Vascular Flashcards
What are the segments of the vertebral artery?
V1: origin off subclavian to foramina of C6
V2: from the foramen of C6-C2
V3: C2 foramen to dura
V4: intracranial
What structure commonly overlies the carotid bifurcation?
the facial vein
What is the first branch off the external carotid artery?
the superior thyroid artery
True or false, the external carotid can be ligated?
true
What is the first branch of the internal carotid?
the ophthalmic artery
Is the internal carotid artery flow high or low resistance?
low resistance, biphasic, no flow reversal
Are the external and internal carotid arteries triphasic or biphasic?
- external: high resistance so triphasic
- internal: low resistance so biphasic
If a patient has hoarseness after carotid endarterectomy, what structure was likely injured? How?
the vagus was likely caught in the clamp applied to the carotid
If a patient has ipsilateral tongue deviation after carotid endarterectomy, what structure was likely injured?
the hypoglossal nerve (XII), which lies just cephalic to the carotid bifurcation
If a patient has ipsilateral mouth droop after a carotid endarterectomy, what structure was likely injured? How?
the marginal mandibular branch of the facial nerve due to traction on the mandible when exposing high lesions
Which nerve lies deep to the posterior belly of the digastric? What defect is associated with injury?
- the glossopharyngeal nerve (IX)
- dysphagia
Which layers are removed during a carotid endarterectomy?
the intima and part of the media
What is the typical location of carotid atherosclerosis?
the bifurcation
What are the indications for carotid endarterectomy?
- over 50% with symptoms
- over 70% or with EDV over 100cm/s
How should a patient with symptoms of carotid stenosis < 50% be managed?
medically with DAPT, smoking cessation, and a statin
How should a patient with a stroke and 100% occlusion of the carotid be managed?
- medically with DAPT or anti-coagulation
- there is no role for recanalization and this would increase the risk of hemorrhagic conversion
In what situation would an emergent carotid endarterectomy be indicated?
crescendo TIAs
Why is cardiac clearance so important before carotid endarterectomy?
MI is the most common non-stroke cause of morbidity and mortality after CEA
When should you operate on a patient who recently had a stroke from carotid stenosis?
- within 2 weeks of symptom resolution for a TIA or small stroke
- 6-8 after a hemorrhagic stroke
What is the downside of carotid shunt during endarterectomy?
it limits visibility of the distal end point
What are four ways to monitor neurologic status and to decide whether to shunt during carotid endarterectomy?
- awake CEA
- EEG
- ICA stump pressures (>40, no shunt)
- cerebral oximetry
How does cerebral hyper perfusion syndrome present?
as headaches and hypertension but normal neurological exam following carotid endarterectomy
What is cerebral hyper-perfusion syndrome?
- a rare, potentially deadly complication of carotid endarterectomy
- usually seen in those with severe, bilateral carotid stenosis
- caused by dysfunction in cerebral vascular autoregulation
- presents as hypertension and headache post-op
- CT is used to rule out acute infarct and is likely to show cerebral edema
- treat medically with BP control, ICU monitoring, and seizure ppx
What is the best next step in a patient who appears to have stroke symptoms in PACU following carotid endarterectomy?
- duplex US
- patent ICA: to CT for distal emboli/watershed infarct
- thromboses ICA: to OR for thromboectomy
What would be reasons to perform carotid stent over CEA?
- history of neck dissection or irradiation
- recurrent carotid disease
- severe cardiac disease
Which surgical treatment of carotid stenosis has the lowest stroke rate?
TCAR
How should you manage asymptomatic, traumatic carotid dissection?
- plavix or heparin
- repeat imaging prior to discharge
How should you manage symptomatic traumatic carotid dissection?
- heparin
- likely to need stent
How should you manage traumatic carotid occlusion?
- heparin
How are carotid body tumors managed?
- all are resected
- consider embolization of feeding branches off the external carotid prior to resection
What is the diagnosis for a young patient presenting with stroke symptoms and beads on a string appearance of the ICA? How is it treated?
- fibromuscular dysplasia
- typically managed with anti-platelet agent
- may require angioplasty if recurrent
Name the structures of the thoracic outlet from anterior to posterior.
- subclavian vein
- phrenic nerve
- anterior scalene
- subclavian artery
- brachial plexus
- middle scalene
- 1st rib
What anatomic abnormality puts patients at risk for thoracic outlet syndrome?
a cervical rib
Which type of thoracic outlet syndrome is most common?
neurogenic (95%)
What are the symptoms of neurogenic thoracic outlet syndrome?
pain, weakness, numbness, and numbness (particularly in the ulnar distribution), which worsen with manipulation and elevation of the arm
How is neurogenic thoracic outlet syndrome treated?
- first line is physical therapy
- if this fails, confirm diagnosis with scalene block
- then perform first rib resection and scalenectomy with neurolysis
A swimmer presents with a blue, swollen arm, what is the diagnosis and management?
- diagnosis is Paget-Schroetter syndrome (subclavian vein thromobosis)
- treat with catheter directed thrombolysis followed by first rib resection
A young person with no risk factors presents with ischemia of the hand. What is the diagnosis and management?
- arterial thoracic outlet syndrome
- perform first rib resection with interposition graft for the thrombosed artery (risk of native artery aneurysm)
Where is the anatomic stenosis that results in subclavian steal?
proximal subclavian, results in reversal of blood flow in the vertebral artery
Why are AVF/AVG preferred over tunneled central lines?
they have lower infectious risk and lower rates of central venous stenosis
What is the “fistula first” mantra?
the idea that reducing catheter days improves live expectancy
How big of an artery and vein are required for AVF formation?
- 3mm vein
- 2mm artery
What characteristics make a suitable artery for AVF creation?
should be at least 2mm and have a triphasic waveform (this reduces the risk of steal syndrome)
What is the most common reason for AVF to malfunction over time?
venous outflow problems
High venous return pressures during dialysis with a AVF indicates what? How is this diagnosed and managed?
- indicative of venous outflow stenosis
- diagnosed with duplex US
- treated with IR balloon angioplasty
What are the criteria for fistula maturation?
should be…
- 6mm in diameter
- less than 6mm deep
- should have more than 600mL/min of flow
What is the best next step for evaluating a fistula that has failed to mature?
duplex US
What symptoms of steal syndrome after AVF creation, mandate intervention?
tissue loss or constant pain
How is steal syndrome after AVF confirmed?
- waveform analysis of the digits with and without compression of the AVF
- 50% improvement with compression confirms the diagnosis
What are the surgical options for AVF steal syndrome?
- ligation or banding
- distal revascularization and interval ligation
- proximalization of inflow
How should a bleeding AVF be managed?
- pinpoint hole bleeding can be managed with a stitch and urgent fistulogram
- ulceration is a surgical emergency
When should you consider fasciotomies in a patient with acute limb ischemia?
when the pathology has been present for > 4hrs
During a lateral fasciotomy incision, what nerve is most likely to be injured and what would be the resulting deficit?
superficial peroneal nerve, leading to difficulties with foot eversion
How do you release the deep posterior compartment of the leg?
through the medial incision, 2cm posterior to the tibia; then take the soles off the tibia
What are the size criteria for treating descending thoracic aortic aneurysms?
over 5.5cm if end-vascular repair is possible; otherwise, 6.5cm
What is the rate of paraplegia after thoracic aortic aneurysm repair?
5% for endovascular and 20% for open
Which thoracic aortic aneurysms are surgical emergencies?
- any type A (prior to takeoff of subclavian)
- type B with rupture or malperfusion
What is the most common type of mesenteric ischemia?
embolic
Which type of mesenteric ischemia will have proximal jejunal sparing?
embolic because it lodges just to distal to first branch of SMA
How do you identify the SMA to perform embolectomy during laparotomy?
- lift the transverse colon cephalad and follow to the base of the mesocolon
- just to the right of the ligament of treats will be the SMA
- mobilize the LOT to access the SMA at it’s origin
How is venous thrombosis mesenteric ischemia treated?
generally with heparin, rarely need surgical intervention for re-vascularization
Where do the gonadal veins drain?
- the right into the IVC
- the left into the left renal vein
Lis the structures of the renal hilum from anterior to posterior.
- vein
- artery
- pelvis/ureter
What is the most common site for an upper extremity embolus to lodge?
the brachial artery at the bifurcation of the radial and ulnar arteries
What is the most common site for a lower extremity embolus to lodge?
the CFA at the bifurcation of the profunda and SFA
What is the recommended BP goal for a patient with ruptured AAA?
SBP 80-100
What is the most common organism in vascular graft infections?
Staph epidermidis
What is the treatment for popliteal entrapment syndrome?
resect medial head of gastrocnemius or resect crossing band or popliteus muscle that is compressing the artery
What size criteria should prompt hepatic artery aneurysm repair?
> 2cm
What size criteria should prompt SMA aneurysm repair?
should repair all these with resection and reconstruction
What size criteria should prompt treatment of an iliac artery aneurysm?
> 3.5cm
What size criteria should prompt repair of a femoral artery aneurysm?
2.5 cm historically but shifting toward 3.5
What criteria should prompt treatment of a popliteal artery aneurysm?
> 2cm or smaller aneurysms with significant mural thrombus
Patients with popliteal artery aneurysms should also be screened for what?
AAA (>50% will have)
How should popliteal artery aneurysms be repaired?
- gold standard is bypass or interposition with vein
- can stent if not a good surgical candidate
If a patient presents in acute limb ischemia from a thromboses popliteal aneurysm, what should you do?
- start with heparin and angiogram
- if there is no runoff, place a lysis catheter with tPA
- if there is a good target, can go straight to bypass
Give the size cutoff for treating the following aneurysms:
- TAA
- AAA
- CIA/EIA
- Femoral
- Pop
- TAA: 5.5 if amenable to endovascular repair
- AAA: 5.5 in males, 5.0 in females, growth > 0.5cm/6mo, growth > 1cm/year
- CIA/EIA: 3.5
- Femoral: 2.5
- Pop: 2.0
What are the size criteria for repairing AAA?
- over 5.5cm in men
- over 5.0cm in females
- over 0.5cm growth in 6 months
- over 1cm growth in 1 year
Which patients should be considered for open AAA repair?
- young patients with good cardiac and pulmonary function
- patients with complex aortic anatomy including no normal infrarenal aorta or small iliacs
During open AAA repair, when should you re-implant the IMA?
- marginal back bleeding (no flow and pulsatile back bleeding mean colon likely doesn’t rely on IMA flow)
- if colon is dusky
- if they’ve had prior colon surgery
What vein is at risk during open AAA repair when clamping the proximal aorta?
could injure a retro-aortic left renal vein
How do you manage chylous ascites?
a low fat, high protein diet with MCFA supplementation
What is the standard surveillance guidelines for AAA?
- every 6 months if > 5cm
- yearly if 4-5cm
What is the preferred management of an infected infrarenal aortic graft?
- ax to bi-fem bypass with graft excision
- alternatively, could explant and reconstruct with femoral vein or cryopreserved aorta
What is the feared surgical complication after extra-anatomic bypass with aortic ligation? How is this best prevented?
- aortic stump blowout
- prevent with oversewing the aorta in multiple layers, cover with omentum, and buttress with tensor fascia lata
What complication presents in patients years after an aortic operation with hematemesis and hypotension? How is it managed?
- aorta-enteric fistula
- treat with EVAR to temporize if unstable
- will ultimately need extra-anatomic bypass with aortic ligation or in-line reconstruction with biologic material
When performing an aorto-bifemoral bypass, how do you decide whether to do an end-to-side or end-to-end anastomosis?
- must ensure perfusion to at least one internal iliac
- if external iliac is patent, can do an end-to-end and rely on retrograde perfusion of internal iliac
How do you tunnel an aorto-bifemoral bypass relative to the ureters?
tunnel under the ureters to prevent hydronephrosis
If a frail patient presents with an occluded aorta, what is your best option for reconstruction?
- too frail to undergo aorto-bifem
- can perform ax to bifem instead (lower morbidity, lower patency rates)
What anatomic criteria are needed to perform an EVAR?
- neck diameter less than 32mm
- neck angle less than 60 degrees
- neck length at least 10mm
- iliac diameters at least 7mm
- lack of thrombus or calcification in infrarenal neck
What are the types of endoleaks?
- Ia: proximal seal breakdown
- Ib: distal seal breakdown
- II: retrograde flow from IMA or lumbars
- III: lack of seal between components
- IV: leak through graft material (porous or torn)
What are the types of endoleaks and their management?
- Ia/b: proximal/distal seal, require a cuff to re-seal
- II: retrograde filling, only require embolization if sac grows
- III: between components, require a cuff to re-seal
- IV: through graft material (tear or porosity), may need to reline
How can you confirm MALS?
if a celiac plexus block relieves pain
How do you calculate an ABI?
highest pedal pressure divided by highest brachial pressure
How does ABI correlate with symptoms?
- 0.9 to 1.4 is normal
- 0.5 to 0.9 is likely to have claudication
- 0.3 to 0.5 is likely to have rest pain
- 0.3 or less is likely to have tissue loss
When are ABIs unreliable? How can you bypass this?
- non-compressible vessels due to calcification
- overcome by checking toe-brachial index
What is the safest and most effective treatment for claudication?
structured exercise therapy
What does medical therapy involve when treating peripheral arterial disease?
- smoking cessation
- anti-platelet therapy
- high intensity statin with goal LDL < 100
What are the indications for operative intervention for PAD?
- lifestyle limiting claudication
- rest pain
- tissue loss
When are endovascular interventions preferred over open repair of peripheral arterial disease?
for short-segment lesions without heavy calcification
Why isn’t the femoral artery often treated endovascularly?
because it is a mobile area that is prone to kinking and because of the relative ease of an open approach
What is a contra-indication to atherectomy?
this end-vascular “rotor-rooter” carries a high risk of distal embolization and is therefore contra-indicated in patients with limited tibial vessel runoff
A lesion in which vessel is likely to result in thigh claudication?
iliac
What test should you perform for a patient who describes classic claudication but has normal ABIs? What explains this finding?
- perform a walking treadmill test until the onset of significant pain and then recheck ABIs
- patients with proximal iliac lesions may have normal ABIs because of collateralization that doesn’t become symptomatic until demand increases
Describe a normal angiogram below the knee.
- popliteal gives off the AT first
- the TP trunk then gives off the peroneal and posterior tibial
- the peroneal runs behind the fibula dn the PT runs behind the tibia
Through which lower leg compartments do the following run:
- anterior tibial artery
- posterior tibial artery
- peroneal artery
- superficial peroneal nerve
- tibial nerve
- AT: anterior
- PT: deep
- peroneal art: deep
- superficial peroneal: lateral
- tibial nerve: deep
A patient presents with unilateral leg swelling and deep venous reflux on US, what can you offer?
- compression stockings an elevation
- cannot ablate these and there is no surgical treatment for deep venous reflux
What is the best treatment for GSV reflux from the sapheno-femoral junction to the thigh?
chemical or heat ablation
What is the best treatment for GSV reflux below the knee?
chemical ablation with glue or sclerosant
Why is heat ablation reserved for the great saphenous vein above the knee?
because below the knee it carries too much risk of saphenous nerve injury
How far away should you begin your ablation from the sapheno femoral junction?
2-3cm to prevent endothermal heat-induced thrombosis from encroaching on the sapheno-femoral junction
How is endothermal heat-induced thrombosis managed?
- invasion into the CFV: anticoagulation x3 months
- flush with the CFV: short-course AC versus repeat imaging in two weeks
- within 2cm of the CFV: repeat imaging in 1-2 weeks
Who is a candidate for GSV stripping?
- rare now
- would be indicated for a very large GSV or one that is too superficial for heat ablation
What is the most common location for DVTs?
iliofemoral
Which leg has a higher rate of DVT?
the left is 2x more common than the right
Where should an IVC filter be placed in relationship to the renal veins?
caudal to them
How long should patients be treated for a DVT if they have active cancer?
until they are cured
How should superficial thrombophlebitis of the GSV be treated?
- if < 5cm and not near the saphenofemoral junction, can treat with NSAIDs and warm compresses
- if longer or near the junction, anticoagulant with fondaparinox for 45 days
What presents with a non-healing wound on the medial malleolus of the left ankle? How is it managed?
- this is a classic venous stasis ulcer
- treat with an unnamed boot
How can you differentiate venous insufficiency from lymphedema of the lower extremity?
venous insufficiency swelling usually stops at the feet
What is the biggest risk factor for ischemic colitis in a patient with a ruptured aneurysm?
preoperative hypotension
What organism causes most mycotic aneurysms?
Staphylococcus
