What you know isn't so - intuition, angioplasty, and colon cleansing

No matter what you're talking about, whatever you say is based upon an assumed body of knowledge. Sometimes our assumptions are wrong, and are challenged when we learn new stuff or re-learn old stuff. This is especially tough when you're talking about things that intuitively appear to be correct. However, our intuition is sometimes faulty, as BusinessWeek notes in discussing angioplasty.

Once hospitals have made big investments in the catheterization laboratories, where the procedures are done, they have every incentive to use them as much as possible. Plus, patients also have bought into the argument that clogged arteries should be propped open. "There is a huge demand from patients for quick dramatic fixes."...

But recent studies have cast doubt on this.

Several recent studies have found that angioplasty doesn't save lives or prevent heart attacks in patients with stable heart disease compared to treatment with drugs. And now, in a study presented at the American Diabetes Assn. meeting on June 7 (and published in the June 11 issue of The New England Journal of Medicine), the limitations of angioplasty are evident even when the procedures were performed on diabetics with heart disease. For those patients, "medical therapy [the use of drugs] rather than any intervention is an excellent first-line strategy," conclude Dr. William E. Boden of the State University of New York at Buffalo and Oxford University's Dr. David P. Taggart in an NEJM editorial.

But these studies have not only led people to question the procedure, but also some of the thoughts underlying the procedure - such as the whole idea of "clogged arteries":

Years ago, before angioplasty, one prominent idea was that heart attacks were not caused by gradually clogging arteries. Instead, the theory went, heart attacks occurred when unstable plaque in the artery suddenly ruptured, leading to dangerous or fatal clots. This idea lost favor once physicians had the ability to prop open or bypass those clogged arteries. Now the theory is coming back. And if unstable plaque is the real culprit, then drugs that reduce inflammation and clotting, including everything from ordinary aspirin to cholesterol-lowering statins from the likes of Pfizer (PFE), Merck (MRK), and AstraZeneca (AZN) make more medical sense than angioplasty does.

So this whole idea of clogged material within your body may be a bunch of B.S. (pending, of course, the next study).

Think about that the next time someone mentions colon cleansing to you. Note the snopes.com article on the topic that refutes claims that John Wayne and Elvis Presley had 40+ pounds of fecal matter in their colon when they died:

Anecdotes such as these are, in a word, crap.