Cochrane Consumer Learning

Why Do We Need Evidence for Users of Healthcare?

Examples:

The Vascular Graft Story
The Stent Story from the Media
Doctors' 'Treat the Numbers' Approach Challenged

Vascular graft story

“I’ve been trying out these new blood vessel grafts recently” - a story written by a surgical resident (trainee) in a big teaching hospital

My beeper went off again. “Code Blue, Ward 17, Code Blue, Ward 17”. I got up and ran.

Ward 17 was the vascular ward. Mrs Latitia Monty had had a vein graft to her groin to bridge the gap between a blocked femoral artery and the rest of her leg circulation. This had been done a week ago and Latitia was to be discharged later today. Five minutes ago, her vein graft had disintegrated and her femoral artery was emptying its contents of high-pressured blood into her groin. The metal clips that held her skin together were giving way and Latitia Monty had now become a monstrous fountain of gushing blood spurting up to the ceiling.

I walked in to see the nurse placing towels around the groin. “Put some pressure on the groin, I called out. The nurse looked at me, startled. Mrs Latitia Monty was amazingly calm. I reached across and put my bare palm on the bleeding. Blood was oozing between my fingers, but it slowed the gushing.

“Call theatre and tell them we need to come up. Call the anaesthetic registrar. Who is the consultant? Call the blood bank and tell them we need some blood. Is there any already cross-matched? Get me the night intern.” This lady could die in the next three minutes if her bleeding were left unchecked.

The challenge was to transport her to theatre with me hanging on to her groin. The only way was for me to jump up on the trolley and straddle her while the whole bed was wheeled to theatre.

Finally, we all made it up to the theatre and into an operating room. The anaesthetic registrar was standing by. She injected her drugs. Latitia was now pain-free, soundly asleep. The registrar intubated her and started the ventilation.

Dr Smith, the vascular surgeon, arrived on the scene….He went into the scrub bay. Smith walked back in. He called out for a vascular clamp. “Okay, let go slowly,” he called to me, clamp in hand. I slowly removed the pressure. The gushing blood hit me square in the face. As I got off the trolley, he tore open the wound with clip removers and was about to apply the vascular clamp. Blood arrived from the blood bank and the anaesthetist hung up the first bag.

“We have it!” Smith shouted

I washed my face, scrubbed and came back in for the four-hour procedure to reconstruct Latitia’s groin and her leg circulation.

“I’ve been trying out these new grafts recently but I don’t think it’s an effective technique,” Smith said, as he put the last stitch into the new Gore-Tex graft.

Source: Making the Cut: A Surgeon’s Stories of Life on the Edge. Chapter 5, pp 63-65. Mohamed Khadra 2007. Random House Australia.

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The Stent Story - from the Media

About different kinds of heart stents:
Stents are metal mesh tubes that keep arteries open after doctors have cleared clogged vessels with tiny inflatable balloons.
Scar tissue can grow around where the stent is imbedded in the blood vessel wall (artery) and can block the artery. To suppress growth of scar tissue, medical device companies started coating stents with drugs used to suppress the immune system or prevent cell growth (division).

Stents Raise Death Risk for Heart Attack Patients
Bloomberg (September 4, 2007)
Drug-coated stents were linked to a higher death rate when given to some heart attack patients in a study
- a finding that may limit doctors' use of the tiny mesh tubes to prop open arteries.

People who had a serious type of heart attack died at more than four times the rate when they received a drug-coated device compared to patients who had received an older, bare-metal stent.

http://www.bloomberg.com/apps/news?pid=20601202&sid=aXPjEzTQZJ9s&refer=healthcare

From Health behaviour News Digest Center for the Advancement of Health (www.cfah.org#digest) (Accessed 2007)

In more detail – the problem is the type of heart attack

The study examined the subset of patients with heart attacks that can be identified in an electrocardiogram, a pattern of the electrical activity that precedes heart muscle contractions

Sept. 4 (Bloomberg) -- Drug-coated stents were linked to a higher death rate when given to people with a certain type of heart attack in a study, a finding that may limit doctors' use of the tiny mesh tubes to prop open arteries.

The heart attack patients died at more than four times the rate when they received a drug-coated device compared with patients who had received an older, bare-metal stent, researchers led by Philippe Gabriel Steg said today at the European Society of Cardiology meeting in Vienna. These patients should no longer be given drug-eluting stents, Steg said.

``This data is serious,'' Eckhart Fleck, the doctor who runs Germany's largest catheterization laboratory in Berlin, said in an interview. ``This will lead to more concrete indications for drug-eluting stents. Not everybody needs to have one.''

Steg's study, part of a larger trial dubbed Grace, followed almost 2,400 heart attack patients for the two years after they had received either a bare-metal or a drug-coated stent. The death rate among drug-coated stent patients was 4.7 times higher when compared to those that had received bare-metal stents, Steg said. After some statistical adjustments, the risk was about six times higher for heart attack patients.

Heart attack patients may be especially vulnerable because the narrowing of blood vessels in response to the heart attack can lead to the wrong size and placement of the stent, producing a gap in which clots can form.

The study examined the subset of patients with heart attacks that can be identified in an electrocardiogram. Other heart attack patients did not have an elevated risk of death.

The research is a type of observational study known as a registry

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Doctors' 'Treat the Numbers' Approach Challenged

It can take scientists a decade or more to determine whether a drug actually works. In the meantime, doctors rely on other measures, like testing blood pressure and cholesterol levels, to determine whether a drug is having positive effects. But recent studies challenge the practice of prescribing medicine based on certain test results.
http://tinyurl.com/3cvmqh

Excerpts from: YOUR HEALTH by Richard Knox (Morning Edition, March 20, 2008)

Doctors call it "treating the numbers" - trying to get a patient's test results to a certain target, which they assume will treat - or prevent - disease.

i. Earlier this year, a study on a widely used cholesterol drug challenged that assumption.
Vytorin, a combination of two cholesterol-lowering agents, certainly lowers cholesterol. But patients taking it didn't have any less plaque in a major artery than those taking a less-potent drug. When the results came out, Dr. Steve Atlas of Massachusetts General Hospital began getting calls from his patients - and his mom......

Ellen Atlas is a tennis-playing 75-year-old who has been taking Zetia — one of the cholesterol-lowering ingredients in Vytorin — because regular statin drugs caused muscle pain, a common side effect. Zetia reduced her cholesterol very nicely. But she wanted to know whether it was doing her any good.

"It was like, wow! I'm treating the number and I'm not going to necessarily prevent the stroke that her mother had? All of a sudden, it was like, 'I don't want to take this medicine!' "
Steve Atlas was brought up short by the surprising cholesterol results.
"It's a big deal because it reminds us of something that we often forget: the number isn't the outcome. And this raises concerns that just lowering the number doesn't get you where you want to be," he says.

During a phone call, Steve Atlas tells his mother, "I obviously hope that your numbers are better with the lifestyle changes [improved her diet and increased her exercise] that you've been making, because that'd be great. But if they're still high, then starting sort of like a baby dose, a really low dose ..." Mother and son hope a low dose of a tried-and-true statin will get her close to the right cholesterol number – without the side effects she suffered before.

2. Dr. Ned Calonge, chairman of a national task force that assesses what works and what doesn't in preventive medicine, says.... the recent study challenges the goal of getting Americans' cholesterol lower and lower.
"Now, what's open is — is lower better? And I think a lot of people believed it would be, and there are many of us that were saying, You're going to need to show me," he says.
Lately, studies have also challenged other cherished assumptions — like lowering blood sugar. For a long time, doctors have believed that getting diabetic patients' blood sugar as close to normal as possible would prevent heart attacks. A drug called Avandia [rosglitazone] lowers blood sugar very well.
It was approved in 1999 and was heralded as "one of the newer and greater drugs for the treatment of diabetes," says Dr. Cliff Rosen. Rosen is the chairman of a Food and Drug Administration advisory panel that concluded unanimously last year that patients taking Avandia actually had more heart attacks and strokes.
Rosen says the Avandia story is a caution against treating millions of patients on unproven assumptions.
Normalizing blood sugar probably does prevent heart disease for patients with Type 1 diabetes. But it's unproven for the far more common Type 2.

"It's not clear yet — even now, even after all these years — that in Type 2 diabetes, keeping your blood sugar at a certain point will prevent heart disease," Rosen says.

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