平日。
まだ風邪が完治しておらず喉が痛い。
最近、新しいタイプのDrug-Coating stents（薬剤溶出性ステントに対して古い単純タイプはBare-Metal stents)に対する問題（the risk of blood clots forming long after the stents are implanted）が報告されていますが、それに対抗する報告例。アメリカの循環器の医師が大勢の患者さんにステント治療をするようになったので、年月が経つにつれ色々な問題が出てきているのだろう。また、ステントに対する適応基準も、このステントが出てきた当初はかなり厳しく患者さんの条件が適応されていたものが、年月が経つに連れて、循環器の担当医の判断で患者さんの適応基準を当初よりは拡大しているのかもしれませんね。
October 4, 2007, 8:34 amDrug-Coated Stents Safe, Latest Study Suggests
Posted by Jacob Goldstein
Patients given bare-metal stents were more likely to die within three years than patients given drug-coated stents, a New England Journal of Medicine study found.
The results from the latest analysis comparing old-style and new-model stents could give a boost to Boston Scientific and Johnson & Johnson which have seen sales of drug-coated stents fall because of concerns about the risk of blood clots forming long after the stents are implanted.
Researchers in Ontario, Canada analyzed a pool of old data for patients who received stents between 2003 and 2005. They plucked nearly 3,800 pairs of patients from a clinical registry. The important difference was that half the patients got bare-metal stents and the others got the drug-coated variety. The three-year mortality rate was 7.8% for those who received bare-metal stents, versus 5.5% for drug-coated.
The main advantage of drug-coated stents — that they’re more likely to keep vessels clear — held true for patients with multiple risk factors (such as diabetes) for re-blockage. But the improvement wasn’t significant for patients with just one or no risk factors.
Backward looking studies like this one are prone to bias and aren’t as powerful as prospective trials. The authors note that there could be factors they didn’t consider that distinguished patients who received drug-coated stents from those who received bare metal — and that made those who received drug-coated stents more likely to survive. “We suggest caution in concluding, on the basis of our study alone, that drug-eluting stents save lives,” they write.
The study was funded by the Canadian government and by Canadian health foundations.
September 14, 2007, 11:27 amWho’s on First? Taxus? No, Cypher. I Don’t Know.
Posted by Ron WinslowStent geeks are being treated to a complex analysis in the Lancet that concludes Johnson & Johnson’s drug-coated Cypher device is “clinically better” than arch-rival Boston Scientific’s Taxus model.
But the technique used to reach that conclusion appears almost as controversial as the heart devices themselves. Researchers led by a group at Switzerland’s Institute of Social and Preventive Medicine in Bern, combined data from 38 studies involving more than 18,000 patients. It’s another so-called meta-analysis that combs data from previous clinical tests for fresh insights. (Look back just a few months at the hubbub triggered by cardiologist Steven Nissen’s meta-analysis of trials of GlaxoSmithKline’s Avandia.)
The stent meta-analysis is even more creative than some because it includes not just head-to-head Cypher-Taxus studies but also trials that compare each drug-coated stent with bare-metal models. So, in no small measure, the conclusion is akin to gauging whether the Boston Red Sox are better than the New York Yankees by looking at each team’s record against the Tampa Bay Devil Rays.
The Health Blog remembers a high school math teacher warning us against leaning too hard on conclusions drawn from the old transitive property of inequalities. Will the Bosox prevail over the Yanks this weekend just because so far this season the Sox have gone 11-4 against Tampa compared with the Yankees’ 8-7 record?Boston Scientific’s chief medical officer Don Baim tells the Health Blog that one problem with the analysis is that bare-metal stents included in the studies have different complication rates: the bare-metal stents used in the Cypher trials, for instance, reclogged in 23.6% of cases compared with 20% in the Taxus studies. In effect, that would mean looking at how the Red Sox do against the Baltimore Orioles and compare that result with how the Yankees do against the Kansas City Royals. “Forcing these two different [bare-metal] stents with different results to be the same . . . creates a distortion” that unfairly favors Cypher over Taxus, Baim says.
The Health Blog also checked in with Peter Jüni, principal investigator of the study and head of clinical epidemiology and biostatistics at University of Bern, about the newfangled network meta-analysis the researchers employed. He rejects Baim’s assertion. If Baim were correct, then you’d expect to see a different result—say, parity—when you looked at the drug-coated devices head-to-head, without the bare-metal devices to confound matters, Jüni argues. But in that part of the analysis, Cypher wins as well, Jüni says, bolstering the findings.
His team, which doesn’t take any industry money and is independently funded, took pains to make sure that “all parts of the different trials were actually providing a coherent picture,” he says. While there were some “minor inconsistencies” in the data relating to reclogging and clots, “we’re very confident that these results are reliable.”
Johnson & Johnson had no complaints about the methods and issued a press release touting the findings of the “largest of its kind” study—including the conclusion that Cypher was “clinically superior” to Taxus.
In an editorial accompanying the study, New Zealand researchers Mark Webster and John Ormiston called the report “the best current comparison of the two drug-eluting stents.” Perhaps the study’s most important conclusion was that death rates for both Cypher and Taxus were essentially the same as those for bare-metal stents, alleviating concerns raised in recent months that the drug-coated devices had a heightened mortality risk.
Photo by Jeff Crupper via Clearwater Threshers Grassy Gang
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