orlando.

Read More: Angioplasty News and Angioplasty Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.