The manner in which the news media covers medical innovations does an unintentional disservice to American health care by reinforcing the idea that newer approaches always represent real medical advances. The media lead the public to believe that amazing new cures for old disease are always on the horizon. This is done, understandably, to hook the readers' or listeners' attention but, in so doing, the news services perpetuate the erroneous belief that in medicine, "new" and "more" is always "better." Often, when the studies that are behind the headlines are closely analyzed, the coverage is misleading or just plain wrong.
A typical example is a news report carried by the AP wire service which recently appeared in my local newspaper with the headline, "Stroke study finds neck stents effective." The article reported the findings of a study which was presented at the American Stroke Association conference looking at the use of stents to reopen narrowed carotid artery. Stents are wire mesh supports that are expanded inside blood vessels so that their metal struts push against the vessels' inside lining. They can be inserted under local anesthesia, thereby avoiding many of the complications associated with surgery. Stents have been used for years with success to establish and maintain patency in partially occluded coronary arteries and it seemed reasonable that they might be similarly used for the carotid arteries.
This study compared inserting a stent to widen a narrowed carotid with the traditional, but more invasive, surgical way of cleaning out the artery, a carotid endarterectomy. The conclusion of this study was that the less invasive stenting was equally effective to the surgery and "if Medicare agrees to cover it, hundreds of Americans a year might be able to have an artery opening procedure and a stent instead of surgery to remove built-up plaque." The article makes stenting the carotid sound like an easy, safe, effective way to prevent strokes that could be of benefit to many Americans once funding becomes available. In fairness to the reporter, the article does mention, in an understated way, that not all other studies agree with this report's conclusions.
In fact, almost all other researchers who have compared stenting carotid arteries to a surgical endarterectomy have found surgery to be more effective. At the same time that this trial was reported, a metanalysis was published in the British Medical Journal comparing stenting to an endarterectomy. A metanalysis is a method of combining the data from multiple clinical trials so that the results can be statistically analyzed like a single, very large study, thereby yielding clinically valid conclusions. This metanalysis included results from 4,796 patients, far more than were included in the report at the American Stroke Association conference.
The BMJ article showed a clear short term benefit to endarterectomies over carotid stenting, trumping the results of the smaller report. Yet, the smaller study was the one with the wide wire service coverage, giving the public an inaccurate impression.
An even more important question that the newspaper report entirely ignored is how much benefit at all are endartectomies in preventing strokes in those with carotid artery narrowing Remember, the studies cited compare stents to surgery-not to medications or to no treatment at all. And the purpose of either intervention is to prevent the debris on the inner surface of the narrowed artery from breaking off and being carried down stream causing a stroke. Do endarterectomies really prevent strokes?
In order to determine the possible value of an endarterectomy in carotid artery narrowing, two clinical factors need to be considered: the degree of carotid obstruction and the presence of symptoms. For example, in patients with carotid blood flow less than 60 percent obstructed, there is a greater likelihood of developing a stroke in patients who have surgery than in those who are just treated medically! So surgery is contraindicated in that situation.
For people with greater than 80 percent blockage the benefit of surgery depends on the presence or absence of symptoms. These symptoms called transient ischemic attacks (TIAs) are small, short lived strokes in which a person has temporary neurological loss such as the loss of strength in an arm or leg or the inability to speak. The symptoms disappear in minutes to hours. For a person with a high-grade carotid blockage and TIA symptoms, about 10 patients need to receive a carotid endarterctomy to prevent a single stroke.
Although the benefits of surgery are not great, preventing one stroke in 10 people is still considered cost-effective and the surgery is worthwhile.For people who have high grade carotid obstruction without any TIA symptoms, the story is quite different. Over 200 carotid endarterectomies would need to be performed to prevent a single stroke. In people with high grade obstruction and no symptoms, surgery is no longer cost-effective since too many people would require a potentially dangerous and expensive procedure to prevent a single stroke.
So, when we cut through the hype, what should the newspaper article really have said? Probably something to the effect of "Carotid stenting is now being performed for carotid artery stenosis. It is probably not as effective as a surgical carotid endarterectomy, which, itself, should be restricted to people with severe carotid artery narrowing and symptoms of TIAs. In the vast majority of people who have a carotid procedure-those with narrowing and no symptoms-there is no convincing evidence that either surgery or stenting should be done."
The truth makes a far less appealing newspaper article than the account reported, but would provide a greater service to the American public in helping them understand what medicine can-and cannot-do. It might also be a small step at helping American medicine cut costs and improve quality.
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