Saturday, September 1, 2012

The End of IABP?

Adding to the "don't do anything, just stand there!" file, another relatively frequently used cardiovascular support tool – intra-aortic balloon counterpulsation – might be on the chopping block.

Typically used in cases of severe cardiogenic shock secondary to acute myocardial infarction, IABP is used to reduce strain on the stunned myocardium.  The first IABP-SHOCK pilot of 45 patients showed no mortality difference, but a significant improvement in BNP levels with IABP use.  This is the follow-up study, enrolling 600 patients to IABP or best available medical therapy.

Both groups were similarly ill – the IABP group had 6% more anterior STEMIs – and had nearly identical outcomes.  There were 1.5% more survivors in the IABP group, but the p value was 0.69.  Adverse events were similar – although the control group tended towards increased sepsis, which seems a little odd.  There was an expected random assortment of subgroups favoring one therapy or another, but nothing that would seem to be specifically hypothesis generating.

In the end, the authors rather grimly state that, despite some surrogate markers appearing to be improved in the IABP group, there is no evidence to support routine use of IABP in cardiogenic shock secondary to acute myocardial infarction.

"Intraaortic Balloon Support for Myocardial Infarction with Cardiogenic Shock"
http://www.nejm.org/doi/full/10.1056/NEJMoa1208410

Thursday, August 30, 2012

FFR(CT) - So Close, Yet So Far

As David Newman will tell you, the additive prognostic and predictive value for stress tests is fairly weak.  CT coronary angiograms are still a test looking for the correct population.  Conventional coronary angiography is expensive, invasive, and clearly not appropriate for the massive population of low risk patients we evaluate.

So, how about a non-invasive test that combines three-dimensional anatomic coronary reconstruction with predictive flow dynamics to identify lesions resulting in ischemia?  This test is CT coronary angiography combined with computed fractional flow reserve.  And, it would be a beautiful thing if it were ready for primetime – but it's not.

I've reviewed a previous trial of FFR(CT).  This is a larger study, published in JAMA, of 285 patients with suspected CAD who underwent CCTA with FFR(CT), followed by conventional coronary angiography with invasive FFR measurement.  Figure 1 summarizes the results relatively succinctly – but essentially, 56 of the 172 FFR(CT) patients with lesions calculated as ischemic were false positives.  On the flip side, 67 of the 80 FFR(CT) patients with lesions calculated as non-ischemic were false negatives.  The per-vessel performance of FFR(CT) basically added no additional diagnostic AUC to CT alone.

The study is sponsed by HeartFlow, and authored by several physicians disclosing conflicts of interest with diagnostic imaging manufacturers.  Unsurprisingly, the authors try to spin the positive out of it in their conclusions and abstract.

"Diagnostic Accuracy of Fractional Flow Reserve From Anatomic CT Angiography"
http://jama.jamanetwork.com/article.aspx?articleid=1352969

Wednesday, August 29, 2012

Pop & Suture Abscesses Closed

Upending another slice of traditional dogma, brought to my attention by Andy Neill, this is a systematic review and meta-analysis of the 7 randomized clinical trials comparing primary closure of cutaneous abscesses with secondary.  I love articles that challenge routine practice – some of which was actually transcribed from stone tablets into Tintanelli by Moses.

Unfortunately, as weak as the evidence may be for packing abscesses, antibiotics with abscess, etc., the evidence from this meta-analysis really is only serviceable as underpinnings to justify further trials revisiting standard practice.  The 915 patients included in this meta-analysis were primarily anogenital abscesses drained in an operating room environment by surgeons and many received antibiotics.  Some of the outcomes measured in this study make sense and are probably generalizable – healing time and time off work – which obviously will favor the patients with primary closure.  The less generalizable is the 600 patient subset which tracked abscess recurrence, which also has a ton of heterogeneity between studies.

Is it reasonable to perform some sort of abscess closure?  I think it probably is – depending on the amount of potential disfigurement, there's probably a discussion of risk/benefit that can be had.  There are also probably varying techniques of suturing that could be entertained, loosely approximating some part of the abscess, perhaps with a wick, rather than tightly re-approximating skin edges.


The authors state they are undertaking their own randomized trial.


"Primary closure of cutaneous abscesses: a systematic review"
www.ncbi.nlm.nih.gov/pubmed/20825801

Monday, August 27, 2012

Who's Burned Out? We Are!

In a survey of U.S. physicians, published in Archives of Internal Medicine, Emergency Physicians hold the dubious honor of being the most "burned out" specialty.  This estimation of burnout is based on survey questions regarding emotional exhaustion, depersonalization, and personal accomplishment.  Unsurprisingly, dermatology was not a terribly burned out specialty – likely because they also ranked quite highly in time for personal and family life.  Surgical specialties, despite ranking at the bottom for family life, were only in the middle of the road for burnout – probably indicating the nature of the work plays a role in the strain.  Self-selection bias always plays a role in these surveys, of course, considering the response rate was only 26%.

Compared with the employed general population, physicians were more burned out and had less time for family – which may or may not be related to the 25% more hours per week worked, although, there were many differences between the physician cohort surveyed and the comparison.  

The New York Times discusses this article and uses a vignette of a "missed diagnosis" as symptomatic of the disruption of quality of care due to burnout.  While it may be true that burnout relates to healthcare quality, the specific case presented seems to fall more into a category of reasonable conservative management of the most likely condition, with appropriate further enquiry made at a re-visit due to persistent symptoms.

"Burnout and Satisfaction With Work-Life Balance Among US Physicians Relative to the General US Population" 
http://archinte.jamanetwork.com/article.aspx?articleid=1351351