January 23rd, 2012

Selections from Richard Lehman’s Weekly Review: Week of January 23rd

CardioExchange is pleased to reprint selections from Dr. Richard Lehman’s weekly journal review blog at BMJ.com. Selected summaries are relevant to our audience, but we encourage members to engage with the entire blog.

Week of January 23rd

JAMA  18 Jan 2012  Vol 307

265     Cangrelor is one of a number of reversible thienopyridine platelet inhibitors competing to replace clopidogrel. This could be an enormous market, but the BRIDGE study, funded by The Medicines Company, begins with a small niche: patients who discontinue antiplatelet treatment before elective coronary artery bypass grafting. The problem that this study is alleged to address is the risk of rebound coronary events in such patients, unless some kind of platelet inhibition is maintained up to near the time of surgery (using IV cangrelor, of course); but in fact a coronary end-point appears nowhere in the trial. Instead, the primary end points are bleeding during surgery and laboratory platelet function tests. These lab tests are the weakest of surrogates, and I am unconvinced that there is a problem here that cannot be addressed in a simpler way. This study really doesn’t belong in a leading medical journal.

NEJM  19 Jan 2012  Vol 366

250   An outstanding review of Cognitive and Neurologic Outcomes after Coronary-Artery Bypass Surgery does much to allay fears raised by studies over the last decade which seemed to indicate that CABG carries a high risk of cognitive impairment. “It is now increasingly apparent that the incidence of both short- and long-term cognitive decline after CABG has been greatly overestimated, owing to the lack of a uniform definition of what constitutes cognitive decline, the use of inappropriate statistical methods, and a lack of control groups.” Older patients undergoing CABG are at high risk of cerebrovascular disease anyway, but “although some degree of short-term cognitive decline may occur days to weeks after CABG, these changes are generally minor and temporary.”

Lancet 21 Jan 2012  Vol 379

229     Critical care units are places where desperate remedies are tried out on desperately sick people. If people on ventilators are choking to death with acute respiratory distress syndrome, then the temptation arises to use intravenous beta-adrenergic agonists.  This British trial (BALTI-2) showed that this induces tachycardia, arrhythmias and lactic acidosis (as expected), and it was stopped once mortality in the treated group significantly exceeded that in the placebo group.

244   Here’s a really great observational study from Sweden looking at over half a million people who were admitted to hospital with an auto-immune disorder. Their overall risk ratio for pulmonary embolism during the first year after admission was 6•38 (95% CI 6•19—6•57). But it was particularly high for certain conditions: immune thrombocytopenic purpura (10•79, 95% CI 7•98—14•28), polyarteritis nodosa (13•26, 9•33—18•29), polymyositis or dermatomyositis (16•44, 11•57—22•69), and systemic lupus erythematosus (10•23, 8•31—12•45). It might seem a bit odd to give anticoagulants for ITP, but it’s looking as if that might be a good idea. Time for yet more trials using next-generation factor Xa and thrombin inhibitors.

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