January 26th, 2015

Selections from Richard Lehman’s Literature Review: January 26th

CardioExchange is pleased to reprint this selection 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 Intern Med Jan 2015 Vol 175

Dietary Sodium Content, Mortality, and Risk for Cardiovascular Events in Older Adults: I have been contemplating writing a blog on salt for the UK Cochrane Collaboration to mark the appearance of the latest Cochrane review of reduced dietary salt for the prevention of cardiovascular disease.

The review concludes that current evidence does not confirm clinically important effects of dietary advice and salt substitution on cardiovascular mortality in normotensive or hypertensive populations. In August, the NEJM published the PURE studies which showed that an estimated sodium intake between 3 g per day and 6 g per day was associated with a lower risk of death and cardiovascular events than was either a higher or lower estimated level of intake. This latest paper in JAMA Intern Med is a cohort study of people aged 71-80 and concludes that in older adults, food frequency questionnaire-assessed sodium intake was not associated with 10-year mortality, incident CVD, or incident HF. So the Salt Reduction Emperor turns out to have few clothes on, if any. But rather than tackle the blushful dictator full-on, we should perhaps allow him the favour of a curtain to hide behind whilst he adjusts his underwear. There are some residual uncertainties, of course we should encourage people to prepare fresh food, more potassium is good too, and so on. It will all take an awfully long time, and I imagine that “healthy eating” guides will still repeat rubbish about vitamins, minerals, antioxidants, and reducing salt for as long as I live. “It is difficult to get a man to understand something when his salary depends on not understanding it” as Upton Sinclair once said. The irony is that the word salary comes from the allowance of salt which was an essential of health in the Roman army.

Lancet 24 Jan 2015 Vol 385

Zotarolimus-Eluting Durable-Polymer-Coated Stent vs. a Biolimus-Eluting Biodegradable-Polymer-Coated Stent in Unselected Patients Undergoing PCI:Zotarolimus-eluting durable-polymer-coated stent versus a biolimus-eluting biodegradable-polymer-coated stent in unselected patients undergoing percutaneous coronary intervention (SORT OUT VI): a randomised non-inferiority trial.” Hey, I hear you say, you told us about this Lancet paper a few weeks ago. Nope, that was “Ultrathin strut biodegradable polymer sirolimus eluting stent versus durable polymer everolimus-eluting stent for percutaneous coronary revascularisation (BIOSCIENCE): a randomised, single-blind, non-inferiority trial.” You clearly aren’t paying attention.

Central Arteriovenous Anastomosis for the Treatment of Patients with Uncontrolled Hypertension: Resistant hypertension is a slippery thing. You may remember that there was a renal nerve ablation device that showed spectacular reductions in an open label study. Then Medtronic bought it up and ran a proper double blinded randomized trial which showed it was little better than a sham procedure. A device company called ROX medical has now come up with a cunning little device which creates a small anastomosis between the iliac artery and vein. In an open label trial, 20% of participants were rewarded with a swollen leg, so that may be a glitch that needs sorting. Some huge reductions in BP were observed, averaging 26.9/13.5mm Hg SBP/DBP. Long-term results including adverse effects like device migration, high output heart failure etc? We have no idea. We’ll need a sham-controlled RCT of long duration.

BMJ 24 Jan 2015 Vol 350

High Sensitivity Cardiac Troponin and the Under-Diagnosis of MI in Women: There has been a lot of publicity for this cohort study of 1126 patients presenting with “suspected acute coronary syndrome” to the Edinburgh Royal Infirmary over a three month period. The use of high sensitivity troponin testing made little difference to the diagnosis rate in men but doubled the number of women diagnosed with myocardial infarction. This is an important and well reported study and I think it calls for an immediate change in practice followed by a series of further studies. I think we are still some way short of knowing how best to diagnose and treat MI in women.

Diagnostic Accuracy of Single Baseline Measurement of Elecsys Troponin T High-Sensitive Assay for Diagnosis of Acute MI in the ED: Using high sensitivity troponin testing appropriately can also help in the early rule-out of MI in patients presenting with suggestive symptoms, according to a systematic review and meta-analysis of studies using a different diagnostic product—the Elecsys Troponin T high-sensitive assay.” The results indicate that a single baseline measurement of the Elecsys Troponin T high-sensitive assay could be used to rule out acute myocardial infarction if lower cut-off values such as 3 ng/L or 5 ng/L are used.” But pay attention to all the basic principles of using diagnostic tests—the pre-test probability in each individual, the likelihood ratio, and the importance of timing.

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