Exam 3 Vascular Surgery Flashcards
What coexisting diseases are seen in vascular surgery patients?
diabetes
HTN
smoking
Renal impairment
pulmonary disease
systemic atherosclerosis
coronary artery disease
What is the leading cause of perioperative death mortality at the time of vascular surgery?
coronary artery disease
How do you recognize a patient is having an MI under anesthesia?
arrhythmias
ST elevation
Hypotension
What is the pathology of atherosclerosis?
generalized, progressive, chronic inflammatory disorder of the arterial tree with development of fibrous intimal plaque associated with endothelial dysfunction
What are the three stages of atherosclerosis?
Stage 1: fatty streak
Stage 2: fibrous plaque
stage 3: advanced lesion
Describe stage 1 of atherosclerosis?
endothelium is damaged due to hemodynamic shear stress, oxidized LDL destruction, chronic inflammatory responses, infection, hypercoagulopathy resulting in thrombosis
What is stage 2 of atherosclerosis?
composed of oxidized lipid accumulation, inflammatory cells, proliferated smooth muscle cells, connective tissue fibers, and calcium deposits
blood flow reduction- ischemia to vital organs and extremities, thrombus risk
What is stage 3 of atherosclerosis?
plaque with expanded lipid rich necrotic ore, calcium accumulation, endothelial dysfunction
physical disruption of plaque’s protective cap (rupture or ulceration), exposes blood to highly thrombogenic material promoting acute thrombus formation and vasospasm
complete occlusion possible (stroke, MI, ischemia)
What three types of atherosclerosis cause morbidity?
enlarged plaque reduces lumen of blood vessel (limb ischemia, stable angina)
plaque rupture/ ulceration, embolization, thrombus formation (unstable angina, MI, TIA, CVA)
Atrophy of media with arterial wall weakening (aneurysm dilation)
What are the most common sites for atherosclerotic lesions?
aortoiliac peripheral 42%
coronary 32%
Arch branches 17%
combined
mesenteric/ renal
vessel bifurications, d/t shear forces
What were the goals of ACC and AHA pre-operative evaluation guidelines?
to optimize patient for surgery
best possible quality care and outcome for the patient
information obtained should be used for both the perioperative period and to inform the long term treatment plan
What are the pre-operative evaluation guidelines?
clinical history (clinical risk factors, exercise tolerance)
supplemental evaluation
perioperative therapy
surgical procedure (low, intermediate, high risk)
What is the critical period of coronary stenting?
6 weeks to endothelialize
bare mental stent- don’t stop <1 year, DES <6months
stopped too soon= MI risk
What dual therapy is need after stenting?
aspirin and plavix
What cardiac function testing is needed prior to vascular surgery? (4)
exercise/pharmacologic stress test
ECHO
Myocardial ischemia, previous MI, valve dysfunction, heart failure
duplex imaging of carotid arteries or angiography
What are pulmonary complications following vascular surgery?
atelectasis, pneumonia, respiratory failure, exacerbation of underlying chronic disease
How can pulmonary complications after vascular surgery be avoided?
incentive spirometry, steroids, regional anesthesia, antibiotics, CPAP
What predicts long term mortality in patients with symptomatic lower extremity arterial occlusive disease?
chronic renal disease
How can renal complications be avoided?
dye use, beta blockers, statins, volume status, perfusion pressures
What is lower extremity peripheral artery disease?
insufficiency in lower extremities presenting with acute or chronic limb ischemia with occlusions distal to the inguinal ligament
What disease population is at higher risk with LE PAD?
DM
What antiplatelet and anticoagulants may be used in LE PAD?
ASA, ticagrelor (P2Y12 inhibitors), rivaroxaban (Xa inhibitors)
When is surgery indications for peripheral revascularization?
severe disabling claudication
critical limb ischemia (limb salvage)
What are indications for peripheral revascularization?
acute ischemia
irreversible damage
chronic ischemia
Describe the traditional surgical approach to peripheral revascularization
donor and recipient arteries exposed, tunnel created and graft is passed
graft may be saphenous vein or prosthesis
heparin IV administered
anastomosis constructed
arteriogram to confirm adequate flow
Why is graft occlusion significant withe general anesthesia then RA?
a. Because GETA causes hypercoagulable state, fibrinolysis decreases after GA (therefore, fibrinogen do not break down=clots), NE/E/cortisol release, patency of graft maintained with RA s/c to increase blood flow with sympathectomy
What should be avoided in peripheral revascularization?
vasopressors
want to keep feet warm
GA for peripheral revascularization
- Opioids, VA, Nitrous okay, NMB
- Minimal opioids to facilitate extubation
- Deepen during tunneling (3-5mcg/kg fentanyl)
- Avoid hemodynamic extremies
Post operative anesthesia management for peripheral revascularization
ECG/ ST anaylsis
normal BP and HR
frequent pulse checks
control pain
avoid anemia (want to ensure adequate O2 carrying capacity to newly vascularized area)
what is the principle cause of carotid endarectomies?
atherosclerosis
Where does carotid endarectomies usually take place
common carotid artery and internal and external carotid arteries
What are S/S of carotid occlusion?
fatal or debilitating stroke
TIA
amaurosis fugax (transient attac of monocular blindness
asymptomatic bruit
What is the 5th leading cause of death in the US
strokes
Describe the pre-operative assessment for a CEA
recent symptoms
optimize medical management (BB, statins, antiplatelet therapy, HTN control, restore intravascular volume, reset cerebral autoregulation, diabetic control)
Coronary angiograms
What is treated first in patients with symptomatic carotid disease and bilateral severe asymptomatic carotid stenosis?
carotid re-vascularization is recommended prior to CABG
What is continued throughout perioperative period for CEA?
ASA
Describe anesthetic management for CEA
i. Awake vs. GETA
ii. Continue ASA throughout perioperative period
iii. ECG
iv. Aline
v. PIV x2
vi. Arms tucked for procedure
Describe GETA set up for CEA
T/S
Aline, act machine, fluid warmer, lower body forced air warming blanket
phenylephrine, remi infusion lines
clevidipine and NTG infusions available
BB + ephedrine
Heparin and protamine
What monitors are needed for GETA CEA
routine + V5/2 and Line
cerebral oximetry (esp if not shunting)
extra pressure tubing and blue male to male connection to adapt to A line transducer
What are goal arterial blood pressures for CEA?
normal to high throughout procedure, particularly during clamping to increase collateral flow and prevent cerebral ischemia
If patient has contralateral internal carotid artery occlusion or severe stenosis how HTN -sive should patient be?
10-20% above baseline during period of carotid clamping
What are the advantages of CEA
i. Reduces shunts, better hemodynamic stability, reduced costs, but requires patient cooperation
Complications of deep cervical plexus block include:
Horner’s syndrome (ptosis, miosis, anhidrosis)
Recurrent laryngeal nerve block
diaphragmatic paralysis
Carotid Artery Stump Pressure
internal carotid stump pressure represents the back pressure resulting from collateral flow through circle of willis through contralateral carotid artery and vertebrobasilar system
<45mmHg
Post-operative Complications of CEA
Thromboembolic and hemorrhage intracerebral events
HTN
Hypotension
Cerebral Hyper-perfusion syndrome
Cranial and cervical nerve dysfunction
Carotid body denervation
Wound hematoma
What is carotid body denervation?
impaired ventilation response to mild hypoxemia, central chemoreceptors are impaired
opioids make worse if bilateral
What is Cerebral Hyper-perfusion syndrome
abrupt increase in blood flow with loss of autoregulation
HA, sz, focal neurological signs, brain edema, possibility of intracerebral hemorrhage
What are the steps of percutaneous transluminal angioplasty and stenting
femoral access, aortic arch angiogram, selective cannulation of common carotid artery origin and angiogram, guidewire placement into external carotid artery, carotid sheath placement and advancement to common carotid artery, placement of embolic protection device, balloon angioplasty of lesion, expanding stent, balloon dilation of stent, completion of angiogram, access site management
Aneurysm
dilation of all three layers
Definition of aortic aneurysm
dilation of all three aortic layers
no false lumen
Predisposing factors to aortic aneurysm
HTN
atheroscleorosis
male
age
family history or aneurysm
smoking
Aneurysm symptoms
asymptomatic or present with pain d/t compression of structures or vessels
Definition of aortic dissection
blood entry into media
Predisposing factors to dissecting aneurysm
HTN
atherosclerosis
pre-exisiting aneurysm
inflammatory disease
collagen disease
family hx
aortic co-arcation
bicuspid aortic valve
turner syndrome
CABG
aortic valve replacement
cardiac catheterization
cocaine
trauma
Symptoms of a dissecting aneurysm
sharp pain in posterior chest or back pain
Risk factors for AAA
male
age
smoker
family history
atherosclerosis HTN
Rare causes of AAA
trauma myocotic infection syphilis and marfan syndrome
When do you repair AAA?
> 6cm or larger
if small aneurysms are less then 5.5cm become symptomatic or >0.5cm in a 6 month period
Triad of ruptured AAA
pulsatile abdominal mass
Back pain
hypotension
Benefits of EVAR
reduced M&M, shorter LOS, less invasive
Complications of EVAR (early & late)
early: paraplegia, stroke, ARI, aneurysm rupture, pelvic hematoma
Late: endoleaks, aneurysm rupture, device migration, limb occlusion, graft infection
What are the two most common sites of chronic atherosclerosis?
infrarenal and iliac arteries
How can aortoiliac occlusive disease be managed?
direct reconstruction (aortobifemoral bypass- gold standard)
extra-antamotic or indirect bypass (axillofemoral bypass)
catheterbased endoluminal techniques (PTA)
What factors determine the pathophysiology of aortic cross clamping? (8)
level of cross clamp
status of left ventricle
degree of periaortic collateralization
intravascular volume and distribution, RAAS
anesthetic drugs and technique
heparinzation
monitor ACTs
Common complications to cross clamping:
i. Renal failure, hepatic ischemia, coagulopathy, bowel infection, paraplegia
What is activated with cross clamping?
Baroreceptor activation resulting from increase aortic pressure should decrease HR, contractility and vascular tone
What happens to total O2 consumption when aortic cross clamping occurs?
decreases by 50%
