Month: June 2020

Selective vs. Universal Screening for BCVI

Chasing down cerebrovascular injury is a controversial topic. The incidence of injury to carotid or vertebral arteries following blunt trauma is extremely low, with relative rarity varying by practice setting. Because of its general infrequency, many settings utilize the “Memphis” or “Denver” screening criteria to improve the value of imaging.

These authors, however, describe their implementation of a universal screening protocol for BCVI as routine component of their “whole-body” CT for “all major adult blunt trauma activations”. The data set analyzed is a retrospective local trauma registry from their level 1 trauma center, and 4,687 activations fulfilled their inclusion criteria. The overall incidence of BCVI in their population was 2.7%, with about half of those being grade 3 or higher (pseudoaneurysm or worse).

Based on case review of these 126 patients with BCVIs, only 91 (72%) would have met the current American College of Surgeons guidelines for imaging, with a handful additional more picked up by expanded Denver criteria. The authors’ conclusion – universal screening should be considered – ties in a bit with their bias towards whole-body CT, presuming these additional detected injuries represent potential reduced downstream morbidity and mortality.

It should be clear, however, these data have somewhat limited generalizability to most of Emergency Medicine. The individuals with BCVI in their cohort suffered substantial numbers of skull base fractures, cervical spine fractures, traumatic brain injuries, and had in-hospital mortality of 12.7%. Outside the context of major trauma, universal screening for BCVI will be of limited value. For the vast majority of us, continuing to refer to the most recent EAST recommendations for selective screening remains a reasonable practice. In the narrower context of major trauma referrals, these data could inform more expansive screening protocols, while universal screening for all major trauma is still likely one step too far.

“Blunt Cerebrovascular Injury – The Case for Universal Screening”
https://journals.lww.com/jtrauma/Abstract/9000/BLUNT_CEREBROVASCULAR_INJURY___THE_CASE_FOR.97839.aspx

New Troponin, Same as Old Troponin?

It doesn’t take more than a quick search through the archives to notice a great deal of gnashing of teeth over the introduction of high-sensitivity troponin. The perpetual concern: trade-offs with sensitivity and specificity, leading to downstream increased resource utilization.

This brief research letter is basically good news: the Mayo Clinic hospital system rolled out high-sensitivity troponin assays and very little changed. Looking at about 54,000 patients divided equally into pre- and post- periods, the diagnosis of myocardial infarction increased significantly. However, most of the change was coded as Type 2 MI, rather than an acute coronary syndrome, leading to little change in resource use – no difference in admissions, echocardiography, stress testing, or angiography.

There’s brief allusion in the article to the underlying protocols in place – in which patients are typically assessed using HEART, along with a system of champions and education supporting the change. Assuming these retrospective coded data accurately reflect practice, it is likely these concerted efforts prevented misinterpretation of detectable troponin levels – hence the increase in Type 2 MI. Implementation of these assays in other health systems may not reflect these same successes, but it is reasonable to expect the on-ramp for high-sensitivity troponin has likely now been long enough most are now familiar with their interpretation.

Finally, the ultimate better question might be – if high-sensitivity assays didn’t clearly impact care, what value do they confer? If there are no measurable improvements in diagnosis of acute MI, is there much utility? However, these data do not provide insight into whether there are downstream changes in medication management potentially reducing long-term cardiovascular adverse outcomes – nor, likewise, any medication changes resulting in increased costs and adverse outcomes without an improvement in cardiovascular health. And, asking these questions is likely moot, regardless – these assays are here and here to stay.

“Implementing High-Sensitivity Cardiac Troponin T in a US Regional Healthcare System”
https://www.ahajournals.org/doi/10.1161/CIRCULATIONAHA.119.045480