SECOND OPINION | To stent or not to stent for chest pain?

The debate over a common heart procedure flares up yet again, new research explores the effect of space travel on astronauts' brains and a reminder that the bubonic plague lives on.

Also, the bubonic plague is still out there

Stents have been a go-to tool for cardiac specialists trying to relieve chest pain for their patients. But a new study raises a question that's been asked before: are they really effective? (Lightspring/Shutterstock)

Here's this week's round-up of eclectic and under-the-radar health and medical science news. ​If you haven't subscribed yet, you can do that by clicking here.

"'Unbelievable': Heart stents fail to ease chest pain" was the sensational headline in the New York Times on Thursday, sparking a heated debate among doctors about their go-to treatment for angina — pain in the chest caused by blocked arteries.

The safety of stents was not challenged. They're still considered to be quite safe. But do they work any better than drugs to relieve chest pain? Maybe not.

The study published in The Lancet found that three different interventions — drugs, stenting, and even a sham procedure tricking people into thinking they had a stent — all had patients reporting improvements in their chest pain.

Almost immediately, experts started pointing out weaknesses in the methodology — the study was short, just six weeks, and small, with just 200 patients.

It was the sound of a medical doctrine being challenged once again.

"Through my training as a cardiologist this has been dogma," said Dr. Sacha Bhatia, a cardiologist at Women's College Research Institute in Toronto. "If an artery is blocked we should open it because that's going to improve blood flow to the muscle and improve patient outcomes and improve symptoms."

He stresses this debate is not about people who are having heart attacks or have unstable disease. But, for patients with stable conditions who want relief from chest pains, the new study will make some cardiologists think twice.

Normally if a patient shows up with a blocked artery and chest pain, Bhatia would recommend putting in a wire mesh stent to open up the blood vessel and improve the blood flow.

It's not a one size fits all approach anymore.— Dr. Sacha Bhatia, cardiologist

"Now we might pause and take the patient off the table and have a discussion with the patient," he said. "Try pills first to see if symptoms will go away and if you can tolerate the medication. We can say that both options will provide similar pain relief."

The patient would then have to weigh the risks of the stent procedure versus the side-effects of pills.

And because the new study used a sham procedure on some patients, tricking them into thinking they'd had a stent, it raised the disturbing question of placebo effect. How much of the pain relief from stents is due to the mysterious tendency for patients to feel better just by believing they've been treated?

An accompanying commentary in The Lancet said the study highlights the need for rigorous testing of all surgical procedures before they're widely adopted.

But what does this mean for people who go to their cardiologist for treatment of angina pain? Those patients now have a choice, Bhatia said.

"The options are not so straightforward anymore as 'I've got angina and I need to get a stent.' It's not a one-size-fits-all approach anymore."

It's not the first time the widespread use of stents has been questioned. Back in 2007 a major study made front-page news when it showed no difference between stents and drugs in preventing death from heart attacks.

Since then, several cardiology associations have narrowed their recommendations about when to use the stenting procedure, known as percutaneous coronary intervention (PCI).  

Space travel could cause more than headaches

A new study by the Medical University of South Carolina suggests long periods of time in space can affect the brains of astronauts.

For the study, published in the New England Journal of Medicine, participants stayed in bed for 90 days with their heads tilted in a downward position to simulate the effects of microgravity.

Neuroradiologist Dr. Donna Roberts used MRIs to examine their brains and muscular responses before, during and after the period of bed rest.

She found "crowding" at the top and back of the brain, in which the bumps and depressions in the brain narrowed. The crowding was more pronounced during longer periods of bed rest.

NASA astronaut Sunita Williams raises her hand during a mission in space. Researchers are trying to better understand the effects of staying in space for long periods of time on the brain. (NASA via Getty Images)

Roberts then got scans of astronauts from NASA and saw similar narrowing and shifting in the brains of many of those who had been in long-duration space missions.  

During extended periods of time without gravity, fluids in the body shift toward the head, explained Lauren Sergio, a professor at the School of Kinesiology and Health Science at Toronto's York University. She was not affiliated with the study.  

Sergio said on Earth, gravity "pulls things down to our toes," but in space things move more freely. Without gravity to hold down the brain and its fluids, it gathers at the top and back, creating pressure on parts of the brain that control vision, spatial awareness and hand-eye co-ordination.

She uses the analogy of being in a skiing accident and bumping your head, with internal bleeding putting pressure on the brain.

But that said, "the human body is really good at adapting," Sergio noted.  

Many astronauts — including Scott Kelly, who spent 340 days in space — have complained about vision problems upon return to Earth.

More research is needed to determine whether the changes in the brain stabilize or progress, the study notes. Increased understanding of how the human body, including the brain, is affected by long-term space travel is especially relevant as scientists work toward the possibility of a journey to Mars, which could take up to six months.   

The bubonic plague? It's still out there

Health workers in Madagascar are fighting an outbreak of the plague. The large island nation off the southeast coast of Africa actually deals with a "plague season" between September and April every year, but the outbreak is grabbing headlines because there are an unusually high number of confirmed or suspected cases — about 1,800, according to the latest World Health Organization (WHO) estimates.

[The plague] has existed in nature for millennia and it will continue to exist in nature.— Dr. Isaac Bogoch, infectious disease specialist

The fact the plague still exists catches some people by surprise, says Dr. Isaac Bogoch, an infectious disease specialist at Toronto General Hospital.

"When we think about the plague, we think about the 1300s when, you know, a half of Europe died," Bogoch said. "[But] it exists in nature and it has existed in nature for millennia and it will continue to exist in nature."

The plague is an infection caused by bacteria, called Yersina pestis, spread between rats and other rodents through flea bites. It's rare for humans to contract the plague, Bogoch said, because they would have to be in close contact with rodents to be bitten by a flea carrying the infection. In that case, they would likely get bubonic plague, which causes swelling of the lymph nodes.

A girl wears a face mask inside a hospital in Madagascar's capital, Antananarivo, in October, as health workers battle an outbreak of the plague. Though it can be deadly if left untreated, the plague is a bacterial infection that can be easily treated with antibiotics. (Alexander Joe/Associated Press)

But if the infection spreads into someone's lungs, it can transform into pneumonic plague — and then it can be transmitted to another person through coughing.

It's an extremely serious disease that can kill you if left untreated, Bogoch said.  But the good news is that doesn't have to happen because it's easily cured with common antibiotics. That — in addition to improved hygiene and sanitation over the past several centuries — is why we don't often see plague move from its natural habitat among rodents to humans.

The challenge in Madagascar and other countries with less developed health-care and public health systems, Bogoch said, is to make sure people get tested during a plague outbreak and that they have access to the necessary antibiotics.  That's why the WHO has stepped in to help with the increased number of cases this year — although no one knows exactly what caused the rise, he said.   

Last summer, the bacteria that causes the plague was actually found in a Saskatchewan prairie dog. The risk to humans was very low — in fact, the last recorded case of the plague in Canada was in 1939.

Eat all the saturated fat you want, grizzly bears

Humans have long wrestled with the pros and cons of saturated fats, but grizzly bears don't seem to have that problem — at least in the short-term, according to a new study published in the Canadian Journal of Zoology.

Researchers from Washington State University fed two groups of captive grizzlies a different diet — one high in "healthy" polyunsaturated fats (oats and salmon) and the other high in saturated fats (beef and cheese) — during a single feeding season before they hibernated.

Unlike bears, we don't hibernate.— Russell de Souza, nutrition epidemiologist

The authors wanted to track the effects that human food — often processed foods high in saturated fat — would have on grizzly bears foraging through garbage near campgrounds and cottages.

After waking up from hibernation, researchers found that bears fed the saturated fat diet had relatively the same cholesterol and insulin levels as the other group.

Furthermore, the study said grizzlies can consume saturated fats at levels that could be associated with risk of Type 2 diabetes and heart disease in humans.

Although these grizzly bears got their feast handed to them at a zoo in La Fleche, France, grizzly bears in the wild often forage through garbage near campgrounds and cottages. New research shows that saturated fats don't have the same health consequences for bears as they do for humans. (Jean-Francois Monier/AFP/Getty Images)

"The animals remained relatively resistant to developing metabolic derangements or severe clinical disease in a time frame when such anomalies would be expected to occur in humans," the study said.

Still, researchers found evidence of mild inflammation and heart strain in the bears fed the saturated fat diet. The study warns "human refuse or bears residing in captive facilities could potentially be more negatively affected over a longer term by similar diets."

So, is there a secret to processing saturated fats that humans can learn from grizzlies? Not according to Russell de Souza, a nutrition epidemiologist at McMaster University's Faculty of Health Sciences.

"Like bears, humans are omnivores and have adapted to survive," he said of saturated fats, commonly found in animal products.

"But unlike bears, we don't hibernate."

Grizzlies "have evolved mechanisms to tolerate obesity" — up to 40 per cent body fat — to help them get through hibernation, the study said. But in humans, that 40 per cent body fat would make them overweight and put them at risk of health problems, said de Souza

So how can humans enjoy saturated fats and maintain the relative health of a grizzly bear?

You've heard the answer before — and it doesn't involve sleeping through the winter.  

"Lots of exercise," de Souza said.

Thanks for reading! You can email us any time with your thoughts or ideas for us to include. And if you like what you read, consider forwarding this to a friend.