Month: November 2018

That Lego is Gone

Lego, a portmanteau of Danish words meaning “play well”, are ubiquitous toys around the world. This means the bite-sized bits are equally prevalent in the hands of infants and toddlers around the world – and in their mouths. What goes in a toddler’s mouth goes into their stomach.

This brief study evaluates six toddlers – ahem, pediatricians – who each swallowed a Lego head:

These adult children subsequently searched stools for signs of the swallowed item, as well as performed an assessment of stool consistency. Most importantly, they were able to derive infantile acronyms for their assessments – the SHAT and FART scores.

One of the six participants was never able to locate the ingested Lego part, despite two weeks of stool searching. The other five found them in their second or third bowel movement, which, on average, was 1.71 days later.  Stool consistency was unrelated to passage of the head.

Obviously, the generalizability and reliability of such a study is quite low, being adults and only six of them. Then, although these authors report “no complications”, they have not yet located one of the six heads – perhaps a future case report: “Acute appendicitis involving an unusual appendicolith”?  At the least, a potential future IgNobel prize awardee.

“Everything is awesome: Don’t forget the Lego”
https://onlinelibrary.wiley.com/doi/full/10.1111/jpc.14309

The Fourth Universal Definition of Myocardial Infarction

You’ve seen Sepsis-3 – but did you miss MI-4?  Not, unfortunately, a James Bond reference – but the “long-awaited” 2018 Fourth Universal Definition of Myocardial Infarction.

Effectively, the crux of this document is to help specifically describe cardiac injury and differentiate the MI and non-MI causes of troponin elevation. This ties to tweezing out the difference between “myocardial injury” and “myocardial infarction”. “Myocardial injury” simply describes circulating cardiac troponin levels ≥99th percentile, and can be acute or chronic. “Myocardial infarction”, on the other hand, is effectively myocardial injury plus supporting evidence for acute myocardial ischemia.

Exciting, I know!

Finally, to recap, the five (six?) types of myocardial infarction:

  • Type 1 – Myocardial ischemia and troponin levels ≥99th percentile resulting from atherosclerosis and thrombosis, encompassing STEMI and NSTEMI.
  • Type 2 – Myocardial ischemia and troponin levels ≥99th percentile resulting from thophysiologic mechanisms leading to a mismatch of oxygen supply and demand.
  • Type 3 – Sudden death suspected to be from new cardiac ischemia, specifically when cardiac biomarkers are not available.
  • Type 4a – Coronary intervention-related MI with troponin levels more than 5 times the 99th percentile, or rising troponin levels, and other supporting evidence for new ischemia within 48 hours of PCI and relating to a specific procedural complication.
  • Type 4b – Same criteria as Type 1 MI, but related to stent/scaffold thrombosis, absent a specific procedural complication.
  • Type 5 – Effectively Type 4a, but with troponin levels 10 times the 99th percentile, and associated with complications from CABG.

Just keeping up, keeping up.

“Fourth Universal Definition of Myocardial Infarction (2018)”
http://www.onlinejacc.org/content/early/2018/08/22/j.jacc.2018.08.1038

Computer Says: Discharge that Pulmonary Embolism!

We’ve learned a couple important things about pulmonary emboli for the past five or so years. First, we diagnose too many of them. Second, all pulmonary emboli do not need to be hospitalized. Knowing, as they say, is half the battle. That’s a start – but it’s not enough.

This study involves important thing number two above, the hospitalization of PE. Kaiser Permanente, in its endless quest for value, has already published several studies demonstrating the safety of discharging patients with PE. However, hidden in the descriptive statistics from those studies are the unfortunate still-low percentages of patients discharged.

In this prospective, multi-center, “convenience-assigned” trial, a computerized decision-support tool was rolled out to support risk-stratification for patients diagnosed with PE. Based on the pulmonary embolism severity index (PESI), patients scoring in class I or II were encouraged to be discharged, while those with higher scores were nudged towards hospitalization. In their pre-post design, little change occurred at the control hospitals, while the percentage of patients with PE discharged from the intervention hospitals jumped from 17.4% to 28.0%. No issues regarding untoward 5-day recidivism or 30-day adverse events were detected.

This is a great step forwards, and, frankly, one of the most prominent examples of decision-support being actually useful to implement practice change.   That said, in the intervention hospitals, there were “physician champions” associated with the roll-out of the CDS intervention, which almost certainly increased update.  Then, 41.2% of patients were PESI class I or II, so there’s even further room for improvement above these topline results – but this is an at least solid effort.

“Increasing Safe Outpatient Management of Emergency Department Patients With Pulmonary Embolism”

http://annals.org/aim/article-abstract/2714293/increasing-safe-outpatient-management-emergency-department-patients-pulmonary-embolism-controlled

The Swiss, Ruling out PE in Pregnancy

Evaluating the average Joe/Jane for pulmonary embolism is rather straightforward – but let’s not go back into that morass of practice variation and low-value over-diagnosis. This is an a study looking at how to diagnose PE during pregnancy, which is fraught with its own unique issues.

Firstly, obviously, CTPA ought to be avoided whenever possible – and moreso when there is a chance of fetal exposure. When the benefits outweigh the risks, of course, it is reasonable to proceed. Then, use of D-dimer as a tool to inform the posterior probability of PE is challenged by its steady increase in pregnancy.  This combination of issues results in general uncertainty with regard to the approach.

This is their algorithm:

Over the course of eight years, at 11 centers, these authors included 395 patients in their study – 357 of whom were evaluated per-protocol. Only a handful were assessed as “high” risk, while the bulk underwent D-dimer testing with a test threshold of 500 µg/L on the Vidas assay. The D-dimer was virtually useless, with only 46 of 392 being excluded from further evaluation. Then, the bilateral lower extremity ultrasound was basically useless, with only 7 positives out of 349 performed – resulting in 342 CTPAs. There were 19 positive CTPA, and then two of the inconclusive CTPA were ultimately diagnosed with PE by V/Q scanning.

What a mess. For those keeping score at home, that’s 7.1% yield for their evaluation of PE, and all their extra hoops prevented little radiation exposure. From a diagnostic evaluation standpoint, of course, their protocol was entirely adequate with regard to missed PE – unsurprising because most patients received all the tests in their algorithm.

The ugliest observation here is their prevalence of 7.1% is actually far lower than the prevalence observed in the non-pregnant population in Europe. Step one in fixing this approach: just apply the same gestalt to this population as the remainder of ED presentations. Then, let’s adopt the YEARS protocol, at a minimum, and consider adopting trimester-adjusted cut-offs for D-dimer. The miss rate will not be zero – but, incorporating appropriate clinical judgment, the net harms from untreated PE will be balanced by the benefit of avoided radiation, anticoagulation, and over-diagnosis.

“Diagnosis of Pulmonary Embolism During Pregnancy: A Multicenter Prospective Management Outcome Study”
http://annals.org/aim/article-abstract/2708166/diagnosis-pulmonary-embolism-during-pregnancy-multicenter-prospective-management-outcome-study

To Lyse Before Endovascular Intervention … or Not

I’ve been of the general opinion that, no, thrombolytics are of low utility prior to endovascular intervention for stroke. The typical candidate for endovascular intervention has a clot in a large vessel. Thrombolytics are overwhelmingly ineffective at treating such lesions, hence, the entire foundational need for endovascular intervention. Then, absent indication creep, the patients for whom endovascular intervention is intended are those with salvageable tissue as resulting from excellent collateral circulation – i.e., the sort of patients for whom the “time is brain” mantra does not strictly apply. Therefore, thrombolytics prior to the definitive procedure are effectively low-value, and deplete the fibrinogen likely needed to reduce serious procedural adverse events.

But, this is just opinion – useful evidence is profoundly lacking.

This article, unfortunately, does not add much to the current body of evidence. These authors present a post-hoc analysis from the ASTER trial, which tested clot aspiration versus stent retrieval. As is typical for these types of trials, those who arrived within 4.5 hours of symptom onset were treated with thrombolytics prior to their procedure, while others were excluded as “outside the window”. There were 381 patients here, 250 of whom were eligible for thrombolytic therapy. These authors pull out all the stops with regard to data analysis, breaking down their outcomes by procedural attempts, reperfusion, complications, clinical outcomes, and hemorrhagic complications. Then, they further generate forest plots for adjusted outcomes depending on the arm of the trial – aspiration or stent retriever.

And, after all this, it’s still just a retrospective data dredge for meaningless signals replete with unmeasured confounders and selection bias. The patients who received thrombolysis initially are different than those who did not, full stop – and no multivariate regression can reliably produce precise estimates of their likely outcomes. I could have told you “we need a prospective trial design” to shed further light on this question, arriving at the same conclusion in six words, rather than in these seven pages.

“Mechanical Thrombectomy Outcomes With or Without Intravenous Thrombolysis Insight From the ASTER Randomized Trial”
https://www.ahajournals.org/doi/10.1161/STROKEAHA.118.021500