A new study published in The Lancet provides the most definitive evidence to date that chronic cerebrospinal venous insufficiency (CCSVI), a hypothetical syndrome of narrowed veins draining the brain that some believe is the true cause of multiple sclerosis (MS), is not associated with MS.
In a science-based world, this study would be yet one more nail in the coffin of this failed hypothesis. But that’s not the world we live in.
CCSVI was first proposed in 2009 by Italian vascular surgeon, Dr. Paolo Zamboni – that multiple sclerosis (MS) is caused by chronic blockage of the veins that drain the brain. The current scientific consensus is that MS is a chronic autoimmune disease, and the pathology is caused by primary inflammation. Dr. Zamboni believes that the venous anomalies he has discovered are the primary cause and the inflammation is secondary. (more…)
It has been very instructive, from a science-based medicine perspective, to watch the story of alleged chronic cerebrospinal venous insufficiency (CCSVI) and multiple sclerosis (MS) unfold over the last three years. In 2009 Dr. Paolo Zamboni, an Italian vascular surgeon, published a paper in which he claimed that 100% of MS patients he investigated showed signs of blockage in the veins that drain blood from the brain, a condition he named CCSVI. This paper sparked immediate controversy. This controversy has been in the news again recently with the making public of the results of an observational study of the liberation procedure to treat CCSVI.
Existing research over the last half century strongly indicate that MS is primarily a disease of immune dysfunction (an autoimmune disease), resulting in inflammation in the brain that causes damage, specifically to the myelin, the insulation around nerve fibers that allows them to conduct signals efficiently. Zamboni is suggesting that MS is primarily a vascular disease causing back pressure on the veins in the brain and iron deposition which secondarily results in inflammation. This would be a significant paradigm shift in MS. It would also not be the first time such a dramatic shift in MS science has been proposed but failed in replication.
The MS community did not give much credence to the notion of CCSVI, but despite this there has been an incredible amount of research on the idea over the last three years (a PubMed search on “CCSVI” gives 103 results). Most of the research has simply attempted to replicate Zamboni’s findings, with mixed but generally unimpressive results. No one has found the 100% results that Zamboni originally reported. The studies have found a range of venous insufficiency in MS patients, down to 0%, but many finding results in the range of 20-40%. However, patients with other neurological disease and healthy controls have also been found to have similar rates of venous insufficiency. Some studies have found a positive correlation with MS, others have not.
I have been following the story of Dr. Zamboni, an Italian vascular surgeon who claims that multiple sclerosis (MS) is primarily caused by blockages in the veins that drain blood from the brain. This results in backup of blood in the brain, leading to inflammation around the blood vessels and MS. He sought to find the cause and cure for MS because his wife suffers from this disease – and he claims to have found one in his own specialty.
New ideas are presented in science and medicine all the time. This is healthy and necessary – we have to keep churning the pot so that new ideas can emerge and our thinking does not become calcified. But science is both a creative and destructive process, and most new ideas fall victim to the meatgrinder of research and peer-review. Ideally this process will take place mostly within the halls of science, and then those ideas that survive at least initial examination will start to penetrate the broader culture.
This is not what often happens today, however. With the internet and mass media, preliminary speculative studies are often presented to the public as if they are a stunning breakthrough. When the scientific community responds with their typical and completely appropriate skepticism, this may lead some to think that they are being stodgy or dogmatic, or even that a cover-up is in the works. The originator of the speculative claim is usually portrayed as a brave maverick, although sometimes the story can be framed as, “Brilliant scientist or dangerous crank? You decide.” When the topic is a new medical treatment, the stakes can be quite high. In this case many patients with progressive MS are seeking treatment with the so-called liberation procedure to treat the highly speculative CCSVI as an alleged cause for their MS.
This story has all the makings of the kind of scientific and medical drama the mass media loves. While the controversy rages, the science is quietly being done in the background, and the results are not heading in a favorable direction for Zamboni. A recent study, the largest to date, drives a further stake into the heart of CCSVI as a cause of MS.
“You are not going to change what we do, you’re not going to change our determination to make these patients better. I see these patients, I know these patients, I value these patients, I’ve looked after them for years. I’ve seen them after the procedure, the vast majority are improved.”
The above quote could be a reference to just about any fringe medical treatment. It is partly an expression of faith in anecdotal experience over scientific evidence. It is partly the fallacy of justifying a treatment because it is needed – whereas the real question is whether or not the treatment works. It is an attempt to justify specific claims with compassion, as if the person quoted cares more for the health of their patients than those who might be skeptical of their claims. And it is an expression of stubbornness – I know the truth, so don’t confuse me with evidence and logic.
Is this person talking about acupuncture? Perhaps they run a stem cell clinic in China, India or somewhere outside the reach of regulation. Or maybe they are defending hyperbaric oxygen therapy for unproven indications, like autism. It could be anything, because this sentiment is the standard mantra of the dubious practitioner, practicing outside the bounds of science-based medicine.
Peter Lipson reported Monday about new research suggesting that Multiple Sclerosis may be caused by venous blockage. He correctly characterized some of the hype surrounding this story as “irrational exuberance.”
This is a phenomenon all too common in the media – taking the preliminary research of an individual or group (always presented as a maverick) and declaring it a “stunning breakthrough,” combined with the ubiquitous personal anecdote of someone “saved” by the new treatment.
The medical community, meanwhile, responds with appropriate caution and healthy skepticism. Looks interesting – let’s see some more research. There is a reason for such a response from experts – experience.