Carotid Disease Flashcards
What percentage of ischemic strokes are due to carotid disease?
20%
In patients with carotid disease - what conditions increase their stroke rate?
HTN, DM, DLD, Smoking, excessive alcohol
How should blood pressure be controlled to reduce risk of stroke?
Decrease Sbp by 10 and dbp by 5 or to 140, or 130 for pt with recent lacunae Treat all patients regardless of baseline BP. In patients with acute stroke, wait 24h to optimize cerebral perfusion.
Which class of antihypertensives is better for stroke reduction?
No benefit of one agent over another
What is target Hgb a1c for stroke reduction?
< 7. Tighter control not more effective in stroke risk reduction and could increase risk of death (ACCORD, ADVANCE)
What did the SPARCL trial conclude?
At 5 years, ARR of subsequent stroke in TIA/stroke pts is reduced with atorvastatin 80 (13-11%).
Define metabolic syndrome
3/5: - large waist circumference - elevated TG - low HDL - high BG - high BP
Which antiplatelet should you put patients on for stroke risk reduction?
ASA - No significant diff with plavix (5.32% plavix, 5.83% asa CAPRIE) - CHARISMA - no difference with asa/plavix vs. ASA alone, but increased bleeding risk
What is the most important predictor of future stroke?
Recent (within 6 months) ipsilateral neurologic symptoms
What is the stroke rate for symptomatic patients >70% stenosis?
26% w BMT vs. 9% w CEA in 2 years
What is the stroke rate for symptomatic patients with 50-60% stenosis?
22% in 5 year (vs 16% with CEA) - NASCET
What is the stroke risk of asymptomatic patients with >60% stenosis?
11% in 5 year (vs 5% in 5 year) - ACAS
How was degree of stenosis measured in NASCET, ECST and ACAS?
Angio - NASCET ECST Duplex us - ACAS
Patients with what life expectancy will benefit from asymptomatic CEA? Symptomatic patients?
3-5 years asymptomatic ACAS/ACST 2 years symptomatic NASCET
Which women benefit from CEA?
Symptomatic >70% (NASCET) ACAS did not find benefit for women but enrollment was small, ACST found benefit in both men and women
What are the indications for carotid stenting over CEA?
Cardiac ischemia/heart failure Lesion above C2 or below clavicle Scarring from radiation or previous surgery Recurrent carotid stenosis (higher risk of CN injury with repeat CEA) Stoma in neck
Is there a benefit of CEA compared with CAS in symptomatic patients?
Yes - 9.4% stroke rate CAS, 2.8% CEA in a metanalysis of 3 European trials
How often does carotid stenosis recur after intervention?
10% (8 for CAS and 12 for CEA)
What are indications for a CEA
Symptomatic >50%, most benefit >70% Asymptomatic > 60% if periop stroke/death < 3% and at least 5 yr life expectancy
Which landmark trial shows peri op CEA w beta blockage with HR 60-80 is recommended
POISE
When should you use IV heparin for carotid disease?
Crescendo TIA. International stroke trial showed no benefit of routine heparin administration. UFH is used intraop but no level 1 evidence.
Does protamine increase stroke risk after CEA?
No (GALA - general anesthesia vs local anesthesia for carotid surgery trial)
What is dextran?
A polysaccharaide that inhibits platelet aggregation to control embolic episode. Rutherford authors use dextran infusion for 24h after CEA.
What are advantages and disadvantages of eversion endarterectomy?
Pro: fast, no patch/foreign material Con: difficult to shunt, difficult to visualize endpoint on ICA and often need completion studies No significant difference with CEA (EVEREST trial)
* Name 11 maneuvers to expose distal internal carotid artery for high lesions?
- Nasotracheal intubation
- Divide ansa, retract hypoglossal
- Division of digastric (risk to hypoglossal, spinal accessory and glossopharyngeal)
- Divide ascending pharyngeal artery
- Divide occipital artery and venous branches
- Divide SCM from mastoid and resect parotid (protect facial nerve)
- Styloid process resection (risk to occipital artery, facial nerve)
- Anterior subluxation of mandible
- Vertical osteotomy through vertical ramus of mandible
- Drill/remove portions of the inferior portin of the petrous temporal bone
- Use shunts or balloons to control ICA back bleeding.
How high should stump pressure be?
>50 mm Hg
What are ways to monitor intra-op cerebral perfusion
Stump pressure EEG Evoked potential TCD Awake
What patch materials are available for CEA?
GSV - prone to aneurysmal expansion in up to 17%, harvest site complications PTFE, Dacron, Bovine pericardium - no difference in outcomes
What is the risk of cranial nerve injury during CEA? Which nerves most likely?
5% in CREST Hypoglossal > recurrent laryngeal > superior laryngeal > marginal mandibular > glossopharyngeal > accessory
Which nerve is responsible for numbness at angle of mandible?
Greater auricular nerve
What post-op BP parameters after CEA?
Within 20 mm Hg of pre-op. Treat hypotension with fluids and phenylephrine if necessary
What are risk factors for recurrent carotid stenosis?
Women, current smokers, DLD, HTN, DM
What branchial arch do carotid body tumours derive from?
3rd
What is the “lyre” sign?
Splayed carotid bifurcation associated with carotid body tumour
What are 3 classes of carotid body tumours?
Sporadic, familial, hyperplastic
What causes hyperplastic carotid body tumours?
Prolonged hypoxia - living at high altitudes or COPD
How does the carotid body work to regulate breathing/BP?
Stimulated by partial pressure of O2 and pH. type 1 glomus cells release neurotransmitters, signals carried through the glossopharyngeal nerve to medulla oblongata.
How does the carotid body respond to hypoxia, hypercapnia or acidosis?
Increase resp rate, increase tidal volume, increase BP with vasoconstriction
Where do malignant carotid body tumours metastasize?
Regional lymph node, cerebellum, thyroid, brachial plexus, lung, kidney, pancreas bones and breast
What symptoms do carotid body tumour patients present with?
Tenderness, fullness, numbness, dysphagia, hoarseness, cough, tinnitus, horners, dizziness. Lateralizing neurologic findings are uncommon
Why is percutaneous needle biopsy or incisional biopsies contraindicated in carotid body tumour?
Too vascular
What is the Shamblin classification?
Type 1 - Small, easily dissected from walls Type 2 - Larger, more adherent to adventitia Type 3 - Encase internal and external carotid arteries Type 2 and 3 may have to resect ECA and uncommonly ICA en bloc
When should you resect carotid body tumours?
As soon as diagnosed. Later it becomes larger, more nerve injury, malignant potential
What treatment options are there for unresectable or recurrent carotid body tumours?
Radiation
What does pre-op carotid body embolization involve?
Selective catheterization of ECA - emboilization of branch vessels feeding the tumour. Usually for shamblin 2 or 3. Controversial.
What are 6 differential diagnoses for carotid body tumours?
- Congenital lesion (AV malformation) - Benign mass (lipoma, cyst) - Infectious lymphadenopathy - Malignancy (h&n cancer, lymphoma) - Carotid kinks/aneurysms - Other cervical paragangliomas
What are the components for stroke TIA/risk - ABCD2?
Age > 60 = 1
BP > 140 or > 90 = 1
Clinical features of TIA (unilateral weakness = 2, speech = 1), Duration of TIA (> 1hr = 2, 10 min-hr = 1)
Type 2 diabetes = 1
What is the carotid duplex criteria for > 70% stenosis?
PSV > 230, EDV > 100.
ICA/CCA > 4
Diameter reduction B mode > 50%
What percent of ischemic strokes are due to carotid dissection?
2% (but 10-20% of stroke in young/middle age people)
What are risk factors for spontaneous carotid dissection?
Connective tissue disease, remote mild trauma/chiropractory, winter - likely because of infections with coughing, HTN