11. Peripheral arterial & venous disease Flashcards
Outline the structure of venous anatomy within the lower limb.
Divided into superficial and deep veins, perforating veins travel from superficial to deep.
What are the deep veins of the lower limb?
External iliac, Femoral, Popliteal vein
What are the superficial veins of the lower limb?
Long and short saphenous
What is the one vein that remains constant in the body, despite anatomical variation?
Long saphenous vein runs anterior to the medial malleolus.
How does the calf muscle pump aid venous flow?
When the calf muscle contracts, the pressure rises due to the deep fascia compartmentalisation, propelling the venous blood towards the heart.
What is the doppler test?
Ultrasound test which uses high frequency sound waves to assess blood flow in a vessel.
What is the pathophysiology of varicose veins?
Vein wall is inherently weak, leading to dilatation and separation of valve cusps, making them incompetent.
What are symptoms associated with varicose veins?
Heaviness, tension, aching, itching
* along the vein itself*
What are the complications of varicose veins ( the veins themselves)?
Vein haemorrhage, thrombophlebitis
What are the complications of varicose veins as a result of venous hypertension?
Oedema Skin pigmentation Varicose eczema Venous ulceration Lipodermatosclerosis
When do varicose veins usually haemorrhage and cause bleeding?
Shower - warm heat causes vasodilation and standing up increases pressure at the feet.
- Lie down and lift leg.
What is thrombophlebitis?
Inflammation and swelling in the veins due to a clot. Inflammatory response initiated!
What symptoms are associated with thrombophlebitis?
Pain
Haemosiderin staining due to increased capillary permeability
What leads to venous ulceration?
Calf muscle pump failure leads to venous hypertension which leads to venous ulceration.
What are some causes of calf muscle pump failure?
- Lack of contraction - immobility, obesity
- Deep vein incompetence
- Volume overload - superficial vein incompetence
How can valve incompetence lead to venous ulceration??
If valve incompetent, blood will return back down superficial vein and back into the calf muscle pump, causing dilation and venous hypertension which can lead to venous ulceration.
= retrograde circuit
Which of virchow’s triad occurs in arteries?
Changes in the lining of the vessel wall
Which of virchow’s triad is common in veins and leads to thombosis?
Changes in blood flow - stasis + another factor leads to venous thrombosis
What can cause venous stasis?
Trauma - surgery
Oral contraceptive pill
Dehydration
Cancer
How do arterial thrombi differ to venous thrombi?
Arteries spurt when they bleed, so thrombi are platelet reach.
Thrombi do not spurt, thrombi are fibrin rich.
What pathways are needed to cause arterial and venous thrombosis?
Venous - intrinisic, then extrinisic.
Arterial - platelets, extrinsic and then intrinsic.
How does the body respond to DVT?
Inflammatory response:
Calor,dolor,rubor, tumor, loss of function
What are the symptoms of DVT?
Pain, cannot walk
Swelling
Blue-red skin discolouration
What are the signs of DVT?
Calf tenderness Skin warmth Skin discolouration Distended, warm superficial veins Oedema Pyrexia
Why is surgery considered a significant risk factor for DVT?
- Immobility prior and following to surgery
- No calf muscle pump during surgery
- Surgery = trauma, prothrombotic state
What is a fatal consequence of DVT?
PE
Explain why a complete arterial occlusion may present without consequences?
If chronic development of an atheroma, body develops collateral circulation which bypasses the stenosis.
What is acute limb ischaemia?
Limb goes from a normal blood supply to greatly impaired within minutes - no time for collateral vessel development.
Patient will die of hyperkalaemia if not amputated.
What are the commonest causes of acute limb ischaemia?
Embolism, trauma
What are the 6 symptoms/signs of acute limb ischaemia?
6 P's: Pain Pallor Paralysis Paraesthesia Perishing cold Pulseless
How might the appearance of a leg with acute limb ischaemia present and progress?
Initially pale, develops blanching patches before fixed, mottling which is non-blanching.
How might chronic peripheral arterial disease present?
Intermittent claudication
Which artery in the lower limb is most commonly diseased?
Superficial femoral artery
Where can arterial pulses be palpated in the lower limb?
Femoral pulse - MIPA
Popliteal pulse - deep
Pedal pulse - dorsalis pedis artery
What pulses will be present if the superficial femoral artery is occluded?
Femoral pulse present
Popliteal & pedal pulses absent
How do the symptoms of critical arterial ischaemia differ from chronic?
REST PAIN - pain in the foot that continues when the patient goes to bed.
Relieved by hanging the foot out of the bed.
What are 3 reasons why the pain is worse when lying in bed?
- No gravity effect
- Decreased CO
- Higher O2 demand - warmer
What can critical arterial ischaemia lead to?
Gangrene
Ulceration (anterior tibia most common)
