Tag Archives: carotid

The October 2020 Trauma MedEd Newsletter: Blunt Carotid and Vertebral Artery Injury

This issue is devoted to an uncommon yet potentially devastating problem, blunt carotid and vertebral artery injury.

In this issue, you will learn about:

  • What BCVI is
  • How common it is
  • The various screening systems and how good they are
  • How to grade it
  • And most importantly, how to treat it

To download the current issue, just click here!

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In The Next Trauma MedEd Newsletter: Blunt Carotid And Vertebral Injury

The next issue of Trauma MedEd will be sent out to subscribers this week, and will provide some interesting information on fblunt carotid and vertebral artery injury (BCVI).

This issue is being released to subscribers at 9am Central time on Tuesday. If you sign up any time before then, you will receive it, too. Otherwise, you’ll have to wait until it goes out to the general public next week. Click this link right away to sign up now and/or download back issues.

BCVI is not something trauma professionals see often. Or is it?

In this issue, learn about:

  • What BCVI is
  • How common it is
  • The various screening systems and how good they are
  • How to grade it
  • And most importantly, how to treat it

As always, this month’s issue will go to all of my subscribers first. If you are not yet one of them, click this link right away to sign up now and/or download back issues.

Best Of AAST #9: Blunt Carotid And Vertebral Injuries

Blunt carotid and vertebral artery injuries (BCVI) are an under-appreciated problem after blunt trauma. Several screening tools have been published over the years, but they tend to be unevenly applied at individual trauma centers. For an unfortunate few, the only indication of BCVI is a stroke while in hospital.

The overall incidence of BCVI is thought to be small, on the order of 1-2%. But how do we know? Well, the group at Birmingham retrospectively reviewed every CT angiogram (CTA) of they did in a recent two year period. They did this after adopting a policy of screening all their major blunt trauma patients. Each patient chart was also evaluated to see if they met any of the criteria for the three commonly used screening systems.

Here are the factoids:

  • 5,634 of 6,800 blunt trauma patients underwent BCVI screening with CTA of the neck
  • 471 patients (8.4%) were found to have BCVI
  • Here are the accuracy statistics for the three screening systems

Here are my comments: The authors found that the incidence of BCVI is about 8x what we previously thought. What we don’t know is the percentage of these patients that go on to cause stroke or other neurologic deficits. But this is somewhat frightening.

Even more frightening is that the screening systems that we rely on fare so poorly. The Denver and Modified Memphis criteria have a true positive rate that is the same as a coin toss. And even if the patient meets none of the criteria in any system, about 5% BCVI will sneak through (NPV 95%).

So the question becomes, do we all perform universal screening for blunt trauma? Or do we still use one of the three systems and keep our fingers crossed that the ones we miss will not progress? Or maybe just give everybody an aspirin a day for a while. And still keep our fingers crossed!

Here are some questions for the presenter and authors:

  • Why did you decide to implement a universal screening protocol in the first place? Bad experience(s)?
  • Do you have any screening recommendations other than to screen everybody? How do you decide which blunt trauma patients to screen? Every car crash? What level of fall? The devil is in the details!

This is an easy to follow paper with a solid analysis and real world implications. Excellent work!

Best Of EAST 2020 #1: Treatment Of Blunt Carotid & Vertebral Injuries

The 33rd Annual Assembly of the Eastern Association for the Surgery of Trauma starts in just two weeks! As usual, I will select several interesting abstracts from the bunch to review. I’ll go over the findings of the research, critique it, and then provide a series of questions for the presenter to consider. These questions are ones that members of the audience may very well ask (hint, hint).

And FYI, I always send a heads-up to the presenters with a link to the post so they can study up beforehand!

So let’s get started with the first abstract that will be kicking off the meeting on January 15. Blunt cerebral / vertebral artery injury (BCVI) is one of those insidious injuries that trauma professionals don’t always think about. But they do occur in about 1% of major trauma patients. It’s one of those injuries that can’t be ignored because very serious complications may occur if it is not treated appropriately (think stroke).

Unless there are extenuating circumstances like bleeding or pseudoaneurysm, treatment is usually pharmaceutical. There are two camps: antiplatelet drugs vs anticoagulant drugs. But there is very little data to determine which one is better.

This abstract is a retrospective review from the National Readmission Database (NRD). This resource is maintained by the US government and provides information on patient readmissions nationally across all payors as well as the uninsured. They included all patients > 18 years old with a BCVI and minor injuries in other body regions. Patients who suffered a stroke complication during their initial hospital stay were excluded.

Patients were divided into two groups: those taking an antiplatelet agent and those prescribed an anticoagulant. Outcomes of interest were readmission with CVA and death, within six months.

Here are the factoids:

  • 725 patients with BCVI were found during the five year study period
  • Patients were propensity matched for a 1:1 ratio of patients taking antiplatelet vs anticoagulant drugs, leaving 370 patients for analysis
  • There was a lower rate of admission in the anticoagulant patients vs the antiplatelet ones (9% vs 26%)
  • There were fewer deaths within 6 months in the anticoagulated patients (1.3% vs 3.9%)
  • Median time to stroke was 6-9 days and was not significantly different between the two groups

The authors concluded that the overall stroke rate after BCVI is 6%. They also found an association with lower rates of CVA within 6 months of discharge in patients on anticoagulants. They recommend further studies to determine which type of chemoprophylaxis is best.

My comments: This is an interesting paper that addresses a problem that we don’t have good answers for. The study was well constructed and simple to follow. The two areas that I have questions about are data quality and statistical power.

The NRD is a powerful tool for research, but does have some shortcomings. It only contains information on readmissions, and may not contain some patients who had asymptomatic strokes or massively stroked and died at home. Not knowing these numbers injects some bias and could change the numbers and findings of the study.

The other issue has to do with statistical power. The overall eligible patient group (725 patients) was small in the first place. Propensity matching for a 1:1 ratio shrunk it to only 370, or 185 in each treatment group. My armchair power calculations show that this study would only be able to detect a 7x difference in mortality, and not the 3x difference seen. I’m glad the authors didn’t claim a “significant decrease in CVA” in the anticoagulated patients vs the antiplatelet drug patients.

Here are my questions for the authors:

  1. What do you see as drawbacks to data quality in your study due to use of the National Readmissions Database? How do you think that patients not included in it impacted your data?
  2. Is there anything you can do to improve the statistical power of the study to see if the mortality difference is truly different? Even though your statistical analysis shows significance, the number of subjects doesn’t allow you to claim this until the mortality in the antiplatelet group reaches 9%. 

This was a simple yet fascinating study, and is a start toward helping us determine which of the two drug classes is most appropriate for patients with BCVI.

Reference: Treatment of blunt cerebrovascular injuries: anticoagulants or antiplatelets? EAST Annual Assembly abstract #1, 2020.

Management Of Blunt Carotid / Vertebral Injury

Yesterday I reviewed the most commonly used grading system for blunt carotid / vertebral injury (BCVI). Today, I’ll describe the usual management of these injuries, by grade. Unfortunately, there is a paucity of definitive literature to guide us because these injuries are rare. So here are our best guesses to date.

There are basically three modalities at our disposal for managing BCVI: antithrombotic medication (heparin and/or antiplatelet agents), surgery, and therapeutic angiographic procedures. The choice of therapy is usually based on surgical accessibility and patient safety for anticoagulation. We do know that a number of studies have shown a decrease in stroke events in patients who are heparinized. Unfortunately, this is not always possible due to associated injuries. Antiplatelet agents are usually tolerated after acute trauma, especially low-dose aspirin. Several studies have shown little difference in outcomes in patients receiving heparin vs aspirin/clopidogrel for BCVI.

So what to do? Here are some broad guidelines:

  • Grade I (intimal flap). Heparin or antiplatelet agents should be given. If heparin can be safely administered, it may be preferable in patients who will need other surgical procedures since it can be rapidly reversed just by stopping the infusion. These lesions generally heal completely, so a followup CT angiogram should be scheduled in 1-2 weeks. Medication can be stopped when the lesion heals.
  • Grade II (flap/dissection/hematoma). These injuries are more likely to progress, so heparin is preferred if it can be safely given. Stenting should be considered, especially if the lesion progresses. Long-term anti-platelet medication may be required.
  • Grade III (pseudoaneurysm). Initial heparin therapy is preferred unless contraindicated. Stable pseudoaneurysms should be followed with CTA every 6 months. If the lesion enlarges, then surgical repair should be carried out in accessible injuries, or stenting in inaccessible ones.
  • Grade IV (occlusion). Heparin therapy should be initiated unless contraindicated. Patients who do not suffer a catastrophic stroke may do well with followup antithrombotic therapy. Endovascular treatment does not appear to be helpful.
  • Grade V (transection with extravasation). This lesion is frequently fatal, and the bleeding must be addressed using the best available technique. For lesions that are surgically accessible, the patient should undergo the appropriate vascular procedure. Inaccessible injuries should undergo angiographic treatment, and may require embolization to control bleeding without regard for the possibility of stroke.

References:

  • Scott WW, Sharp S, Figueroa SA, et al. Clinical and radiographic outcomes following traumatic Grade 1 and 2 carotid artery injuries: a 10-year retrospective analysis from a Level I trauma center. J Neurosurg 122:1196, 2015.
  • Scott WW, Sharp S, Figueroa SA, et al. Clinical and radiographic outcomes following traumatic Grade 3 and 4 carotid artery injuries: a 10-year retrospective analysis from a Level 1 trauma center. J Neurosurg 122:610, 2015.
  • Scott WW, Sharp S, Figueroa SA, et al. Clinical and radiological outcomes following traumatic Grade 1 and 2 vertebral artery injuries: a 10-year retrospective analysis from a Level 1 trauma center. J Neurosurg 121:450, 2015.
  • Scott WW, Sharp S, Figueroa SA, et al. Clinical and radiological outcomes following traumatic Grade 3 and 4 vertebral artery injuries: a 10-year retrospective analysis from a Level I trauma center. The Parkland Carotid and Vertebral Artery Injury Survey. J Neurosurg 122:1202, 2015.