May 29th, 2012
Selections from Richard Lehman’s Literature Review: Week of May 28th
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 23 May 2012 Vol 307
Treating Obstructive Sleep Apnoea (pg. 2161): Daytime sleepiness is one of the main reasons for treating obstructive sleep apnoea, another one being the risk of cardiovascular events and hypertension in untreated OSA. Continuous positive airway pressure is the standard treatment, and observational evidence suggests that as well as keeping people more alert by day, it may also reduce adverse cardiovascular consequences. I hadn’t realized before reading this paper (and the associated editorial) that there is no evidence for this from randomized trials. The Spanish Sleep and Breathing Network considered that it would be unethical to do an RCT in symptomatic OSA: instead they selected people with OSA but without daytime sleepiness and randomized them to a prescription of CPAP versus no prescription. Many of the CPAP group found the fiddle of using it all night long too much, and rarely did, so that on an intention-to-treat basis this trial could prove nothing: in those who were compliant, there was a trend to better outcomes.
The same Spanish team also offers an observational study showing that OSA is associated with hypertension, and in those who use CPAP it seems to progress less.
NEJM 24 May 2012 Vol 366
Aspirin for VTE (pg. 1959): Ah, Perugia! Town of my dreams, the very epitome of Italian civilization, cradle of Raphael, home to Perugino and Pinturicchio, a hill covered with miraculous architecture, including an ancient University, from which this paper originates. What a neat little study this is, enrolling just so many subjects as were needed to prove that taking low dose aspirin for two years following unprovoked venous thromboembolism reduces recurrence by nearly a half without an increase in significant episodes of bleeding. And now it is time for lunch – the linguine with black truffle shavings are so good – and a siesta – and then we must visit the astounding Palazzo dei Priori, taking in the annual chocolate festival a little later. One day soon, perhaps.
BMJ 26 May 2012 Vol 344
Prothombotics: Drugs which inhibit thrombosis get an airing pretty well every week in these columns, but the pro-thrombotic drug tranexamic acid languishes on the sidelines, despite some startling evidence of benefit in certain situations, such as early use in bleeding trauma patients (CRASH-2). There have been lots of trials in elective surgery too, and this systematic review and cumulative meta-analysis demonstrates that there is a sound body of evidence for a substantial reduction in blood transfusion in a variety of procedures. What is not so certain, unfortunately, is the rate of thrombotic events or the effect on total mortality.