Tag Archives: carotid

Anatomy

Who Is At Risk For Blunt Cerebrovascular Injury?

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Yesterday, I wrote about proper screening for blunt cerebrovascular injury (BCVI). But, as you know, it’s important to screen only when there is a significant risk of the injury being present. Screening using the shotgun approach (screen everyone for everything) yields enough false positive results to present potential danger to your patient.

A variety of authors on this topic have promoted a number of high risk criteria to trigger a screening test. Most make sense, and are related to the anatomy of the vessels in question. The carotid arteries are relatively unprotected, although a bit deep, as they course up the neck. Thus, it is possible to damage them when they suffer a direct and significantly hard blow. Once they enter the skull, they are better protected. However, fractures through key areas of the skull base and face can injure the vessels, even in these protected locations.

The vertebral arteries are deep and relatively protected as they course through the vertebral foramina. However, if the vertebrae are fractured or subluxed, vessel injury can occur.

Finally, and as always, the physical exam is important. If there are unexpected neurologic changes that can’t be explained by other injuries, or there are indications of deep vascular injury, BCVI needs to be considered.

Here is my list of indications to screen for BCVI:

  • Neurologic abnormality not explained by diagnosed injury
  • Arterial epistaxis†
  • Seat belt sign on neck†
  • GCS < 8 (this is the most commonly forgotten one)
  • Petrous bone fracture
  • C‐spine fracture (C1‐C3) or subluxation at any level†
  • Fracture through foramen transversum†
  • LeFort II or III fractures

Bottom line: Be on the lookout for any of the criteria listed above in your trauma patient. If you find one during your initial evaluation, be sure to order a CT angiogram of the neck. And keep an eye out while scanning the head and cervical spine. If any of the other radiographic indications become apparent, add on the CT angiogram at that point.

General

What’s The Best Test For Blunt Cerebrovascular Injury?

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Blunt injury to the carotids or vertebrals (BCVI) is a little more common than originally thought, affecting about 1% of blunt trauma patients. We have many tools available to help us diagnose the problem: duplex ultrasound, CT angiography (CTA), MR angiography (MRA), and even good old conventional 4 vessel angiography. 

But which one is “best?” This is a tough question, because there is always some interplay between clinical accuracy and cost. The surgical group at the Medical College of Wisconsin – Milwaukee did a nice job teasing some answers from existing literature on the topic. The authors tried to take a comprehensive look at costs, including money spent to prevent stroke, the cost of complications of therapy, and the overall cost to society if the patient suffers a stroke.

Here are the factoids:

  • For patients at risk for BCVI, the stroke rate is 11% without screening, 6% with duplex ultrasound screening, 4% with MRA, and 1% with either CTA or conventional angiography
  • From a societal standpoint (includes the lifetime costs of stroke for the patient), CTA is the most cost effective at $3,727 per patient
  • From the hospital standpoint (does not include lifetime cost), no screening is the most cost effective, but has the highest stroke rate (11%)
  • CTA prevents the most strokes, and costs about $10,000 per patient while decreasing societal costs by about $32,000 per patient screened

Bottom line: The “best” test for patients at risk for blunt cerebrovascular injury is the CT angiogram. It minimzes the stroke rate, and provides information on all four vessels supplying the brain, which is probably why the duplex ultrasound has a higher miss rate (can’t see the vertebrals or into the skull). But how do you decide who is at risk for this problem. Tune in tomorrow!

Reference: Screening for Blunt Cerebrovascular Injuries is Cost-Effective. J Trauma 70(5):1051-1057, 2011.

General

Outcome After Blunt Cerebrovascular Injury (BCVI)

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Blunt injuries to the carotid and vertebral arteries are not as uncommon as we used to think. Unfortunately, there’s a lot of controversy surrounding everything about them: screening, management, and outcome. A paper just out detailed outcomes in a (relatively) large series of these patients. 

As expected with this rare injury, it’s a retrospective study. A busy Level I center identified 222 patients with 263 BCVIs over a 4 ½ year period. Twenty four died before discharge and 11 afterwards. Of the remaining patients, only 74 could be located and only 68 could be persuaded to complete an interview and evaluation of their functional status. Functional Independence and Functional Activity Measurements were assessed (FIM/FAM).

Pertinent findings were:

  • 8 patients suffered a stroke during their initial hospital stay (5 were present on arrival in the ED)
  • 5 additional patients had a stroke after discharge
  • Only 20% reached the maximum FIM/FAM scores, even including patients who did not have a stroke
  • Patients with stroke had a significantly lower FIM/FAM
  • There was no difference in FIM/FAM in patients with carotid vs vertebral injury

Bottom Line: Even though it is limited, this is one of the best studies we will see on BCVI because it’s an uncommon problem at most centers. The most important fact here is that the stroke rate was 19% despite discharge on antiplatelet or anticoagulant medications. And if stroke occurs, it causes significant functional problems, as expected. It’s critically important that this injury be screened and identified appropriately, then given appropriate prophylaxis. More on this tomorrow.

Related posts:

Reference: Functional outcomes following blunt cerebrovascular injury. J Trauma 74(4):955-960, 2013.

General

Carotid and Vertebral Artery Injury From Blunt Trauma

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Blunt injury to the carotid or vertebral arteries (BCVI) is relatively uncommon, but potentially very deadly. Up to 2% of patients with high energy blunt trauma suffer this injury. Many are not diagnosed until the patient has ischemic symptoms or a stroke. However, more aggressive screening has shown a higher incidence that previously thought and may allow intervention before neurologic injury occurs.

Recently, a series of 222 patients with 263 BCVI was retrospectively reviewed, with an eye toward effectiveness of interventions. A total of 29 strokes occurred in the hospital in these patients, but only 7 of these occurred after diagnosis of the BCVI. Mortality was much higher in the stroke group (34% vs 7%). The authors looked at both medical and interventional therapies.

This paper identified the following items:

  • Car crash was the most common mechanism of injury (81%)
  • Vertebral arterial injury was slightly more common than carotid artery BUT
  • Women were much more likely to sustain a carotid injury
  • Older patients were more likely to have a vertebral injury

These authors found that CT angio was not sufficiently sensitive to identify all BCVI. They recommend a formal 4-vessel arteriogram in patients with a negative CT angio who have significant risk factors (unexplained neurologic deficit, Horner’s syndrome, LeFort II or III injury, cervical spine injury, soft tissue injury of the neck).

If a BCVI is identified, the patient should be heparinized until all other injuries are definitively managed. At that point, they should be preloaded with clopidogrel and aspirin and a repeat arteriogram should be performed. Endovascular stenting using a bare metal stent should be performed when possible because it results in the lowest stroke rate and requires the shortest duration of anti-platelet therapies. Patients then continue on aspirin and clopidogrel for an appropriate period of time.

To download the algorithm used by the authors, click here.

Reference: Optimal outcomes for patients with blunt cerebrovascular injury (BCVI): tailoring treatment to the lesion. J Am Coll Surg 212(4):549-559, 2011.