Nav: Home

Study of heart stents for stable angina highlights potential of placebo effect

November 02, 2017

Coronary artery stents are lifesaving for heart attack patients, but new research suggests that the placebo effect may be larger than previously thought.

The findings come from the ORBITA trial; a blinded, randomised, placebo-controlled study of 200 patients with stable angina, in which researchers compared the artery-widening technique (stenting) with a simulated procedure - where a stent was not implanted - for the first time.

Results from the trial show that the treatment had no significant additional benefit on patient symptoms or quality of life.

Carried out in the UK and led by researchers at Imperial, the trial provides the first evidence of a direct comparison between stenting for stable angina and placebo, for patients on high quality tablet treatment.

The researchers have published their findings in The Lancet and will present them today (Thursday, 2 November) at the Transcatheter Cardiovascular Therapeutics 2017 conference in Denver, Colorado.

Dr Rasha Al-Lamee, lead author of the study from the National Heart & Lung Institute at Imperial College London, said: "The most important reason we give patients a stent is to unblock an artery when they are having a heart attack. However, we also place stents into patients who are getting pain only on exertion caused by narrowed, but not blocked arteries. It's this second group that we studied."

"Surprisingly, even though the stents improved blood supply, they didn't provide more relief of symptoms compared to drug treatments, at least in this patient group," said Dr Al-Lamee, who is also an interventional cardiologist at Imperial College Healthcare NHS Trust.

"While these findings are interesting and deserve more attention, they do not mean that patients should never undergo the procedure for stable angina. It may be that some patients opt to have an invasive procedure over taking long-term medication to control their symptoms," she added.

Stable angina is a common condition in adults in which patients feel chest pain as a result of over-exertion due to restricted blood flow to the heart. It is typically caused by the build-up of fatty plaques in the arteries and a hardening of the blood vessel walls, which makes them narrower and less flexible.

Patients can manage the condition with drugs such as beta-blockers or nitro-glycerine, however, some may undergo an invasive procedure, known as angioplasty with stent or Percutaneous Coronary Intervention (PCI). An estimated 500,000 patients around the world undergo PCI each year for stable angina, and the procedure is thought to bring substantial relief from symptoms for patients.

However, since the procedure was introduced it has been unclear whether the relief of symptoms is due to the treatment or to a placebo effect.

As part of the multi-centre ORBITA trial, the researchers recruited 200 patients through hospitals in London and the south of England. All patients had stable angina, and had a narrowing in one single coronary vessel. Once enrolled the patients had a six-week phase of intensive medical treatment in which the medications used to treat angina were introduced and increased to maximal doses.

Patients were randomised to receive either a heart stent, or to undergo a placebo procedure in which they had an angiogram procedure, but did not receive the stent.

Of the patient group, half received the stent and half had the placebo procedure. For the next six weeks the patients and their doctors did not know which one they had had.

Both before and six weeks after undergoing the procedure, patients had exercise tests to assess how fast they could walk on a treadmill while their heart and lung function were measured. The key outcome was a change in the amount of time they could exercise after the procedure.

They found the average increase in overall exercise time was 28·4 seconds for patients who had PCI and 11·8 seconds for the placebo group. However, the difference between the groups was not statistically significant, meaning they could not say the effect was down to the stent, or down to chance. There were also no significant differences in patient-reported improvement of symptoms in either group.

However the tests did confirm that stenting significantly relieved the narrowing in the coronary artery and improved the blood supply to the heart. This was puzzling as the researchers had expected that exercise capacity and symptoms would improve once the artery had been opened and the blood supply improved.

The researchers explain that they took high doses of medication before the procedure which may not be adhered to in the real-world setting. They also stress that the study group only contained patients with the single-vessel form of disease and that patients with multi-vessel form of disease may get more symptom relief from stenting.

More analysis is expected from the ORBITA trial as the researchers aim to delve deeper into the data to see whether there are subgroups of patients whose angina improves more after stenting.

"It seems that the link between opening a narrowing coronary artery and improving symptoms is not as simple as everyone had hoped," said Dr Al-Lamee. "This is the first trial of its kind and will help us to develop a greater understanding of stable angina, a disease which affects so many of our patients every day."

'Objective Randomised Blinded Investigation with optimal medical Therapy of Angioplasty in stable angina (ORBITA trial): a randomised double-blind trial' by Al-Lamee, R et al. is published in The Lancet.
-end-


Imperial College London

Related Heart Attack Articles:

Muscle protein abundant in the heart plays key role in blood clotting during heart attack
A prevalent heart protein known as cardiac myosin, which is released into the body when a person suffers a heart attack, can cause blood to thicken or clot--worsening damage to heart tissue, a new study shows.
New target identified for repairing the heart after heart attack
An immune cell is shown for the first time to be involved in creating the scar that repairs the heart after damage.
Heart cells respond to heart attack and increase the chance of survival
The heart of humans and mice does not completely recover after a heart attack.
A simple method to improve heart-attack repair using stem cell-derived heart muscle cells
The heart cannot regenerate muscle after a heart attack, and this can lead to lethal heart failure.
Mount Sinai discovers placental stem cells that can regenerate heart after heart attack
Study identifies new stem cell type that can significantly improve cardiac function.
Fixing a broken heart: Exploring new ways to heal damage after a heart attack
The days immediately following a heart attack are critical for survivors' longevity and long-term healing of tissue.
Heart patch could limit muscle damage in heart attack aftermath
Guided by computer simulations, an international team of researchers has developed an adhesive patch that can provide support for damaged heart tissue, potentially reducing the stretching of heart muscle that's common after a heart attack.
How the heart sends an SOS signal to bone marrow cells after a heart attack
Exosomes are key to the SOS signal that the heart muscle sends out after a heart attack.
Heart attack patients taken directly to heart centers have better long-term survival
Heart attack patients taken directly to heart centers for lifesaving treatment have better long-term survival than those transferred from another hospital, reports a large observational study presented today at Acute Cardiovascular Care 2019, a European Society of Cardiology congress.
Among heart attack survivors, drug reduces chances of second heart attack or stroke
In a clinical trial involving 18,924 patients from 57 countries who had suffered a recent heart attack or threatened heart attack, researchers at the University of Colorado Anschutz Medical Campus and fellow scientists around the world have found that the cholesterol-lowering drug alirocumab reduced the chance of having additional heart problems or stroke.
More Heart Attack News and Heart Attack Current Events

Trending Science News

Current Coronavirus (COVID-19) News

Top Science Podcasts

We have hand picked the top science podcasts of 2020.
Now Playing: TED Radio Hour

Making Amends
What makes a true apology? What does it mean to make amends for past mistakes? This hour, TED speakers explore how repairing the wrongs of the past is the first step toward healing for the future. Guests include historian and preservationist Brent Leggs, law professor Martha Minow, librarian Dawn Wacek, and playwright V (formerly Eve Ensler).
Now Playing: Science for the People

#565 The Great Wide Indoors
We're all spending a bit more time indoors this summer than we probably figured. But did you ever stop to think about why the places we live and work as designed the way they are? And how they could be designed better? We're talking with Emily Anthes about her new book "The Great Indoors: The Surprising Science of how Buildings Shape our Behavior, Health and Happiness".
Now Playing: Radiolab

The Third. A TED Talk.
Jad gives a TED talk about his life as a journalist and how Radiolab has evolved over the years. Here's how TED described it:How do you end a story? Host of Radiolab Jad Abumrad tells how his search for an answer led him home to the mountains of Tennessee, where he met an unexpected teacher: Dolly Parton.Jad Nicholas Abumrad is a Lebanese-American radio host, composer and producer. He is the founder of the syndicated public radio program Radiolab, which is broadcast on over 600 radio stations nationwide and is downloaded more than 120 million times a year as a podcast. He also created More Perfect, a podcast that tells the stories behind the Supreme Court's most famous decisions. And most recently, Dolly Parton's America, a nine-episode podcast exploring the life and times of the iconic country music star. Abumrad has received three Peabody Awards and was named a MacArthur Fellow in 2011.