HEART STENTS ARE USELESS, BUT STILL WIDELY USED
Most patients probably don’t need them — this is hard for patients and physicians to accept because in their experience, patients who got stents got better,
WHEN my children were little, if they complained about aches and pains, I’d sometimes rub some moisturiser on them and tell them the “cream” would help. It often did. The placebo effect is surprisingly effective.
Moisturiser is cheap, it has almost no side effects, and it got the job done. It was a perfect solution.
Other treatments also have a placebo effect, and make people feel better. Many of these are dangerous, though, and we have to weigh the downsides against that benefit.
Lots of Americans have chest pain because of a lack of blood and oxygen reaching the heart. This is known as angina. For decades, one of the most common ways to treat this was to insert a mesh tube known as a stent into arteries supplying the heart. The stents held the vessels open and increased blood flow to the heart, theoretically fixing the problem.
Cardiologists who inserted these stents found that their patients reported feeling better. They seemed to be healthier. Many believed that these stents prevented heart attacks and maybe even death. Percutaneous coronary intervention, the procedure by which a stent can be placed, became very common.
Then, in 2007, a randomised controlled trial was published in The New England Journal of Medicine. The main outcomes of interest were heart attacks and death. Researchers gathered almost 2,300 patients with significant coronary artery disease and proof of reduced blood flow to the heart. They assigned them randomly to a stent with medical therapy or to medical therapy alone.
They followed the patients for years. The result? The stents didn’t make a difference beyond medical treatment in preventing these bad outcomes.
The problem was that it was difficult to know whether the stents were leading to pain relief, or whether it was the placebo effect. The placebo effect is very strong with respect to procedures, after all. What was needed was a trial with a sham control, a procedure that left patients unclear whether they’d had a stent placed.
Many physicians opposed such a study. They argued that the vast experience of cardiologists showed that stents worked, and therefore randomising some patients not to receive them was unethical. Others argued that exposing patients to a sham procedure was also wrong because it left them subject to potential harm with no benefit. More sceptical observers might note that some doctors and hospitals were also financially rewarded for performing this procedure.
Regardless, such a trial was done, and the results were published this year.
Researchers gathered patients with severe coronary disease at five sites in Britain, and randomised them to one of two groups.
All were given medication according to a protocol for a period of time. Then, the first group of patients received a stent. In the second, patients were kept sedated for at least 15 minutes, but no stent was placed.
Six weeks later, all the patients were tested on a treadmill. Exercise tends to bring out pain in such patients, and monitoring them while they’re under stress is a common way to check for angina. At the time of testing, neither the patient nor the cardiologist knew whether a stent had been placed. And, based on the results, they couldn’t figure it out even after testing: There was no difference in the outcomes of interest between the intervention and placebo groups.
Stents didn’t appear even to relieve pain.
Some caveats: All the patients were treated rigorously with medication before getting their procedures, so many had improved significantly before getting (or not getting) a stent. Some patients in the real world won’t stick to the intensive medical therapies, so there may be a benefit from stents for those patients (we don’t know). The follow-up was only at six weeks, so longer-term outcomes aren’t known. These results also apply only to those with stable angina. There may be more of a place for stents in patients who are sicker, who have disease in more than one blood vessel, or who fail to respond to medical therapy.
But many, if not most patients, probably don’t need them. This is hard for patients and physicians to wrap their heads around because, in their experience, patients who got stents got better. They seemed to receive a benefit from the procedure. But that benefit appears to be because of the placebo effect, not any physical change from improved blood flow. The patients in the study felt better from a procedure in the same way that my children did when I rubbed moisturiser on them.
The difference is that while the moisturiser can’t really harm, stent placement can. Even in this study, two per cent of patients had a major bleeding event. Remember that hundreds of thousands of stents are placed every year. Stents are also expensive. They can add at least US$10,000 (RM39,300) to the cost of therapy.
Stents still have a place in care, but much less of one than we used to think. Yet, many physicians, as well as patients, will still demand them, pointing out that they lead to improvements in some people, even if that improvement is from a placebo effect.
Stents are probably not alone in this respect. It’s possible that many procedures aren’t better than shams. Although we would never approve a drug without knowing its benefits above a placebo, we don’t hold devices to the same standard. As Rita Redberg noted in The New England Journal of Medicine in 2014, only one per cent of approved medical devices are approved by a process that requires the submission of clinical data, and that data is almost always from one small trial with limited follow-up. Randomised controlled trials are very rare. The placebo effect is not.
Yet, many physicians, as well as patients, will still demand them, pointing out that they lead to improvements in some people, even if that improvement is from a placebo effect.