Peripheral Vascular Disease 1 + 2 Flashcards
Examples of acute limb threats? (3)
- Acute limb ischaemia
- Acute on chronic limb ischaemia
- Diabetic foot sepsis
What is an aneurysm? Normal aortic diameter? When is aorta called aneurysmal?
- Dilatation of vessel by more than 50% of its normal diameter
- 1.2 – 2.0 cm
- > 3cm called aneurysmal
True aneursysm? False aneurysm? Causes of false aneurysm? (2)
What kind of aneurysm is abdominal aortic aneurysm (AAA)?
- Vessel wall is intact (i.e. bulge involves all 3 layers)
- breach in vessel wall (surrounding structures act as vessel wall)
- Fractures, surgical interventions
- True aneurysm
Shapes of aneurysm? (3)
What shape are the majority of aortic aneurysms?
What shape has higher risk of rupturing?
- Saccular
- Fusiform
- Mycotic - arises secondary to infection, involving all 3 layers of the artery
- Fusiform - majority of aortic aneurysms
- Saccular higher risk of rupturing than fusiform
What is the pathology of abdominal aortic aneurysm (AAA)? (4 + 1 other pathology)
Medial degeneration
- Regulation of elastin/collagen in aortic wall
- Aneurysmal dilation
- Increase in aortic wall stress
- Progressive dilation
Atherosclerosis
What are risk factors for AAA? (5)
- Age - increases with age
- Gender (male:female = 6:1)
- Smoking
- Hypertension
- Can run in families
Prevalence of abdominal aortic aneurysm? (3)
- 8% of men >65 yrs
- 25% with AAA have popliteal aneurysms
- Ruptured AAA 7th most common cause of male death in UK
Presentation of AAA? (2)
Asymptomatic (75%) or symptomatic (25%)
How is asymptomatic AAA diagnosed? Clinical presentation of symptomatic AAA?
Asymptomatic
- Identified on imaging for other pathology e.g. kidney disease
- Screening programmes
Symptomatic
- Pain (may mimic renal colic)
- Trashing - forms clots in lumen which can break off and impact other vessels
- Rupture
What can symptomatic AAA pain mimic? What is “trashing”?
- Mimic renal colic
* Formation of clots in lumen which can break off and impact other vessels
Symptoms of AAA rupture? (4)
- Sudden onset epigastric/central pain
- May radiate through to back
- May mimic renal colic
- Collapse
Clinical presentation of AAA rupture? (5)
- May look well
- Hypo/hypertensive
- Pulsatile, expansile mass in abdomen that may be tender
- Transmitted pulse
- Peripheral pulses
What are the types of AAA rupture? What percentage of those with AAA rupture will not make it to hospital? Will die in surgery?
- Retroperitoneal (majority) - contained rupture
- Free intra-peritoneal rupture - rapidly fatal
- 75% do not make it to hospital
- 50% operative mortality
When to intervene with AAA? (3)
- If AAA symptomatic
- In asymptomatic - if >5.5cm AP diameter (<5.5 very unlikely to rupture)
- If asymptomatic - if >0.5 cm/6 months or >1cm/year
Relationship between size of aneurysm and rupture?
Bigger the aneurysm, the bigger the risk of rupture
What imaging techniques are used for AAA?
- Duplex ultrasound
* IV contrast CT of arteries (angiogram)
What is a Duplex ultrasound used for in AAA? What can it tell you? (2) What can it not be used for? (2)
- Used for asymptomatic aneurysms and surveillance
- Can tell you AP diameter of aneurysm and involvement of iliac arteries
- Does not tell you if aneurysm ruptures or is mycotic
What does IV contrast arterial CT tell you with regards to AAA? (3)
- Shape, size of aneurysm
- Iliac involvement
- ONLY way to identify ruptured AAA
What are forms of AAA management? (3)
- Surveillance
- Open repair
- Endovascular aneurysm repair (EVAR)
Explain open repair process? (3)
Why do you not want the graft touching the bowel?
What is Dacron graft made of?
- Laparotomy
- Clamp aorta + iliacs
- Dacron graft (tube or bifurcated graft depending on location) - LISTEN TO AUDIO
- Made of polyester
- Stitches do not dissolve so can eat into bowl, causing haematemesis and death
Explain EVAR process? (3)
Advantages?
Drawbacks?
- Exclusion of AAA from inside the vessel
- Tubing inserted via peripheral artery
- X-ray guided
Advantage - much less invasive than open repair
Disadvantage - patients with EVAR will need further procedures throughout lifetime whereas if open repair, will not need further amendments
Aetiology of AAA? (6) Pathology? (2)
Clinical features?
AUDIO
- Smoking, hypertension, diabetes, raised cholesterol, CVD
- Medial degeneration, Law of Laplace
- Clinical features - symptomatic (exclude rupture EVAR), asymptomatic (rupture risk)
Outcome of AAA management? (2)
Mortality of rupture?
- 2-5% mortality elective reapir (EVAR/Open)
- 30-50% morality rupture repair (EVAR/open)
- Overall rupture mortality 75-90%
What is acute limb ischaemia? Causes?
- Sudden loss of blood supply to limb
* Occlusion of native artery or bypass graft
What will determine urgency and treatment of limb ischaemia?
Determining whether it is acute or acute on chronic
Causes of sudden artery occlusion in acute limb ischaemia? (5)
- Embolism (commonly from heart)
- Atheroembolism
- Arterial dissection
- Trauma
- Extrinsic compression e.g. tumours
Symptoms of acute limb ischaemia? (6)
Clinical features of acute limb ischaemia? (3)
- Pain
- Pallor
- Pulseless
- Perishingly cold
- Paraesthesia - tingling
- Paralysis
- No prior history of claudication
- Known cause for embolism
- Full complement of contra-lateral pulses (not on affected leg)
What is claudication? When is it worse?
- Leg pain when walking (etc) due to narrowing or blockage of leg artery
- Worse when walking uphill
Describe the pain of acute limb ischaemia? (4)
AUDIO
- Severe
- Sudden onset
- Resistant to analgesia
- Calf/muscle tenderness with tight (‘woody’) compartment indicates muscle necrosis (often irreversible ischaemia)
Describe pallor of acute lumb ischaemia? (3)
- Limb initially white with empty veins
- Later, capillaries fill with stagnated de-oxygenated blood giving a mottled appearance (blanching mottling - salvageable if prompt revascularisation)
- Arteries distal to occlusion fill with propagated thrombus with rupture of capillaries (non blanching mottling – irreversible ischaemia)
With regards to pallor, when is limb salvageable? Non-salvageable?
What is mottling?
- Salvageable - blanching mottling
- Non-salvageable - non-blanching mottling
- Tissues adopt purple-bluish tinge
What does paraesthesia/paralysis of limb indicate? Is the limb salvageable?
- Indicative of muscle and nerve ischaemia
* Salvageable if promp revascularisation
Clinical features of acute limb ishacemia from 0-4 hrs? (4)
- White foot
- Painful
- Sensorimotor deficit (parasthesia, paralysis)
- Salvageable
Clinical features of acute limb ishacemia from 4-12 hrs? (3)
- Mottled
- Blanches on pressure
- Partially reversible
Clinical features of acute limb ishacemia >12 hrs? (5)
Why must you NOT perfuse tissue after 12 hours?
- Fixed mottling
- Non-blanching
- Compartments tender/red
- Paralysis
- Non-salvageable
Tissue is dead so will spread toxins to other areas of the body (kill kidneys, kill heart etc)
How is acute limb ischaemia managed? (5)
Why is anticoagulation part of acute limb ischaemia management?
- ABC – resuscitate and investigate
- FBC, U/Es, CK, Coag +/- Troponin
- ECG – MI, dysrhythmia
- CXR – underlying malignancy
- Anticoagulate
Why?
- Stops propagation of thrombus (enlargement)
- May improve perfusion
Is arterial imaging required for acute limb ischaemia? When is arterial imaging required? Examples of arterial imaging? (2)
Not if
- No prior history of claudication
- Cause for embolism known
- Full complement of contra-lateral pulses
- Required if doubts to history
- e.g. urgent CT angiogram, catheter angiogram
How is acute limb ischaemia managed is limb is salvageable? (3)
Non-salvageable? (2)
Salvageable
- Embolectomy
- Fasciotomy
- Thrombolysis
Non-salvageable
- Palliation
- Amputation
What should be done if there are concerns about inflow or run off in embolectomy? What are problems with inflow/run off? What is often present in occluded artery even if primary cause is embolic? Why?
AUDIO (next slide also)
- Intra operative angiogram
- ie Fogarty embolectomy catheter not passing up/down artery
- Atherosclerosis
- Due to ageing population
Explain the process of embolectomy
AUDIO
What do diabetic foot problems encompass? (3) What does this triad lead to? What may this result in?
- Diabetic neuropathy
- Peripheral vascular disease
- Infection
- Leads to tissue ulceration, necrosis and gangrene
- May result in limb amputation
What accounts for more hospital admissions than any other long term complication of diabetes? Strongest factor for limb loss? What percentage of diabetics will undergo contra-lateral amputation within 5 yrs of the first?
- Foot problems
- Diabetes
- 50%
What are sources of diabetic foot sepsis? (3) Where does no. 3 occur?
- Puncture wound
- Infection from nail plate or inter-digital space
- Neuro-ischaemic ulcer
- Neuro-ischamic ulcers occur on areas of increased pressure i.e. under metatarsal heads
Why is diabetic foot sepsis a problem? (5)
- In foot, intrinsic muscles of the digits are confined within compartments
- Infection travels into compartments
- If pus cannot escape, pressure builds up in compartment
- Leads to impairment of capillary blood flow, further ischaemia and tissue damage
- Can ultimately lead to sepsis and limb loss
What are compartments of the foot bound by? (3)
- Plantar fascia
- Metatarsal bones
- Interosseous fascia
Name the labelled foot compartments (Pic)
A - lateral compartment B - interoesseous compartments C - Medial compartment D - Calcaneal compartment E - Central compartment
Urgency of diabetic foot sepsis?
Is a vascular surgical emergency
Systemic features of diabetic foot sepsis? (5)
- Pyrexia
- Tachycardic
- Tachypnoeic
- Confused
- Kussmauls breathing – very acidotic (blow off CO2 to raise pH)
Local features of diabetic foot sepsis? (8)
- Swollen affected digit (‘sausage’ like)
- Swollen forefoot (‘boggy’ feeling to swelling)
- Tenderness
- Ulcer with pus
- Erythema may track up the limb
- Patches of necrosis
- Crepitus in the soft tissues of the foot (gas from gas forming organisms)
- Pedal pulses may or may not be present
What causes crepitus in soft tissues of the foot in diabetic foot sepsis?
Gas from gas-forming organisms
What organisms may be involved in diabetic foot sepsis? (3)
So what antibiotics must be used?
- Gram +ve cocci (Staph aureus, steptococcus)
- Gram -ve bacilli (E.coli, Klebsiella, Enterobacter, Proteus and Pseudomonas)
- Anaerobes (bacteroides)
Very broad spectrum
Management of diabetic foot sepsis? (3) What is done if patient is very ill?
- Broad spectrum antibiotics
- Surgical removal of infected tissue
- Wound left open to encourage drainage (prevent pockets of infection)
- Guillotine procedure - foot cut off above the ankle
How can diabetic foot problems be prevented? (3)
- Patient education
- Foot assessment (diabetic foot clinic, podiatrist)
- Pressure offloading footwear
Is diabetic foot sepsis a problem of ischaemia? Explain (4)
More of a problem of pressure rather than ischaemia
- Compartment pressure
- Vascular compromise
- Necrotic tissue
- Limb loss
Explain branching of the aorta from level of the bellybutton (6)
- At level of bellybutton, aorta splits into 2 common iliacs
- Common iliacs split into internal and external iliacs
- External iliac becomes femoral artery which splits into 2 to form deep and superficial femoral
- Superficial femoral becomes popliteal
- Popliteal branches into anterior tibial artery and tibioperoneal trunk
- Tibioperoneal trunk becomes peroneal artery and posterior tibial
What do problems with internal iliac affect? External iliac? Superficial femoral?
- Pelvis
- Thigh
- Lower leg/foot
What is intermittent claudication? (2)
- Occurs when insufficient blood reaches exercising muscle - MUSCLE ISCHAEMIA
- After variable periods of exercise patient develops ischaemic pain in the affected limb, which is relieved by rest
When are symptoms of intermittent claudication worsened?
- Further
- Faster
- Steeper
- Heavier
Explain the appearance of the angiogram (pic)
- Left - superficial femoral artery (open all the way down)
* Right - superficial femoral artery, blockage = formation of collaterals
Relationship between age and intermittent claudication?
- Prevalence increases with age
What are risk factors for intermittent claudication? Surprising risk reducing factor?
- Male gender
- Age
- Diabetes
- Smoking
- Hypertension
- Hypercholesterolaemia
- Fibrinogen
- Reduces risk - alcohol consumption
What are the underlying pathologies of peripheral vascular disease? (3)
- Coronary artery disease (8%)
- Cerebro-vascular disease (7%)
- Atherosclerosis (100%)
Non-invasive investigations of lower limb ischaemia? (2) Invasive? (3)
Non-invasive
- Measurement of ABPI
- Duplex ultrasound scanning
Invasive
- Magnetic resonance angiography
- CT angiography
- Catheter angiography
What is ABPI? Equation?
- Ankle Brachial Pressure Index - non-invasive test for lower limb ischaemia
- ABPI = ankle pressure/brachial pressure
What do different values of ABPI mean? (3)
What does it mean if ABPI is lowered?
What can give a false positive result in PAD?
- Normal (0.9 - 1.2)
- Claudication (0.4 - 0.85)
- Severe (0 - 0.5)
- Problem with arteries
Calcified vessels (e.g. in diabetes and kidney failure) can give false positive results
As ABPI does not allow the location of arterial problem to be identified, what is the next step? What does this allow? (4)
- Duplex ultrasound scanning
Allows you to:-
- See artery
- See turbulent flow
- Assess speed of flow
- Assess ratio of normal flow to turbulent flow
What is MRA? Advantage?
- Magnetic resonance angiography - invasive test for PVD
* No radiation
What is CT angiography? Advantage? Disadvantages? (2)
- Invasive test for PVD
- Advantage - quick
- Disadvanatages - contrast CT can affect kidneys, uses ionising radiation
What is catheter angiography? Explain procedure (3)
- Invasive investigation for PVD
- Needle inserted into artery followed by catheter
- Contrast injected
- X-ray taken
Treatment of lower limb ischaemia to slow progression?
- SMOKING
- lipid lowering
- antiplatelets
- hypertension Rx
- diabetes Rx
- life style issues
Treatment of lower limb ischaemia that improves claudication symptoms?
- Exercise training
- Drugs
- Angioplasty / Stenting
- Surgery
What does exercise training for PVD involve? Drug treatment? What are the benefits of exercise treatment? (2)
- 1 hour per day - 30 mins 3 times per week for a minimum of 6 months
- Cilostozol
- 20-200% improvement in walking distance
- Vessels dilate so blood can bypass claudication
Describe the process of angioplasty + stent insertion (3)
What are risks with this procedure? (2)
- Tiny holes in artery to deliver fairly large balloon
- Cracks open diseased segment
- Stent deployed
Risks
- Risk of balloon popping, rupturing artery
- Cracking open diseased segment can result in emboli breaking off
What are surgical options for PVD?
- Endarterectomy
* Bypass surgery
What is an endarterectomy? What tissues can be used in bypass surgery?
Surgical removal of plaque from blood vessel
- Anatomic
- Prosthetic (dacron, ePTFE)
- Vein
What are clinical features of critical limb ischaemia? What can ulcers/gangrene be caused by? (2)
- Rest pain due to toe/foot ischaemia e.g. when lying/sleeping
- Uclers/gangrene due to severe ischaemia and damage
- Caused by trauma and footwear
Symptoms of critical limb ischaemia? (2) What are reliving factors? (2)
Clinical features of critical limb ischaemia? (4)
- Rest pain
- Worse at night
- Helped by sitting and putting the leg in a dependent position
- Helped by getting up and walking about
- Cool to touch
- Absence of peripheral pulses
- Colour change
- Hair loss
What are risk factors for amputation in PVD?
- Smoking - 1 in 10 patients will lose a leg every 5 years if they continue to smoke (10% increase in limb loss)
- Diabetes - 45% of all major amputees diabetic
Treatment of critical limb ischaemia? (3)
Rank asymptomatic PAD, intermittent claudication and critical limb ischaemia in order of amputation risk?
- Analgesia
- Angioplasty/Stenting
- Surgical reconstruction/ amputation
Risk
- Asymptomatic PAD (lowest risk)
- Intermittent claudication (1%)
- Critical limb ischaemia (25% - highest risk)
What does amputation level affect? (2) Relationship? Mortality of amputation?
- Healing
- Function
- The lower down you amputate in lower limb, the greater the chance it will heal
- Mortality = 15-20%
By what percentage does risk increase with above knee operation as opposed to below knee?
15%
What is the pathology in intermittent claudication and critical limb ischaemia?
Pathology
