- The Basics on Heart Stent Surgery Safety
- Coronary angioplasty and stenting
- Performing coronary angioplasty
- Stent placement and drug-eluting stents
- Thousands of heart patients get stents that may do more harm than good
The Basics on Heart Stent Surgery Safety
When you have coronary heart disease, one or more of the arteries that supply your heart muscle with blood have narrowed, usually by plaque build-up. Treatments for coronary heart disease can vary depending on the severity of it; for some people, medications and lifestyle changes may be enough. But for some, surgery may be recommended to open the clogged arteries that supply blood to your heart. One such option is cardiac angioplasty.
In cardiac angioplasty, a tiny balloon on the end of a catheter threaded into the blocked coronary artery is inflated to stretch open the blockage. In about 70 to 80 percent of these procedures, a stent is then inserted to keep the blood vessel from closing up again. Think of a heart stent as a permanent wire mesh scaffold put in place to prop open the heart’s artery.
For many people, a heart stent is the right solution for this serious heart condition. “The main symptom of decreased blood supply caused by a blocked coronary artery is the chest pain that doctors call angina,” says Thomas C. Piemonte, MD, an interventional cardiologist at the Lahey Clinic in Burlington, Mass. If you have unstable angina, which means you have unpredictable chest pain that is not well-controlled, heart stent surgery may be the best treatment for you.
If you have a sudden onset of severe chest pain caused by a heart attack, an emergency angioplasty with heart stent surgery may save your life.
Success Rate of Heart Stent Surgery
Studies show that if you have only an angioplasty without heart stent surgery, there is about a 35 to 40 percent chance that your artery will close up again within six months. This closing-up process is called restenosis. If you have heart stent surgery at the time of your angioplasty, your restenosis rate drops down to about 20 percent.
The use of stents that are coated with medicine to prevent restenosis, called drug-eluting stents, may make heart stent surgery even more effective. “The advantage of drug-eluting stents is that they reduce the need to return because of restenosis by more than half,” says Dr. Piemonte.
A recent study published in the New England Journal of Medicine found that the restenosis rate for drug-eluting stents was 10 percent after 13 months, compared to 22.9 percent for bare-metal (or coated) stents.
Heart Stent Surgery Safety Numbers
The actual angioplasty and heart stent surgery procedure is very safe, with a mortality rate below one percent. “Besides the risk of the actual surgery, you also need to take into consideration the risk of bleeding after surgery,” notes Piemonte. “You will need to be on aspirin for the rest of your life and on another blood-thinning medication for a year or longer.”
Experiencing a blood clot in your stent after heart stent surgery is dangerous and may cause a heart attack — this type of clot-induced heart attack can be fatal in about 30 to 60 percent of cases. That’s why you must follow all of your doctor’s instructions concerning aspirin and blood-thinning medication after heart stent surgery.
Here are revealing statistics on heart stent surgery safety:
- Drug-eluting stents cut back on restenosis, but may carry an increased risk of blockage from a blood clot. A Duke University study found that there was a 1 in 40 chance of forming a blood clot in a drug-eluting stent when people were on blood-thinning medicine, but a 1 in 20 chance for people who stopped taking blood-thinning medicine after six months.
- Another study found the chance of being alive after drug-eluting heart stent surgery is about 99 percent after one year.
- One study found that the risk of developing a serious bleeding problem, while on blood-thinning medication and aspirin after heart stent surgery, is about 3 percent over an 18 month period. Another study found the risk of moderate or severe bleeding was about 3.8 percent over 28 months while the same risk for people on low-dose aspirin therapy alone drops to about 2.6 percent.
- According to an American Heart Association report, heart stent surgery is as safe and effective for patients over age 70 as for younger coronary heart disease patients. Older patients treated with drug-eluting stents had a 54 percent lower need for repeat treatments than those treated with bare-metal stents.
“For the right patient, angioplasty with heart stent surgery can be the best treatment. The most important thing is to find a doctor you can work closely with and have faith in,” says Piemonte.
Coronary angioplasty and stenting
Often used in combination, coronary angioplasty and stenting are leading therapies for coronary artery disease (also called heart disease). In coronary artery disease, blood supply to the heart is obstructed by plaque — a waxy substance consisting of fats, cholesterol, calcium and fibrin, a blood-clotting protein. An oxygen-starved heart can lead to chest pain (called angina pectoris) or, in time, heart attack.
Coronary angioplasty (also called balloon angioplasty, percutaneous coronary intervention and percutaneous transluminal coronary angioplasty), is performed to re-open arteries narrowed by coronary artery disease with a small, catheter-guided balloon. To keep the artery open, a wire mesh tube called a stent is inserted into the formerly blocked area.
At HonorHealth, coronary angioplasty is typically performed by an interventional cardiologist in a cardiac catheterization lab. Interventional cardiology is a specialized branch of cardiology that relates specifically to catheter-based treatment. A catheter is a tube inserted into the body.
This nonsurgical procedure can be performed during a diagnostic cardiac catheterization procedure — as blockage is identified, especially in emergency situations — or be scheduled for a future date.
Performing coronary angioplasty
Traditionally, doctors have performed balloon angioplasty by guiding the catheter along the femoral artery, which runs from the groin to the heart. However, cardiologists recently discovered the benefits of inserting the catheter into the radial artery in the wrist or arm with a small incision, leaving a minimal scar.
Before inserting the catheter, a thin tube (sheath) is inserted first. Next, a longer and thinner tube (catheter) is slid into the sheath. With the help of high-resolution imagery projected on a video monitor, the catheter is guided through the body to the site of the blockage.
The doctor may then perform a coronary angiogram, an imaging procedure that uses a harmless contrast dye to measure the size and location of the blockage.
A tiny balloon is then passed through the catheter and guided to the narrowed area. Finally, a needle penetrates the blockage and the balloon is expanded, pushing plaque out of the way and restoring blood flow.
Stent placement and drug-eluting stents
In most cases, angioplasty is followed by the insertion of a stent — a collapsed, wire mesh tube that is expanded by the balloon. Much like reinforcement for a tunnel, the stent will keep the artery open, restoring blood flow to the heart.
Stent placements also are used commonly in other parts of the body to open the carotid arteries of the neck and peripheral arteries in the legs.
Some stents gradually release medications over time to prevent the growth of scar tissue around the stent. These drug-eluting stents maintain the smoothness of the artery, reducing risk of restenosis when the artery becomes blocked again.
Serious complications of coronary angioplasty — which include bleeding from the blood vessel where the catheter is inserted, as well as blood vessel damage caused by the catheter — are infrequent. Risks of complications are higher in persons aged 75 or older, persons who have kidney disease or diabetes, women, patients with poor blood-pumping function in their hearts, and patients with extensive heart disease.
While the success rate for coronary angioplasty is high, approximately 30 percent of patients will experience restenosis — re-closing of the artery, often due to scar tissue around the stent — and require another angioplasty procedure. Typically detected within six months after balloon angioplasty, restenosis is more common when a stent is not placed in the blocked artery.
You’ll typically be discharged from the hospital on the day after your angioplasty. You may return to normal daily activities and work within one or two days of returning home. To allow the coronary artery, as well as the catheterized artery, time to heal, you shouldn’t lift heavy objects or over-exert yourself for two weeks following the procedure.
Thousands of heart patients get stents that may do more harm than good
There’s an epidemic of unnecessary medical treatments, as David Epstein of ProPublica recently documented in a terrific investigation: Doctors routinely perform procedures that aren’t based on high-quality research, or even in spite of evidence that contradicts their use.
One of the prime examples of a dubious treatment that Epstein and others have pointed to is cardiologists putting little mesh tubes called stents in patients with stable angina — chest pain caused by clogged coronary arteries that arises only with physical exertion or emotional stress.
Doctors insert the devices into narrowed or blocked arteries to pop them open, helping blood flow to the heart again. The idea is that stents should help soothe the suffering of patients with angina (or chest pain) and drive down the risk of a heart attack and death in the future.
But studies show that stable angina can be well controlled with medication. And researchers have found that stenting chest pain patients doesn’t help them live longer or reduce their risk of disease — in fact, heart attacks and strokes can be potentially deadly side effects of stent procedures. There’s also been a lingering question about whether stents truly work to relieve pain.
Now, researchers from the United Kingdom have published a high-quality study in the Lancet that helps answer the pain question. Building on years of lower-quality evidence, the well-designed study suggests stents may in fact be useless for pain in people with stable angina who are being treated with medication.
“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 Rasha Al-Lamee, lead author of the study and a researcher at the National Heart and Lung Institute at Imperial College London, in a statement. This doesn’t mean stents should never be used in stable chest pain patients — some patients can’t take the medications that control angina, for example — but doctors may want to consider inserting these devices as a last resort.
Considering 500,000 patients get stents for stable angina each year in the US and Europe alone, and the devices can cost up to $67,000, depending on the hospital and a patient’s insurance coverage, the Lancet paper is poised to shake up cardiology, as the New York Times reported.
The trial is also important for another big reason: It raises critical questions about the quality of evidence doctors rely on to make life-and-death decisions for their patients.
The controversy over stents for patients with stable chest pain
Over the years, studies have been piling up that suggest stenting stable angina patients may not actually be all that helpful.
A decade ago, researchers published a study in the New England Journal of Medicine showing that stents did not improve patients’ mortality risk or cardiovascular disease outcomes. Since then, meta-analyses of randomized controlled trials on stents in stable angina patients have similarly found the devices don’t outperform more conservative medical therapies (such as medication) when it comes to preventing heart attacks or extending patients’ life expectancy in the long term.
There was still a question about using stents in stable patients, whether the devices could relieve chest pain in the shorter term. Data from low-quality studies suggested this was possible.
The only way to resolve the question would be to perform a double-blind “sham control” study of stents: giving half of the patients a fake stent and the other half a real stent, with both doctors and patients unaware of (or “blinded” to) which procedure they were involved with. Since we know medical procedures can produce a strong placebo effect, this kind of study could tease out whether it was the stent that was reducing patients’ pain or a placebo effect produced by the operation.
But no one had ever done a double-blind sham-control study — the gold standard of evidence for medical device studies — on stents in stable chest pain patients, until this new Lancet paper.
How researchers used a fake operation to test whether stenting works
The authors of the Lancet paper enrolled 230 patients with stable angina and at least one narrowed coronary vessel. For six weeks, they made sure the patients were getting the best medical treatment for angina, like beta blockers or long-acting nitroglycerine.
What came next rarely happens in medical device trials (and it’s why cardiologists are applauding this study): They gave half the patients a sham stent. So after the six-week startup phase, where patients were stabilized with medications, 195 of them were randomly assigned to get either a stent in their clogged artery or a sham stent procedure. The study was double-blinded — again, the patients and doctors didn’t know which procedure they were involved in — to reduce the risk of bias.
The doctors then followed up with their patients after another six weeks. The main outcome they were interested in was how much time each group could spend exercising on a treadmill, since angina often acts up with exertion. (They also looked at other secondary endpoints, such as changes in oxygen uptake and the severity of chest pain.) By the end of the study, the researchers found there were no clinically important differences between the real stent group and the sham stent group.
So actual stents didn’t outperform the placebo stents. “It’s just like a sugar pill,” said University of California San Francisco cardiologist Rita Redberg. “We know sugar pills make a lot of people feel better — though sugar procedures make even more people feel even better.”
Here’s the most disturbing part: One in 50 stent patients will experience serious complications — such as a heart attack, stroke, bleeding, or even death. So these devices don’t come without risks, and this Lancet paper again suggests they may not be helping patients.
“This should make us take a step back and ask questions about what we are accomplishing for this procedure,” said Yale cardiologist Harlan Krumholz.
David Brown, a Washington University School of Medicine cardiologist who has been studying the effects of stents for a decade, said he wasn’t surprised by the findings.
“ is based on a simplistic 20th-century conceptualization of the disease,” he said. “It’s like the artery is a clogged pipe and if you relieve those blockages, the water will flow freely.” But this study suggests most patients’ pain symptoms may actually be coming from disease in their smaller blood vessels, not from blockages in the large coronary vessels that are always the targets for stents, he added.
In an editorial that accompanied the Lancet paper, Brown and Redberg wrote that medical guidelines need to change so that stenting for stable angina is only recommended as a last resort. “Patients should also be told that sham controlled trials don’t show any benefit,” Brown added.
This study speaks to a much bigger problem with medical evidence
The study represents the best available evidence on the impact of stenting for pain in stable angina patients — and could eventually avert unnecessary, costly procedures in the future. But the study is also important for what it says about the quality of medical evidence doctors often rely on to make decisions.
“This is a great example of a device that got on the market without ever having a high-quality trial behind it,” Redberg says. “For 40 years, we have been doing this procedure without any evidence that it’s better than a sham procedure.”
Right now, medical devices are less rigorously regulated than drugs: Only 1 percent of medical devices get FDA approval with high-quality clinical trials behind them. Even in these cases, devices typically reach the market based on data from a single small, short-term trial, Redberg wrote in a 2014 editorial in the New England Journal of Medicine, where she called for a sham control study of stents.
The new Lancet study demonstrates why this kind of investigation is so critical in medicine. “The results of ORBITA show (once again) why regulatory agencies, the medical profession, and the public must demand high-quality studies before the approval and adoption of new therapies,” Redberg and Brown wrote in their recent editorial. Right now this isn’t happening. And stents surely aren’t the only device patients may be getting that are more placebo than proven, and have potentially deadly side effects.