Vascular Flashcards
1
Q
13 µs rule
A
Propagation velocity equals time
The signal obtained at 13 µs is from 1 cm deep
2
Q
Doppler angle of insulation for vascular applications is
A
60° or less
3
Q
Two types of continuous wave Doppler
A
Analog/think average
Digital/detail 
FFT analyzes and displays all the frequencies moving through sample area
4
Q
PW Doppler
A
The primary technique used in duplex scanning
Pulse Doppler has range or depth resolution
May alias if the Doppler shift at frequency is greater than 1/2 the PRF/Nyquist limit
5
Q
Sample volume size for most arterial applications
A
1.5 to 2.5 mm.
6
Q
Arterial system anatomy
A
Arteries/transport, gases, nutrients, and other essential substances to the capillaries.
Arteriolae’s /resistance vessels, assist with regulating blood flow through contraction and relaxation
Capillaries/nutrients and waste products are exchanged between the blood and tissue
Venules/collect blood from the capillary beds
Veins/collect blood from the venules and return it to the heart
7
Q
Anatomy of a vessel walls
A
Tunica intima/innermost layer
Tunica media/metal and thickest layer
Tunica adventitia, externa/the outer most layer contains fibrous, connective, tissue and muscle fibers. Also contains the vasa vasorum ( the blood supply within the blood supply )
8
Q
Aorta
A
Aortic arch/3 main branches
Ascending aorta/from the aortic valve to the first branch
Descending thoracic aorta/from the arch to the diaphragm
Abdominal aorta/begins as the aorta passes through the diaphragm and terminates at the aortic bifurcation into the iliac arteries 
9
Q
Branches of the aortic arch
See diagram
A
Brachiocephalic trunk (innominate) artery/1st and largest branch off of the aorta, begins directly after aortic arch. Bifurcates into right subclavian, and right common carotid arteries.
Left common carotid artery/2nd branch directly off of the aortic arch
Left subclavian artery/3rd branch off aortic arch
10
Q
Upper extremity arteries
See diagram
A
Subclavian artery/terminates into axilla artery at the first rib
Axillary artery/passes behind clavicle and terminates into the brachial artery at the axilla
Brachial artery/main blood supply to the arm, divides into radial and ulnar
Radial artery/lateral, thumb side, terminates in deep palmar arch
Ulnar artery/medial, pinky side, terminates into superficial palmar arch
11
Q
Abdominal aorta and visceral branches
See diagram
A
Celiac artery/supply, stomach, liver, pancreas, duodenum, spleen. Divides into left gastric artery, common hepatic artery, and splenic artery
* left gastric artery supplies, stomach, esophagus. Common hepatic artery supplies, liver. Splenic artery, supplies, spleen.
Superior mesenteric artery (SMA)/ supplies, the small intestine, cecum, parts of colon.
* SMA, and celiac may have a common trunk
Renal arteries/ just below SMA, supplies, kidneys, suprarenal gland’s, ureters. And transverse, the left renal vein is a landmark for identifying renal arteries.
Inferior mesenteric artery/supplies, transverse and descending colon, rectum
To potential collateral connections between the SMA and IMA /
Marginal artery of the colon (a.k.a. the marginal artery of drummond) and arc of Riolan
12
Q
Aortic bifurcation
A
Common iliac arteries/supply the pelvis, abdominal wall, lower limbs
Divides into the :
Internal iliac artery/hypogastric artery, supplies, pelvis, and inner thigh
External iliac artery/supplies the leg
Terminates into the common femoral artery. **Landmark- Psoas Major muscle
13
Q
Lower extremity arteries
See diagram
A
CFA / EIA Becomes the CFA at the inguinal ligament
SFA/medial thigh, becomes the pop artery
DFA/supplies thigh, collateral pathway via connections to the pop artery (genicular branches)
Pop artery/continuation of the SFA as it passes through the adductor hiatus where there is an opening and two adductor Magnus muscle. Genicular branches connect with the profunda branches. Terminates into the trifurcation.
ATA/the first branch of the distal pop artery, terminates into the DPA
Tibial/peroneal trunk/branches into PTA and peroneal artery
PTA/medial side of leg, branches are plantar arteries, supplies foot
Peroneal/fibula side, supplies, leg, and foot
Plantar arch/digital arteries/ I DPA, and PTA form the plantar arch
Are plantar and dorsal metatarsal arteries, arise from the plantar arch and supply the digits
14
Q
Atherosclerosis obliterans (ASO)
A
The most common arterial pathology
Thickening and hardening of plaque within the arterial wall between the intimal and medial
Claudication, exertional, leg pain, is the most common symptom and PAD
Ischemia and possible amputation is most feared consequence
15
Q
Arterial occlusion
A
Thrombosis/progression of disease until the stenosis thrombosis and includes completely.
Embolus/obstruction of a vessel, by foreign substance, most frequent, thrombus or plaque.
6 P’s associated with a Q arterial occlusion
Pain
Pallor
Pulselessness
Paresthesia
Paralysis
Poikiloderma/ Polar
16
Q
Aneurysm
A
Dilated artery greater than 1 1/2 times the diameter of the adjacent artery ** 50% increase in diameter
Dilatation of the artery involving all three layers of the arterial wall (intima, media, adventitia)
Classified by morphology
-Fusiform/spindle-shaped
-saccular/sac off vessel
Most common location is infrarenal, abdominal aorta
Patience with an aneurysm, have a much higher incidence of another
50% of patients with pop artery aneurysm will have an aortic aneurysm
Most frequent complications :
AAA-rupture
Peripheral artery aneurysm (leg/arm)-embolization
17
Q
Arterial dissection
A
Intimal wall layer develops a tear and filled with blood, dividing the vessel into a true lumen, and a false lumen
Active flow in both lumens
Most often occurs in thoracic aorta
Cause/spontaneous, trauma, hypertension
18
Q
Coarctation of the aorta
Say diagram
A
*narrowing
Congenital anomaly
Involves thoracic aorta
Symptoms include leg, pain, absent, pulses, hypertension, due to decreased renal perfusion
19
Q
Fibromuscular dysplasia
(FMD)
A
Non-atherosclerotic disease, that results in abnormal cellular growth in the walls of the medium and large arteries affecting the medial layer of the vessel
Rare disease, primarily found in middle, aged women
Commonly seen in the distal ICA and renal arteries
Beading of the vessel lumen
“ string of pearls”
20
Q
Arteritis
A
Inflammation of the arterial wall
More common in small vessels, digital arteries, tibial vessels
Three types :
-Buerger’s disease/occurs primarily in men less than 40 and heavy smokers. Often present with occlusion of the distal arteries and rest pain/ulceration.
-Takayasu’s arteritis/affects the aortic arch and its branches. Most common in females referred to as pulselessness disease.
-Temporal arteritis/affects temporal artery. Untreated may lead to blindness.

21
Q
Vasospastic disorders
A
Raynauds phenomenon/digital ischemia due to small vessel, vasospasm secondary to cold, exposure or stress.
-Primary raynauds/ common in younger women, hereditary
-Secondary raynauds/ vasoconstriction with another condition
22
Q
Entrapment syndromes
A
Popliteal artery entrapment/popliteal artery is compressed by the medial head of the gastrocnemius muscle. May result in stenosis, aneurysm. Often found in young athletes.
Thoracic outlet syndrome/compression of the Nuro vascular bundle by the shoulder structures. Cervical rib, clavicle, scalene, muscles, numbness, tingling of arm, pain and arm. 
23
Q
Claudication
A
The most common symptom of peripheral artery disease
Due to inadequate blood flow
Pain usually distal to the disease often in calf
Example/Leriche syndrome- aorta iliac obstruction. More common in males.
24
Q
Pseudo claudication
A
False claudication
Referred to as neurogenic claudication
Pain due to neurogenic cause / ex- spinal stenosis, or nerve compression
25
Ischemic rest pain
Pain at rest
Inadequate blood flow
Typically affects the toes, foot, heel
26
Tissue loss
Insufficient blood flow to maintain cell metabolism
Gangrene/tissue necrosis
27
Skin conditions
Pallor/white
Rubor/reddish
Cyanosis/bluish
Elevation/dependency changes - pallor with elevation and rubor with dependency.
28
Blue toe syndrome/trash foot
Suggestive of distal micro emboli
29
Capillary refill times
An increase in capillary refill times suggest decreased arterial pressure perfusion
Normal refill time is less than three seconds
30
Circulatory system
Pressure is greatest at the heart, decreasing distally
Cardiac output determines the amount of blood entering the system
Venous return equals cardiac output
Movement of any fluid requires a pathway and a pressure/energy differential
Amount of flow depends on energy difference, and resistance
31
Circulatory system
Arteries/distribute blood to the body
Arterioles/slow flow velocity, increased resistance
Capillaries/nutrient exchange
Venules/collect blood from the capillary beds
Veins/high capacitance blood storage
32
Blood leaves the heart with a meannn pressure of
85 to 95MMHG
33
Small arteries and arterioles are the
Resistance vessels and pressure falls from 80 to 25/30 MM Hg
34
Blood moves from
High pressure to low pressure area
35
Flow
How much blood is moving
Volume
Liters/minute
36
Velocity
How fast the blood is moving/speed
Centimeters/ sec
37
Flow types
Steady flow/constant velocity
Pulsatile/variable velocity due to cardiac contractions
Phasic/variation in velocity and low pressure venous circulation due to respiration
38
Energy
Potential/pressure energy:
The ejection of blood from the heart into the arteries distends the elastic arterial wall, and this becomes stored energy
Kinetic/motion energy :
Movement of blood, as it’s ejected from the heart
Gravitational energy or hydrostatic pressure:
Weight of the column of blood from the heart to the level with the pressure is measured, position a patient
MMHG - pressure
For example, flash and a supine patient the arteries and veins are about the same level as the heart and the hydrostatic pressure is near 0MMHT. When the patient stands, the HP increases adding 100 MM Hg at the ankle.
Ankle pressure standing = circulatory pressure + gravitational(100mmghg)
39
Energy loss as blood flows
Friction (common)- fractional losses occur when one object rubs against another, energy converted to heat
Viscosity (least likely) - thickness of fluid
Inertia and momentum - objects in motion tend to stay in motion and objects at rest and stay at rest. Energy is lost when the velocity or the direction of the fluid changes.
40
Blood flow patterns
See diagram
Laminar flow/fluid particles, flow smoothly in an organized manner. Two types of laminar flow.;
-Plug flow/the last things that are similar from wall-to-wall
-Parabolic flow/flow that is faster in the center of the vessel
Disturbed flow/, disruption of stream lines, Bends, bifurcates, stenosis area
Turbulent flow/flow with varying direction and velocitys, associated with disease
41
Reynolds number
Predicts when stable flow becomes unstable
<1500 means laminar
> 2000 means turbulent flow
42
Factors affecting resistance
See diagram
Movement of fluid depends upon physical properties (blood density, viscosity) and what it’s moving through (blood vessel)
Resistance is directly proportional to viscosity, and length, resistance increases with increasing viscosity and length
Resistance is inversely proportional to the vessel, radius, resistance increases as vessel, radius decreases
43
Poiseuilles law
Flow (Q)= pressure (P) / resistance (R)
Describe the relationship between pressure flow and resistance to flow
Defines how blood moves through a given vessel segment
*Vessel radius, or area, is most important
44
Pulsatile flow
See diagram
Early systole/cardiac contraction, opens
Late systole, early diastole/closes, dicrotic notch represents aortic valve closure
Lake diastole/proves recoil
45
Waveform morphology
High resistance flow:
Forward flow during systole, late systolic flow reversal
Supplies most peripheral vascular beds ; arms, legs, splanchnic vessels, and fasting patients
Low resistance flow :
Forward flow throughout the cardiac cycle
Supplies, Oregon’s with HAIM, metabolic rate, brain, kidneys, vessels after eating, ICA
* low resistance= life
46
Law of conservation of mass
Q=A x V
Area and velocity are inversely proportional
Area decreases, velocity increases
47
Flow characteristics of a stenosis
As blood velocity increases through a stenosis, kinetic (motion)energy increases, and potential (pressure) energy decreases.
Proximal to stenosis/flow pattern, may or may not be altered
At stenosis/velocity increases, flow is disorganized, spectral, broadening
Post stenosis/Turbulence
48
***
50% diameter reduction =
75% area reduction
49
An arterial occlusion or stenosis may result in_____ pressure distally.
Decreased
(The peripheral resistance will change from high to low)
50
Systolic acceleration time
(AT)
Hemodynamically significant stenosis, may also affect the speed of pulse wave and results in a delayed systolic acceleration time.
51
Sympathetic nervous system includes
Cerebral, coronary, Renal
52
Collaterals
Collateral circulation is an alternative pathway that may supply blood around an obstruction
These collateral vessels, Mesa Place, efficient, blood volume to maintain normal, peripheral resistance and blood flow despite disease
53
Exercise is a very potent vasodilator
Transform flow patterns from high to low resistance
Vasoconstriction at rest = high resistance
Vasodilation = low resistance
Flow to cool Limb- vasoconstriction, high resistance
Flow to warm limb - vasodilation, low resistance
54
Viscosity
Internal friction dependent upon the thickness of the fluid
Increased hematocrit/increased viscosity
Anemia results in decreased viscosity
55
Hemodynamics
Systolic upstroke-shows where the blood came from
(Delayed systolic upstroke means stenosis, proximal)
Diastolic flow - shows where the blood is going
(Resistance of the downstream, vascular bed)
56
Plethysmography
Measurement of blood volume changes as a result of the blood moving through the limb.
2 types
-Volume Plethysmography (PVR)- reflects amount of blood, moving under cuff
-photoplethysmography (PPG)- assessment of cutaneous blood flow. Skin level/ ulcers.
57
CW Doppler velocimetry
Analog/uses zero crossing frequency detector
Digital/spectral analysis
FFT, analyzes and displays all frequencies moving in sample area
58
Quantitative Doppler waveform interpretation
Pulsatility index (PI)-calculates peak to peak frequency difference.
Normal > 4.0
Abnormal < 4.0 consistent with >60% stenosis, proximal to the sample
Systolic acceleration time -proximal obstruction results in delayed time interval, between systole and peak velocity
Normal AT < 133 ms
Abnormal AT > 133 ms proximal obstruction
59
Inflow/outflow disease
Inflow disease/represents the blood flowing into the lower. Ex, aorta, iliac disease.
Outflow disease/represents the blood flow going out into the extremity , ex, for femoral popliteal disease 
60
Segmental pressures
Only detect significant disease. Cannot discriminate normal from mild disease or stenosis from occlusion.
Do not do pressures on patients with;
DVT
fistula or graft
Lymphedema
Post bypass graft with stenting
Four cuff method, two thigh cuff
Three cuff method, single, thigh cuff
* see diagram
Lower extremity cuff size -
10 to 12 cm cuff for brachial
10 cm calf and ankle
12 cm thigh cuffs for 4 cuff method
19 cm thigh cuff for 3 cuff method
Upper ext. cuff size-
12 cm cuff for brachial
10 cm cuff for forearm
61
20% rule
Width of cuff 20% greater than the diameter of the limb
Using a too small cuff results in artifactually high pressure
62
4 cuff vs. 3 cuff
4 cuff method-
Two thigh cuffs provide a proximal and distal thigh measurement
Differentiates between aorta iliac (inflow) and superficial femoral artery disease
The 2 thigh cuffs violate the 20% rule and will result in artifactually elevated high pressures, and pressures will be **30 mmHg higher***
3 cuff method-
1 thigh cuff
Accurate thigh pressure
If abnormal, cannot differentiate between inflow and SFA disease 
Inflate cuff 20-300 mm/Hg higher than the brachial pressure
63
ABI interpretation
>1.0- normal
In between/ probably abnormal
< 0.5- multi level disease or occlusion
Under is ischemic pain
ABI of > 1.3 is not valid/ calcified
64
Wound healing
Toe pressure 30mm/Hg or less has very poor healing potential
65
Segmental pressure interpretation
Lower extremity
> 20 to 30 abnormal
Upper extremity
> 15 to 20 abnormal
A difference of >20 mmhg between the radial and ulnar, suggests obstruction in the vessel with the lower pressure 
66
Exercise testing
The most common symptom of peripheral artery disease is exertional pain
Exercise testing allows the differentiation of vasculogenic claudication from pseudo claudication, such as neural spinal compression or arthritic pain
There will always be a pressure drop when patient experiences the pain of true vasculargenic claudication 
Normally, the ankle pressure should be the same or higher
Post treadmill -
Larger the drop longer return to baseline corresponds to lesion severity. Drop in ankle >20 confirms vascular ideology for claudication
*Length of time to recover -
2 to 6 minutes single level disease
6 to 12 minutes multilevel disease
Post occlusive reactive hyperemia
Normal Limb Michelle at transient drop of up to 30%
< 50% drop single level disease
> 50% drop multilevel disease
67
Digit interpretation
Functional disease/consistent with vasospasm
Baseline/resting -normal Doppler, PPG, waveforms and pressures
Abnormal cold response -fails to return the Baseline
Peaked pulse seen with Raynauds
Finger brachial index
Normal 0.8 to 0.9.
Abnormal < 0.8.
Tell brachial index
Normal > 0.75.
Abnormal < 0.66.
<30 mm/Hg = poor healing potential
68
Lower extremity artery
Velocity ratio= highest PSV in the stenosis divided by the PSV proximal to the stenosis
2:1 ratio > 50% diameter reduction
4:1 ratio > 75% diameter reduction
PSV > 400 cm/s = > 75% reduction 
69
Aneurysm
Peripheral artery aneurysm- dilated artery > 1 1/2 times the diameter of the adjacent artery
Patience with an aneurysm in one location or more likely to have an aneurysm elsewhere
Embolization is the most like a complication for peripheral aneurysms
70
Aorta iliac artery duplex imaging
See diagram 
AAA-
Dilated segment > 1 1/2 times the diameter of the normal artery segment
Infra renal/ most common
Supra renal/uncommon
Aneurysm/rupture
Peripheral/emboli
71
Stenosis, interpretation, iliac, arteries
2:1 ratio increase= > 50% diameter reduction
4:1 ratio increase= > 75% diameter reduction
72
Upper extremity artery imaging
See summary chart
Interpretation:
-Aneurysm:
subclavian artery aneurysm, most common, associated with distal emboli.
Ulnar artery aneurysm typically secondary to Hypothenar hammer syndrome, trauma. 
Hypothenar hammer syndrome/
Repetitive blunt trauma to the superficial palmar arch of the owner artery
73
Arterial duplex following intervention
Bypass grafting:
Used to round blood around the occluded segment
Named for type of graft and location, for example, aorta bifemoral , a bifurcated graft from the aorta to the CFA bilaterally, aorta iliacs occluded
Extra anatomic/placed, where a vessel does not typically run
Grafts are made of :
-synthetic/ polytetrafluorethylene (PTFE) or dacron (plastic)
-autogenous vein/ uses patients own vein or artery to create. *common for stenosis. Two types, in situ and reversed.
*In sutu tributaries not ligated may become arteriovenous fistulas.
Anastomosis/the connection of the bypass graft to the artery
Higher velocities, through stent
Native arteries 2:1 ratio = > 50% stenosis
74
Most common site of stenosis and grafts
Vein grafts- retained valves
Synthetic grafts- anastomosis
75
Endovascular aneurysm, repair
EVAR
Catheters used to position a graft inside of the aneurysm, expanded, and then hooked in the place with stents
Most commonly performed on AAA
76
Endoleak
Flow within the aneurysms sack outside of the graft walls
**
Type 1- leak from the attachment site
Type 2- patent branch with retrograde flow into the aneurysm
Type 3- graft defect
Type 4- graft porosity, flow through holes in the material
Type 5- endotension, enlarging aneurysm sac with no detectable leak.
77
Intravascular Ultrasound
IVUS
Tiny transducer at the top of a catheter provides an image from inside out
78
Pseudoaneurysm
Fake aneurysm
CFA is the most common site
A defect or hole in the arterial wall typically from trauma and often hospital acquired, such as catheterization
To and fro flow pattern
79
Anteriovenous Fistula
AVF
An abnormal connection between the high-pressure arterial system, and the low pressure venous system
Congenital or traumatic
High velocity’s in the connection
Erratic at beginning of connection
See diagram
80
Entrapment syndromes 
Thoracic outlet syndrome (TOS)
Compression of nerves, arteries, veins
Common and athletes
Three main types, neurogenic (most commo) Venus, reduced venous, outflow and arterial, reduced arterial blood flow
Popliteal artery entrapment syndrome (PAES)
Dorsiflexion, gastrocnemius muscle contraction, results in compression of the pop artery
81
Arteritis
Buergers Disease
Typically affects small vessels in upper and lower extremities (hand, foot) Occurs primarily in men < 40 years, heavy tobacco abuse
Takayasus Arteritis
And tomorrow, fibrosis and vascular narrowing, most commonly affecting large arteries, usually the aorta and its main branches. Often young women of Asian dissent. Pulseless disease.
Temporal arteritis
Inflammation of the arterial wall of the superficial temporal artery. May lead to blindness, often described as halo.
82
Vasospastic disorders
Raynauds phenomenon
The arterial spasm results and decrease blood flow typically affecting the fingers. Two main types;
Primary Raynauds/most common, vasospasm only
Secondary Raynauds/vasospasm with a secondary cause and tissue that necrosis
* see picture
83
Penile imaging
Anatomy(see picture)-
Dorsal arteries
Cavernosal artery
Superficial and deep dorsal vein
Penile brachial index
Normal > 0.75.
Abnormal < 0.65 (impotence)
Diameter of cavernosal arteries should increase post injection
Flow resistance/ High pre-injection, low post injection. PSV should increase >30cm/ sec, less than 30 is abnormal
Dorsal vein velocities should not increase. And increase is suggestive of Venus leak.
Normal <3cm/sec
Abnormal >20
84
<30 mmHg ——-
Poor healing potential
Wound unlikely to heal
85
Hydrophone
A microphone that detects sound waves underwater
Today used to test, power and intensity levels by the ultrasound beam
86
Allen’s test
Tests the patency of the Poolmart arch
Radial and ulnar artery is are manually compressed
Ulnar released, observe for refilling. Repeat radial.
Normal colors should return in < 10 seconds
87
Preoperative arterial mapping
See chart
88
Visceral artery duplex imaging
Anatomy (see pic)
Celiac artery : left gastric artery, common hepatic artery, splenic artery
SMA
Renal arteries
IMA
Mesenteric artery : (see picture)
Achy or crampy abdominal pain 15 to 30 minutes post prandial
Two Possible connections between the SM A, and IMA
-Marginal artery of the colon (marginal artery of Drummond)
-arc of riolan
SMA/preprandial, high resistance, and post prandial converts to lower resistance
89
Extrinsic compression
AkA- Median arcuate ligament syndrome
Compression of the celiac artery origin by the median arcuate ligament of the diaphragm
Rarely symptomatic
90
Renal artery, duplex
Identify renal stenosis before Reno failure
Most hypertension is called
"essential hypertension" - that is from no direct identifiable cause.
Secondary hypertension is
hypertension that is the result of some other disease, commonly of the kidney.
**Renal artery stenosis may cause the release of renin, promoting conversion of angiotensinogen to angiotensin, causing vasoconstriction and subsequent high blood pressure. This is called renovascular hypertension.
Eventually results in renal failure.
91
Reno aortic ratio
RAR = highest renal artery, PSV, divided by aorta PSV
Normal < 3.5
Abnormal > 3.5 consistent with 60% or greater diameter reduction.
Do not use if AAA is present or aortic PSV < 40 or > 90 cm/s
Resistivity Index (RI)
RI= PSV - EDV/PSV
Normal < 0.8
Abnormal >0.8
End Diastolic Ratio (ED)
Parenchymal Resistance Ratio
EDR = EDV/PSV
Normal > 0.2
Abnormal < 0.2
92
Acceleration time
AT
Helps determine proximal stenosis
Obtained from the distal renal artery at the hilum
Normal < 100 ms
Abnormal > 100 ms, consistent with >60% stenosis proximately
Delayed time = stenosis
93
A lesion in the mid or distal renal artery segment is typical of
Fibromuscular dysplasia
94
Renal transplant
Renal vein anastomosed to the external or internal iliac vein
Renal artery anastomosed to the external or internal iliac artery
Diagnosis of rejection -biopsy
95
Hemodialysis access evaluation
High blood flow volumes
Types of dialysis access:
-synthetic grafts/material used to connect an artery to a vein
-Native autogenous fistula/ vein is connected directly to the artery. Fistula will mature and vein dilate in response to the artery pressure.
-Breccia cimino fistula-describe a radial artery to cephalic vein fistula
Inflow artery, outflow vein
Bruit or thrill normal
Venus anastomosis and outflow vein most common sites of stenosis
96
Hemodialysis velocity criteria
General velocity criteria for >50% stenosis
At the anastomosis
• PSV > 400 cm/s
• Velocity ratio >3
• Intraluminal defect
Along the venous outflow
• PSV > 300 cm/s
• Velocity ratio > 2
• Velocities <50 cm/sec
Normal/high velocity, low resistance
Abnormal/high resistance, or decreased systolic upstroke
Volume flow interpretation
Normal > 800 ml/min
<500 ml/min suggestive of a failing access
97
Hemodialysis
Velocity versus volume flow
Velocity
Identify a stenosis
Does not relate to performance of
access
Useful to follow trends in individual patients
Volume flow
Indicates performance of access
Suggest, but does not identify stenosis
Useful to follow, trans an individual patience
98
Hemodialysis pathologies
Extravascular mass/anechoic mass with no flow (seroma, hematoma, thrombosed, pseudoaneurysm)
Pseudoaneurysm
No thrombin injections on dialysis patients
Axis aneurysm
Steel syndrome/arterial flow distal to fistula is reversed, flowing into the venous circulation, fistula, steals, radial, and ulnar blood
99
Cerebrovascular
See pic
ICA. Is the primary blood supply to the brain, low resistance, approximately 80% of the volume moving through the CCA travels into the ICA.
ECA has a branches, supplies, the face and scalp, high resistance
* first branch off of ECA/superior thyroid
Facial and superficial temporal artery branches
Collateral pathways
ECA - ICA via ophthalmic and orbital arteries
Occipital branch of ECA with Atlantic branch of vertebral
Cervical subclavian branches to vertebral artery branches
Largest collateral pathway is the circle of Willis (pic)
100
Cerebrovascular pathology
Atherosclerosis
Atherosclerosis (ASO)/
Most common pathology affecting their carotid vessels
Types of Atherosclerotic plaques
Fatty Streak - thin layer of lipid material in intimal layer
Fibrous Plaque - accumulation of lipids
Complicated lesion - a fibrous plaque that includes fibrous tissue and collagen
Ulcerative lesion - fibrous cap deteriorates - increased incidence of embolus
Intraplaque hemorrhage - rupture of the vaso vasorum with bleed inside the plaque
101
Cerebrovascular pathology
Fibromuscular dysplasia
Most common in distal ICA
Rare condition/cellular growth in the walls of the medium and large arteries
Common in women
Irregular appearance of the lumen
102
Cerebrovascular pathology
Neointimal hyperplasia
Occurs after endarterectomy/trauma
Intimal thickening from rapid, smooth muscle cell growth
103
Cerebrovascular pathology
Carotid, body tumor
Carotid body is a small sensory organ just above the bifurcation
AKA/ paraganglioma
Usually fed by branches of the ECA
104
Cerebrovascular pathology
Carotid dissection
Tear in the intimal lining
Creates false lumen
105
Cerebrovascular pathology
Aneurysm
Rare in carotids
1.5 x’s normal diameter
106
Transient ishemic attack
TIA
Temporary cut off of blood flow
107
Cerebrovascular symptoms
Lateralizing symptoms
Hemispheric symptoms that are contralateral
Ex-right hemisphere CVA affects left side of body
TIA/resolve completely within 24 hours
Resolving ischemic neurologic deficit/last longer than 24 hours but resolve
Completed stroke/permanent
Paresthesia- Tingling, pins and needles, prickling of the skin
Paresis-Weakness, numbness, or paralysis
Hemiparesis -Weakness, numbness, or paralysis on one side of the body
Hemiplegia-Paralysis on one side of the body
Aphasia -Inability to speak
Dysphasia -Difficulty speaking, loss of power of verbal expression
Dysarthria -Difficulty with speech due to the dysfunction of the muscles o nerves involved with speaking
108
If an ICA lesion embolize is to the——
*ACA/ likely to affect the leg more than the arm
*MCA/likely to affect the arm
Dysphasia likely to be MCA
109
Cerebrovascular symptoms
Non-lateralizing
Terminology:
Dizziness-impairment in spatial, perception, and stability
Dyssynergia (ataxia)-lack of muscular coordination
Diplopia-double vision
Drop Attack-sudden fall without loss of consciousness
Dyslexia-difficulty reading, or interpreting words
Syncope-sudden loss of consciousnes
Vertigo-difficulty with equilibrium
110
Amaurosis fugax
Loss of vision in one eye on ipsilateral side
Ex: right ica embolus to the right ophthalmic artery who would result in right amaurosis fugax
111
Homonymous hemianopia
Last of the visual field of view that impacts both eyes
Right brain hemisphere damage may result in a left homonymous hemianopia and the last of the left field of view in both eyes
112
Hemispatial neglect
Example left hemispatial neglect, may result in damage to right hemisphere
Impaired body position or spatial orientation on one side of the body
113
Main symptoms highly associated with carotid artery disease
Hemiparesis
Aphasia/dysphasia
Amaurosis fugax
114
Hollenhorst plaque
A cholesterol embolus that typically originates from the ipsilateral carotid artery, travels into the ophthalmic artery, and lodges in a blood vessel of the retina
Possible emboli from ICA/ aorta/heart
115
Cerebrovascular velocities
See pic
Pg178
116
Bilateral abnormal upstroke
Cardiac issues
117
Vertebral artery
First branch arising from subclavian artery
Joint in the posterior aspect of the brain to form basilar artery
118
Subclavian steal
Occlusion of the subclavian artery with flow, traveling up one vertebral artery, down the contralateral artery in via the best seller artery to supply the arm
119
Subclavian artery
Stenosis/occlusion more comment on the left
Blood pressure differential between arms >15-20 mm/hg
120
ICA / CCA ratio
PSV in the ICA / PSV distal CCA
Normal ICA / CCA ration < 2.0
>4.0 70% threshold
121
NASCET
North American symptomatic carotid endarterectomy trial
> 50% stenosis , > 180 cm/s PSV
> 70% stenosis, > 260 cm/s PSV
Trial that determined the efficacy for carotid artery disease
122
Carotid artery intervention
- endarterectomy/surgical procedure in which the artery is isolated and opened, plaque is removed, artery sutured closed
-Angioplasty with or without stent/balloon catheter, is passed into the artery and positioned within the stenosis. Balloon is inflated, opening lumen, and then deflated and removed.
Post endarterectomy -intimal hyperplasia most common 3 to 24 months and recurrent atherosclerotic disease > 24 months
123
Transcranial Doppler
Circle of Willis (see pic)
Anterior communicating artery
Anterior cerebral arteries
Small portion of the distal ICA
Posterior communicating arteries
Posterior cerebral arteries
* middle cerebral artery as an extension of the ICA and not part of the circle of Willis
Ophthalmic artery branches off of the terminal ICA
Supraorbital artery arises from the ophthalmic artery, notably, the Superficial temporal artery
Frontal artery arises from the ophthalmic artery, exits, the orbit to supply the forehead
* transorbital approach- follow ALARA
124
Transcranial Doppler 
2 MHz Doppler
Zero angle of incidence
Mean velocity used, not PSV
Three acoustic windows -
Transtemporal (ICA, MCA, ACA, PCA)
Transorbital (opthalmic art, carotid siphon)
Transforamenal/ Sub-occipital (distal vertebral, basilar arteries)
125
Factors that may alter intracranial blood flow
Age
Sex
Hematocrit
Arterial blood gas
Metabolic demands
126
Transcranial Doppler
Collateral pathways
Crossover/antegrade flow in the ACA from crossover collaterization
ECA to ICA; retrograde flow in the ophthalmic artery
Posterior to anterior/increase flow in the posterior cerebral artery with reversed low in the posterior communicating artery
127
Sickle cell disease
Most common inherited disorder of the blood
Number of red blood cells decreases from rupture, anemia results
Affects primarily Africans
128
Transcranial Doppler
Vasospasm
• Most accurate in the MCA
Mean Velocity >120 cm/sec
Severe vasospasm >200 cm/sec
129
Transcranial Doppler
Micro emboli detection
Gas or solid microemboli within the MCA can be detected by TCD as H
Transient Signals (HITS), also called micro-embolic signals (MES).
• Characterized by:
Duration <300 milliseconds
Higher amplitude than the background blood flow signal;
Typically, unidirectional and occur randomly
Characteristic sound like a "moan" or "chirp" on audio
The emboli comes from carotid stenosis
PFO/ patentamen ovale-
Hole in heart, blood/emboli travel from venous circulation to arterial
130
Transcranial Doppler
Transmandibular acoustic window
Can access the mId and distal segment of the ICA
Is primarily for emboli monitoring
131
Venous anatomy
Same three layers as arteries
Intima
Media/thin compared to artery
Adventitia/thickest layer
Peripheral veins, return, deoxygenated blood to the heart/right atrium

Veins with valves -
*Infrainguinal deep veins increase in number, distally, especially infrapopliteal
*GSV has as many as 10 to 20
Small saphenous, 6 to 12
Veins without valves -
SVC/IVC
*Soleal veins/ sinuses
Intracranial
132
Venous anatomy
Divided into three systems
-superficial system/change the skin and subcutaneous tissues, empty into the superficial truncal veins or directly into the *deep system
Perforated veins/perforate the facia and connect the deep and superficial system
Deep system/carries 85 to 90% of the blood out of the lamb
133
Superficial venous system
* drain the skin and subcutaneous tissues
Two primary superficial truncal veins:
-GSV/ has its own fascial compartment, longest vein in the body. Immediately from foot to the CFV forming the saphenofemoral junction
-SSV/ origin is dorsal, venous arch, termination, often a pop, but highly variable
True trunks are contained within the saphenous fascia
134
Accessory saphenous systems
Anterior accessory, great saphenous vein ( AAGSV) / alignmen sign, aligns with the superficial femoral artery
Posterior accessory great saphenous vein (PAGSV) / ** enlarges with pelvic congestion. Posterior thigh, termination, GSV. Often leg source of posterior thigh varicosities
135
Venous anatomy
Other Important veins
Superficial epigastric vein(SEV) /
Drains the skin of the lower abdomen
* an important landmark for venous interventional procedures
Giacomini Vein/ connects, the SSV with the GSV or joins the posterior accessory that joins the GSV. Plays a role in the development of chronic venous disease.
Perforating veins /perforate the fascia, and carry blood from superficial veins into the deep veins
136
Perforating veins from groin to foot
See pic
Saphenofemoral Junction
GSV
Perforators of the femoral canal
Paratibial Perforators
Posterior tibial perforators
Medial ankle perforators
137
Venae comitantes
A pair of veins, occasionally more, that closely accompany an artery.
Most deep veins!
138
Gastrocnemius veins
Paired vein sets
Within the gastrocnemius muscle of the calf, companion artery, join the popliteal vein
139
Soleal veins
Within the Solias muscle, drain into the calf veins
No paired artery
140
Lower extremity venous sinuses
Major component of the calf muscle pump
Drains blood into PTV, Pero
Soleal/gastrocnemius muscles
141
Pop V
Formed by the ATV and tibial, peroneal trunk
142
Femoral Vein
Passes through adductor hiatus
Terminates in Scarpas triangle
143
Profunda /deep femoral vein
Ascends deep and lateral to the femoral vein
144
External iliac vein
CFV becomes the EIV as it passes beneath inguinal ligament
Joins the internal iliac vein to form the common iliac
145
Internal iliac vein
Ascends through pelvis
Drains the pelvis
146
IVC
Formed by the common iliac vein’s
Penetrate the diaphragm and terminates in the right atrium
147
Renal veins
Drain the kidney and suprarenal glands and empty into the IVC
148
Portal venous system
Portal vein/formed by superior mesenteric and splenic veins. Drains, abdominal digestive, tract, pancreas, spleen, gallbladder.
* carries blood into the liver
* carries 80% of blood flow into liver
Hepatic veins/drains liver, empties into IVC, carries blood away from liver
149
Upper extremity veins
Superficial:
Basilic vein/
Empties the medial aspect
Joins brachial vein to form axillary vein
Can be harvested for bypass
Cephalic/
Formed by digital veins
Empties lateral aspect
Joins axillary to form subclavian
Can be used for bypass
Deep:
Radial/ formed by deep, palmar, arch, empties lateral hand and forearm
Ulnar/ formed by superficial palmar, arch, empties, medial hand, and forearm
Brachial/ formed by radial and ulnar
Axillary/foreign by brachial and basilic
Subclavian/formed by axillary and cephalic 
150
Innominate vein
Brachiocephalic vein
Formed by subclavian and internal jugular veins
151
IJV
See pic
Collects blood from brain, face and neck
152
Intracranial, venous sinus
Drains blood into IJV
153
Central veins
Superior vena cava
Formed by innominate vein’s
Trains, head, neck, upper extremities
Terminates in right atrium
Inferior vena cava
Formed by common iliac vein’s
Drains lower half of body
Terminates in right atrium
154
Venous hemodynamics
Venous system:
Serves as a reservoir for blood
Approximately 2/3 of total blood volume resides in the venous system
Returns blood to the heart
Venous return = cardiac output
Affective venous return requires;
Central pump(heart)
Pressure gradient
Peripheral venous pump
Competent venous valves
155
Two main types of pressure in the venous system
Dynamic pressure and hydrostatic pressure
Dynamic pressure :
From the cardiac contraction
Drives blood through the system
When supine/ 8mm/Hg in the leg and 0 mm/Hg at the right atrium
* due to the low venous pressure, respiratory motion, influences venous return
Hydrostatic pressure :
The weight of the column of blood from the heart to any given spot on the body
Hydrostatic pressure = pgh
p = specific gravity of blood Den rite
g = acceleration of gravity
h = height (distance from the heart)
The hydrostatic pressure at the ankle of a normal height person STANDING is approximately 100 mm/Hg.
What about body part above the right atrium?
• Negative hydrostatic pressure would be
= - 50 mm/Hg
• But veins collapse at 0 mm/Hg
O mm/Hg is the minimum measurable
Standing and raising right arm -50
156
Inspiration/expiration
Inspiration - Lowers the diaphragm, decreases intra-thoracic pressure AND increases intra-abdominal pressure -
•Decreased venous return from the lower extremities
•Increased venous return from the upper extremities
Expiration - Raises the diaphragm, increases intrathoracic pressure AND decreases intra-abdominal pressure
• Increased venous return from the lower extremities
• Decreased venous return from the upper extremities
157
Ineffective calf muscle pump or outflow obstruction
Results in venous, pooling and ambulatory venous hypertension
158
Venus properties
The volume of blood carried by the arteries is the same because Cardiac output= venous return
Compliance - Ability to accommodate a large change in Volume with a small change in Pressure
Capacitance - Ability to accommodate a large change in Volume in a short period of Time
159
Transmural pressure
Transmural Pressure
Relative pressure difference from within the vessel (intravascular pressure) to the out (tissue pressure)
**By convention, this is always referenced from the inside of the vessel
When tissue pressure exceeds the intravascular pressure, the transmural pressure is considered low, and the vessel "collapses"
** high venous pressure/low tissue pressure
** Low, venous pressure/high tissue pressure
Low transmural pressure/collapsed vein -higher pressure
160
Virchows triad
Trauma
Stasis
Hypercoagulability
161
Venus thrombosis
1) trauma (blunt, or surgical)
-Paget scheoetter syndrome/involves axillary and subclavian veins, may be component of thoracic outlet syndrome
-PICC line/catheter damages, venous, endothelium. Thrombus often occurs at the proximal end of the PICC line.
2) venous stasis/decreased venous return
Ex: and mobility, obesity, COPD, long flight(coach class syndrome) previous DVT
3) hypercoagulability/when your blood clots
Ex: protein deficiency, hormones, pregnancy
162
Phlegmasia cerulea dolens
bluish discoloration due to severely limited venous outflow, a precursor to gangrene.
163
Phlegmasia alba dolens
white discoloration, "milk leg" compromised arterial inflow
164
Continuous flow
In a vein can= proximal obstruction
165
Rouleaux formation
Red blood cells arranging a stack like a roll of coins
Sluggish flow
Most likely normal, but could indicate slow flow due to proximal obstruction
166
Venous reflux
Retrograde flow
167
Cephalad
Normal flow
168
IVC tumor
Renal cell carcinoma is the most common solid renal mass in the adult
Tumor invades the renal vein, extending into the ivc
The most common cause of IVC tumors as a renal cell carcinoma
169
May Thurner syndrome
Iliac compression syndrome
170
Nutcracker syndrome
Left renal vein compression
Results in renal venous hypertension
Dilatation of the ovarian or gonadal vein’s, contributes to pelvic congestion syndrome
171
Budd Chiari syndrome
Result of hepatic vein occlusion
172
Portal hypertension
Increased blood pressure in the portal vein, the most common cause is cirrhosis
Treatment/transjugular intrahepatic portosystemic shunt (TIPSS)
The most common cause of cirrhosis
173
Tourniquet interpretation
Tourniquet Interpretation
Superficial system incompetence = Abnormal VRT ≤ 20 secs without tourniquet but normalizes (>20 seconds) with tourniquet
174
Statistics
Chapter 29
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