Vascular surgery introductory lecture Flashcards
What causes chronic limb ischaemia?
Atherosclerosis causing stenosis of peripheral arteries
What are risk factors for chronic limb ischaemia?
Smoking Diabetes Hypertension Stroke IHD Hyperlipidaemia Renovascular disease
How does chronic limb ischaemia present?
Intermittent claudication- cramping pain in calf, thigh or buttock after walking for a given distance (the claudication distance) and relieved by rest
What is considered ‘best medical therapy’ for chronic limb ischaemia?
- Stop smoking
- Treat hypertension and high cholesterol (prescribe statin even in patients who’s cholesterol is currently normal)
- Prescribe an antiplatelet agent to prevent progression and reduce cardiovascular risk
- Exercise- esp. supervised exercise programs. Reduce symptoms of claudication by improving collateral blood flow
What are the ‘Six P’s of acute limb ischaemia? Which of these are late changes?
- Pallor
- Pulselessness
- Pain
- Perishing with cold
- Parasthesia (late change)
- Paralysis (late change)
What is the significance of the 6 P’s in acute limb ischaemia?
If a patient presents with all 6 P’s including the late changes, there is SIX HOURS to act before the patient is at serious risk of losing the limb
What are the main causes of acute limb ischaemia?
- Thrombosis in situ (40%): more likely in patients with known vasculopathy
- Emboli (38%)
- Graft/angioplasty occlusion
- Trauma
Ideally, surgical intervention should be immediate upon presentation of acute limb ischaemia. However, sometimes no immediate intervention is available, e.g. if patient presents in the middle of the night. How should such cases be managed?
May be a case for heparinisation (stops clot propagating) and waiting till morning. This is often better for patients as surgeons generally operate better by day
If there is evidence of gangrene, administer antibiotics
What defines critical limb ischaemia?
Advanced stage acute or chronic limb ischaemia defined as the combination of evidence of ischaemia together with any of ischaemic rest pain, non-healing ulcers, or gangrene.
CLI is the point at which the lack of blood flow has crossed a threshold, threatening the sustainability of the limb
What is the difference between wet and dry gangrene?
Wet:
- Tissue death and infection (associated with discharge) occurring together
- Acute emergency
- Requires antibiotics and often amputation
- No clear demarcation between gangrenous area and perfused area
Dry:
- Necrosis in the absence of infection
- Not an acute emergency- can often be left alone e.g. if just a toe has try gangrene it can be safest to leave it to fall off
- Clear demarcation between gangrenous and perfused tissue
How does critical limb ischaemia present?
- Pain at rest, often with onset at night
- Gangrene
- Iscaemic (arterial) ulceration
What are the reconstruction options in critical limb ischaemia?
- Thrombolysis
- Angioplasty
- Bypass
What is the Fontaine classification for peripheral arterial disease?
- Asymptomatic
- Intermittent claudication
- Ischaemic rest pain
- Ulceration/gangrene
What signs might be seen on examination in a patient with peripheral arterial disease?
- Absent femoral, popliteal or foot pulses
- cold, white leg(s)
- Atrophic skin
- Punched out ulcers
- Postural/dependent colour change
- In severe ischaemia
- Vascular (Buerger’s angle) 15s
What is Buerger’s test?
Patient lies flat on couch- look at the colour of their feet
Lift the legs in the air and see if they go pale- the angle at which the feet go pale is Buerger’s angle
Let the legs dangle over the edge of the bed and see if they go red and then bright red
If feet go pale and then red this is a positive Buerger’s test and is a sign of ischaemia
What is an ABPI? What is a normal value for an ABPI? What is the range of ABPI which indicates peripheral artery disease? What is the range of ABPI which indicates critical limb ischaemia?
Ankle-brachial pressure index.
Normal: 1-1.2
PAD: 0.5-0.9
CLI: <0.5
What is indicated by buttock claudication?
Iliac disease
Where is claudication felt when there is femoral disease?
The calf
What are the drawbacks of thrombolysis to treat critical limb ischaemia?
- Contraindications for thrombolysis e.g. bleeding risk, recent surgery etc
- Thrombolysis of a whole limb takes 24-36 hours. Thus if a patient presents with “6 P’s” and has 6 hours before they lose their limb, there is not enough time to thrombolyse
What is PTA? When might this be used as a treatment of critical limb ischamnia? What are the drawbacks?
Percutaneous transluminal angioplasty
Used for disease limited to a single arterial segment
5 year patency is only 55% in femoral artery and 79% in iliac vessels
N.B. stents can be used to maintain patency
What is a subintimal angioplasty?
The angioplasty balloon is placed in between the media and intima, forming a new channel between these layers
Describe surgical reconstruction of critical limb ischaemia
If atheromatous disease is extensive but distal runoff is good (i.e. peripheral arteries are filled by collateral vessels), consider arterial reconstruction with a bypass graft. Ideally the patients own vein should be used as the graft, usually saphenous vein. No foreign body is used so risk of infection is reduced. The vein used may be in situ or reversed (reversed vein has slightly worse prognosis as the blood supply is changed)
A synthetic graft may be used (PTFE or dacron ring supported synthetic vessel) but outcomes are worse
How is phantom limb pain treated following amputation?
gabapentin
What are indications for lower limb amputation?
Irreversile ischaemia
Refractory ulceration
Loss of function
Extensive rhabdomyolysis
What is an aneurysm?
Localised dilatation of an artery by >50% its normal diameter
What is meant by a true or a false aneurysm?
True: involves all three layers of the wall of an artery (intima, media and adventitia
False: a hematoma that forms as the result of a leaking hole in an artery. Note that the hematoma forms outside the arterial wall, so it is contained by the surrounding tissues. Also it must continue to communicate with the artery to be considered a pseudoaneurysm
What are the two different shapes of aneurysms that may form?
Fusiform: artery is dilated symmetrically on both sides e.g. most AAAs
Saccular: One side of the artery appears normal, the other bulges out in a spherical shape e.g. Berry aneurysm
Is AAA more common in men or women?
Men (5:1)
Risk factors of AAA
Age Male Smoking Hypertension Family history Connective tissue disorder e.g. Ehlers Danlos
What shape of aneurysm is more likely to become mycotic (infected)
saccular
What are the symptoms of an AAA
None until rupture or impending rupture
Intermittent or continuous abdominal pain radiating to back, iliac fossae or groins
Hypotension
Tachycardia
Confusion
On palpation is felt as an expansile abdominal mass
At what point is elective surgery considered for an AAA?
when the aneurysm is >5.5cm. At this points risks of aneurysm rupture outweight risks of surgery
What is the interventional treatment of choice for AAA?
EVAR- endovascular aneurysm repair
Stent graft is introduced using a guide wire and is maneuvered into the aneurysm
Stent is opened to allow blood flow through the stent so it doesnt circulate in the aneurysm.
What are the advantages/disadvantages of EVAR vs. surgery for AAA?
Advantages: less early mortality due to surgical complications
Disadvantages: more expensive. Higher graft complications e.g. failure of stent to completely exclude blood flow to the aneurysm–> leak
Describe the pathology of varicose veins
Blood from the superficial veins in the leg passes into deep veins via perforator veins and at the sapheno-femora and sapheno-popliteal junctions. Valves prevent blood from passing from deep to superficial veins. Valves also prevent backflow of venous blood being pumped back up to the heart. If these valves become incompetent, there is venous hypertension and dilatation of superficial veins occurs. Veins appear tortuous and dilated
Which veins are most commonly varicose?
long and short saphenous; tributaries of the saphenous veins (reticular veins)
What are risk factors for varicose veins?
Family history Females (5:1 reduced to 2:1 after the 6th decade) Age over 50 Pregnancy OCP Prolonged standing Obesity
Symptoms of varicose veins
Cosmetic dissatisfaction "my legs are ugly" Pain Cramps Tingling Heaviness Sweliing
Signs of varicose veins
Distended veins on standing Telangiectasia (also known as spider veins- small dilated blood vessels near the surface of the skin) Eczema Oedema Ulcers
What advice might a doctor give to a patient with varicose veins who did not qualify for treatment? Why would the patient not qualify for treatment?
Elevate legs wherever possible Avoid prolonged standing Compression socks Lose weight Regular walks (as calf muscle action aids venous return)
NHS only treats cases of VV if patient is in pain or has bleeding, ulceration or superficial thrombophlebitis (vein inflammation related to a clot). I.e. not for cosmetic reasons alone
What is the endovascular treatment of varicose veins? What are the advantages of this over surgery?
- Radiofrequency ablation: A catheter is inserted into the vein and heated to 120 degrees to destroy the endothelium and close the vein
- Endovenous laser ablation: similar but uses a laser
- Injection sclerotherapy: Foam is injected into the affected veins, the injection guided by ultrasound. The foam scars the veins, which seals them closed.
Less pain and earlier return to activity than surgery
What is the surgical treatment for varicose veins?
Saphenofemoral ligation and stripping: affected vein is tied off and removed
What are the complications of treatment of varicose veins?
- Recurrence is very high
- Nerve damage
- Bruising
- Infection
- Bleeding
- DVT
- Pigmentation
What is chronic venous insufficiency?
Untreated primary varicose veins rarely result in CVI. However, it is common following DVT in Post Phlebitic/ Post thrombotic syndrome. It presents with swelling, hyperpigmentation, oedema, ulceration and lipodermatosclerosis (inflammation of the layer of fat under the skin)
What is the role of the lymphatic system? What happens if the lymphatic system fails?
It moves extracellular fluid from the interstitial space back into the circulation and is a vehicle for the immune system. Failure of the lymphatic system results in lymphoedema
What is Stemmer’s sign?
The inability to pick up a fold of skin at the base of the second toe. This is usually positive in lymphoedema.
What are the signs and symptoms of lymphoedema?
- Initially pitting but becomes non-pitting oedema
- Positive stemmer’s sign
- Sausage-shaped toes
4, Distal to proximal distribution - Skin changes such as hyperkeratosis and ‘bubbly’ appearence of the skin
How is lymphoedema classified?
- Primary: Caused by abnormal development of the lymphatics with no clear underlying cause. Can be congenital, praecox (appearing in 2nd or 3rd decade) or tarda (appearing after 35 years)
- Secondary: due to damage of an otherwise normal lymphatic system e.g. infection, cellulitis, trauma, radiation injury
How is lymphoedema treated?
- DLT- decongestive lymphatic therapy. Involves, compression stockings, good skin care, exercises and manual lymphatic drainage- specialised massage techniques to stimulate the flow of fluid in the lymphatic system and reduce swelling
- Surgery- removal of sections of excess skin and tissue (debulking) OR removal of fat from affect limbs (liposuction)
What are the four types of leg ulcer? How can they be differentiated?
- Arterial: seem in the extremities/toes. Confer severe pain. Minimal or no bleeding. Clear margins
- Venous: above medial malleolus. Moderate pain. May ooze. Diffuse margins
- Neuropathic: Seen in pressure areas e.g the sole of the foot; no pain may ooze; shape defined by location
- Mixed of the above
What is the ‘triad’ of the diabetic foot?
- Neuropathy- ulceration at pressure points; charcot joints
- Infection- presents late due to reduced nociception; may spread proximally unnoticed
- Ischaemia
At what percentage of stenosis is surgical intervention considered necessary if there is occlusion of the internal carotid?
> 70%
