All Glory to the Triple-Rule-Out

The conclusions of this study are either ludicrous, or rather significant; the authors are either daft, or prescient. It depends fundamentally on your position regarding the utility of CT coronary angiograms.

This article describes a retrospective review of all the “Triple-Rule-Out” angiograms performed at a single center, Thomas Jefferson University Hospital, between 2006 and 2015. There were no specific circumstances under which the TRO were performed, but, grossly, the intended population were those who were otherwise being evaluated for an acute coronary syndrome but “was suspected of having additional noncoronary causes of chest pain”.

This “ACS-but-maybe-not” cohort totaled 1,192 patients over their 10 year study period. There were 970 (81.4%) with normal coronary arteries and no significant alternative diagnosis identified. The remaining, apparently to these authors, had “either a coronary or noncoronary diagnosis that could explain their presentation”, including 139 (11.7%) with moderate or severe coronary artery disease. In a mostly low-risk, troponin-negative population, it may be a stretch to attribute their symptoms to the coronary artery disease – but I digress.

The non-coronary diagnoses, the 106 (8.6%) with other findings, range from “important” to “not at all”. There were, at least, a handful of aortic dissections and pulmonary emboli picked up – though we can debate the likelihood of true positives based on pretest odds. However, these authors also credit the TRO with a range of sporadic findings as diverse as endocarditis, to diastasis of the sternum, and 24 cases of “aortic aneurysm” which were deemed important mostly because there were no priors for comparison.

The authors finally then promote TRO scans based on these noncoronary findings – stating that, if a traditional CTCA were performed, many of these diagnosis would likely be missed. Thus, the paradox. If you are already descending the circles of hell, and are using CTCA in the Emergency Department – then, yes, it is reasonable to suggest the TRO is a valid extension of the CTCA. Then again, if CTCA in the acute setting is already outside the scope of practice, and TRO is an abomination – carry on as if this study never existed.

“Diagnostic Yield of Triple-Rule-Out CT in an Emergency Setting”
http://www.ncbi.nlm.nih.gov/pubmed/27186867

But Where is the Antidote to the Poison @NEJM?

Andexanet alfa is the long-awaited antidote for the Factor Xa inhibitors – rivaroxaban, apixaban, edoxaban, and their ilk. This publication, featured at the European Stroke Congress and in the New England Journal of Medicine, is Portola’s latest update regarding its utility. Is it better than their previous update – their failure to receive initial FDA approval – or just another “incomplete” like their publication last fall?

This is ANNEXA-4, an open-label, single-group study purporting to evaluate the efficacy and safety of andexanet for clinical hemostasis in actively bleeding patients with concomitant use of Factor Xa inhibitors. Or, more specifically, these are interim results – the first 67 of 250 planned for enrollment. The clinical efficacy endpoint is a complex series of adjudicated judgements regarding the cessation of bleeding, hematoma expansion, or change in hematocrit, depending on the type of bleeding enrolled. The primary safety endpoint is death or thrombotic event within 30 days – stroke, myocardial infarction, venous thromboembolism, etc.

There is virtually nothing positive to relate here. The authors, of course, relate that somewhere around 80% of the 47 patients included in their efficacy analysis obtained “good” or “excellent” hemostasis with 12 hours following their andexanet infusion. But, these essentially arbitrary labels at a potentially clinically unimportant timepoint tells us virtually nothing regarding its value versus observation, or an alternative treatment such as prothrombin concentrate complexes.

On the negative side, the list is endless. There is the baffling offensiveness of publishing what amounts to a quarter of a trial in the New England Journal of Medicine.  The mean time to andexanet bolus was nearly 5 hours, raising concern regarding the acuity and severity of bleeding in enrolled patients.  The vague, patient-oriented endpoints are meaningless – with or without a comparator – and thus, this boils down to basically a pharmacokinetic observational study. Even then, the pharmacokinetics don’t appear terribly favorable – andexanet dramatically reduces Factor Xa activity during infusion, but pops back to therapeutic anticoagulation following cessation. A concerning 18% had thrombotic events within 30 days – but, again, without any control group, little can be concluded regarding safety.

Finally, clearly, the NEJM has given up publishing the conflicts-of-interest for the authors because it would sum up to half the journal – this article directs the reader to the disclosure forms on the web. For the eagle-eyed reader, however, they can pick out this text as part of the author affiliations: “Portola Pharmaceuticals, San Francisco (J.T.C., A.G., M.D.B., G.L., P.B.C., S.G., J.L., B.L.W.)”. Yes, eight of the authors are employees of Portola Therapeutics, the manufacturer. Better even, are their ICJME form disclosures. John Curnutte, the Head of Research and Development, has checked the box stating he has no relevant conflicts of interest with the work under consideration for publication – but, you know, outside the submitted work he happens to be an employee for Portola. In fact, from what I can tell, every employee authoring this article declared they have no COI with the work under consideration for publication.

Inconceivable!

Andexanet Alfa for Acute Major Bleeding Associated with Factor Xa Inhibitors
http://www.nejm.org/doi/full/10.1056/NEJMoa1607887

Not Seeing Any Value in RINSE

If a little bit of cooling – or at least Targeted Temperature Management – can preserve brain function, why not start it when the brain is most susceptible to injury? Why not start it when CPR is in progress, and the initial injury from poor perfusion begins?

That was, essentially, the question asked by the RINSE Trial, which randomized out-of-hospital cardiac arrest patients to either rapid infusion of cold saline or standard “ambient” fluid administration. Eligible patients received an initial round of CPR, defibrillation if indicated, and epinephrine if indicated, and were then randomized to one of the two arms.

Unfortunately, there’s not much in this trial favoring the intervention. RINSE was stopped early after receiving hospitals changed their temperature management protocols following the publication of TTM, but still managed to randomize 1,198 patients with similar baseline characteristics between cohorts. About half of patients had non-shockable rhythms, and pre-hospital results were similar. The other half, however, had shockable rhythms, and an excess of 10.2% of these patients died at the scene after cold saline infusion was initiated. Thus, the only trend observed here is one favoring standard care.

There are a few quirks to consider. Only a little more than 10% of all potentially eligible OHCA were enrolled, with no information regarding the unenrolled cohort or reasons for exclusion. The temperature difference between the two groups, based on pre-hospital tympanic membrane measurements, was only 0.7°C. Lastly, the primary outcome measure used was survival to hospital discharge, and not one of neurologic function – which may have been better aligned with the underlying neuropreservation hypothesis.

Regardless, there certainly isn’t anything here to trump up enthusiasm for further exploration, even if the magnitude of harm observed probably exceeds the expected effect of their intervention.

“Induction of Therapeutic Hypothermia During Out-of-Hospital Cardiac Arrest Using a Rapid Infusion of Cold Saline (The RINSE Trial)”

http://circ.ahajournals.org/content/early/2016/08/25/CIRCULATIONAHA.116.021989

Beware Good Times; Beware!

I imagine some of you are active travelers, eating on the go. Perhaps you have business interests and frequently dine out of the home. Sadly, your rock and roll lifestyle may yet be the end of you.

This is an interesting analysis of the “Progression of Early Subclinical Atherosclerosis” study, breaking down participants into dietary spectra. Based on cross-sectional analysis of the reported eating habits of participants, there were three distinct dietary patterns cohorted together: Mediterranean, Western, and and a “social-business” eating pattern. Approximately 40% were in each the Mediterranean and Western cohorts, with the remainder in “social-business”. The general attributes of each diet are shown in the figure below:

eating patterns image

The finding of note – after all participants underwent atherosclerotic screening tests – is that the “social-business” pattern of consumption is, quite obviously, the highest risk for disease progression. Whereas the Mediterranean cohort had only 36% with generalized or intermediate atherosclerosis, the “social-business” cohort totaled an impressive 68%. The Western diet was slightly above the Mediterranean, at 41%.

Stay healthy, my friends.

“Association Between a Social-Business Eating Pattern and Early Asymptomatic Atherosclerosis”

http://content.onlinejacc.org/article.aspx?articleID=2544530

Tylenol & Case of the Flawed Fetus

If you’re like most folks advising pregnant patients on pain and fever control, you’ve advised against ibuprofen and recommended acetaminophen. It is, after all, considered to be generally safe throughout pregnancy, in contrast to the alternatives.

I’m afraid I do not know precisely what to make of this study, but it is the latest in a context of several other studies linking maternal acetaminophen use during pregnancy with behavioral issues in young children. These authors link surveys of pregnant women performed over a decade ago with follow-up surveys of their children, with specific emphasis on identifying potential cofounders for their observed association.

The ultimate conclusion is fairly clear from just the title, with the subtitle of “Evidence Against Confounding”. An association is clearly observed between those they identify with likely or confirmed usage of acetaminophen and increased behavioral and attention difficulties in childhood. However, the evidence against confounding is rather incomplete. There are small differences in maternal psychiatric illness, maternal smoking, and maternal alcohol use favoring normally behaved children – and, while these authors attempt to control for these factors, this still introduces some element of statistical tomfoolery. There are also several non-genetic and non-prenatal risk factors for ADHD, and these authors are able only to collect a handful of these – absent completely any observations of the home environment of the children evaluated. Finally, no dose-response relationship is ultimately measured, as well.

I would, of course, ultimately advise minimal medication exposure in pregnancy, regardless. If pain control is necessary, it is not clear this risk – if true – is specifically of greater magnitude than those associated with alternative analgesia. For, this does not yet change practice.

“Association of Acetaminophen Use During Pregnancy With Behavioral Problems in Childhood”

http://archpedi.jamanetwork.com/article.aspx?articleid=2543281

The High-Sensitivity Troponin Ennui

They’re coming. It’s inevitable. They have yet to be approved in the the United States, but every year the news is the same: they’re coming.

High-sensitivity troponins have been both lauded and mocked from various perspectives. The literature is replete with examples of expedited rule-outs in the Emergency Department owing to their improved lower limit of detection for myocardial injury. However, every study touting the benefits of improved sensitivity has begrudgingly or worse acknowledged the correspondingly diminished specificity.

This, then, is a randomized trial of reporting either a conventional troponin assay result or a high-sensitivity troponin assay result, with a multitude of patient-oriented short- and long-term outcomes measured. The specific assays used here were either a c-TnT with a threshold of detection of 30 ng/L, or a hs-TnT with a threshold of detection of 3 ng/L. Clinicians caring for patients were randomized to making care decisions based on one, without knowledge of the other.

For all the various propaganda for and against high-sensitivity troponins, this trial is highly anticlimactic. There were, essentially, no changes in physician behavior resulting from the additional information provided by the more sensitive assay. No fewer patients were admitted, similar numbers of ultimate downstream tests occurred, and there were no reliable differences in long-term cardiac or combined endpoint outcomes.

The only outcome of note is probably consistent with what we already knew: any circulating troponin portends worse outcomes. This may be most helpful in directing the long-term medical management of those whose troponin levels were previously undetectable with a conventional assay; these patients clearly do not have the same virtually-zero risk as a patient with undetectable troponin levels. Indeed, troponin levels alone were a better predictor of long terms outcomes than the Heart Foundation Risk Stratification, as well.

I’ll let Judd Hollander sum it up in his most concise – with a link to much more verbose – terms:

“Randomized Comparison of High-Sensitivity Troponin Reporting in Undifferentiated Chest Pain Assessment”
http://circoutcomes.ahajournals.org/content/early/2016/08/09/CIRCOUTCOMES.115.002488.abstract

Your New Career in “Waiting Room Medicine”

A few years back, a facetious advertisement in the Canadian Journal of Emergency Medicine promoted the availability of fellowship positions in “Waiting Room Medicine”, a comedic take on the struggles of the specialty to manage increasing patient volume with limited resources. While there are certainly Emergency Departments with ample space and “white glove”-type service – see the for-profit expansion of free-standing EDs in states like Texas – there are also publicly-funded and other EDs that struggle with physical bed space for patients for a variety of reasons.

This study attempts to quantify the effect of an intervention utilized by many overburdened or otherwise saturated EDs – starting the initial evaluation in triage with either provider-directed or protocolized orders. At UCLA/Olive-View, all patients presenting to an already-full ED received an initial rapid evaluation by an attending physician or nurse practitioner. During their 10-month study period, non-pregnant adults with abdominal pain were randomized to either receiving initial evaluation orders following this evaluation, or to be returned to the waiting room to await full evaluation at a later time pending bed availability.

There were 1,691 enrolled and randomized, with approximately 10% excluded from analysis mostly because they left the ED before their evaluation was complete. Overall, the initiation of the work-up in triage saved patients approximately a half-hour, on average, of bedded time in the ED. This was reflected by a similar absolute decrease in overall ED length-of-stay. There were a couple other interesting tidbits unique to their execution:

  • The most profound difference associated with WR medicine was simply blood and urine testing. While imaging could be ordered up front, it was rarely done.
  • Some of the advantages related to the WR blood testing were minimized by ~13% of patients receiving further testing after being bedded in the ED.
  • Patients randomized to WR medicine received, on average, a greater number of diagnostics per patient, probably representing resource waste.

So – yes, this probably accurately reflects the impact of orders placed in triage: some wasted resources based on the initial, incomplete evaluation, with a trade-off of potential time savings. The extent to which your system might benefit from a similar set-up is probably related to your level of chronic bed scarcity.

“Initiating Diagnostic Studies on Patients With Abdominal Pain in the Waiting Room Decreases Time Spent in an Emergency Department Bed: A Randomized Controlled Trial”
http://www.annemergmed.com/article/S0196-0644(16)30360-2/abstract

Shaking Out Stroke Mimics

In a world of continued aggressive guideline- and pharmaceutical-sponsored expansion of stroke treatment with thrombolytics, this article fills and important need – better codifying the predictors of stroke mimics. While other editorials espouse the need to be fast without being sure, this is frankly irresponsible medicine – and, in resource-constrained environments, unsustainable.

These authors at two academic centers performed a retrospective clinical and imaging review of 784 patients evaluated for potential acute cerebral ischemia. Patients were excluded if they had signs of acute stroke on initial non-contrast imaging, and if they did not subsequently undergo MRI. Based on review of the totality of clinical information for each patient, 41% of this cohort were deemed stroke mimics. The authors scoring system, then derived 6 variables – and 3 or more were present, the chance of stroke mimic being cause of the current presentation was 87.2%. Their criteria:

  • Absence of facial droop
  • Age <50 y/o
  • Absence of atrial fibrillation
  • SBP <150 mm Hg
  • Presence of isolated sensory deficit
  • History of seizure disorder

When the rate of tPA administration to stroke mimics is ~15%, and 30-40% of patients evaluated for stroke are stroke mimics – there is a lot of waste and potential harm occurring here. These authors suggest the use of this score could potentially halve these errant administrations for 94% sensitivity, or cut errant administrations down to 2% with 90% sensitivity. Considering the patients for which stroke/stroke mimic is an ambiguous diagnosis, it is reasonably likely the symptoms are of lesser severity – and in the range for which tPA is of most tenuously “proven” value. While their rule has not been prospectively validated, some of these elements certainly have face validity, and can be incorporated into current practice at least as a reminder.

“FABS: An Intuitive Tool for Screening of Stroke Mimics in the Emergency Department”

http://stroke.ahajournals.org/content/early/2016/08/04/STROKEAHA.116.013842.abstract

Save the FFP, Save the World

This is a trial that does a couple things I really love: it nails inappropriate usage of the International Normalized Ratio to the wall, while simultaneously offering a viable alternative.

The INR is intended for one thing and one thing only: monitoring anticoagulation with warfarin. The INR, as a proxy for the PT, has instead been utilized as a pointless and misleading instrument for screening adults for previously undiagnosed coagulopathy. The PT, in the correct, narrow clinical context, has value – the INR does not.

This trial beautifully illustrates this point. These are patients with severe cirrhosis and end-stage liver disease undergoing invasive procedures. With thirty patients in each group, they were randomized to either standard pre-procedure prophylactic transfusion per-protocol based on INR guidelines, or the necessity of blood product was determined via thromboelastography. In the standard care group, the mean INR was 2.01, and, thus, per protocol, the typical patient received an appropriate dose of 4 units of FFP for “correction”. In the TEG group, only a handful of patients were deemed to actually have a coagulopathy for which FFP was indicated. No patients in the TEG-guided cohort had procedure-related bleeding and identical numbers of patients needed red cell transfusions.

Transfusions are expensive and dangerous: transfusion-related circulatory overload, transfusion-related lung injury, various incompatabilities and allergic reactions are not terribly infrequent. They should be avoided whenever possible, and this study beautifully illustrates the disutility of the INR for screening for bleeding risk. ESLD patients have elevated INRs from their inability to synthesize Vitamin K-dependent clotting factors, but they also do not synthesize Protein C and S, and there are a variety of other compensatory mechanisms. These patients do not routinely need transfusions of FFP prior to procedures, despite most centers being replete with similar protocols.

“Thrombelastography-Guided Blood Product Use Before Invasive Procedures in Cirrhosis With Severe Coagulopathy: A Randomized, Controlled Trial”
http://www.ncbi.nlm.nih.gov/pubmed/26340411

Don’t Stop at the Headline

The verdict is in: “Aspiration Thrombectomy No Help for Large-Clot Strokes”, reports MedPage Today.

Except, they’re not precisely correct – in a way, you could even say they’re wrong.

This is THERAPY, an endovascular trial in acute stroke featuring the Penumbra aspiration device.  This is somewhat unique, as the technology differs from the otherwise popularized Solitaire retrieval system. This trial is also different from the most contemporary comparators, as its imaging criteria did not rely on perfusion imaging, but, rather, simply large-vessel occlusion with a clot length of 8mm or greater.

The results of the trial, as you might have picked up from the lay press headline, were negative – that is to say, they did not reach statistical significance. Their primary endpoint for modified Rankin Scale of 0-2 was achieved in 38% receiving endovascular treatment and 30% receiving intravenous thrombolysis alone, and this 8% absolute difference produced a p-value of only 0.52. However, the trial was initially scheduled to enroll 692 patients to be powered to detect a 10.6% difference, but stopped enrollment after 108 based on the publication of other positive endovascular trials.

So, simply put, this trial tells us hardly anything. Is the Penumbra system just as good as Solitare? Probably, but perhaps we’ll never know for certain. Does the 8% difference seen in this trial reflect the lower magnitude of effect of treatment relating to lack of perfusion imaging? Probably, as well, based on the the larger evidentiary context.

But, at the minimum, the medical reporting has simply gone off course with their headline.

“Aspiration Thrombectomy After Intravenous Alteplase Versus Intravenous Alteplase Alone”
http://www.ncbi.nlm.nih.gov/pubmed/27486173