Major risk factor for PVD
atherosclerosis
Atherosclerosis is an _______ process.
inflammatory, body recognizes LDL as a foreign substance, get pro-inflammatory cytokines
Tell me about coronary artery plaques Ie- stable or unstable?, rupture or occlude?
Unstable and prone to rupture Thin cap with thick lipid core
Tell me about carotid artery plaques- ie stable or un?, rupture or occlude?
Unstable, more likely to occlude Thin cap with thick lipid core (like coronary plaques)
common sites for plaque lesions
bifurcations! turbulent flow, high pressure, vessel wall shearing coronary arteries carotid bufurcation abdominal aorta illiac arteries
PVD s/sx
50% have none or mild s/sx claudication numbness or weakness of LE Cold legs/ feet Non healing ulcers Hair loss on legs, shiny skin Impotence
What are the 3 theories explaining PVD?
Virchow's - endothelial injury is caused by physical and enviro factors, sub endothelium is exposed, smooth muscle proliferation and Plt adherence occursMonoclonal - cell proliferates 2/2 a mutagen or virusClonal senescence - smooth muscle proliferation inhibition decreases with aging
What is an aneurysm?
localized dilation or out-pouching of a vessel wall
Why is the aorta particularly susceptible to aneurysms?
High constant stress to vessel wall Absence of penetrating vasa vasorum in the adventitial layer
Major causes of aneurysms
HTN and atherosclerosis Genetic component, most have a 1st degree relative who also has it
What is systemic vasculitis?
blood vessel inflammation (caps, arteries, and veins)
S/sx vasculitis
fever wt loss fatigue muscle and joint pain loss of appetite
Implications of vasculitis
Can rx blood flow to organs causing major damage
Systemic vasculitis: Buerger's dz
inflammation and clots in BV of arms and legs assoc with cigarette smoking typically occurs in middle aged jewish males
Systemic vasculitis: Takayasu's arteritis
includes largest arteries in the body, including the aorta typically occurs young asian females
Systemic vasculitis: Kawasaki disease
most often affects kids < 5 yo s/sx : fever, rash, eye inflammation
Systemic vasculitis: Giant cell arteritis / temporal arteritis
Usually occurs in ppl > 50 yo Inflammation of arteries in neck, upper body, arms, and head (esp. the temples) Most common vasculitis in US Assoc with PMR Tx= corticosteroids S/sx= H/A, scalp tenderness, jaw pain, blurred vision, blindness
Systemic vasculitis: Raynaud's
cold induced arterial spasm of the extremities Often found in adult females Assoc with SLE and scleroderma Avoid VC with regional anesthesia
Systemic vasculitis: Wegener's granulomatosis
inflammation of blood vessels in nose, sinuses, throat (URI), lungs, and kidneys s/sx= SOB, nosebleeds, nose ulcers Pts may be immunosuppressed due to tx with cyclophosphomide
Systemic vasculitis: polyarthritis nodosa
affects medium sized BV in many different parts of the body most common in F, ages 20-60 s/sx= purpura, ulcers, muscle and joint pain, abd pain, HTN
Systemic vasculitis: Moyamoya disease
narrowing or occlusion of both IC arteries may cause TIAs in kids and IC hemorrhage and IC aneurysms in adults
CAD risk in pts having vascular surgery
< 10% have normal coronaries
Intermediate clinical predictors of increased peri-op CV risk (MI, HF, and death)
mild angina previous MI CHF DM CRI (Cr > 2)
Minor clinical predictors of increased peri-op CV risk (MI, HF, and death)
adv age abn EKG Rhythm other than sinus Low func. capacity H/O CVA Uncontrolled HTN
Major clinical predictors of increased peri-op CV risk (MI, HF, and death)
Unstable coronary syndrome (acute or recent MI), unstable or severe angina Decomp HF Signif arrhythmias (high grade AVB, symptomatic vent arrhythmias, uncontrolled SVT) Severe valvular disease
Most common cause of peri-op death with vascular surgery
MI usually occurs post-op (but we play a role with our emergence and wake-up)
When in the vascular surgery peri-op period to most MIs occur ?
24-48 hour period
T or F, vascular surgery is considered intermediate risk
F, it's high risk
Why is peripheral vascular surgery reserved for severe ischemia?
Limited durability of bypass graft
What is the ankle/ arm index?
Used to evaluate severity of arterial insufficiency Compare BP on arm and on calf Normal- ratio = 1 (they are equal)
What type of vascular surgery involves aortic cross clamping?
Aortofem bypass
Factors to be avoided post-op for prevention of MI with vascular surgery
tachycardia hypothermia hypervolemia pain
Adv / disadv of use of regional anesthesia in vascular surgery
IV anticoag must be stopped prior to regional Stable HD with incremental dosing Improved graft patency limited duration (case may be long) thoracic epidurals are difficult to place risk sympathectomy
Adv / disadv of use of general anesthesia in vascular surgery
pt can stay on IV anticoag able to graft UE hypercoagulable state increased post-op catecholamines possible ventilatory challenges post-op (abd surgery)
Neuraxial level needed for vascular surgery
T10-T12 T8 if exposing the pelvis
Major risks associated with CEA
MI and CVA
For what degree of ICA narrowing is CEA beneficial
60-90% No benefit in pts with < 60% narrowing
T or F, its with LM CAD are more likely to have carotid disease
True False
T
S/sx carotid stenosis
TIA, CVA, UE or LE numbness or weakness, unilateral monocular blindness
What type of CVA is likely to occur with a CEA
embolic
Increased risk of poor neuro outcome is seen in its undergoing CEA with what issues?
Poor collaterals Contralateral carotid occlusion Renal insufficiency, (Cre > 2) Poorly controlled HTN CAD requiring bypass Decreased LOC pre-op Active neuro process pre-op
The glossopharyngeal nerve (CN 9) runs alongside what structures? What are the implications?
Of concern with a CEA Runs along side ICA, where the carotid body and sinus are located Damage to carotid body- insensitivity to hypoxia Damage to carotid sinus- vagal response (baroreceptor)
2 major vessels supplying the brain
IC and vertebral artery
What structure provides collateral circulation to the brain? How does it work?
circle of willis, so if either the IC or vertebral artery is occluded, brain still receives adequate flow
Goal ETCO2 for CEA, why?
normocarbia avoid steal as thick stenotic vessels aren't affected by CO2 level so blood is directed away from areas that need it
Anesthetic agent selection for CEA
short acting to allow a smooth and fast wakeup assess neuro status avoid coughing and bucking with emergence
Goal fluid management for CEA
euvolemia
What factors can increase myocardial O2 demand?
Increase in: HR, diastolic volume, contractility, BP
What factors can decrease myocardial O2 supply?
Decrease in coronary blood flow (incr HR, diastolic volume, coronary VC or thrombosis) Decrease in O2 content (decr Hct or O2 sat)
Goal BP for CEA
20% ABOVE baseline
Normal cerebral blood flow
50 ml / 100g brain
Factors that will affect EEG with CEA
propofol, volatiles, bovie
How is an awake CEA performed- what's the benefit
With a carotid plexus block (C2-4) Adv= Constant neuro assessment
T or F, use of carotid plexus block is associated with a decrease in post-op CVA incidence
F, no difference with regional vs. GA
contraind to regional anesthesia for CEA
high carotid lesion language barrier claustrophobia pt preference
Adv of using GA for CEA
ability to manip HD decrease O2 demand and catecholamine level airway security
Can N20 be used for a CEA
Yes, however there's a risk of air exposure with shunt placement and during release of cross clamp- so if using shut it off prior
Risks associated with CEA
Damage to recurrent laryngeal nerve CVA Carotid body denervation Hyperperfusion syndrome (HA, sz, vision changes)
T or F, barbs and etomidate are known to be cerebral protectant and are rec for use with CEA
True False
F
Risk of AAA rupture increases with diameter of ____.
> 4.5- 5 cm
Elective repair of AAA is indicated with a diameter of ____ or _____.
6 cm or greater > 0.5 cm increase in 6 mo or symptomatic
Risk factors for AAA
adv age smoking > 40 yrs HTN incr LDL low Plt count atherosclerosis more prevalent in males
CV changes assoc with aortic cross clamping for AAA repair
Increased MAP and SVR Slight decrease in CO Decreased O2 consumption Preload may increase with myocardial dysfunction MI
Interventions to counteract CV changes assoc with aortic cross clamping
vasodilators (nitroprusside, fenoldapam, volatiles, NTG, BB)
Metabolic changes assoc with aortic cross clamping for AAA repair
decreased total body O2 consumption (above and below clamp) decreased CO2 prod incr epi and NE resp alk met acidosis
T or F, renal blood flow is preserved with infra-renal aortic cross clamping?
F, RBF is decreased
Strategies to maintain renal perfusion with AAA repair
euvolemia (optimize pre-op) mannitol lasix dopa mucomyst fenoldopam
Coagulation changes assoc with aortic cross clamping
Clotting factor consumption, can get DIC Hypocalcemia Thromboxane causes increased vasc permeability leading to pulm edema
artery of adamkiewicz
risk of damage with AAA repair can lead to SC ischemia joins anterior spinal artery btw T8-12
Goal BP with aortic dissection / decr thoracic aneurysm
SBP 90-120 mmHg
What type of endoleaks are the most concerning and why?
Type 1 and 3 assoc with incr risk of rupture, require aggressive tx both involve leaking with forward flow of blood into aneurysm sac
Which procedure is safer open or endovascular AAA repair
endovascular
Possible post-op complication of desc thoracic aneurysm
post-op paraplegia due to interruption of blood flow from artery of adamkiewwicz
What is the mainstay of tx for AAA repair
volume and fluid replacement
Why is it difficult to estimate EBL with AAA repair surgery
due to the venous capacitance of the splanchhic circulation
therapeutic interventions with aortic cross clamp release
volume neo calcium ephedrine epi Na bicarb incr MV