cervical artery dissection: quick review

CAROTID (AND VERTEBRAL) DISSECTIONS: QUICK HITS


--first consult call to Neurologists (less commonly Vascular Surgeons)


--Vascular imaging is a must, but CTA is more sensitive than MRA.  


--To catch on MRI, specific sequences are required so check with your Neurologist/Radiologist to figure out which.  


--Dissections that extend intracranially have a high incidence of forming SAH, especially when heparin is started, thus making heparin have higher mortality than anti-platelet drugs.  


--Extracranial dissections are usually treated with antiplatelet drugs and anticoagulation. 

Submitted by T. Boyd.



Reference(s): Shea et al. Carotid and Vertebral Artery Dissections in the Emergency Department. Emergency Medicine Practice.14;4. April 2012; picture

Spontaneous Cervical and Intracranial Arterial Dissections

(scroll to bottom for quick hits)

Background
-Arterial dissections can cause stroke in both young in old populations, and is the most common cause of stroke in the young

-Extracranial dissection is more common than intracranial dissection

-Stroke is generally caused by either diminished blood flow from intraluminal thrombus or embolized clot


Pathogenesis (stick with it)
-Dissection are believed to begin with a tear in the media of the vessel wall, leading to bleeding in the wall itself

-partially coagulated intramural blood can enter the lumen which activates platelets and
the coagulation cascade leading to intraluminal thrombus.

-Intramural blood can accumulate leading to compression of the lumen



Risk Factors
-Connective tissue and vascular disorders are thought to be main risk factors:
(e.g. Ehlers-Danlos Syndrome (type IV), Marfan Syndrome, Polycystic kidney disease, cystic medial necrosis, Fibromuscular dysplasia)

-many are caused by trauma




Diagnosis
-based on radiologic criteria taken from the Strategies Against Stroke Study for Young Adults in Japan (SASSY) using CTA or MRI/MRA

-Primary rules are based on finding an intimal flap or double lumen on Angiogram or MRI/MRA, or repeated non-specific findings associated with dissection on multiple studies.



Symptoms
-Head or neck pain

-Horner Syndrome - occurs when the sympathetic fibers on the ICA are stretched. It is usually just partial with ptosis and miosis but no anhidrosis.


Difference between Carotid and Vertebral Dissections
-Transient monocular blindness occurred only with internal carotid dissection

-Ischemic stroke is more common in vertebral dissections

-Neck pain and recent minor cervical trauma are more common in vertebral dissections

-Proportion of men and a recent infection are more common in ICA



Treatment
-Antithrombotic therapy (antiplatelet or anticoagulation) is the primary initial treatment for ischemic stroke and TIA caused by arterial dissection

-For intracranial dissection, antiplatelet therapy is often the treatment of choice

-For extracranial dissection, anticoagulation initially followed by 6 months of warfarin therapy as opposed to antiplatet therapy is often chosen

-Endovascular and surgical therapy are generally only reserved for recurrent ischemic events


BOTTOM LINE:
-arterial dissection is more common cause of stroke in the young
-extracranial (vertebral, carotid) more common than intracranial dissection
-sx: headache, neck pain, stroke-like symptoms, Horner's syndrome (for ICA)
-risk factors: connective tissue disorders, trauma
-dx: angiography, MRI/MRA
-tx: antithrombotics/anticoagulation (aspirin, heparin, coumadin, etc.); surgical/endovascular for recurrent events


Submitted by J. Grover.


Reference(s): Caplan, LR and Biousse V. “Cervicocranial Artery Dissections.” J Neuro-Opthalmol. 2004; 24:299-305. Maruyama, H et al. “Spontaneous Cervicocephalic Arterial Dissection with Headache and Neck Pain as the Only Symptom.” J Headache Pain (2012) 13: 247-253. “Spontaneous Cerebral and Cervical Artery Dissection: Treatment and Prognosis”. Uptodate.  “Spontaneous Cerebral and Cervical Artery Dissection: Clinical Features and Diagnosis”. Uptodate., picture

what's a TAVI?

RAGING HYPOTHETICAL:
--Hypotensive, elderly gentleman presents to your ED, records show he's had a TAVI

--You nod your head with a reassurring look, then run to google...

--Next time you won't need to - because you read this post.

WHAT'S A TAVI?

Transcatheter Aortic-Valve Implantation (TAVI) for patients with severe aortic stenosis who are not candidates for surgery.

What it looks like:

How it is placed: (so cool and worth watching)
The implantation procedure involves accessing a femoral artery, performing balloon valvuloplasty, then advancing the device across the native valve. During rapid right ventricular pacing, a balloon is inflated to deploy the valve and the frame.

Video animation: http://youtu.be/_eiI6S62zOs

and http://www.nejm.org/doi/full/10.1056/NEJMoa1008232 (NEJM)

Evidence it works:

At one year, the rate of death from any cause was 30% with TAVI vs. 50.7% with standard treatment (balloon aortic valvuloplasty and or medical therapy)

Not so good: TAVI had a higher incidence of strokes and major vascular complications compared to standard treatment, however this was included in rate of death.

Now you know :)

Submitted by S. Morris.

Reference(s): Leon MB, Smith CR, Mack M, Miller DC, Moses JW, Svensson LG, et al. PARTNER Trial Investigators. Transcatheter aortic-valve implantation for aortic stenosis in patients who cannot undergo surgery. N Engl J Med. 2010;363(17):1597–607.; http://medgadget.com/2010/09/transcatheter_aorticvalve_implantation_tavi_reduces_mortality_rate_compared_to_standard_therapy.html (image)

where do patient’s with Marfan Syndrome dissect?

AORTIC DISSECTION & MARFAN SYNDROME:
--The major cardiovascular manifestation in Marfan Syndrome is a progressive dilatation of the ascending aorta, leading to aortic aneurysm formation and eventually to fatal aortic rupture or dissection. Aortic dissection in early adult life is the leading cause of death.

--The ascending and descending aorta are both abnormal in Marfan Syndrome.

· The descending aorta is affected in two out of three patients during aortic dissection, and is the site of most complications which occur during follow-up.

· Aortic dissection limited to the descending aorta can occur in patients without dilatation of the ascending aorta.

--Dissection of the descending aorta was associated with dissection of ascending aorta in 43% and was isolated in 20% of cases.

BOTTOM LINE:

--dissections in Marfan involve descending aorta ~2/3 of the time, but these frequently involve the ascending aorta also

--if you have a patient with Marfan, and are worried about a dissection...worry about both (ascending/descending)

Submitted by J. Gullo.

Reference(s): PMID: 20232788, medscape article, picture

blood pressure control guidelines (head bleed, dissection, AAA)

RAGING HYPOTHETICAL:

--you have a patient with a vessel somewhere that has either ruptured or is about to

--you call the appropriate surgeon, who is on the way, but in the meantime, what can you do?

MINIMIZE THE DAMAGE:

ICH:

--lowering to SBP 140-160 probably safe

--theory: less/slower hematoma growth

--options: nicardipine (less cerebral vasospasm)

AORTIC DISSECTION:

--SBP 100-120, HR <60

--theory: reduce shear forces

--options: beta blocker (labetolol push, esmolol drip), nitroprusside

RUPTURED AAA:

--goal SBP 80-100

--theory: permissive hypotension; bleed slower, less likely to blow out the few clots they're making

Reference(s): uptodate.com: Ruptured abdominal aortic aneurysm, management of aortic dissection, Spontaneous intracerebral hemorrhage: Prognosis and treatment, Kodama K, et al. Tight heart rate control reduces secondary adverse events in patients with type B acute aortic dissection, picture