Vascular Flashcards
What is peripheral vascular disease?
A slow and progressive circulation disorder that causes the narrowing, blockage or spasms of blood vessels outside the heart e.g. arteries, veins or lymphatic vessels.
What is peripheral arterial disease?
Atherosclerosis of arteries supplying the limbs causes reduction in blood supply (mostly affects lower limbs but can also affect upper limbs and gluteal region).
What is the most common cause of peripheral vascular disease?
Atherosclerosis
What is the difference between chronic, acute and critical limb ischaemia?
Chronic → When the reduction in blood supply becomes symptomatic e.g. intermittent claudication
Acute → A sudden decrease in limb perfusion that threatens limb viability (symptoms develop <2 weeks)
Critical → Circulation is so severely impaired that there is an imminent risk of limb loss (i.e. advanced form of PAD)
What is the most common cause of acute limb ischaemia?
Thrombosis when an atherosclerotic plaque ruptures
Non-modifiable risk factors for PVD?
- Increasing age
- History of heart disease
- Male gender
- Post-menopausal women
- FH pf high cholesterol, high blood pressure or PVD
- Black ethnicity
Modifiable risk factors for PVD?
Same as CVS risk factors:
- Diabetes
- Smoking
- Coronary artery disease
- High cholesterol
- Hypertension
- Obesity
- Physical inactivity
What are the 2 biggest risk factors for PVD? Why?
Those who smoke** or have **diabetes have the highest risk of complications from PVD because these risk factors also cause impaired blood flow.
What are the complications of PVD?
- Impaired quality of life & limitation of mobility
- Sepsis
- Acute-on-chronic ischaemia
- Amputation
- 5 year mortality rate in those diagnosed with chronic limb ischaemia is around 50% (also due to associated CVS risk factors)
What is the mortality rate in those diagnosed with chronic limb ischaemia?
5 years
How can PVD lead to sepsis?
2ary to infected gangrene
Symptoms of PVD?
- Often asymptomatic
- Intermittent claudication
- Ischaemic pain
- Changes in skin e.g. decreased temperature, thin/brittle/shiny skin on legs & feet
- Weakness of muscles
- Hair loss
- Thickened toenails
- Loss of sensation e.g. numbness
- Poor wound healing
- Gangrene/ulceration (severe)
What is intermittent claudication?
A cramping type pain in calf/thigh/buttock after walking a fixed distance (claudication distance) relieved by rest within minutes.
Which artery is most commonly affected by intermittent claudication?
Superficial femoral artery (hence why most common site of pain is the calf)
Intermittent claudication of the calf indicates PVD of which artery?
Superficial femoral artery
Are arterial or venous ulcers painful?
Arterial
Do arterial or venous ulcers have irregular borders?
Venous → irregular
Arterial → punched out w/ regular borders
Are arterial or venous ulcers deeper?
Arterial
Onset of symptoms in acute vs chronic limb ischaemia
Acute:
- Sudden onset leg pain or sudden deterioration in claudication, loss of pulses & pallor
- Coldness & cyanosis of limb or loss of muscle power and sensation
Chronic:
- Progressive development of intermittent claudication, non-healing wounds etc
Onset of symptoms in acute vs critical limb ischaemia
Acute → <2 weeks
Critical → >2 weeks
Pulses in acute vs critical limb ischaemia?
Acute → absent
Critical → reduced/absent
What is the main differential of acute limb ischaemia?
Critical limb ischaemia
Pain in acute vs critical limb ischaemia?
Acute → Sudden, at rest, calf tenderness
Critical → Gradual, at rest
Appearance of leg in acute vs critical limb ischaemia?
Acute → pale, ‘marble white’
Critical → pink
Temperature in acute vs critical limb ischaemia?
Acute → Cold
Critical → Warm
Are ulcers & gangrene present in acute or critical limb ischaemia?
Critical (critical implies chronicity)
Is paralysis & paraesthesia present in acute or chronic limb ischaemia?
Acute
Is acute or critical limb ischaemia an emergency?
Acute
What is rest pain? Is it seen in critical or acute limb ischaemia?
Constant burning pain you may experience in the lower leg, feet or toes. Patients may have to hang foot out of bed.
Critical limb ischaemia
Purpose of Buerger’s test?
Buerger’s test is used to assess the adequacy of the arterial supply to the leg.
Describe how Buerger’s test is performed
- Patient supine on bed
- Lift up leg to 45 degrees and hold for 1 minute (if the pain allows)
- Observe the elevated leg for; a) pallor, b) venous guttering
- Drop the leg down over the side of the bed
- First will go blue due to blood moving through hypoxic tissues
- Then will go bright red as the foot is reperfused due to arteriolar dilatation 2ary to hypoxia
What are the 6 cardinal signs of acute limb ischaemia?
- Pain — constantly present and persistent.
- Pulseless — ankle pulses are always absent.
- Pallor (or cyanosis or mottling)
- Paralysis or power loss
- Paraesthesia or reduced sensation or numbness.
- Perishingly cold
What is buerger’s angle?
Angle at which leg goes pale, <20 degrees suggests severe disease
What Buerger’s angle indicates severe disease?
<20 degrees
Purpose of performing an ABPI?
The ABPI is used to assess patients for peripheral arterial disease as a fall in blood pressure in an artery at the ankle relative to the central blood pressure would suggest a stenosis in the arterial conduits somewhere in between the aorta and the ankle.
What is a normal ABPI result?
Around 1 (0.9-1.2)
What does an ABPI result of >1.2 indicate?
Arterial calcification (false result) → think diabetes
What would an ABPI of <0.8 indicate?
PAD
What would an ABPI of <0.5 indicate?
Severe PAD
An ABPI cannot exclude PVD and further investigations will be needed. Why may a duplex US be performed?
- For those who might be suitable for revascularisation
- Can determine the site, severity and length of stenosis
If a patient with PAD is <50 with no obvious risk factors, what 2 screening tests can be performed?
- Thrombophilia screen
- Homocysteine levels
What is thrombophilia? How can this cause PAD?
If you have thrombophilia, it means your blood can form clots too easily.
Thrombophilia can encourage clot formation in your peripheral arteries that can cause blockages (PAD).
How can homocysteine levels affect PAD risk?
The risk of PAD is significantly associated with serum homocysteine levels → high levels of homocysteine in the blood are associated with atherosclerosis
Diabetic patients with new foot ulceration should be seen in a diabetic foot clinic within how long?
Within 24 hours of presentation
Lifestyle advice for PVD?
- Smoking cessation
- Supervised exercise programme/increased physical activity
- Weight reduction
Pharmacological management of PVD?
Managing CVS risk:
- Antiplatelet therapy → clopidogrel 75mg daily (aspirin only prescribed if clopidogrel is not tolerated/contraindicated)
- Lipid lowering therapy → atorvastatin 80mg once nightly
- Diabetic control
- HTN management
Analgesia → naftidrofuryl oxalate (vasodilator that can alleviate pain in PVD)
Which antiplatelet is used in the management of PVD?
Clopidogrel 75mg daily
Which statin is used in the management of PVD?
Atorvastatin 80mg nightly
1st line analgesic in PVD?
Naftidrofuryl oxalate (vasodilator that can alleviate pain in PVD)
Surgical management of PVD?
- Revascularisation
- Surgical bypass +/- stent (severe)
- Amputation
Define acute limb ischaemia
A severe, symptomatic hypoperfusion of a limb occurring for <2 weeks. This is a vascular emergency as the viability of the limb is threatened. Majority of cases involve the lower limbs.
Mortality rate of acute limb ischaemia?
20%
What is the most common cause of acute limb ischaemia?
Thrombosis
How can thrombosis lead to acute limb ischaemia?
- Most commonly due to plaque rupture in an atherosclerotic segment (thrombosis-in-situ) in patients with PAD
- A thrombus may also form in the context of:
- Hypovolaemia
- Thrombophilia
- Hypotension
- Malignancy
What is the 2nd most common cause of acute limb ischaemia?
Embolism
What condition is acute limb ischaemia 2ary to embolism typically due to?
Atrial fibrillation - thrombus forms in LA and embolises
How can an MI lead to acute limb ischaemia?
Mural thrombus emoblises
What is compartment syndrome?
Compartment syndrome occurs when the pressure within a compartment increases, restricting the blood flow to the area and potentially damaging the muscles and nearby nerves.
Theory behind chronic compartment syndrome?
Chronic compartment syndrome usually occurs in young people who do regular repetitive exercise, such as running or cycling.
Give some traumatic causes of acute limb ischaemia
- Iatrogenic injury during interventional procedures e.g. percutaneous coronary intervention (increasing prevalence)
- Compartment syndrome
- Fractures
In which condition can vasospasm lead to acute limb ischaemia?
Raynaud’s phenomenon
Describe onset of acute limb ischaemia in cases 2ary to thrombosis vs embolism
Thrombosis → typically has a sub-acute onset and patients have features of peripheral vascular disease in the contralateral limb
Embolism → more acute onset
Risk factors for acute limb ishaemia?
similar to PAD:
- Smoking
- Diabetes mellitus
- Obesity
- Hypertension
- Hyperlipidaemia
Give some complications of acute limb ischaemia
- High mortality rate 15-20%
- Reperfusion injury
- Extensive tissue necrosis
- Limp amputation
- Compartment syndrome
- Peripheral nerve injury
- Psychosocial impact & physical morbidity
Clinical features of acute vs critical limb ischaemia
Signs & symptoms in acute limb ischaemia
SYMPTOMS:
- The 6 P’s of acute limb ischaemia:
- Pallor
- Pulseless
- Perishingly cold (poikilothermia)
- Paraesthesia (altered sensation)
- Pain (usually present at rest)
- Paralysis (late sign)
SIGNS
- Marble white appearance of skin
- Absent limb pulses on palpation
- Cold limb
- Paraesthesia (reduced or complete loss of light touch sensation in distal limb)
- Paralysis (inability to wiggle toes/fingers)
- Muscle weakness
- Gangrene
- N.B. a normal contralateral limb with palpable pulses is a sensitive sign for embolic occlusion in the abnormal limb
What is a normal contralateral limb with palpable pulses is a sensitive sign for in acute limb ischaemia?
Embolic occlusion in the abnormal limb
Bedside investigations in acute limb ischaemia?
- Vital signs
- 12-lead ECG → look for AF or MI
- Doppler/Duplex US → to confirm absence of pulses
Which blood test can assess severity of ischaemia in acute limb ischaemia?
Serum lactate (VBG)
Which imaging can guide revascularisation if limb is viable in acute limb ischaemia?
CT/MR angiography
An ABCDE approach is required in acute limb ischaemia. Why should the patient be kept nil by mouth?
In case need for surgery
What anticoagulant is 1st line choice in acute limb ischaemia?
IV heparin → to prevent thrombus propagation
Analgesia choice for acute limb ischaemia?
paracetamol + an opioid
Why does an embolic ALI threaten the limb more than a thrombotic ALI?
The sudden nature of embolic ALI does not provide the body enough time to build up compensatory collateral
Clinical features of thrombotic vs embolic cause of ALI:
Define an aneurysm
An aneurysm is an abnormal dilatation of a blood vessel by >50% of its normal diameter
Define an abdominal aortic aneurysm (AAA)
An AAA is a dilatation of the abdominal aorta by >3cm (normal diameter of abdominal aorta is <2cm).
What is the main cause of an AAA?
Atherosclerosis
Who is routinely offered screening for AAAs?
Screening offered to all men in UK aged 65 and over
How are AAAs typically detected?
On screening
AAAs are more likely to be symptomatic if expanding/burst. What symptoms may be present?
- Sudden onset abdominal/flank pain
- Back or loin pain
- Distal embolism producing limb ischaemia
- Syncope
- Pulsatile abdominal mass
What size AAA would indicate the need for surgical repair?
>5.5cm or expanding >1cm/year
Management of a burst AAA?
- ABCDE
- Permissive hypotension (BP <100 mmHg) → this involves managing trauma patients by restricting the amount of resuscitation fluid and maintaining BP in the lower than normal range if there is continuing bleeding
What is permissive hypotension?
Managing trauma patients by restricting the amount of resuscitation fluid and maintaining blood pressure in the lower than normal range if there is continuing bleeding during the acute period of injury.
Mortality rate of a burst AAA?
80% of patients with burst AAA die before reaching hospital
Open repair vs endovascular repair of AAA?
Open repair → unstable patients
Endovascular repairs (EVAR) → stable
What are varicose veins?
Dilated, tortuous veins which mainly occur in the superficial venous system of the legs.
How common are varicose veins?
High prevalence; 1/3 of population developing them at some point in their lives.
Prognosis of varicose veins?
Often asymptomatic or only a cosmetic concern.
Superficial veins drain into the deep venous system via what veins?
Superficial veins drain into the deep venous system via perforator veins that penetrate muscle fascia in the legs
Why can blood flow only move unidirectionally in superficial veins?
- Blood flow can only move unidirectionally towards the deep veins due to the presence of valves in the superficial veins
- This is to overcome the hydrostatic pressure imposed on distal blood by gravity (effect greatest in lower limbs)
Pathophysiology behind varicose veins?
Incompetence of the one-way valves → leads to leakage, retrograde flow and pooling of blood in the superficial venous system.
Why are superficial veins more prone to varicose veins than deep veins?
- The weaker, thinner walls of the superficial veins (as opposed to the stronger and thicker walls of the deep veins) makes them more prone to the effects of the high-pressure build-up of blood
- This leads to distension of the venous walls and tortuosity of the affected venous segment which manifest as bulging of skin over the affected vein
most common cause of varicose veins?
Idiopathic
2ary causes of varicose veins?
2ary causes arise from mechanisms of venous outflow obstruction which can either be:
- a) Intravascular (e.g. DVT)
- b) Extravascular (e.g. pelvic masses, including tumours, fibroids and pregnancy)
Risk factors for varicose veins?
- FH of varicose veins (90% risk if both parents affected)
- Older age (>40 y/o)
- Pregnancy (higher parity equals higher risk)
- Female sex
- History of DVT
- Obesity
- Prolonged standing/sitting (including an occupation involving this)
- Previous lower limb fracture
- Caucasian
Potential complications of varicose veins?
- Bleeding
- DVT
- Changes to skin pigmentation
- Ulceration
- Impaired quality of life
- Superficial thrombophlebitis
Symptoms of varicose veins?
- Often asymptomatic (cosmetic concern)
- Pain (dull ache or burning of skin)
- Leg fatigue, discomfort or worsening pain after prolonged standing (relief after leg elevation)
- Leg cramps (usually nocturnal)
- Restless legs
- Skin discolouration over affected areas (haemosiderin deposition)
- Heaviness of legs
What is lipodermatosclerosis?
Lipodermatosclerosis (which may be acute or chronic) results from chronic inflammation and fibrosis of the dermis and subcutaneous tissue of the lower legs.
What is telangiectasia?
Telangiectasias are small, widened blood vessels on the skin.
Compression stockings may be indicated in varicose veins. What is the major contraindication for compression therapy? How can this be ruled out?
Severe PAD → use ABPI
What is the cause of arterial ulcers?
Peripheral arterial disease
Features of arterial ulcers?
- Punched out appearance
- Ulcer and surrounding skin are cold, white and shiny
- Other signs of PAD may be present e.g. intermittent claudication (pain on walking that is relieved by rest)
Are arterial ulcers cold or warm?
Cold (and surrounding skin is cold too)
Colour of arterial ulcers?
White
When may arterial ulcer pain particularly occur? How is this relieved?
Pain may occur at rest, usually at night when the legs are elevated → this is relieved by hanging feet off end of bed
What ABPI result indicates PAD?
<0.9
Cause of venous ulcers?
Chronic venous insufficiency
Where are venous ulcers typically found?
Above the medial malleolus
Are venous ulcers cold or warm?
Warm
Give some signs of venous insufficiency
- Venous ulcers
- Lipodermatosclerosis
- Haemosiderin deposition
- Venous/stasis eczema
- Varicose veins
- Ankle swelling
What investigation must be performed in a venous ulcer? Why?
ABPI/doppler → to rule out arterial disease
management of venous insufficiency?
Treatment is with compression bandaging (after ruling out arterial disease)
What is lipodermatosclerosis?
- The skin change seen in chronic venous insufficiency
- There is subcutaneous fibrosis and hardening of the skin
- The skin is dry and is often the site for venous ulcers to develop
