4. QuickReminders
• Arteries
Large
Medium
Small
• Arterioles
Higher muscle ratio and
can completely occlude
lumen
2/3 of total systemic
resistance
• Capillaries
One-cell thick
Highest cross-sectional
area
Exchange nutrients
• Venules
Collect blood
• Veins
Blood reservoir (64%)
8x more distensible
Low pressure
Thin walls (less muscle)
7. Bottom Line Up Front
• Also known as peripheral artery disease, peripheral arterial disease,
peripheral vascular disease, peripheral arterial insufficiency, chronic
arterial insufficiency, PAD, PVD
• Miller: Aneurysmal or occlusive arterial disease of the extremities,
visceral organs, head, neck, and brain
• Defined as compromised blood flow to the extremities
• Ankle brachial index < 0.9
• Peripheral disease imparts a three to five times higher rate of
cardiovascular ischemic events
• 91.5% of vascular surgery patients have abnormal coronary arteries
• More than 60% have advanced (>70% stenosis) CAD
• 20% PAD patients have >70% carotid artery stenosis
• Claudication usually masks ischemic heart disease (functional decline)
• Primary anesthesia goal is to preserve cardiac and vital organ
function
8. Risk Factors
• Male
• Older age
• Family history
• Marfan syndrome
• Ehler’s Danlos
• Low high-density lipoproteins
• Smoking (doubles risk and causes progression)
• Diabetes mellitus
• Hypertension
• Obesity
• Dyslipidemia
• Homocysteine, fibrinogen, lipoprotein(a), apolipoproteins B
and A-I, C-reactive protein levels
9. LesionLocations
• Most commonly from
atherosclerosis in
large to medium
vessels, at sites of
turbulent flow
• Peripheral disease
mirrors that of the
aorta, coronary
arteries, and
extracranial cerebral
arteries.
16. Diagnosis
• Ankle-Brachial Index
• 1.0-1.1: Normal
• <0.9: Intermittent claudication (other texts say < 0.5)
• <0.4: Rest pain
• <0.25: ischemic ulceration & gangrene (other texts say < 0.2)
• Indicates disease proximal to measurement
• Transcutaneous oximetry
• Normal in the resting foot: 60 mm Hg
• <40 mm Hg: ischemic ulceration
• MRI and contrast angiography
• Used to guide surgical intervention
17. Treatment
• Exercise programs
• Modifying risk factors
• Smoking cessation
• Lipid-lowering therapy
• Glucose control
• Pharmacologic
• Antiplatelet drugs (ASA, clopidogrel)
• Statins
• Lumbar sympathectomy for persistent vasospasm
• Revascularization (Endovascular and Surgical)
• For severe claudication, rest pain, non-healing wound, acute
occlusive event
18. Treatment (Endovascular)
• Highest success with percutaneous transluminal angioplasty
(PTA) of the iliac arteries
• Femoral & popliteal artery PTA less successful
• Intraarterial thrombolytic therapy
• Balloon catheter embolectomy
• Stents
• Stent placement has improved both approaches
• Restenosis still a large problem
19. Treatment (Surgical)
• Depends on location and severity
• Endarterectomy
• Bypass grafting
• Saphenous (reversed) > umbilical vein and
polytetrafluoroethylene
• Aortobifemoral bypass for aortoiliac disease
• Aortoiliac reconstruction
• Axillobifemoral bypass (circumvents the abdominal aorta)
• Femorofemoral bypass for unilateral iliac artery disease
• Infrainguinal bypass
• Femoropopliteal
• Tibioperoneal
• Amputation
20. Anesthesia for PAD (Preop)
• Risk factor modification more important than anesthetic
approach
• Patient’s usually can’t perform ETT, so they receive MPS with
TTE
• May require PCI for ischemic heart disease first (ACC/AHA
guidelines)
• Statin therapy
• β-blocker therapy (but not initiated day of surgery). At least 7-
10 days prior
21. Anesthesia for PAD (Intraop)
• Principle risk is myocardial ischemia
• “Tight” hemodynamics
• Avoid hypervolemia, tachycardia (HR <85), anemia (HgB >9.0g/dL)
• Virtually all patients require intra-arterial monitoring
• Allen test is pretty much useless
• Radial artery preferred (collateral circulation)
• Regional (neuraxial) vs. general
• Inconclusive as to one benefiting over the other
• GA: Hypercoaguable state, higher cortisol
• RA: attenuates clotting, stress response, better pain control
• Intraoperative heparinization (at least 1 hour after epidural placement)
• Often on clopidogrel
• Delayed 12-24 hours after last dose of LMWH
• Aortoiliac/Aortofemoral surgery
• Infrarenal aortic cross-clamping vs. aortic cross-clamping
• Heparin prior to clamping
• Spinal cord damage unlikely and special monitors not normally used
22. Anesthesia for PAD (Postop)
• Analgesia
• Anxiety
• ST-segment analysis
• Frequent peripheral pulse checks
• Fluid and electrolyte derangements
• Ready for urgent re-stenosis management
24. Raynaud’s Phenomenon
• Episodic vasospastic
ischemia of the digits
followed by vasodilation and
hyperemia
• Women > men
• Associated to cold exposure
& sympathetic activation
(stress)
• Primary: Raynaud’s disease
• Secondary: Scleroderma and
systemic lupus
erythematosus, beta-
blockers, TCA, ergot
alkaloids, amphetamines
implicated
• Diagnosis: history and
physical, with inflammatory
markers sent to diagnose
secondary causes
• Treatment: Protect from
cold, CCB, alpha blockers,
surgical sympathectomy
• Anesthesia: Keep room
warm, NIBP, regional
anesthesia (without
epinephrine)
25. Peripheral Venous Disease
Conditions
• Superficial
thrombophlebitis
• Deep vein thrombosis
• Chronic venous
insufficiency
Risk Factors
• Virchow’s triad
• Venous stasis
• Surgery
• Trauma
• Immobility
• Pregnancy
• Low cardiac output
• Stroke
• Hypercoagulability
• Surgery
• Estrogen therapy
• Cancer
• ATIII, protein C, protein S deficiency
• Stress
• Inflammatory bowel disease
• Vessel wall abnormality
• Varicose veins
• Drug-induced
• History of thromboembolism
• Morbid obesity
• Advanced age
26. Venous Thromboembolism
Prevention
• Early ambulation
• Compression stockings
• Procedure < 1 hour
• Subcutaneous heparin 5000
units BID – TID
• Intermittent external
pneumatic compression
devices
• Use of regional anesthesia
• 20-40% reduction after total
hip or knee surgery
(vasodilation)
• Allows for earlier ambulation
(analgesia)
Treatment
• Heparin (LMWH or
unfractionated)
• Warfarin (INR 2-3)
• Inferior vena cava filter
• Thrombophilia workup
• Factor V Leiden
• Antithrombin III deficiency
• Protein C deficiency
• Protein S deficiency
• Plasminogen
• Increased antiphospholipid
antibodies
28. Key Points to Vasculitis
• “Angiitis, arteritis”
• Signs/Symptoms: fever, myalgias, arthralgia, malaise
• Understand what vessels are affected
• Large vessels: aorta and main branches
• Medium vessels: coronary arteries
• Small vessels: arterioles, venules, and capillaries. Type III
immune complex reactions. Serum antineutrophil cytoplasmic
antibodies (ANCA) correlate to disease severity.
• Treatments usually include glucocorticoids (adrenal
suppression), underlying pathology, and immunosuppression
agents
29. Systemic Vasculitis Types
Large Artery
• Takayasu’s arteritis
• Temporal (giant cell)
arteritis
Small & Medium Artery
• Kawasaki’s disease
• Thromboangiitis obliterans
• Wegener’s granulomatosis
• Polyarteritis nodosa
33. Thromboanglitis Obliterans
• “Buerger’s disease”
• Associations
• Men <45 yo
• Tobacco use
• Raynaud’s
• Small-Medium arteries
and veins of the
extremities
• Treatment
• Stop smoking
• No established drug
therapy
• Anesthesia
• Avoid triggers
• Warm room
• Warmed and humidified
gas (maintain body temp)
• Meticulous padding of
pressure points
• NIBP
• Avoid epinephrine if using
regional anesthesia
34. Wegener’s Granulomatosis
• Necrotizing
gramulomas in vessels
• CNS
• Airways
• Lungs
• Cardiovascular
• Kidneys
• Treatment
• Glucocorticoids
• Methotrexate
• Rituximab
• Maintenance with
azathioprine or
methotrexate
• Anesthesia
• Sinusitis may be present
• Renal failure may be
present
• Laryngeal mucosa
replaced by granulation
tissue (narrowed, stiff)
35. Churg-Strauss Syndrome
• Small-medium vessels
• Respiratory system
• Rhinitis
• Asthma
• Eosinophilia
• Treatment
• Glucocorticoid
• Immunosuppression
• Anesthesia
• Often come in for nasal
polypectomy &
myringotomy tubes
• Reactive airway
37. Key References
1. Hall JE. Guyton and Hall Textbook of Medical Physiology. Elsevier
Health Sciences; 2016.
2. Stoelting RK, Hines RL, Marschall KE. Stoelting's anesthesia and co-
existing disease. 6th ed. Philadelphia: Saunders/Elsevier; 2012.
3. Miller RD. Miller's anesthesia. 8th ed. Philadelphia, PA:
Elsevier/Saunders; 2015.
4. Yao FSF, Fontes ML, Malhotra V. Yao and Artusio’s Anesthesiology:
Problem-Oriented Patient Management. Wolters Kluwer Health;
2012.
5. Horlocker TT, Wedel DJ, Rowlingson JC, et al. Regional Anesthesia
in the Patient Receiving Antithrombotic or Thrombolytic Therapy:
American Society of Regional Anesthesia and Pain Medicine
Evidence-Based Guidelines (Third Edition). Regional Anesthesia
and Pain Medicine. 2010;35(1):64-101.
Editor's Notes
Figure 14-1: Hall JE. Guyton and Hall Textbook of Medical Physiology. 13th ed. Elsevier Health Sciences; 2015. https://books.google.com/books?id=krLSCQAAQBAJ.
Arteries are classified as large, medium, and small based on compliance. Arterioles are the site of highest systemic vascular resistance (remember in the large cross-sectional anatomy that in parallel, we can change the circuit’s resistance). Capillaries are where nutrient exchange occurs, and are only one cell thick without musculature.
Venules receive blood from the capillaries and feed to the blood reserviour – the veins. Veins are more highly distensible, and the peripheral veins have valves (whereas the larger abdominal and thoracic veins do not).
FIGURE 30.2 • Blood vessels—microanatomy of the artery, vein, and capillary beds. (From McConnell T. H., Hull K. L. (2011). Human form human function: Essentials of anatomy & physiology (p. 433, Figure 11–12). Philadelphia, PA: Wolters Kluwer/Lippincott Williams & Wilkins.)
All vessels are three layers, except capillaries. Endothelial cells form a continuous lining – the endothelium. It regulates molecule transfer, platelet adhesion, modulation of blood flow, metabolism of hormones, regulation of immune and inflammatory reactions, and produce nitric oxide and endothelins. The endothelium is a huge site of interest as a biologically active tissue.
Tunica media is smooth muscle interconnected with gap junctions. Norepinephrine is released from sympathetic nerves regulating tone here (remember the SVR).
Blood flow is regulated by myogenic means, production of local metabolites, and can auto-regulate between 70 – 175 mm Hg (systemic vasculature). External regulation occurs from sympathetic tone (and occasionally parasympathetic producing Nitric Oxide, as in the case of the naught—bits), and hormones.
Just a quick reminder of a few last physiology concepts:
Poiseulle’s law tells use flow is fastest away from vessel lumens.
As diameter changes in vessels, the conductance is altered by a fourth power.
Figure 14-8: Hall JE. Guyton and Hall Textbook of Medical Physiology. 13th ed. Elsevier Health Sciences; 2015. https://books.google.com/books?id=krLSCQAAQBAJ.
Peripheral arterial disease is known by many names, as listed. By definition, PAD is an ankle brachial index < 0.9 (this correlates very well to angiographic-evidenced PAD). The major concern is perioperative cardiac events more than developing critical limb ischemia, as evidenced by the 91.5% association with abnormal coronary arteries. Our primary goal is preserve cardiac and vital organ perfusion.
1
Stoelting RK, Hines RL, Marschall KE. Stoelting’s Anesthesia and Co-Existing Disease. Vol 6. Saunders/Elsevier; 2012. https://books.google.com/books?id=LXPBrqZAIiEC.
Occurs in 70% of persons over 75 years old.
I bolded the modifiable risk factors (hence, the ones we can “optimize” the patient prior to surery). Claudication and PVD risk is doubled in smokers with higher rates of disease progression (leading to amputation)
Notice that the disease primarily occurs at bifurcations. The most common sites are the aortoiliac vessels, with a close second at the coronaries. The key point is that peripheral vessels mirror central vessels.
And with mono
The “fatty streak” begins in childhood
FIGURE 30.8 • Fibrofatty plaque of atherosclerosis. (A) In this fully developed fibrous plaque, the core contains lipid-filled macrophages and necrotic smooth muscle cell (SMC) debris. The “fibrous” cap is composed largely of SMCs, which produce collagen, small amounts of elastin, and glycosaminoglycans. Also shown are infiltrating macrophages and lymphocytes. Note that the endothelium over the surface of the fibrous cap frequently appears intact. (B) The aorta shows discrete raised, tan plaques. Focal plaque ulcerations are also evident. (From Rubin R., Strayer D. (Eds.). (2012). Rubin’s pathology: Clinicopathologic foundations of medicine (6th ed., p. 447–448). Philadelphia, PA: Lippincott Williams & Wilkins.)
Type
Intermittent claudication occurs when metabolic demand exceeds oxygen delivery
Rest pain occurs without exertion.
Usually the first sign is decrease peripheral pulses
Bruits can indicate the site of the lesion.
Hanging the extremity increase hydrostatic pressure in the arterioles, facilitating better oxygen delivery
Beta blockers have been theorized to evoke peripheral cutaneous vascoconstriction, but RCTs have failed to bear this out.
Regional: can reduce change of postoperative delirium, allows for patient to communicate myocardial ischemia symptoms, less activation of the coagulation system, fewer post operative pulmonary complications
Intraoperative heparinization is not a contraindication. Surgical team should be aware that if a blood tap occurs, procedure may need to be delayed
General anesthesia: for longer procedures, vein harvesting from upper extremities. Cardiac preconditioning from inhaled agetns?
Infrarenal aortic cross-clamping associated with fewer hemodynamic changes than aortic cross clamping (same for unclamping).
Occlusion of subclavian or innominate artery proximal to vertebral artery origin. The occlusion causes a reversal of flow through the ipsilateral vertebral artery into the distal subclavian artery. Diverts blood from the brain to the arm.
Signs and symptoms are CNS ischemia and ipsilateral arm ischemia. Extremes of neck movements and exercise and produce symptoms. Pulses can be absent or diminished in the affected arm with SBP 20 mm Hg lower in that arm (like coarctation of the aorta). Bruit over the subclavian artery
Occurs with proximal stenosis of the left subclaviarn artery causing reversed blood flow through a patent internal mammary artery graft.
Signs and symptoms are angina pectoris and 20 mm Hg or more decrease in systolic BP in the ipsilateral arm.
Surgical embolectomy is used for large vessel occlusion that are not atheromatous. Atheromas fragment with manipulation.
Superficial thrombophlebitis: palpable cord-like veins, localized swelling and pain.
DVT: generalized pain, unilateral limb swelling. Compression ultrasonography highly sensitive for proximal thrombus but less for calf thrombus. Can also consider venography
Takayasu’s is rare, idiopathic, chronic, progressive occlusive vasculitis that causes narrowing, thrombossis, or large vessel (aorta) anuerysms. Mostly in Asian women < 40 years old.
Takayasu’s is rare, idiopathic, chronic, progressive occlusive vasculitis that causes narrowing, thrombossis, or large vessel (aorta) anuerysms. Mostly in Asian women < 40 years old.
