Have you ever wondered if there’s a natural way to lower your high blood pressure, guard against Alzheimer's, lose weight, and feel better? Well as it turns out there is. Michael Greger, M.D. FACLM, founder of NutritionFacts.org, and author of the instant New York Times bestseller “How Not to Die” celebrates evidence-based nutrition to add years to our life and life to our years.

Do Stents Work? Part 2

Are doctors killing or stroking out thousands of people a year for nothing? Here are some answers.

This episode features audio from The Risks of Heart Stents, Angioplasty Heart Stent Risks vs. Benefits, and Do Heart Stent Procedures Work for Angina Chest Pain?. Visit the video pages for all sources and doctor’s notes related to this podcast.


Did you ever wonder if the food you eat has a direct effect on your health, well-being – and longevity?  Well, I’m here to end that mystery.  You ARE the foods you eat.  Welcome to the Nutrition Facts podcast – I’m your host, Dr. Michael Greger.

Today – we have part two in our series on stents – for patients with coronary artery disease. And we start by asking – why are doctors killing or stroking out thousands of people a year for a procedure that offers little benefit? Here are some answers.

Millions of people have gotten stents for stable coronary artery disease, yet we now know that for such patients, angioplasty and stent placement doesn’t actually prevent heart attacks, doesn’t even offer long-term angina pain relief, and doesn’t improve survival. Why? Because the most dangerous plaques—the ones most vulnerable to rupture leading to a heart attack—are not the ones doctors put stents in, not the ones often even seen on angiogram to be obstructing blood flow. So “[w]e need to avoid the ’therapeutic illusion’ that we are accomplishing more than is shown by the evidence.” It looks great. You’re opening up blood flow. But if it doesn’t actually help, why do it?

And we’re not just talking about billions of dollars wasted. Stent placement and the blood-thinner drugs you have to go on can cause complications, including heart failure, stroke, and death. The risks are relatively low; less than a 1 percent chance it will kill you or stroke you out. The 15 percent risk of heart attack is only if your stent clogs off at a later date, which only happens in about 1 percent in the near-term. The 13 percent kidney injury is legit, though, due to the dyes they have to inject, but that typically just heals on its own. The most serious complications, like death, only happen in about 1 in 150 cases. But you have to multiply that by the fact that hundreds of thousands of the procedures are being done every year.

In an emergency setting, like while you’re actively having a heart attack, angioplasty can be lifesaving, but these hundreds of thousands are for stable coronary artery disease, for which there appears to be no benefit. So then, doctors are killing or stroking out thousands of people a year for nothing. And that’s not even counting the tens of thousands of silent mini-strokes that may contribute to cognitive decline caused by these procedures. Between 11 and 17 percent of people who go through angioplasty or stenting come away with new brain lesions. That’s like up to one in six.

How do doctors convince patients to sign up for these when they don’t lower the risk of death, or heart attack, or offer long-term symptom relief? Apparently by conveniently failing to inform their patients that they don’t lower the risk of death or heart attack, or offer long-term symptom relief.

Cardiologists are aware of how little they help, but studies have consistently demonstrated that patients think stents will reduce their risk of heart attack or death. More than 70 percent of patients erroneously believed that stents would extend their life expectancy or prevent future heart attacks. That’s why this study was done—to figure out where patients are getting these crazy ideas from. And the answer is that many patients are being kept in the dark, pressured into procedures that won’t benefit them the way they think, by doctors that overstate the benefits and understate the risks. Why would they do that? Well, one reason could be because doctors may be paid per procedure. Doctors are paid more for offering stents than common sense diet and lifestyle changes.

Patients with stable coronary disease undergoing angioplasty and stent placement are frequently misinformed. Of 59 recorded conversations, only two included all seven elements of informed decision-making—in other words, telling people they have a choice, explaining the problem, discussing alternatives and the pros and cons, informing patients the procedure may not work, asking if they understand, even just asking if patients have any questions, and asking patients what they want to do. Only 3 percent of doctor-patient discussions about stents hit even just these basic elements. And that’s when the doctors knew they were being recorded. So, if anything, this may be like the best-case scenario. Only 3 percent! Quoting from the Cleveland Clinic Journal of Medicine, when it comes to angioplasty and stents, “[t]rue informed consent rarely occurs.”

No wonder that among the nearly 1,000 patients surveyed across 10 U.S. academic and community hospitals, just 1 percent knew the truth. Remarkably, some blame the patients for their ignorance: they’re the ones that “overestimate or misunderstand the benefits … such as patients with cancer who believe [their chemo] offers the potential for cure—the ‘therapeutic misconception.’”

Don’t look at the patients to find out why so many patients are accepting procedures with questionable benefits. “Patients think they are having life-saving procedures because medical professionals want them to believe that this is so.” Now, it’s not like those 95 percent of cardiologists are lying to their patients and saying that it will reduce their risk. They just happened to conveniently have omitted that little detail. But in the absence of information to the contrary, most patients are going to naturally assume that’s the case.

Why would they just assume that? Because patients have this crazy concept of “personal care”—that a physician’s first obligation is solely to the patient’s well-being. How naïve can you get? And so, in the absence of information, or even when presented with evidence to the contrary, patients tend to believe that treatments offered will be beneficial.

It’s true, even if you explicitly tell patients that stents do not reduce the risk of heart attacks. Yes, you can cut that misperception in half. That’s great that with two sentences you can dispel the myth in most people. But many participants continued to believe that angioplasty and stents prevent heart attacks, even when explicitly told they do not, along with a detailed explanation why. After all, why would doctors be pushing them if they didn’t help? That’s a good question, which we’ll address next.

In our next story we look at what physicians and stent companies have to say for themselves, given that they are promoting expensive, risky procedures with no benefit.


Angioplasty and stent placement continue to be frequently performed for patients with non-emergency coronary artery disease, despite clear evidence that it provides minimal benefit. For example, it does not prevent heart attacks or death, yet as many as 9 out of 10 patients mistakenly believed that the procedure would reduce their chances of having a heart attack. But at the same time, the cardiologists weren’t stupid. Those who referred them for the stent and those who performed the procedure didn’t believe that. Okay, then why were they doing it? Focus groups of cardiologists have documented a chasm between knowledge and behavior. While aware of the evidence to the contrary, they recommend and perform PCI (angioplasty and stents), because they somehow believe that it helps in some ill-defined way. “[P]hysicians tended to justify a non-evidence-based approach (“I know the data shows there is no benefit, but”) by focusing on [how easy it is to do the procedure] and belief that an open artery was better” even if it didn’t actually affect outcomes, all the while minimizing the risks. I mean the procedure only kills 1 in 150. So, here some are blaming the patients for not listening, but maybe it’s the physicians who are the ones ignoring the evidence.

Or maybe physicians have too poor a grasp of the relevant statistics to adequately inform the patient? Regardless, what we’ve got here is a failure to communicate. So, tools have been developed. For example, a sample informed consent document that lays out the potential benefits and risks, even laying out how many procedures your doctors have done and your out-of-pocket costs. Note there are a lot of blanks to be filled in, though. What are some concrete numbers?

The Mayo Clinic came up with some prototype decision-making tools. In terms of benefits, will having a stent placed in my heart prevent heart attacks or death? No, stents will not lower the risk of heart attack or death, but a week later those getting stents report they feel better at least, though a year later even the symptomatic-relief benefit appears to disappear. Okay, so there appeared to be this temporary-relief-in-chest-pain benefit. What about the risks?

During the stent procedure, out of 100 people, two will have bleeding or damage to a blood vessel, and one will have a tad more serious complication such as heart attack, stroke, or death. And then, after that, during the first year after the stent, three will have a bleeding event because of the blood thinners you have to take because you have this foreign material in your heart, but that doesn’t always work, and so two will have their stent clog off leading to a heart attack.

What does the world’s #1 stent manufacturer have to say for itself? They acknowledge the evidence shows stents don’t make people live longer, but living longer is overrated. Look, if all we cared about was living longer, entire disciplines of medicine would disappear. Why go to the dentist? Of course, the difference is that 80 percent of people don’t believe that getting a cavity filled is going to save their life, like they mistakenly do for stents, and there isn’t a one in a hundred chance you won’t make it out of the dentist chair.

The stent companies actively misinform with ads like this. “Open your heart and your life.” “Life wide open.” “Freedom begins here.” Their TV ad mentioned a few side effects. Turns out they missed a few, but more importantly, they’re giving the false impression that stents are more than just expensive, risky band aids for temporary symptom relief. But what’s wrong with symptom relief? Look at those smiling faces. Even if the benefits are only symptomatic and don’t last long, if people think that outweighs the risk, what’s the problem?

What if I told you that even the symptom relief may just be an elaborate placebo effect, and you could get the same relief with a fake surgery; so, there really weren’t any benefits at all? We’ll see what the science says next.

Finally today, we look at how sham surgery trials prove that procedures like nonemergency stents offer no benefit for angina pain—only risk to millions of patients.


Angioplasty and stents for non-emergency coronary artery disease is one of the most common invasive procedures performed in the United States. Though it appeared to offer immediate relief of angina chest pain in stable patients with coronary artery disease, it didn’t actually translate into a lower risk of heart attack or death. This is because the atherosclerotic plaques that narrow blood flow tend not to be the ones that burst and kill you. But hey, symptom control is important—that’s much of what we do in medicine. But cardiology has a bad track record when it comes to performing procedures that don’t actually end up helping at all.

Case in point: internal mammary artery ligation. Though it didn’t make much anatomical sense, why tying off arteries to the chest wall and breast would somehow improve coronary artery circulation, it worked like a charm. Immediate improvement in 95 percent of hundreds of patients. Could it have been just some elaborate placebo effect, and they were cutting into people for nothing? There’s only one way to find out. You cut into people for nothing.

They randomized people to get the actual surgery or a fake surgery where they cut you open and get to the last step, but don’t actually tie off those arteries. And … the patients who underwent the fake surgery experienced the same relief. Check out the testimonials. “[I]mmediately, I felt better.” “ …95 percent better.” “No chest trouble even with exercise.” “ … I’m cured!” And these are all people who got the sham surgery. So, it was just an extravagant placebo effect. Think about it. Some frightened, poorly-informed man with angina chest pain, winding himself tighter and tighter, sensitizing himself to every twinge of chest discomfort, who then comes into the environment of a great medical center and a powerful, positive, paternalistic personality and hears how great it’s going to be, goes through the whole operation and leaves a new man with his trademark scar.

One sham patient was actually cured though. “The patient is optimistic and says he feels much better.” Office note the next day: Patient dropped dead. So, no more chest pain!

This has happened over and over. I’ve got an idea! How about we burn holes in the heart muscle with lasers to create channels for blood flow. Worked great, until it was proven that it doesn’t work at all. Cutting the nerves to your kidneys was heralded as a cure for hard-to-treat high blood pressure until sham surgery proved the procedure itself was a sham. The necessity for placebo-controlled trials has been rediscovered several times in cardiology, typically to considerable surprise. Before they are debunked, often the therapy is thought to be so beneficial that a placebo-controlled trial is deemed unnecessary and perhaps even unethical. That was the case with stents.

Hundreds of thousands of angioplasties and stents are done every year, yet placebo-controlled trials had never been done. Why? Because cardiologists were so unquestionably sure it worked that it would be unethical to perform a fake procedure to prove something we already know is true. When patients are aware that they have had a stent, they have a clear reduction in angina and improved quality of life. But what if they weren’t aware? Would it still work?

Enter the ORBITA trial. After all, anti-angina medication is only taken seriously if there is blinded evidence of symptom relief against a placebo pill; so, why not pit stents against a placebo procedure. In both groups, doctors threaded a catheter through the groin or wrist of the patient, and with X-ray guidance, went up to the blocked artery, and then either inserted a stent or just pulled the catheter back out.

They had problems even getting the study funded. They were told we already know the answer to this question—of course, stents work—and that’s even what the researchers themselves thought. They were interventional cardiologists themselves. They just wanted to prove it. Boy, were they surprised. Even in patients with severe coronary artery narrowing, angioplasty and stents did not increase exercise time more than the fake procedure.

“Unbelievable” read the New York Times headline, remarking that the results “stunned leading cardiologists by countering decades of clinical experience.” In response to the blowback, the researchers wrote that they sympathize with everyone’s shock and disbelief. Yes, we could have tried to spin it somehow, but they had a duty to preserve scientific integrity.

While some commended them for challenging the existing dogma around a procedure that has become so routine, ingrained, and profitable, others questioned their ethics. After all, four patients in the placebo group had complications from the guide wire insertion and required emergency measures to seal the tear they made in the artery. There were also three major bleeding events in the placebo group; so, they suffered risks without even a chance of benefit. But “[f]ar from demonstrating the risks of sham-controlled trials, this demonstrates exactly what patients are being subjected to on a routine basis” for nothing.

Those few complications in the trial are dwarfed by the thousands that have been killed or maimed by the procedure over the years. You want unethical? How about the fact that an invasive procedure has been performed on millions of people before it was ever actually put to the test? Maybe we should consider the absence, not the presence, of sham control trials to be the greater injustice.

When a former FDA commissioner was asked at the American Heart Association meeting whether sham controls should be required for the approval of all devices, he replied, “Do you want to get the truth or not?”

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