We live in the age of acronym. To read a medical journal is sometimes like trying to decipher a code; once, when I was a judge in a competition of medical poetry, I read a poem composed entirely of figures and acronyms:
RTA [road traffic accident]
ETA [expected time of arrival] 13.20 hrs
CGS [Glasgow Coma Scale] 3…
The last line of the poem, inevitably, was:
Sometimes one has the impression that the acronym has been devised before the thing that it is attached to has been decided. In a recent paper in the New England Journal of Medicine, for example, I came across the acronym SWEDEHEART. It stood for the Swedish Web System for Enhancement and Development of Evidence-based Care in Heart Disease Evaluated According to Recommended Therapies. If the web system come before the acronym, however, you could see why the latter was necessary, the former being longer than the average tin-pot dictator’s list of honorific titles.
The paper in which the acronym occurred was yet another in which a common medical practice was shown to be valueless, or very nearly so. It turns out yet again that doctors do things not because they do the patients any good, but because they can do them.
The paper was a controlled trial of removal from the coronary artery by aspiration of the thrombus (blockage) that causes an acute heart attack. This is routinely performed before the insertion of a stent to allow the blood to flow again: for it is the interruption of that blood flow that cases the heart muscle to die.
It sounds like a good idea, mere common sense in fact, to remove the obstruction that causes the problem in the first place, especially when it is done within a short time of the development of symptoms. But while it sounds like a good idea, nobody had actually proven that it was.
A research team in Sweden, then, divided patients with acute heart attacks randomly into two groups as far as their treatment was concerned, one that received clot aspiration before its stent, and the other that received a stent alone.
There were 7244 patients who entered the trial, which is the first I have ever seen of such a size in which every single patient was followed up and not a single one lost. The Swedes are not known, perhaps, for their sense of fun, but they are certainly well-organized.
They compared the recurrence of blocked arteries and the death rate from heart attack and all other causes in the two groups, at three months and a year after the initial heart attack. What they found was that there was no statistically significant difference between the two groups. In other words (though the authors did not put it in quite so blunt or crude a manner), cardiologists had been wasting their time for years performing by the thousand a procedure of no benefit to the patients, all on the supposition that what they were doing must do good because it was mere common sense that it should.
However, I noticed one strange thing in the table of results, which broke down the 7244 patients into many subgroups. Although there was no statistically significant benefit to aspiration in the vast majority of the subgroups, nevertheless the death rate was slightly lower in almost all of them than for those who did not have an aspiration of their clot. Statistical significance does not prove that a difference is significant in any other sense, or even that it did not in fact arise by chance; likewise, statistically insignificant results may not be insignificant in any other way. There is thus a ray of hope, a get-out clause, for cardiologists in this paper, if not for their patients.