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November 16, 2006

Modern Day Leeches

Just to freak folks out a bit, angioplasties and stents -- two canonical treatments for blocked arteries -- are rapidly being proven worthless. Not totally worthless in every case, but given their frequency, pretty damn worthless. A similar thing, incidentally, is happening to bypass surgeries, which don't exhibit anything near an efficacy justifying their ubiquity.

Libertarian response: If consumers had more "skin in the game" (and by skin we don't mean actual skin, which is already "in the game," but more financial vulnerability), they'd demand more comparative studies and begin weeding out such ineffective treatments.

Paternalistic liberal response: It's been so hard to conduct studies on these treatments precisely because desperate patients adore their promise and doctors know they'd be considered monsters if they put unsuspecting individuals in a "control group" that was denied a treatment that soon proved effective. Patients are terrible at evaluating care -- look at the holistic health industry, and the limitless range of unproven supplements and treatments -- and skin in the game will always be overwhelmed by lives-on-the-line. On the other hand, if doctors lacked their current incentives for providing such intensive medical procedures, we could begin to make a dent.

Bipartisan response: In 100 years, a good half of our medical treatments will look to our descendants like leeches look to us.

Update response: And yes, leeches are back in use in very limited contexts. Much as the research shows angioplasties should be.

November 16, 2006 in Health and Medicine | Permalink


Those libertarians and bipartisans are pretty sharp.

Posted by: ostap | Nov 16, 2006 11:06:54 AM

Leeches actually have been shown to be pretty useful for a variety of ailments. (There was a recent piece in the New Yorker about them)

Posted by: xavier | Nov 16, 2006 11:08:08 AM

Of course, we're using leeches (and maggots) again in some medical treatments.

Posted by: Thud | Nov 16, 2006 11:08:41 AM

I too was coming in here to telling you to stop the hating on our friends the leeches. Bloodletting, say, genuinely seems to have been misconceived.

Posted by: Allen Knutson | Nov 16, 2006 11:10:43 AM

Hey, don't pick on the leeches! (see further below for comment on the NYT article).

In June 2004, the Food and Drug Administration cleared the first application for leeches (Hirudo medicinalis) to be used in modern medicine as medical devices.
Surgeons who do plastic and reconstructive surgery find leeches especially valuable when regrafting amputated appendages, such as fingers or toes. Severed blood vessels in such cases often are so damaged that they lack the ability to clear the area of blood. In these cases, it is difficult for the surgeon to make a route for blood to leave the affected part and return to circulation.

The idea behind the leeches is to cause blood to ooze so that the body's own blood supply will eventually take over and the limb can go on and survive," says Rod J. Rohrich, M.D., president of the American Society of Plastic Surgeons and chairman of the Department of Plastic Surgery at the University of Texas Southwestern Medical Center. Leeches apply the perfect amount of suction to get the blood flowing. But Rohrich also says he uses the leeches only when there's a compromised situation, such as following surgery, "when the patient's own blood supply isn't adequate."

Packing a one-two chemical punch, the benefit of leech therapy comes not from the amount of blood that is extracted, but in the powerful anti-clotting agent hirudin, contained in the parasite's saliva, which keeps blood flowing freely. At the same time, leeches emit a natural anesthetic that minimizes pain during their feast.

[note that maggots have been rehabilitated too in treating wounds for removal of dead tissue - the maggots eat only the dead cells.]

I think your comment is over-broad, Ezra. Did you miss this paragraph?

Although such treatment can be lifesaving in the early stages of a heart attack, the study found that opening the artery later did no good at all.

But, the thrust of the article seems to be 'off-label' use of drugs and devices, and when and how testing of treatments should be done. This seems very alarming:

The F.D.A. does not regulate surgery at all. Nor does any other federal agency. THAT is a serious problem needing progressive thought for solutions.

The FDA is just one of a number of consumer-protection agencies that has become a political arm of conservative philosophy of the Bu$hCo form. The anti-regulators and industry lobbyists are now several layers deep into the FDA organization, including political tests of career civil service appointees. The hackneyed phrase 'foxes guarding the hen-house' applies directly to the agency under Bush.

Our whole regulatory setup puts the burden on pre-approval testing, and almost never do agencies require post-approval follow-up studies of efficacy. THAT is another major problem requiring a progressive solution.

Posted by: JimPortlandOR | Nov 16, 2006 11:26:54 AM

Ezra, your lead is full of felgercarb. What percentage of untreated recent heart attack patients are stable and free of chest pain? Unless it's well over 50%, your "mostly" is flat out wrong.

The study itself, as reported, suffers from the flaw that afflicts, to a greater or lesser degree, pretty much every large study ever done, namely that it focuses entirely on endpoints that are easy to measure: death, heart attack, heart failure (and all within three years of operation). There's nothing said about patient reports of additional chest pain, ability to return to work or activities of daily living, or of any of the interesting side effects of beta blockers (except for a note that some minority of patients can't tolerate them).

I have no doubt that stents are being overused, cardiologists and surgeons being who they are, and medical-equipment manufacturers being who they are. But big sweeping claims on the basis of questionable, partly irrelevant evidence is what got everyone into using stents in the first place..

Posted by: paul | Nov 16, 2006 11:28:43 AM

Post MI stents represent, I suspect, only a small number of the stents placed. Emergent angioplasty and stenting for acute ECG changes and symptomatic heart disease are the norm. I would also wonder whether the results of this study apply to diabetics and non-diabetics equally. Diabetics frequently have neuropathy and lose their ability to sense cardiac pain.

Posted by: J Bean | Nov 16, 2006 12:09:44 PM

Wow! It's quite something to see the leech apologists out in force.

Posted by: Neil the Ethical Werewolf | Nov 16, 2006 12:53:03 PM

"Unfortunately, we barbers aren't gods. You know.. medicine is not an exact science, but we are learning all the time. Why, just fifty years ago, they thought a disease like your daughter's was caused by demonic possession or witchcraft. But nowadays we know that Isabelle is suffering from an imbalance of bodily humors, perhaps caused by a toad or a small dwarf living in her stomach."

Posted by: Michael F. Cannon | Nov 16, 2006 1:36:32 PM

Um, not only did the article say that the procedures can be lifesaving in the early stages of a heart attack, it said that the question of how effective they were _prior_ to a heart attack was not addressed at all. So the study found that angioplasty was not very useful for people who'd already had their hearts damaged, but had no opinion about whether it is a good precautionary measure before heart disease progresses to full fledged heart damage.

Does anybody here know the breakdown on angioplasty for before, early, and late in heart disease? Because the people I know who've had them had them _before_ they had their heart attack.

Posted by: James Killus | Nov 16, 2006 6:35:03 PM

As someone who had an incredibly successful multiple vessal angioplasty 14 years ago, and a very difficult multi-CABG this year, perhaps I can shed a little light on this.

1. No one undergoes these procedures lightly. When I had the first, I had survived two episodes of crushing chest pain, and continuing instances of unstable angina. An angiogram showed 90% blockage of the LAD (otherwise known as the 'widowmaker'). Untreated, I was an obvious candidate for sudden cardiac death. I was also very lucky, because I had three vessals treated, and none restenosed, only about a 15% chance given typical outcomes at the time. None of these sites was involved in my CABG.

2. Again, when I decided on the CABG procedure, it was both quality of life (I couldn't breathe very well under even mild exercise) and survival. This time I wasn't so lucky in the outcome; I ended up in the hospital for a total of 6 weeks with major post-op infections, and 2 of the 6 bypasses closed up immediately after surgery. On the other hand, I survived the infection, my heart function is normal, and I can breathe again, and am at no more than normal risk of sudden cardiac death.

Using the results of this study to critique either of the procedures I had would be wrong, because the pre-conditions are so different.

Oh, and when your cardiologist introduces your surgeon-to-be, and explains how you can have the surgery and live, or not, and die, shopping isn't a practical alternative.

Posted by: John Casey | Nov 16, 2006 11:55:32 PM

After my heart attack, I had an angioplasty done. It seems to be working so far. It's been over 10 years.

Posted by: merlallen | Nov 17, 2006 7:03:07 AM

I'll also note that there is a quality of life issue. Every single person I know who has had either angioplasty or bypass surgery reported _major_ improvements in activity levels, ability to tolerate exercise and general health. Again, it doesn't look like this was addressed in the study at all.

And one final note: remember, science is _never_ about the results of a single study. All the talk here is way premature in that sense.

Posted by: James Killus | Nov 17, 2006 1:42:54 PM

I already responded to this, but having read more carefully the NYT article (which was pretty dreadful itself), and Ezra's post, it now must be said:

Ezra, in this, you are a fucking idiot.

The study upon which all this hoohaw is based addresses one particular use of angioplasty/stent: post MI re vascularization _after the MI has resolved_. In other words, the study concludes that restoring blood flow to dead cardiac tissue isn't particularly useful.

Interesting, not all that surprising.

The "fucking idiot" part comes when Ezra takes this study as a license to whack _all_ angioplasty/stent work, most of which, as in my case and that of other commenters, involves increasing blood flow to cardiac tissue _that isn't dead_.

Ezra, you know a lot of stuff, and write really well; please don't confuse the talents you have for universal expertise.

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