15. Peripheral arterial and venous disease Flashcards
Where are the deep and superficial veins located and which way does blood flow between them?
Deep: underneath the deep fascia with the major arteries
Superficial: located in the subcutaneous tissue
Blood flows from superficial to deep veins through perforating veins
What are the major superficial veins of the lower limb and which deep vein do they drain into?
Long Saphenous vein drains into common femoral vein
Short Saphenous vein drains into the popliteal vein
What are the major deep veins of the lower limb?
Common femoral vein superficial and deep femoral vein Popliteal vein anterior tibial vein posterior tibial vein peroneal vein
Where does the long spahenous vein pass relative to the malleoli?
Passes in front of the medial malleolus
What are perforating veins?
Connects superficial to deep veins
Describe the calf muscle pump and which muscles contribute to it.
Soleus and gastrocnemius muscles contribute to pushing blood against gravity back towards the heart. Every time the muscles contract, they squeeze the deep veins in the legs together and transport the blood further.
What is the function of the valves in the veins?
When open, the blood is pushed from superficial veins to perforating veins to deep.
Valves close to Prevent retrograde movement.
Perforating valves open again allowing filling from the superficial veins
how does the venous pressure in the foot change during exercise?
Venous pressure in the foot reduced during exercise as the increased activity of calf muscles means blood is pushed back up to the heart and is not pooling in the leg
What is the effect of long periods of standing or sitting on the venous return?
long periods of standing or sitting can result in the pooling of blood in the legs as there’s less force to push blood back to the heart.
What is peripheral venous disease?
Peripheral venous disease is a term that describes damage, defects or blockage in the veins that carry blood from the hands and feet to the heart
What are varicose veins and which veins are most commonly affected?
- Varicose veins are superficial veins that have become enlarged and twisted,
- Swollen and enlarged veins that usually occur on the legs and feet
- saphenous veins most commonly affected
What causes varicose veins and how does it affect blood flow through them?
Walls of veins weaken → varicosities develop and valve cusps separate, becoming incompetent
Can result in blood stasis or even retrograde flow due to ineffective valves
Don’t cause problems in their own right but can present
symptomatically
Veins tend to be tortuous, twisted
How might a patient describe symptoms of varicose vein?
Describe heaviness and aching, muscle cramps and throbbing.
Thin itchy skin, along affected veins
What are the complication of varicose veins?
Varicose veins near the surface of the skin can also rupture and bleed spontaneously or due to minor damage (haemorrhage).
Varicose eczema is an inflammatory skin disorder that can develop in those with varicose veins.
You can also develop superficial vein thrombophlebitis (this is an inflammatory condition of the veins due to a blood clot just below the surface of the skin). This causes a painful erythematous and this increases the risk of DVT.
What is chronic venous insufficiency?
Venous wall and/or valves in the leg veins are not working effectively, making it difficult for blood to return to the heart from the legs. CVI causes blood to “pool” or collect in these veins, and this pooling is called stasis and associated hypertension
What are the complications of CVI?
– reflux and or obstruction → venous hypertension
• oedema
• haemosiderin staining
• lipodermatosclerosis (inflammation and thickening of fat layer under the skin)
• venous ulceration
What is haemosiderin staining?
This is a dark purple discolouration if the lower legs caused by chronic venous disease. It occurs when iron from haemoglobin are released as a result of the breakdown of RBCs.
- leakage of RBCs from venules
- inflammatory response by macrophages
- oxidation occurs
- Fe2+ to Fe3+ (which is rust)
What are the symptoms of varicose eczema?
- itchy
- red and swollen
- dry and flaky
- scaly or crusty
What can varicose eczema lead to and how can it be differentiated from normal tissue?
Can lead to lipodermatosclerosis - which is hard to the touch
- c.f. other fatty tissues above or below
Where does ulceration due to CVI usually develop?
Around nodular areas
- typically the medial malleolus
Who is at risk of calf muscle pump failure?
Immobile, obese, injured etc.
What is deep vein and superficial vein incompetence?
Deep: retrograde flow in the deep veins
Superficial: retrograde flow from deep to superficial through perforating veins
What can cause vein incompetence and what can it lead to?
Can be caused by calf muscle failure and can lead to ulceration
Why can the calf muscle fail?
The calf muscle will fail if it’s being underused. In order to prevent this it’s very important to be using the calf muscles regularly and properly e.g plantarflexion (calf raises) of the ankle joint when walking. This can then result in venous hypertension (high pressure in the veins of the legs).
How can superficial vein incompetence be treated?
Ligation and vein stripping to prevent blood flow back into superficial veins.
What is the most common cause of arterial thrombus and what type of thrombus is it?
Atheroma most common cause
- platelet rich thrombus
What is the most common cause of venous thrombus and what type of thrombus is it?
Caused by stasis and usually another factors (trauma, COCP, dehydration, chemotherapy inflammatory conditions, pregnancy)
Low flow and little platelet component, fibrin rich
What are the signs of a DVT?
- Calf tenderness
- Warmth
- Distended and visible superficial veins
- Oedema
- Pyrexia with no other obvious cause
- Asymmetry
What are some differential diagnosis for DVT?
Soft tissue trauma, cellulitis, lymphatic obstruction
What can be done to prevent DVT post surgery?
- Prophylaxis
- Promote mobility soon after surgery
What happens in deep vein thrombosis?
• Clotting of blood in a deep vein – commonly calf
- impaired venous return and hypercoagulability
• Inflammatory response produced following thrombosis
- pain, swelling, redness
What is a fatal consequence of DVT?
pulmonary embolism
What is the leading cause of acute and chronic limb ischaemia?
Peripheral arterial disease
What physiological structures are present to prevent incidence of acute ischaemia (e.g. bending joint)?
Collateral circulation
What is an adaptive response to stenosis of a major vessel over a period of months or years?
Collateral circulation
What are the causes of acute limb ischaemia?
Trauma and embolism - atrial fibrillation, popliteal artery aneurysm, sudden rupture of atherosclerotic plaque
What are the 6P’s of leg ischaemia?
Pain Pallor* Perishing with cold* Pulseless Paraesthesia* Paralysis or reduced power* * may be subtle -compare both limbs
What is the treatment for acute limb ischaemia?
Depends on severity:
angioplasty/thrombectomy/intra-arterial thrombolysis/amputation
What is acute limb ischaemia?
Occlusion occurs acutely – minutes to days – no collateral circulation can develop in this time
What occurs as a result of chronic peripheral arterial disease?
Intermittent claudication of the lower limb (or upper limb) caused by atherosclerosis.
- exercise induced - like stable angina (oxygen demand/supply ratio)
- pain relieved on rest
How is Chronic peripheral arterial disease managed?
exercise, smoking cessation antiplatelet drugs, angioplasty, bypass graft
When is pain felt in critical ischaemia?
Rest pain - blood supply so poor pain at rest - like unstable angina.
In critical ischaemia, what provides some relief of pain?
“hanging foot out of bed relieves pain”
- gravity moves blood along the arteries
What is the end result of untreated critical ischaemia?
Ulceration and gangrene - viability of limb severely compromised (like MI)
Where is claudication most common and which artery is usually affected?
Where is claudication most common and which artery is usually affected?
In arterial stenosis, what dictates where claudication presents and where pulses can be felt?
Where the stenoses presents (in which artery)
What needs to be done when a patient presents with critical ishaemia?
Referral to vascular surgical unit immediately – extent of
threat of limb survival dictates action – imaging →
angioplasty/thrombectomy/intra-arterial thrombolysis or
amputation
Why is it important to feel different pulses in suspected arterial stenosis?
Can asses where and how bad the stenosis is.
Where can pulse be palpated in the lower limb?
• Femoral pulse - felt at the mid inguinal point
midway between anterior superior iliac spine
and pubic symphysis
• Popliteal pulse - deep in the popliteal
fossa
• Dorsalis pedis pulse - just lateral to extensor
hallucis longus tendon
• Posterior tibial pulse - just behind the medial malleolus
What is used to measure realtime flow and velocity of blood?
Sonogram using ultrasound and the Doppler effect
- doppler ultrasonography
When is doppler ultrasonography useful?
Useful for recording flow and velocity of blood
- in the heart as part of echocardiogram - HF, valve disease…
- in distal vessels - legs when diagnosing peripheral arterial disease atheroma → stenosis → flow and velocity changes
How does doppler ultrasonography work and how is blood differentiated from stationary tissue?
Echoes (sound) produced from moving blood that are detected and computed into flow direction and velocity
Echoes from stationary tissues are the same from pulse to pulse
What does size of doppler signal depend on?
Blood velocity, ultrasound frequency (balance between penetration and resolution) and the angle of insonation
Why can doppler ultrasonography be used to locate a stenosis?
Change in velocity (increases) at stenosis and turbulence beyond this point
What is the Ankle-brachial pressure index (ABPI)?
- Ankle-brachial pressure index (ABPI) – measurement of blood pressure in brachial, dorsalis pedis and posterior tibial arteries
- Divide ankle systolic by brachial systolic
- ABPI <0.9 indicates peripheral artery disease
