Chronic Arterial Insufficiency Flashcards
Assessment of vascular system
- Golden 5 - consent, chaperone, privacy, exposure, confidentiality
- Observations - calculate NEWS score
- Radial pulse - peripheral pulse, rate rhythm, volume, character, delay + capillary refill
- Carotid pulse - central pulse, not at same time, check peripheral and central at same time
- CVS exam - listen to heart sounds
- Lower limbs - inspection (standing) and palpation
- Inspect - hair changes, swelling, assymetry, skin changes
- Palpation - examine normal side first
- Pulses - distal to proximal (dorsalis pedis first)
What happens in CAI?
- Collateral vessels form
- Allow blood supply to go past blockage
- Body does not have time to do this in acute cases
What is AI?
- Anything that hinders blood flow in arteries
- More common in men than women
- Increased prevalace with age
- Presents with intermittent claudication usually
- Atherosclerosis common cause
Composition of arteries vessels
- Tunica adventitia
- Tunica media
- Tunica intima (inside) - this is what atherosclerosis affects
Large plaques can affect nutrition to tunica media from tunica intima = apoptosis = damage to wall = aneurysms
Lower limb vasculature
- L4 = level of common iliac
- Then external and internal iliac
- As external iliac crosses inguinal ligament = femoral artery
- Femoral triangle
- Profunda femoris and superficial femoral artery branch
- Knee - superficial artery –> Popliteal artery
- –> anterior and posterior tibial artery (posterior) and peroneal artery (lateral)
Arteriosclerosis
- Hardening of arteries due to thickening of BV wall, medium and large arteries
- Can be split into atherosclerosis (intima), arteriolosclerosis (small arteries hyaline) Monkeberg medial calcific sclerosis (calcium in media)
What is atherosclerosis and atheromatous plaques
- Hardening of arteries due to intimal atheromatous plaque
- Has necrotic lipid core (cholesterol) with fibromuscular cap - can rupture
- Damage endothelium = lipid moves into intima
- Lipids oxidised and consumed by macrophages = foam cells
- = inflammation, SM proliferation, deposition of ECM
- = turbulant blood flow
Consequence of turbulant blood flow in arteries
- Arterial thrombus
- As can cause endothelial injury and stasis of blood
RF for CAI
Same as CVS
* Age
* Smoking
* Hypertension
* Smoking etc etc
Classification of PAD
- Fontaine classification
Fontaine classification
1 - Asymptomatic
2 - intermittent claudication (2a is more than 200m, 2b is within 200m)
3 - rest pain
4 - ulceration, gangrene or both
What is intermittent claudication?
- Cramp like pain felt in muscles
- Commonest site = calf
- As superficial femoral artery most commonly affected
- Brought on by walking, relieved by standing still (unlike neuropathy) not present on first step (like OA)
Classifcation of IC
- Boyds Classification
- I-IV
Claudication distance?
- Relative - Distance a person can walk before the onset of pain
- Absolute - distance person can walk before they cannot walk anymore
What is rest pain?
- Pain in limb at rest
- Classically at night time - felt in foot most common
- Exacerbated by lying down/elevating foot
- May improve by hanging foot out of bed
- Due to involvement of vasa nervorum (nerves in tunica adventitia)
- Pressure of enviroment on foot makes it worse - even touching can hurt with duvet
Management of rest pain
- Analgesia - need to help sleep
What is critial stenosis / critical limb ischaemia?
- Critical stenosis is occlusion of greater than 70%
- Imminent threat to limb
- Can cause tissue loss
Tissue loss in PAD
- Ulceration or gangrene
- Gangrene can be wet or dry
- Divide foot into forefoot, midfoot and hindfoot
- Zone of demarcation - clear between devitalised and healthy tissue?
- Sometimes associated erythema
Wet vs dry gangrene
- Wet has additional infection on top of necrosis
Types of gangrene
- Dry
- Wet
- Gas - clostridium perfringens
Investigations for gangrene
- X-ray to check for osteomyelitis
Management PAD 4 meds and lifestyle
- DATES - Diet, alcohol, tabacco, exercise, stress
- Antiplatelets (Clopidogrel, if not aspirin)
- Statins (high intensity)
- PPI? - Lansoprazole if high risk
- Naftidrofuryl oxalate (5-HT2 receptor antagonist that acts as a peripheral vasodilator)
Antiplatelets for PAD
- Aspirin - COX (cyclooxygenase) inhibitor, prevents formation of thromboxane from arachidonic acid
- Clopidogrel - binds to ADP and inhibits
MOA of statins
- Inhibit HMG Co-A reductase
- = decreased liver cholesterol increased LDL receptor expression
What NOT to give someone with PAD in hospital and why?
- TED stockings - thromboembolic deterrent stockings
- Further impede blood flow in arteries that are already compromised
- Use LMWH if need instead
Investigation for PAD - of choice
- Often clinical, can use ABPI too
- USS doppler
- CT angiogram if needed before surgery sometimes or if higher up as bowel gas can get in way of USS - contrast needed
Things to check before CT with contrast
- Allergies
- Kidney function
- Pregnancy
Surgical options for PAD
- Angioplasty
- Bypass
- Amputation if not suitable for revascularisation
Whats angioplasty?
- Minimally invasive
- Through groin vessel usually
- Go in with catheter
- Inflate balloon and can leave stent in place if needed
- Sometimes have antiplatelet drugs on stent?
What is bypass?
- Use graft to bypass blockage in artery
- Bypass sometimes needed if vessel is too narrow for angioplasty
- Can use long saphenous vein for this or omniflow (biosynthetic graft)
How can veins be used for arterial replacement in bypass?
- Remove valve function - reverse
- Need at least 3mm calibre to be suitable
- Assess intraoperatively to check for leaks
- Superficial vein used - long saphenous vein, allows deep system to take over if it needs t
Which vessels most least likely to be involved in PAD?
- Upper limb arteries eg Brachial artery is uncommon
What symptoms are associated with PAD?
- Intermittent claudication
- Rest pain
- Dry or wet gangrene
- Sexual dysfunction
- Cold peripheries
BMT for PAD
- Antiplatelets (NOT anticoags)
- Statins
- PPIs
- DATEs
Test for PAD severe ischaemia
- Buergers test
- Patient lie supine and raise legs until they go pale
- Lower them until colour returns
- Angle at which limbs go pale = Buergers angle
- Less 20 degrees = severe ischaemia
What is Leriche syndrome?
- Type of PAD affecting aortic bifurcation
Presents with:
* Buttock pai or thigh pain
* Erectile dysfunction
How can critical limb threatening ischaemia be defined?
- Ischaemic rest pain greater than 2 weeks
- Presence of ischaemic legions/gangrene
- ABPI less than 0.5
Can see gangrene, hair loss and thickened nails on exam
Differentials for claudication presentation
- Spinal stenosis - symptoms relieved by sitting rather than standing still
- Acute limb ischaemia - present within hours, less than 14 days duration of symptoms
ABPI and severity of PAD
