Uni lectures Flashcards
(265 cards)
1
Q
What is another name for perfusion of blood?
A
Volume flow
2
Q
What is the equation to calculate perfusion?
A
Q = v * A
3
Q
Do doppler waveforms show velocity or flow?
A
Velocity
4
Q
How do arteries modify waveforms?
A
Arteries have elastic walls which aid pulse propagation and flow
5
Q
What happens to blood pressure following a stenosis?
A
There is turbulence and a loss of energy after stenosis which causes a pressure drop
6
Q
What percentage diameter drop causes a significant drop in pressure?
A
50%
7
Q
What are the first 3 branches to come off the aorta? (excluding coronary)
A
Brachiocephalic, Left CCA, left subclavian
8
Q
How do veins relate to oedema?
A
Reduced venous return can cause dilation of veins or transfer of fluid to the surrounding tissue (interstitial space)
9
Q
Which arteries above the thorax have continuous diastolic flow?
A
Vertebral arteries and ICAs
10
Q
What waveform feature determines the end of systole and the start of diastole in carotid arteries?
A
The dicrotic notch
11
Q
What causes the multiphasic waveform?
A
Reflections from distal branches
and elasticity of vessel walls
12
Q
What is the diastolic component of the waveform very sensitive to?
A
Posture, gravity, temperature, disease, peripheral resistance
13
Q
What is hyperechoic plaque?
A
Echogenic, bright plaque (often calcified)
14
Q
What is hypoechoic plaque?
A
Dark, echolucent plaque
15
Q
Which veins surround the SSV?
A
Gastrocnemius veins
16
Q
What percentage of strokes are haemorrhagic?
A
15%
17
Q
What percentage of strokes are embolic?
A
85%
18
Q
What percentage of strokes are due to carotid disease?
A
15 - 20%
19
Q
What is the name of the artery formed by the two vertebral arteries?
A
Basilar artery
20
Q
What symptoms are associated with vertebro-basilar disease
A
Dizziness and loss of balance (supplies the hind brain
21
Q
What do the systolic and diastolic aspects of waveforms show in terms of disease?
A
Systolic = proximal disease
Diastolic = distal disease
22
Q
What would a vein with no phasic flow with respiration suggest?
A
A proximal obstruction
23
Q
What percentage of diabetics are type 1?
A
10%
24
Q
What is type 3 diabetes?
A
Pancreatectomy / cystic fibrosis
25
What are the pancreas' exocrine functions?
Secretes trypsin (protein), lipase (fat) and amylase (starch)
26
What are the pancreas' endocrine functions?
Secretes glucagon and insulin
27
What does insulin increase?
Glucose transport into cells
Liver glyconeogenesis
Utilization of glucose
28
How many diabetics are there?
3.7 million
29
How many diabetics are not diagnosed?
1/2 a million
30
What percentage of the NHS budget is spent on diabetes care?
10%
31
How does life expectancy decrease with type 1 and 2 diabetes?
Type 1 - reduced by 20 years
Type 2 - reduced by 10 years
32
How is diabetes diagnosed?
Fasting glucose >7
OGTT >11
HbA1c >48
33
What are diabetes risk factors?
- Obesity
* Race
* Hypertension
* Age
* Family History
* Inactivity
*Pregnancy
34
What is Buerger's Syndrome?
A condition affecting blood vessels (usually in the limbs)
- causes vessels to swell, reducing blood flow
- this can make blood clotting more likely
35
What is aspirin?
An anti-thrombotic, anti-platelet drug
- also has anti-inflammatory properties
36
What is clopidogrel?
Anti-platelet drug
37
What is heparin?
Anticoagulant
38
What is warfarin?
Anticoagulant
39
Is CT or MRI more sensitive for detecting brain ischemia in TIA patients?
MRI
40
What is sensitivity? And when is it very important
Sensitivity = TP / (TP +FN)
Tests with high sensitivities are essential for serious diseases (or where treatment is very expensive)
41
What is specificity? And when is it important
Specificity = TN / (TN + FP)
It is important when individuals identified as having the disease may be subject to many additional tests or invasive procedures
42
How many diagnostic tests that use ultrasound take place each year?
~ 9.5 million
43
What is the range of frequencies used in ultrasound?
Around 1 - 20 MHz
44
What part of the probe produces soundwaves?
The transducer
45
What is a bistable image?
Image only containing black and white
46
What is the range of costs of ultrasound machines?
£30 - 100K
47
What are the two main ultrasound scans during pregnancy?
1. 11 - 14 weeks dating scan
2. 18 - 20 week foetal anomaly scan
48
How can age of foetus be estimated using ultrasound?
Crown rump length
Biparietal diameter
49
When can you see foetal hearts beat?
6 / 7 weeks
50
What appearance may cancerous deposits have on ultrasound?
Bright white areas
51
What appearance may metastases have on ultrasound?
Darker larger structures
52
What is a pseudoaneurysm?
A hole in an artery often caused by catheter or needle insertion
53
What is FAST scanning?
Scans performed in A&E following trauma.
Focused assessment using sonography for trauma. Assesses: heart, spleen, liver, pelvis, aorta
54
What is sheer wave elasticity?
Ultrasound scan that measures small changes in displacement
- disease alters elasticity of structures
55
When was ultrasound first used in medicine?
1941 - second world war
56
What are two reasons why ultrasound is used in obstetrics?
Estimating foetal age and looking for foetal anomalies
57
What is the pressure in the pulmonary circulation?
25 / 15 mmHg = upper limit
15 / 10mmHg = lower limit
58
What are the 3 main layers of arteries?
Intima, media, adventitia
(also has elastic lamina between layers)
59
What are the 3 main layers of veins?
Intima, media, adventitia
(NO elastic lamina between layers)
60
Which layers of veins form the valves?
Intima and media
61
What is artery intima composed of?
Vascular endothelium
62
What is artery media composed of?
Elastin + collagen + smooth muscle
63
What is artery adventitia composed of?
Strong thick collagen layer with some elastin
64
Which veins have smooth muscle control?
Only the portal system
65
Which veins have valves?
Distal veins
66
How big are arterioles?
< 1 mm in diameter
67
What is the function of arterioles?
Control perfusion of capillary bed
68
What are pre-capillary sphincters?
Smooth muscle segments that direct blood flow into capillaries
69
What muscle in the neck is seen on carotid scans?
Sternomastoid
70
What bone is scanned over when viewing subclavian?
Clavicle
71
Are the branches of the aorta anterior or posterior to the superior vena cava?
Posterior
72
Which arteries usually come off the aorta anteriorly?
Cephalic trunk, IMA and SMA
73
Where do the gonadal arteries come off the aorta?
Between the renals and IMA (usually)
74
What artery comes off the abdominal aorta inferiorly, between the iliacs?
The median sacral artery
75
What are perforator veins?
Veins that connect the superficial and deep venous systems - from superficial to deep
76
Roughly how many perforating veins are there in each leg?
150
77
How is the basilic vein related to the cephalic vein anatomically?
Basilic vein is more medial
78
How is the IVC related to the aorta?
Is posteriorly and to the right
79
How is blood flow homeostatically controlled?
1. Arterial sensors - carotid and aortic arch
2. Venous sensors - atrial stretch
3. Cerebrovascular control centre
4. Renal perfusion
5. Local factors
80
What forces determine fluid exchange in capillaries?
Starling's Forces:
1. Hydrostatic pressure
2. Osmotic pressure
81
In addition to measuring > 5.5cm in diameter, what other classification can be used for AAAs?
> 1.5 times the suprarenal diameter
82
Is diabetes a risk factor for AAAs?
No, the risk of developing a AAA is halved with diabetes
83
What imaging modality is used to assess AAA rupture?
Usually CTA
84
How does ethnicity impact risk of AAA?
Whites are more likely to develop an AAA that Asians or African Americans
85
What management can help slow AAA growth?
Only stopping smoking. Not exercise, drugs etc.
86
What events are AAAs associated with?
Cardiovascular events
87
What percentage of aneurysm ruptures are fatal?
Over 80%
88
What is a juxtarenal AAA?
An AAA extending up to but not involving the renal arteries
(no neck)
89
What is a suprarenal AAA?
An AAA extending up to the SMA, involving one or both of the renal arteries (i.e. no neck)
90
What size is considered an aneurysmal common iliac?
> 18 mm in men and >15 mm in women
- >1.5 times the normal diameter
91
What size is considered an aneurysmal internal iliac?
> 8 mm
92
How many different classifications of iliac aneurysms are there?
4
93
What are mycotic AAAs?
Infected AAAs
94
What is an artery dissection?
A tear in the intima layer
95
What is a pseudoaneurysm?
Caused by injury, they are a tear in the vessel wall where blood leaks out
- the wall of a pseudoaneurysm contains clotting factors
96
When does the thoracic aorta become the abdominal aorta?
When it crosses the diaphragm
97
What mechanisms can cause wall weakening and aneurysms?
(4 reasons)
Inflammation, oxidative stress, mechanical stress and proteolysis
- decreases levels of structural proteins including elastin and collagen
98
How many deaths per year do ruptured AAAs in England and Wales cause?
4000
99
What are symptoms of a AAA rupture?
Sudden intense back or abdominal pain, hypotension, high heart rate
100
What measurements are taken in NAAASP?
2 AP measurements
- 1 in transverse and 1 in longitudinAL
101
In which state of the cardiac cycle should we measure AAA size?
Peak systole - aorta is widest
102
What is the interoperator variability of scanning 4 - 5.5 cm AAAs?
0.2 cm
103
Other than DUS, which imaging modalities can be used for AAAs?
CT and MRI
104
What is a type 1 endoleak?
Proximal or distal leakage of blood into sac from EVAR attachment site
105
What is a type 2 endoleak?
Leak into the sac from aortic side branches
106
What is a type 3 endoleak?
Defect in the stent or tear in fabric
107
What is a type 4 endoleak?
Graft porosity
108
What is a type 5 endoleak?
An endoleak with no known cause
109
What are the sensitivities and specificities of using ultrasound for AAA screening?
Specificity = 98 - 100%
Sensitivity = 94 - 100%
110
In the MASS trial, what was the percentage of elective AAA repair deaths compared with emergency repairs?
Elective mortality = 6%
Emergency mortality = 37%
111
What is CRP indicative of?
CRP is produced by the liver in response to inflammation
112
What are the two types of antithrombotic drugs?
1. Anticoagulants
2. Antiplatelets
113
What are common anticoagulants?
Heparin, warfarin and DOACs (riveroxiban and other bans)
114
How do anticoagulants work?
Slow down clots and prevent them from forming by reducing fibrin formation - used to help prevent DVTs unlike antiplatelets
115
What are some of the main differences between antiplatelets and anticoagulants?
Anticoagulants are used to prevent DVTs and in AF
Antiplatelets are used to prevent heart attacks
116
Which drugs cause the breakdown of clots?
Thrombolytics
117
What are examples of thrombolytics?
Streptokinase, reteplase, alteplase (other -ase or -kinase drugs)
118
How is the basilic vein related to the cephalic?
The basilic vein is more medial
- Note: both veins extend down the length of the arm, including the forearm
119
What are the deep veins of the arm?
Axillary -> Brachial -> radial and ulnar
120
Where do most of the gastrocnemius veins drain into?
The popliteal vein
121
How do ultrasound probes create soundwaves?
Displacement of particles in longitudinal plane
122
What is the equation for the speed of sound?
c = lambda * f
123
What is the speed of sound in bone?
3500 m/s
124
What is the speed of sound in air?
330 m/s
125
What is the assumed speed of sound in tissue?
1540 m/s
126
What is the named frequency on an ultrasound probe?
Its resonant frequency - the frequency when the thickness of the element is half the wavelength of sound created within it
127
What is the equation for calculating distance of an ultrasound image?
c = 2 * d / t
d = tc / 2
128
How many cycles of a soundwave are typically transmitted in a pulse?
1 - 3
129
What happens to the range of frequencies within the pulse when pulse length is reduced?
The number of frequencies increases
130
What determines the proportion of sound reflected and transmitted at an interface?
The acoustic impedance of the interface
131
What does increased acoustic impedance cause?
Increased reflection at the boundary
132
What is the ratio of sound reflected at muscle/blood interface?
0.03
133
What is the ratio of sound reflected at muscle/bone interface?
0.63
134
What is the ratio of sound reflected at soft tissue / air interface?
0.9995
135
Why is microvasculature assessment difficult?
1. Vessel structure is spatially inhomogeneous
2. Perfusion varies greatly over time
136
What are the 4 established methods for microvascular assessment?
1. Laser doppler perfusion imaging
2. Laser speckle contrast imaging
3. Thermal imaging
4. Nailfold capillaroscopy
137
Why is microvascular assessment important in burns patients?
It can be used to assess depth of burn
138
What is Raynaud's?
Exaggerated response to cold or emotional stress with vasospasm and ischemia of the extremities
139
How does infrared thermography assess perfusion?
Secondary to skin temperature
140
What two qualities are ideal for tests measuring microvascular function?
1. Assess wide surface area
2. Rapid frame rate
141
What is pre-arterial sympathectomy?
A surgical procedure where specific nerves are chemically inactivated, reducing sympathetic vasomotor tone
- causes targeted vasodilation
142
What is a limitation of laser doppler perfusion imaging?
Slow data capture
143
How does the body control the microvascular system?
1. Monitors - temperature, blood pressure and tissue oxygenation
2. Response - using hormones and parasympathetic NS
3. Action - smooth muscle cells via [Ca2+] or myosin dephosphorylation
4. Vasodilation and constriction can be localised or systemic
144
What are the 4 main ways microcirculation can go wrong?
1. Sudden drop in BP - vasovagal syncope
2. Over-reaction to cold exposure - reactive hyperaemia
3. Chronic hypertension
4. Chronic inflammation - cell damage, impaired healing
145
Which diseases can affect the microvascular system?
1. Connective tissue disorders
2. Vasculitis
3. Diabetes mellitus
4. Chronic kidney disease
5. Arterial hypertension
6. Raynaud's phenomenom
146
What are the tri-phasic colour changes of Raynaud's?
White - vasoconstriction
Blue - tissue hypoxia
Red - hyperaemia
147
How is Raynaud's phenomenon detected?
1. 10 min baseline scan of hands
2. Cold challenge - 1 min with gloved hands in 20 degree water
3. Rewarming images (10 mins)
148
What is capillaroscopy?
Illumination of the nailfold by green wavelength light which is selectively absorbed by red blood cells
149
What are 4 aspects of pathology that can be identified within the microvascular circulation?
1. Dilation - normal diameter < 20um, slightly enlarged (non-pathological) 20-50um, Pathological = Giant loops - diameter >50um
2. Density - can grade mild, moderate or extensive loss
3. Bushing - tortuosity, branching, angiogenesis
4. Extravasation - haemorrhaging capillaries
150
What are treatments for Raynaud's?
1. Conservative management - gloves
2. Vasodilators - Ca channel blockers, ACE inhibitors, PDE5 inhibitors (Viagra)
151
What are treatments for more seriously threatened microvascular ischemia? e.g. digital ulcers secondary to scleroderma
IV prostacyclins e.g. iloprost
152
What is fluorescence?
Light at one wavelength re-emitted at a longer wavelength
153
What are the 3 light techniques used to measure microvascular function and some examples?
1. Visualising microvascular structure - near infrared imaging, microscopy (capillaroscopy) optical coherence tomography
2. Determining tissue composition - pulse oximetry, photoplethysmography, hyperspectral imaging, tissue oxygen saturation
3. Measuring/imaging microvascular function - Thermal imaging, laser doppler flowmetry, laser doppler imaging, laser speckle contrast imaging
154
What is Klippel-Trenaunay syndrome? And how can it present?
A rare congenital condition whereby blood vessels or lymph vessels fail to form properly
- presents as port wine stains, varicose veins and hypertrophy of bony and soft-tissues
155
What is giant cell arteritis?
Inflammatory disease of the large blood vessels of the scalp, neck and arms.
- inflammation causes narrowing or blockages in the blood vessels
156
When is ultrasound ineffective for giant cell arteritis patients?
When they have already started steroids - reduces inflammation
157
Why are RBCs not visualised well on ultrasound?
They are smaller than
158
What are the risk factors for giant cell arteritis?
> 50 years old
Female - 3F : 1M
159
What are some symptoms of giant cell arteritis?
Temple tenderness, tongue or jaw claudication, constitutional (e.g. weight loss, fatigue), arm claudication
160
What is the treatment for giant cell arteritis?
Steroids e.g. prednisone
161
What is Buerger's syndrome?
Swelling and inflammation of the arteries
- prevents blood flow and encourages clot
162
Who are typical Buerger's syndrome patients?
Young male smokers
163
What are some symptoms of Buerger's syndrome?
Pain, tissue loss, gangrene, amputation
164
What can be compressed in TOS?
Subclavian artery, subclavian vein and brachial plexus
165
What are the two common causes of compression in TOS?
Cervical rib or muscular
166
How can you determine which TOS it is?
Neural - arm weakness, finger pain, most common form
Females > Males
Arterial - persistent pain + numbness, impaired temperature sensation, cold limb, least common
Males = Females
Venous - oedema, cyanosis, deep pain
Males > Females
167
What compresses in Adsons TOS and what position?
Cervical rib or scalene
- and with arm out
168
What percentage of the population experience popliteal entrapment?
10 - 15%
169
What are the symptoms of Pop entrapment?
Sudden onset calf pain
170
What percentage of strokes in patients aged < 45 are caused by carotid dissection?
25%
171
What is Klippel-Trenaunay syndrome?
Triad of:
1. Capillary malformations (port-wine
stains) (98%)
2. Large venous malformations or
varicosities (72%)
3. Bone and soft tissue hypertrophy (67%)
172
How does renal stenosis often present?
Persistent, treatment resistant hypertension
173
How does renal stenosis cause symptoms?
Activation of RAAS pathway -> AT2 production -> sodium excretion, sympathetic nerve activity, prostaglandins, NO -> Renovascular hypertension
174
How do you calculate volume-flow (perfusion)?
velocity * area
175
What is an ectatic aorta?
A diffuse/global widening of the aorta diameter, however not of aneurysmal size
176
What are the arteries of the Circle of Willis?
Basilar, vertebral, median communicating, anterior communicating, posterior communicating arteries
177
What is the biggest risk factor for developing an AAA?
Smoking
178
Are the popliteal veins usually paired?
No
179
Is there a brachiocephalic vein?
Yes - there are two
180
What are the continuations of the subclavian artery?
Vertebral and axillary arteries
181
Is CLI pain relieved by sitting?
No
182
Which imaging modalities are useful for investigating PAD?
ABPI, Doppler, CTA and MRA
183
What medications are PAD patients prescribed?
Clopidogrel, statins, ACE inhibitors, BP control
- note: not anticoagulants
184
What is the difference in use of anti-platelets and anti-coagulants?
Anticoagulants (e.g. warfarin, heparin, DOACs) are used in DVT patients & in HF patients
Anti-platelets are used in PAD patients
185
True or False: Iliac arteries respond poorly to stenting - bypass is preferred
False
186
If sensitivity is a priority when imaging a deep artery at 7cm, which probe should be used?
The lowest frequency one (e.g. 3MHz)
187
What percentage of ultrasound is reflected and absorbed by bone?
Around 50% (actually 64%) is reflected but it also absorbs ultrasound
188
What percentage of US is reflected at soft tissue / air boundary?
99%
189
What percentage of US is reflected at bone/muscle boundary?
64%
190
What percentage of US is reflected at fat/muscle boundary?
10%
191
What percentage of US is reflected at muscle/blood boundary?
3%
192
What is attenuation?
Loss of energy from the ultrasound beam as it passes through the tissue
- the more energy that is attenuated by the tissue, the less that returns to the probe
193
What are some of the several processes that cause attenuation?
Absorption (causes conversion to heat)
Scattering
Reflection
Divergence
194
What is the average attenuation coefficient at 1MHz in soft tissue?
70
195
What happens to attenuation coefficients as tissue density increases?
They increase
196
Are higher or lower US frequencies attenuated more quickly?
Higher
197
How many piezoelectric elements are typically in an ultrasound transducer?
128
198
What are the two methods for increasing amplitude of returning US signal?
Increasing power output (i.e. amplitude) and increasing receiver gain
- increasing power causes the patient to be exposed to more US energy
199
True/False: Handheld dopplers use the doppler effect to calculate flow velocity
False
- they calculate frequency shift for waveform
200
What is the y axis on spectral waveforms?
Frequency shift
201
What is the greyscale on spectral waveforms?
The number of reflectors
202
How can you calculate Doppler shift from observed and transmitted frequencies?
fd = fr - ft
frequency difference = frequency received - frequency transmitted
203
What is the Doppler equation?
fd = (2 * v * ft * Cos(theta)) / c
ft = frequency transmitted
v = velocity
c = speed of sound
204
What is the output of continuous wave handheld dopplers?
Frequency shift
205
What is aliasing caused by?
Insufficient sampling of the signal
206
What is frequency shift proportional to?
Relative velocities of the source
207
What is A-mode ultrasound?
The simplest form - transmits a single pulse through the body
208
What makes up most of the received ultrasound signal?
Backscatter
209
When does scattering of an ultrasound beam occur?
At rough surfaces or at small particles
210
Does 1 large stenosis or 2 shorter adjacent ones cause a greater drop in blood pressure?
2 shorter ones
- the entrance and exit of a stenosis accounts for most of the pressure drop
211
Are ultrasound waves transverse or longitudinal?
Longitudinal
212
How many dimensions do ultrasound waves have?
3D
213
What does speed of sound depend on?
Density and stiffness
214
What can cause ultrasound waves to have increased brightness on the greyscale?
Increased amplitude (power output)
215
What is the ceramic in ultrasound probes usually made from?
PZT
Lead Zirconate Titanate
216
What are the basic components of a PZT transducer?
Front and rear electrodes, lens, electrical leads, backing layer, matching layer
217
What is the role of the backing layer in the transducer?
It absorbs unwanted waves
218
What is the role of the matching layer in the transducer?
To prevent unwanted internal reflections
219
How many frames per second for a normal B-mode display?
10 - 30 frames per second
220
How can cellulitis impact the colour of interstitial fluid on B-mode displays?
It makes interstitial fluid appear dark
221
What does duplex mean?
Imaging plus doppler
222
What is the doppler equation?
fd = (2 * v * ft * Cos(theta)) / c
223
How many transmission pulses does a colour line require?
7 - 10
224
What is the typical protocol for treadmill exercise ABPIs?
1. 5 mins
2. 3 km/h
3. 10 degrees slope
4. 250m
225
What ABPI values indicate incompressible foot arteries?
> 1.4 = compressible (sometimes stated as > 1.2)
226
What ABPI value range indicates mild arterial disease?
0.8 - 0.9
227
What ABPI value range indicates severe arterial disease?
< 0.5
228
What ABPI value range indicates moderate arterial disease?
0.5 - 0.8
229
What ABPI value range indicates a normal result?
0.9 - 1.4
230
How many people die from cardiovascular disease each year?
160,000
231
How many people die from strokes each year?
41,000
232
How many people die from arterial, arteriole or capillary disease each year?
10,000
233
How many people die from ruptured AAAs each year?
6000
234
What cost per QALY is deemed effective by NICE and what is the maximum cost of treatment for one QALY?
£20,000 per QALY is considered effective and with greater evidence, up to £30,000 could potentially be implemented
235
What is Virchow's triad?
The 3 cellular factors contributing to thrombosis:
1. Intravascular vessel wall damage
2. Stasis of flow
3. Presence of hypercoagulable state
236
What is thrombosis?
Formation of blood clot within a vessel
237
Following DVT, what percentage of patients develop PTS?
20 - 50%
238
What are symptoms of PTS?
Similar to venous reflux e.g. pain, swelling, oedema, reflux, skin changes
239
Are varicose veins more common in men or women? and what are estimated percentages in the population?
More common in women than men
Female = 20 - 25%
Male = 10 - 15%
240
What separates the deep from the superficial veins?
The muscular fascia
241
Where is the soleal vein located?
In the middle of the calf, posteriorly
- branches superiorly to TPT
(note the peroneal is lateral posterior)
242
Which calf veins are paired?
ATA, PTA, Pero A and gastrocnemius
(not Pop A)
243
Is the profunda artery more medial or lateral when compared with the SFA?
Prof A is more lateral
244
What artery runs proximally through the adductor canal?
SFA
245
Which veins usually do not have valves?
IVC, CIV don't have valves
EIV and CFV don't in most of population
Usually valves start at the proximal end of the CFV
246
What causes venous ulceration?
Chronic venous hypertension
247
What length of reflux is present in normal valve function?
< 0.5 seconds
248
What length of reflux is present in moderate reflux?
0.5 - 1 second
249
What length of reflux is present in significant reflux?
1 - 2 seconds
250
What length of reflux is present in gross reflux?
> 2 seconds
251
Is the brachial vein paired?
Yes, most people have 2
252
How do prostacyclins work?
They inhibit platelet activation and cause vasodilation by reducing smooth muscle tone
253
What is the difference between CLTI and ALI
Acute limb ischemia only lasts < 2 weeks
254
What are the muscles of the calf?
Gastrocnemius and Solial
255
In regards to colours of the fingers, what do the colours show:
1. White
2. Blue
3. Red
1. Vasoconstriction
2. Tissue hypoxia
3. Hyperaemia
256
What does primary Raynaud's mean?
No underlying cause e.g. connective tissue disorder
257
What is the difference between supra-renal, para-renal, juxtarenal and infrarenal AAAs?
Supra-renal include renals and SMA
Para-renal extend up to and include renals
Juxtarenal are just below the renals
Infra-renal are below the renals
258
When does the axillary vein become the subclavian?
After the cephalic has joined it
259
When does the brachial vein become the axillary vein?
When the basilic vein joins it
260
What vein joins the cephalic to the basilic vein?
The median cubital vein
261
Are the brachial veins paired?
Yes
262
How is ABPI calculated?
The highest from the PT or DP and the highest brachial artery
263
What are some examples of microvascular deformities seen in capillaroscopy?
Dilation
Reduced density
Bushing
264
What test is used to identify Reynaud's phenomenom?
Medical thermography
265
How do the treatments for type 1 and 2 diabetes vary?
Type 1 = treat with insulin
Type 2 = treat with oral hypoglycaemic agents
