A Medtronic device used to remove clots during stroke.
This brief article explains why a certain subset of people who have strokes may be treated more effectively with a new procedure than with existing alternatives. The new procedure sends a thin wire tube through their blood vessels to the location of a clot in the brain and removes it. The story did an excellent job of listing the complex criteria required to find the patients for whom this procedure is now recommended. It could have provided more specifics about the benefits associated with the procedure and its costs. And one of the experts tapped for commentary is a paid consultant to companies who make the devices used in this procedure, and the story should have alerted readers to that fact. The new guidelines are the result of months of study by a committee of the American Heart Association.
Implementation of these guidelines will require much more systematic coordination of stroke care than currently exists. Currently, smaller community hospitals can quickly assess a patient, get an imaging study, and start tPA (clot-busting medication delivered by IV) within an hour or two after symptoms begin. But to assess eligibility for endovascular clot retrieval (the procedure discussed here), and transport patients to centers that provide the highly specialized procedures, could take time. There is good-quality evidence that such coordination of stroke care would produce clinically important benefits, but the logistical and cost challenges that have yet to be addressed are significant.
The article does not mention, even generally, what removing a clot using these devices might cost. In a broader way, we would have welcomed discussion of how much treating strokes costs the entire health system and how risks versus benefits of different strategies may have large effects throughout the health system. For example, if this new intervention prevents disability for more patients, might it save the system those costs?
This story is not about a single research study, so it is perhaps understandable that it remains general in its comments about benefits. But we found only statement from an expert that addresses the issue: “All of these studies showed that the device can safely and effectively stop a stroke by removing blood clots.”
While stopping a stroke is clearly a benefit, that sentence does not tell us by what percentage of people randomly chosen to receive the new procedure have a better long-term outcome in terms of quality of life, or die less often of later complications, or any other measurable difference.
The outcome assessed in the studies, “functional independence after stroke,” is easy to understand. And the benefits were significant: 53-71% of treated patients were functionally independent following the stroke, compared to 29-40% of untreated patients.
The article meets the standard by including this sentence: “The major risk of using the device is that it could tear an artery and cause bleeding in the brain, particularly since it will be used on people who have already received very potent blood thinners, Kandzari said.”
It also notes, “clinical trials have shown that the risk of brain bleeding for people who received tPA and then went through mechanical clot removal is no greater than for people who just receive the blood thinner.” Some caution about the fact that we don’t know if that risk will be as low when the procedure is rolled out more widely (as opposed to being used in a highly controlled study environment) would have been welcome.
This story is about a set of guidelines and not about a single research study. The guidelines are themselves based on six different randomized trials described elsewhere as of high-quality.
Guidelines like these are very carefully considered by a committee. The quote from the story is: “The outcomes were uniformly positive in all of the trials,” he said. “It’s really, really good evidence.” The story also notes that the guidelines have been endorsed by other medical societies. In addition, there is discussion of limitations insofar as the story addresses how narrowly one must filter patients in order for them to fit these new guidelines.
We think the discussion of evidence is sufficient to convey the quality of the research, but we wouldn’t have minded some additional detail. For example, the related news release issued for the guidelines says:
“The evidence backing this new recommendation received the highest rating based on the scientific evidence reviewed, and suggests the benefits substantially outweigh the potential risks in these patients.”
and further:
“Evidence-based guidelines are based on clinical trials, which tell you that if you have a patient with the same characteristics of those in the trials, on average they will do much better with the treatment than if you treat them another way,” Powers said.
The story quotes two experts, one of whom chaired the committee that wrote the guidelines (Powers) and the other (Kandazari) who was apparently independent of the guideline-writing process. The solicitation of an outside expert opinion is commendable, but the story should have notified readers that Dr. Kandazari is a paid consultant for companies, such as Medtronic and Boston Scientific, that make the devices that are used in these procedures. See this Wall Street Journal report and the disclosures on this online CME program.
The alternative to endovascular clot retrieval is no procedure, and is made clear in the article.
It’s clear from the story that these procedures can only be performed by highly-trained interventionists at specialized stroke treatment centers. The story emphasizes the importance of getting patients to these centers quickly. That’s sufficient for a Satisfactory rating, but it would have been nice to know how many of these stroke centers there are throughout the country. And do most residents in the US live close enough to get to one within the magic short window?
We believe the story establishes that the procedure has been under study for some time and that the guidelines issued are new.
The story quotes the author of the guidelines, and one other expert who is not an author. It does not rely solely on the news release.
Systematic, Criteria-Driven
The tale of two “negative” studies. Or, how spin is applied to make research findings look more impressive. A must read. https://johnmandrola.substack.com/p/the-tale-of-two-negative-studies
The @nytimes chose to interview one of the editors of the @AnnalsofIM (publisher of this paper) who "gushed with extraordinary glee: It’s huge! There are very few things that reduce your mortality by 30%."
Turns out coffee is not one of those few things despite all that glee. https://twitter.com/garyschwitzer/status/1533202075928215558
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