March 12th, 2012
Selections from Richard Lehman’s Weekly Review: Week of March 12th
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 March 12th
Lancet 10 Mar 2012 Vol 379
Stem Cells for the Heart (pg. 895): “The Lancet, you may have noticed, is a seriously weird journal. One of the things it likes to do is publish the results of cutting-edge human experiments before they have any clear outcomes” I wrote here two weeks ago. This hasn’t changed in a fortnight, and in fact it hasn’t changed in over a decade. During this time there have been lots of small trials of stem cells for repairing myocardium: these were novel and exciting to begin with, but you might be forgiven for wanting some evidence of actual benefit by now. Here in the latest phase 1 trial, CADUCEUS, the stem cells were cardiosphere-derived, i.e., grown from the patients’ own cardiomyocytes obtained by endocardial muscle biopsy. Cultured autologous precursor cells were introduced by coronary artery infusion, and at six months there was MRI evidence of scar repair and new myocardium but no change in functional indices at all. There will now be a phase 2 trial. Can’t wait. You may want to read more about what hasn’t yet happened in this field in the review article (pg. 933), Towards regenerative therapy for cardiac disease.
BP in Both Arms and Vascular Disease (pg. 905): In the days when I was still a proper doctor with a consulting room of my own, I used to shock and confuse visiting health professionals by keeping a mercury sphygmomanometer with an adult cuff that covered 80% of the upper arm. That way I could at least believe my own blood pressure readings. I even tried to keep abreast of the hypertension literature for a while, since it seemed best to know something about the commonest reason for treating healthy people in primary care. And I even uncovered the odd case of primary hyperaldosteronism. But I very rarely measured the BP in both arms, except in one memorable lady with a cold hand and a loud subclavian murmur, who provided my one and only diagnosis of subclavian stenosis. Here is a frustrating systematic review of the difference in BP between arms and vascular disease and mortality – frustrating because it doesn’t place its findings in any useful context. In particular there is a digression about the ankle/brachial pressure index without a direct comparison with the arm/arm BP index, but without clarifying which is more useful in which clinical situations. The authors are willing to commit no further than some mights and coulds: “A difference in SBP of 10 mm Hg or more, or of 15 mm Hg or more, between arms might help to identify patients who need further vascular assessment. A difference of 15 mm Hg or more could be a useful indicator of risk of vascular disease and death.”
Ann Intern Med 6 Mar 2012 Vol 156
How Patients and Caregivers Interpret Prognostic Information (pg. 360): Doctors can be very poor at handling numerical data; there have been lots of studies in patients too, and some in surrogate decision makers. Here is a mixed-methods (hurray!) study of how relatives and decision-making carers of people incapacitated by serious disease interpret prognostic information, whether given as numbers or words. Such discussions usually take place in the context of continuing life-supporting treatment, so this could hardly be less trivial. And the investigators find that misunderstanding is rife – and tends to be in one direction only, so that it is not simply misunderstanding but cognitive bias towards optimistic interpretation.