October 8th, 2012
Selections from Richard Lehman’s Literature Review: October 8th
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.
JAMA 3 Oct 2012 Vol 308
Beta-Blockers: No Cardioprotective Effect for Certain Patients (pg. 1340): This week’s most fascinating and practice-changing paper must be this large observational study of beta-adrenergic blocking drugs and clinical outcomes in three classes of patients: those with a remote history of myocardial infarction, those with stable coronary artery disease (CAD) and those with risk factors for CAD. The primary outcome was a composite of cardiovascular death, nonfatal MI, and nonfatal stroke. The result of this propensity-matched analysis was even more startling than the authors let on in their abstract: not only was there no significant benefit to patients with past MI, there was statistically significant harm to those with CV risk factors but no known CAD (see Figure 1: HR 1.18 (95%CI 1.02-1.36). When I first started doctoring, ß-blockers (a brand new British invention) were considered a panacea for everything cardiovascular, except heart failure. Now it seems they are useless for most things cardiovascular, except heart failure.
NEJM 4 Oct 2012 Vol 367
Intra-Aortic Balloon Support for MI with Cardiogenic Shock (pg. 1287): Cardiogenic shock is the kind of situation where people want to rush in and do things. It is not for me to criticize such people, as I am rarely faced with patients suddenly on the cusp of death; but reading the literature, it does strike me that their intentions are often better than their results. Case-hardened, cash-starved British cardiologists often refer to intravenous inotropes as “embalming fluid,” but they still sometimes use them: intra-aortic balloon support, on the other hand, has never really caught on over here. Nor should it, according to this admirable German trial which randomized 600 patients in cardiogenic shock following myocardial infarction to receive intra-aortic balloon counterpulsation or none, prior to intended revascularization. The 30-day mortality in both groups was the same, at 40%. The study had more than 240 primary end-points—an insurance policy gone mad—but it still could not prove that the procedure has any real value. These balloons should be filled with helium and sold at street corners.
Prasugrel vs. Clopidogrel for Acute Coronary Syndromes without Revascularization (pg. 1297): More disappointment comes in this long-awaited trial of prasugrel versus clopidogrel for acute coronary syndromes without revascularization. Since a substantial proportion of people lack the ability to convert clopidogrel to its active metabolite, the newer drug prasugrel (which doesn’t need this conversion) should be much the better platelet inhibitor. But this just doesn’t seem to happen in real life. Eli Lilly and Daiichi Sankyo spent tens of millions of dollars recruiting 9326 patients at 966 sites in 52 countries and following them up for two and a half years—all to prove that their new drug is no better than the old one which costs twenty times less. Much as we would welcome a better drug for cardiovascular protection, this is good news for cash-strapped health systems.
C-Reactive Protein, Fibrinogen, and CVD Prediction (pg. 1310): Erasmus of Rotterdam visited Cambridge in England in the 1510s and was struck by its polyphonic music (which he couldn’t follow) and its futile scholastic learning, both of which he went on to ridicule in Encomium Moriae (literally Praise of Fools, but also containing a friendly pun on the name of his friend Thomas More). How little has changed in 500 years. The Cambridge (UK) authors of this study demonstrate that if you add high-sensitivity C-reactive protein to the risk score of a European population of mean age 60, you can reclassify enough intermediate risk individuals to make them worthy of a statin and so prevent one cardiovascular event (non-fatal or otherwise) in 10 years for every 400-500 people screened. That’s assuming you follow the current rules and don’t just lower the general threshold for statin prescribing to age 50, or something like that. You cannot help feeling sorry for the Emerging Risk Factors Collaboration which did this study: for all its clinical relevance it might as well be the St Thomas Aquinas Institute for Angel-Counting. But there are still a lot of great choirs to be heard in Cambridge, and someone could write a motet for them about it: O sensitivissimum protein C-reactivum, imple in cordibus servorum tuorum etc.
Lancet 6 Oct 2012 Vol 380
A Comparison of Thrombectomy Devices for Acute Ischemic Stroke: Britain’s premier medical journal gets more bizarre with each issue. Thrombectomy devices for acute stroke have yet to earn any place at all in mainstream clinical practice, but the Lancet gives all its research space this week to commercial studies comparing one device with two others. I would like to like the Lancet, but it’s very difficult.