August 19th, 2013

Selections from Richard Lehman’s Literature Review: August 19th

CardioExchange is pleased to reprint this selection from Dr. Richard Lehman’s weekly journal review blog at Selected summaries are relevant to our audience, but we encourage members to engage with the entire blog.

JAMA  Intern Med  12/26 Aug 2013  Vol 173

Correlates of Repeat Lipid Testing in Patients With CHD (pg. 1439): Over in the USA, they treat to a target of HDL-cholesterol: over here, we treat to a target of total cholesterol. Let’s call the whole thing off. Both strategies are stupid. Treat to risk, not to target. Once an at-risk person is taking a maximum tolerated dose of statin—as a personal choice—there is no earthly reason ever to measure their lipids again.

JAMA  Vol 310  14 Aug 2013

QRS Duration, Bundle-Branch Block Morphology, and Outcomes Among Older Patients With HF Receiving CRT (pg. 617): I am a fan of cardiac resynchronization (CRT) for heart failure: it helps many people to feel better, and the evidence seems to point to underuse, whereas for implantable cardioverter-defibrillators, the evidence points to overuse. It’s crazy that patients are expected to have both together in nearly all cases. In this large registry study, there was no attempt to distinguish between them, because dual chamber pacing (CRT) was accompanied by defibrillator placement in all 24,169 subjects. It seems to me it should have been accompanied by very careful shared decision making with each patient. But that’s how it was, and this study shows that the benefit of CRT was greatest in those with either left bundle branch block or a QRS duration of 150 ms or greater. As expected.

BMJ  17 Aug 2013  Vol 347

Perceived Job Insecurity as a Risk Factor for Incident CHD: We British GPs may feel harassed, our earnings may be falling, but we know there will always be work for us. But job insecurity is an increasing threat for most people, particularly in the underclass that our present government seems so intent on burdening and disempowering. The poorer you are, the less secure is your employment, so the innumerable authors of this attempted systematic review of the link between perceived job insecurity and coronary heart disease are forced to conclude that the two are essentially inseparable: “The modest association between perceived job insecurity and incident coronary heart disease is partly attributable to poorer socioeconomic circumstances and less favourable risk factor profiles among people with job insecurity.”

Obesity During Pregnancy and Premature Mortality from CV Event in Adult Offspring: And these days, the poorer you are, the more obese you tend to be. But was that true in Scotland sixty years ago? Or even thirty? I find myself making no sense of this record linkage cohort analysis which attempts to link maternal obesity during pregnancy with increased mortality from cardiovascular events in adult offspring in 37 709 Scots with birth records from 1950 to present day. The authors conclude that, “Maternal obesity is associated with an increased risk of premature death in adult offspring. As one in five women in the United Kingdom is obese at antenatal booking, strategies to optimise weight before pregnancy are urgently required.” Hmm. And just what would those strategies be?

Lancet  17 Aug 2013  Vol 317

Cardioprotective and Prognostic Effects of Remote Ischemic Preconditioning in Patients Undergoing CABG (pg. 597): Ischaemic preconditioning is a phenomenon so simple and so weird that it is taking people a long time to come to terms with it. It is as simple as squeezing any part of the body so that its arterial supply is compromised for a short while. Then if you cut off the arterial supply in any other part of the body, you will cause less damage, even if the blockage is permanent. The effect of preconditioning is immediate and lasts for days. In this German trial, they tried it on patients undergoing coronary artery bypass grafting, a procedure which is often accompanied by subclinical cardiac ischaemia, as demonstrated by troponin rises. In the intervention arm, patients under anaesthesia were subjected immediately before CABG to three 10 minute cycles of arm compression to 200mg Hg followed by decompression. Not only were there lower rates of troponin elevation, but “All-cause mortality was assessed over 1•54 (SD 1•22) years and was lower with remote ischaemic preconditioning than without (ratio 0•27, 95% CI 0•08—0•98, p=0•046).” Note the wide confidence intervals, but this is nonetheless pretty amazing.

Reperfusion Therapy for STEMI: Is There Still a Role for Thrombolysis in the Era of Primary PCI? (pg. 624): With you in mind as ever, dear reader, I waded through this cardiology-heavy issue of The Lancet, trying to make sense of special pleading in two industry-funded trials which sought to promote prasugrel and platelet reactivity testing, respectively. Even if I were a cardiologist, this would have been a waste of time. But the clinical review articles are much more worthwhile, and the first one addresses a question which has bugged us all for over a decade: given that timely immediate percutaneous intervention is not always possible for myocardial infarction, what might be the continuing role of immediate thrombolysis as an alternative?  The article goes through the evidence meticulously, and ends up sitting on the fence somewhat, but the message of the conclusion is worth chewing over: “The preferred reperfusion option for patients with STEMI is timely primary PCI, although the recommendation for this approach was based on comparisons with inhospital fibrinolysis alone. Delay to delivery of reperfusion, which predominantly affects primary PCI, leads to an attenuation of benefit compared with fibrinolysis. When the difference in delivery between the two strategies is more than 60 min they seem equal. Furthermore, a pharmacoinvasive strategy of prehospital fibrinolysis plus planned angiography (at 6—24 h in haemodynamically stable patients) and rescue angioplasty for failed fibrinolysis has now been shown to be equivalent (by results of the STREAM trial) or better (by results of the CAPTIM trial) to primary PCI in patients who present early.”

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