Saturday, February 25, 2012

An Overblown Critique of CMS OP-15

OP-15 for imaging effectiveness in atraumatic headache is coming, vigorously opposed by many.  To date, most of the opposition has been in principle, or with specific clinical concerns.

This is a different approach to the problem - looking at whether the patients that CMS identified as "inappropriate" were actually appropriate exceptions.  This was a retrospective chart review of 748 charts that were referred back to 21 hospitals as "inappropriate" following a "dry run" of OP-15.  Based on individual chart review, the authors found documentation of one of the exclusion criteria in 489 of them - 479 based on the clinical criteria, and 35 based on administrative criteria (some met both).  They then look at those 259 patients for whom there is no CMS exception for their CT, and they claim that 136 of those were clinically warranted.  They therefore conclude that only 125 of the original 748 were accurately identified by this quality measure as inappropriate use of CT in atraumatic headache, and that this measure is garbage.

And, a quick Google News search finds an extensive parade of indignant headlines pulled from ACEP's press release, condemning the measure.

But, this study misses the point.  It's not CMS' responsibility to comb through individual charts to find these exclusion criteria.  The onus is on clinicians and hospitals to ensure their documentation clearly expresses the indications for CT in those cases that meet the exclusion criteria, and the purpose of this dry run is to help hospitals identify where the information they are supplying to CMS is deficient.

Then, I expect CMS to take a low opinion of the additional patients in whom these authors felt the imaging was clinically warranted.  Of the 78 patients for whom the authors felt ACEP guidelines for imaging were met, 73 of them met only the Level C recommendation: >50 years of age with a new type of headache and a normal neurologic examination.  Then, there is another set of patients with headaches on warfarin, who had recent neurosurgery, or had known hydrocephalus that they claim are misclassified by CMS - but I can't see how the misclassification isn't on the documentation end, as headaches in all those patients should meet ICD-9 339.44 "Other complicated headache syndrome," which is an exclusion to the rule as well.

So, even just on first pass, I'm not sure this is an effective tool with which to influence revision of OP-15.  I expect this measure to go into effect as planned - and it will be up to us to document appropriately and thoroughly, and then to monitor and demonstrate that compliance results in measurable patient harms.

"Assessment of Medicare’s Imaging Efficiency Measure for Emergency Department Patients With Atraumatic Headache"
http://www.annemergmed.com/webfiles/images/journals/ymem/FA-JDSchuur.pdf

Thursday, February 23, 2012

Unneeded Stents Are Bad And Bad For You

Well past a decade into the stent era, there's finally a growing recognition and furor over the costs and potential harms of unnecessary stenting.  While interventional cardiologists are great for the bottom line of hospitals, a few high profile cases have demonstrated that PCI and stenting might be performed more than indicated.


And, not only is it costing those patients more in procedural billing, it's likely harmful to them as well.


This concept of "Fractional Flow Reserve" has been developing in cardiology literature to better evaluate whether a stenotic lesion is actually significantly impairing the perfusion of myocardium.  These authors, part of a French cohort study called "DEFER," are following up prior studies showing FFR-guided selective stenting for left main disease is reasonable, and looking back at what they call "small vessel" coronary disease - LAD, RCA, and LCx.


This is, unfortunately, a retrospective analysis, and there are huge differences between the groups that underwent angiography-guided PCI and the group that underwent FFR-guided PCI - but not enough difference to account for the additional hazard ratio acquired by the angiography-guided PCI.  Angiography-guided PCI, in their propensity-score adjusted hazard ratio, still had significant associations with increased non-fatal MI and future revascularizations during their five-year follow-up period.  Indeed, the FFR-guided PCI group that did not find any vessels requiring intervention did outstanding - suggesting this perfusion-based strategy might be better for ensuring the benefits of stents do not outweigh the risks.


"Long-Term Clinical Outcome After Fractional Flow ReserveGuided Percutaneous Coronary Revascularization in Patients With Small-Vessel Disease"
http://www.ncbi.nlm.nih.gov/pubmed/22319067

Tuesday, February 21, 2012

Is Midazolam Really Superior to Lorazepam?

Or, more accurately, is it reasonable to perform an intramuscular injection of midazolam rather than an intravenous injection of lorazepam for seizure-like activity in the prehospital setting?

Almost certainly.

In fact, some folks are taking this article and claiming that intramuscular midazolam is superior to intravenous lorazepam, that it's a "game changer."

Well, let's not go crazy here.

As with any piece of literature, the more vocal the giddiness I see perpetuated about the internet, the more cautious I am with rushing to judgement.  It is, of course, a very well-designed, prospective, double-dummy, randomized, non-inferiority comparison between midazolam and lorazepam.  The aim of the study is, essentially, to show that, even though midazolam is not typically as rapidly effective at terminating seizures, the time difference is made up by intramuscular route versus the time required for an IV start.

What's kind of odd that I see in this article is that nearly a third of the lorazepam group did not receive the benzodiazepine portion of the intervention - and they compare it to the midazolam group in which all but 5 patients received the intervention.  When their primary outcome is the number of folks who arrived seizure-free in the Emergency Department - it seems as though the 7% absolute difference between the two groups could be easily explained by the fact that a third of the lorazepam group didn't receive an intervention.  Most of the lorazepam group had the intervention withheld because they stopped seizing of their own accord at the time of enrollment, with a minority having the intervention withheld because IV access could not be obtained.

And, the differences favoring midazolam are hard to pin down whether it's actually medication superiority, or something different about the seizures.  42 patients in the lorazepam group failed to stop seizing after additional therapy, compared with only 22 in the midazolam group - is this a difference in efficacy, or a difference in the underlying disease process - which appears to be more resistant to any therapy, including rescue, in the lorazepam group?

But, in any event, this just nitpicking against the superiority argument, and not the non-inferiority argument.  From a clinical standpoint, it is clearly safe and effective to use intramuscular midazolam for seizures in the prehospital setting.  However, what I'd prefer to see is a similarly powered trial of intranasal midazolam, which takes all the injection risks for patient and provider out of the equation during the seizure.  This is a good first step, but I think we can make effective treatment even safer if intranasal can be shown non-inferior as well.

"Intramuscular versus Intravenous Therapy for Prehospital Status Epilepticus"
http://www.nejm.org/doi/full/10.1056/NEJMoa1107494

Sunday, February 19, 2012

No One Knows How To Diagnose CAD

And, once they diagnose it - it doesn't seem like anyone knows what to do with it, considering all the brouhaha these days about potentially unnecessary PCI and stenting.

But, this is a prospective coronary CT angiography registry that was reviewed to determine whether any value was added with the CCTA over conventional stress testing in patients without known CAD.  They reviewed 22,551 patient records, excluded patients with known CAD, incomplete data, and patients who hadn't undergone a recent (<3 months) cardiac stress test, and ended up with 6,198 patients.

The point the authors seem to be trying to make is that CCTA is a better test than stress testing, but that's only part of the story.  What they note that is interesting along the way is that there is absolutely no correlation between stress testing results and CCTA results.  Patients with normal, equivocal, and abnormal stress results had, essentially, the same incidence of normal, <50%, and >50% coronary stenosis.  And, the hidden story about how CCTA is being used in their patient cohort is fascinating - a younger group with typical chest pain and normal stress tests referred to CCTA vs. an older group with less typical symptoms and abnormal stress tests referred to CCTA.

But, then, finally they compare both of their disparate tests to the "gold standard" of invasive angiography, and they find that both tests are awful at predicting >50% coronary stenosis.  Stress testing was 60.4% sensitive and 34% specific, while CCTA was 94% sensitive and 37% specific.  So, we have two tests that are wrong about the presence of disease twice as often as they're right - and these authors are using a clinically irrelevant 50% stenosis as their "gold standard".

Rather entertaining to observe the difficulty the cardiology literature is having reconciling all their different imaging options with clinically relevant stenoses, much less outcomes.  Good thing all these inadequate tests are cheap and harmless....

"Coronary Computed Tomography Angiography After Stress Testing"