April 24th, 2014

Selections from Richard Lehman’s Literature Review: April 24th

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.

NEJM  17 Apr 2014  Vol 370

Aspirin in Patients Undergoing Noncardiac Surgery (pg. 1494): Back in the 1970s, people used to say that we had entered an era of safe surgery and dangerous medicine. I find it odd that people are now trying to make surgery safer by using a variety of moderately dangerous drugs on healthy people about to have operations. We now know from other trials that beta-blockers given before non-cardiac surgery may actually do harm. This large 2×2 factorial trial tests the effect of aspirin 200mg given before non-cardiac surgery and continued at 100mg daily for 30 days after. “Administration of aspirin before surgery and throughout the early postsurgical period had no significant effect on the rate of a composite of death or nonfatal myocardial infarction but increased the risk of major bleeding.”

Clonidine in Patients Undergoing Noncardiac Surgery (pg. 1504): In case you wondered why they needed a 2×2 factorial trial to test a single intervention, the answer is that Salim Yusuf et al were testing pre-op clonidine at the same time. Clonidine is a drug that reduces central activation of the sympathetic nerves. It is hardly used these days, though in theory it could be beneficial in the post-op period when levels of sympathetic activation are high. Patients in the clonidine group were given 0.2mg before surgery and for three days after. “Administration of low-dose clonidine in patients undergoing noncardiac surgery did not reduce the rate of the composite outcome of death or nonfatal myocardial infarction; it did, however, increase the risk of clinically important hypotension and nonfatal cardiac arrest.” I think bananas should come next: “Administration of bananas in patients undergoing noncardiac surgery did not reduce the rate of the composite outcome of death or nonfatal myocardial infarction. They did, however, increase the risk of clinically insignificant hyperkalaemia, and two banana-skin related injuries were reported.”

Changes in Diabetes-Related Complications in the United States, 1990–2010 (pg. 1514): Something very good happened to diabetes care in 1995. Up to then, American rates for adverse outcomes in diabetes were on the rise, but since that time there has been a steady fall in rates of myocardial infarction, stroke, amputation, and end stage renal disease. Blindness is not documented in this survey. My hunch is that all of this is due to statins, smoking cessation, and better control of blood pressure; and that feeling is reinforced by seeing similar trends in the general population. Sadly, however, the absolute numbers of diabetic complications are rising, because of a steep increase in the incidence of diabetes.

BMJ  19 Apr 2014  Vol 348

Chronic Hypertension and Pregnancy Outcomes: Here is another meta-analysis, this time of observational data. Something can definitely be taken away from this one. High blood pressure in women of childbearing age is a marker for something we don’t understand. It is associated strongly with adverse outcomes in pregnancy, increasing the risk of pre-eclampsia by 7.7, of preterm delivery by 2.7 and of perinatal death by 4.2.

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