The Surgical Review- Vascular Flashcards
three layers of blood vessel walls and tissue composition
- Tunica intima: endothelial cells
- Tunica media: smooth muscle cells
- Tunica Adventitia: adipose and supportive connective tissue (in large vessels this contains the vasa vasorum which is the blood supply of the vessel wall)
what are 2 ways HTN causes atherosclerosis
- Direct endothelial damage
- HTN -> elevated levels of angiotensin II (potent vasoconstrictor) that produces superoxide anions and pro inflammatory cytokines from smooth muscle cells leading to endothelial injury
why do diabetic patients have impaired vasodilation?
- Dysfunction of endothelial nitric oxide synthase
2. increased production of endothelia-1, a potent vasoconstrictor
what are the key components of the atherosclerotic plaques?
- necrotic core containing foam cells and extracellular lipids
- fibrous cap of smooth muscle cells, lymphocytes and connective tissue
the two most common structural sources of emboli?
- Internal carotid
2. Cardiac
what is the gold standard for diagnosing carotid stenosis?
contrast angiography but this is reserved for complex or equivocal cases, screen with CDUS (carotid duplex US) and confirm with MRA
which nerve is most often traumatized during CEA?
vagus!
What are the six P’s of acute ischemia?
- Pain** most common
- Pallor
- Paresthesias
- Pulselessness
- Poikilothermia
- Paralysis
initial management of acute limb ischemia?
start SQH and take to arteriography
what can cause neurogenic claudication?
- Spinal stenosis
- Nerve compression
- Diabetic Neuropathy
what does ischemic rest pain indicate?
that the blood supply is insufficient to meet the metabolic demands of the resting tissue, thus pain is aggravated by elevation of the extremity
what tests an be used to establish diagnosis of arterial occlusive disease? (3)
- Segmental systolic blood pressure
- The ABI
- Pulse volume recordings (PVRs)
How do you test segmental systolic blood pressures?
- Doppler segmental pressures of brachial aa to the proximal femoral aa: should have change >20mmHg
- Measure proximal and distal thighs, and proximal and distal calves: a pressure drop of >30mmHg signifies a significant obstruction
What are the ranges of ABI for normal, claudication and critical ischemia?
Normal: ABI >1.0
Claudication: ABI 0.5-0.84
Critical Ischemia: ABI
what are the three common time points for bypass graft failure and what are the usual causes?
- Early (2yrs): natural progression of atherosclerotic disease
atherosclerotic disease is the major cause of aneurysmal disease in all areas except what?
ascending aorta 2/2 cystic medial necrosis
screening and diagnostic tests of choice for AAA?
screening: abd US
diagnostic: CTAngio
when do you operate on a AAA?
> 4.5-5.5cm
prior to aortic cross clamping in AAA repair, what two anatomic considerations must be made?
- identify the left renal vein and protected to avoid injury
- if the IMA is sacrificed, in regards to pelvic outflow, at least one hypogastric (internal iliac aa) must have good flow to prevent colon ischemia and vasculogenic impotence
which visceral arteries are known to have aneurysms? how do you repair?
- Hepatic- repair
- Renal- repair
- Splenic- can monitor with exceptions
* repair is with exclusion and bypass grafting
When should one repair a splenic aneurysm?
- In pregnant women or those about to become pregnant
2. Those larger than 2cm
when should iliac artery aneurysms be repaired? how to repair?
- Symptomatic
- Larger than 3cm
- Mycotic
* repair with stent or bypass graft and exclusion
when should femoral artery aneurysms be repaired? how to repair?
- Symptomatic
- Larger than 2.5cm
- Mycotic
* repair with bypass and exclusion
when should popliteal aa aneurysms be repaired?
- Symptomatic
- Larger than 2 cm
- Mycotic
* repair with exclusion and bypass grafting or stent
Renal artery stenosis is mostly caused by what two pathologies?
- Atherosclerotic disease: more common on left side, older tips
- Fibromuscular dysplasia: younger women, bilateral or right sided disease
whats the most commonly performed confirmatory test for renal artery stenosis?
renal vein renin assay: measures renin activity in the renal vein and compares it to systemic renin activity in the case of bilateral renal artery stenosis
what is the most commonly affected upper extremity vessel in upper extremity arterial occlusive disease?
subclavian artery
explain subclavian steal syndrome
- occurs with proximal stenosis or occlusion of the subclavian artery
- the delivery of blood to the extremity thus depends on reversed flow through the ipsilateral vertebral artery via the circle of willis
- strenuous activity of the affected UE results in stealing blood from the circle of willis and results in vertebrobasilar insufficiency = syncope/neurologic symptoms
what are the components of the scalene triangle?
- Anterior scalene
- Middle scalene
- First rib
- the subclavian aa and brachial plexus pass through this
- in thoracic outlet syndrome, anomalous cervical rib or hypertrophy of the anterior scalene muscle can cause compression on the plexus, artery or vein
what neurologic symptoms do you see in thoracic outlet syndrome?
- pain in subscapular/scapular/cervical regions
- paresthesias and numbness of hand and medial forearm (ulnar distribution)
- weakness and atrophy of the triceps mm, intrinsic mm of the hand, wrist flexors
What is Paget vonschrotter disease?
- compression of the subclavian vein in thoracic outlet syndrome presenting as effort-induced thrombosis
- young men
- arm swelling painful during strenuous upper extremity activity
diagnose: venous duplex
tx: thrombolytics and anticoagulation followed by surgical therapy to relieve compression
what is the most common site for an embolus to lodge in mesenteric ischemia?
- SMA: origin of the middle colic artery (distal to the first jejunal branches)
if mesenteric ischemia is suspected but no peritonitis yet, what procedure?
mesenteric angiography
what is the main cause of nonocclusive mesenteric ischemia?
- severely diminished cardiac output with corresponding splanchnic vasospasm
what is mesenteric venous thrombosis
- affects younger pts with an underlying hyper coagulability disorder
- thrombosis develops distally and propagates to the larger veins
- peritonitis is RARE
what does CT show in mesenteric venous thrombosis
- enlarged superior mesenteric vein with a central lucency
what do you see on angiography in fibromuscular dysplasia?
“string of beads” appearance from fibrous constrictions alternating with aneurysmal dilatation
What is Buerger disease?
thromboangiitis obliterans
- severe progressive nonatherosclerotic arterial occlusive disease
- symptoms: lower extremity claudication with rapid progression to rest pain and ischemic ulceration +/- raynaud in UE
what is the typical pt in Buerger disease?
- young male smoker of eastern european, middle eastern or asian descent
treatment of bueger disease?
absolute cessation of smoking results in disease remission in most patients
what does angiography show in bueger disease? (3)
- absence of atherosclerotic disease
- severe occlusive disease of small vessels
- corkscrew collaterals along the course of the occluded vessels
what is popliteal entrapment syndrome?
rare disease affecting young adults
- the popliteal aa devates around the medial head of the gastrocnemius m
- pts present with mild claudication
- loss of distal pulses with plantar flexion
treatment of DVT for:
1st occurence
2nd occurence
3rd or PE occurence
1st = 6 months warfarin
2nd = 1 year
3rd or PE = lifelong
what is filariasis?
a parasitic infection that obstructs lymphatic channels causing secondary lymphedema
What are the different types of endoleaks?
Type I: an inadequate seal between the graft and the landing zone
A = proximal
B = distal
Type II: collateral flow into the aneurysm sack (lumbar aa or IMA)
Type III: graft components are inadequately sealed to eachother (IIIA) or when a hole in the graft develops (IIIB)
Type IV: porosity of the graft fabric and are self limited
what is hypothenar hammer syndrome? how do you diagnose?
- fibromuscular dysplasia in the ulnar artery, predisposing to aneurysm formation -> thrombus formation
diagnose: arteriography
how do you treat hypothenar hammer syndrome?
surgical resection of aneurysm with reconstruction using vein interposition graft
what is dysphagia lusoria?
difficulty in swallowing due to compression of the esophagus by an aberrant right subclavian aa
what is a kommerell diverticulum?
result of abnormal regression of the fourth aortic arch and persistence of patency of the right eight dorsal aortic segments -> an aortic diverticulum is found at the site of origin of the atretic arch
what is a bovine arch??
normal variant in which the left common carotid artery and the innominate artery share a common origin off the aortic arch
what are the most common visceral artery aneurysm?
splenic artery
what is the double rupture phenomenon of the splenic artery aneurysm?
- bleeding is initially contained in the lesser sac with subsequent free intraperitoneal rupture resulting in hemodynamic compromise
management of Splenic Artery Aneurysms in men and asymptomatic women who are not of child bearing age?
- observation if 3cm
what surgical technique is used for splenic artery aneurysms that warrant repair?
proximal: exclusion with proximal and distal ligation of the splenic artery
middle third lesions: excision of the aneurysm
distal: splenectomy or aneurysm exclusion and vascular reconstruction
when do you surgically repair a pseudoaneurysm?
- infected or rapidly expanding pseudoaneurysms
what is different about aneurysms in HIV patients? three most common locations of aneurysms?
- typically young and lack the usual risk factors
- aneurysms are multiple and occur at:
1. common carotid
2. superficial femoral arteries
3. abdominal aorta
whats your concern in blunt trauma, hemiplegia in the absence of abnormalities on head CT?
think blunt carotid injury
treatment of blunt carotid injuries?
anticoagulation with heparin followed by warfarin for 2 months
whats the triad of horners syndrome?
- Ptosis
- Miosis
- Anhidrosis
what approach do you take to explore zone I penetrating injuries?
Right: median sternotomy
Left: left anterolateral thoracotomy
when should a zone II penetrating injury be explored? (4 hard signs)
- neurologic deficit
- expanding hematoma
- pulsatile bleeding
- palpable thrill
how do you repair the carotid artery with a penetrating injury?
primary repair or interposition grafting
Three zones of the retroperitoneum?
- Zone I: midline retroperitoneum
- Zone II: perinephric space
- Zone III: Pelvic retroperitoneum
In colonic ischemia following AAA repair, what is the difference in management between partial thickness and full thickness ischemia?
Partial: NPO, IVF, broad spectrum abx, NGT decomp
Full: (see peritonitis and unremitting acidosis) laparotomy with colonic resection and colostomy
A successful EVAR requires what length of proximal neck?
15mm minimum
- max diameter 25-30mm
- less than 60degree angulation between the prox neck and the suprarenal aorta
What are the guidelines for intervention in renal artery stenosis? (5)
- Sudden worsening of preexisting HTN
- Resistant HTN despite at least 3 antihypertensive drugs
- Worsening renal function after administration of ACEi
- Unexplained atrophy of one kidney
- HTN resulting in end organ damage (renal insuff, CHF)
what Is white clot syndrome?
- aka heparin induced thrombosis (type II)
- immune mediated disorder, antibodies against platelet factor 4, neutrophil-activating peptide 2, and/or Il-8
- initial finding is thrombocytopenia
- clot is platelet rich and relatively devoid of fibrin and red cells = white clot
what are the risk factors for rupture of AAA?
- COPD
- Ongoing cigarette smoking
- Poorly controlled HTN
when is surgical intervention indicated in AAA?
when its above 5.5cm
when do you reimplant the IMA in AAA repair to prevent colonic ischemia?
- IMA orifice patent but back bleeding is poor (indicates bad collaterals, brisk back bleeding indicates good collaterals)
- IMA stump pressures
what is the MOA of heparin?
binds to antithrombin III, which becomes activated
- activated AT III inactivates thrombin and factor Xa, inhibiting clot formation
what is the most common peripheral artery aneurysm?
popliteal
3 Indications for repair of popliteal aneurysm?
- Aneurysm >2cm
- Aneurysm with intraluminal thrombus, regardless of size
- symptomatic or evidence of previous embolization
what is standard operative approach to repairing a popliteal aneurysm?
- bypassing the aneurysm with saphenous vein and interval ligation of the popliteal aa
pt w an upper GI bleed and a hx of aortic surgery should be presumed to have ____ until proven otherwise
an aortoenteric fistula
what is the threshold for elective repair of asymptomatic patients with common iliac aneurysm?
treatment of choice?
> 3.5cm
treatment of choice: stent grafting
most common symptom of popliteal aneurysm?
thrombosis
they rarely rupture
what is barnham sign?
on fistula compression (traumatic fistula), the heart rate decreases
what is the most common organism cultured from a mycotic aneurysm?
staph
followed by salmonella
If a AAA is approaching 5cm, how often should screening occur?
3-6months
what are the 4 compartments of the leg?
Anterior
Lateral
posterior superficial
posterior deep
what nerves run through the difference compartments of the leg?
Anterior = deep peroneal n
Lateral = superficial peroneal n
posterior superficial = sural
posterior deep = tibial
what is the intracompartmental threshold for diagnosing compartment syndrome?
> 30mm using Stryker intracompartmental pressure monitoring system
