Arterial occlusive disease Flashcards
(37 cards)
What is peripheral arterial disease
narrowing or occlusion of peripheral arteries, affecting the blood supply to lower limbs
What can chronic limb ischaemia present as
Intermittent claudication
Cirtical limb ischaemia
Chronic limb-threatening ischaemia
What is acute limb ischaemia
– sudden decrease in arterial limb perfusion, due to thrombotic or embolic causes
What is intermittent claudication
diminished circulation leads to pain in the lower limb on walking or exercise that is relieved by rest (‘angina’ of limbs’)
What. is critical limb ischaemia
where circulation is so severely impaired that there is an imminent risk of limb loss
What is chronic limb-threatening ischaemia
represents end stage peripheral arterial disease where there is threatened limb viability relayed to several factors
What is atherosclerosis
Deposition of fatty plaques and thickening of walls in medium to large sized arteries
Process of atherosclerosis
1) Endothelial dysfunction
2) Causes inflammation of artery wall and platelet adhesion to wall
3) Inflammation leads to recruitment of mediating cells
4) Macrophages ingest cholesterol which form foam cells
5) Foam cells then form fatty streak
6) Leads to atheroma plaque formation
7) These atheroma have lipid cores and fibrous caps
8) Over time, weakening of fibrous cap
9) Plaque rupture
10) Thrombus formation
Common sites of atherosclerosis
Where vessels branch, curve or are irregular and where blood undergoes sudden changes in velocity and direction of flow
1) Circle of WIllis
2) Carotid arteries
3) Popliteal arteries
4) Coronary arteries
5) Abdominal aorta
bruce Willis Catches a Perceptive Criminal named hAns
Resulting pathology of atherosclerosis
Weakening of vessel wall- arterial aneurysm or dissection
Demand-supply mismatch- coronary heart disease, peripheral arterial disease, vascular dementia
Thrombosis- Acute coronary syndromes, acute ischaemic stroke, acute limb ischaemia
Atherosclerosis of renal artery can lead to renovascular hypertension
Risk factors for atherosclerosis and chronic peripheral arterial disease
Obesity Physical inactivity Hypertension Smoking Hypercholesterolaemia Diabetes mellitus Old age
Clinical signs of atherosclerosis
Xanthelasma
Bruits (carotid or abdo)
Aortic aneurysm on palpation
Poor peripheral pulses
What is chronic peripheral arterial disease associated with
Coronary heart disease
Cerebrovascular disease
Diabetes
Causes of chronic peripheral arterial disease
Atherosclerosis (most common cause)
Vasculitis (inflammation of vessel or artery)
Fibromuscular dysplasia
Why does intermittent claudication lead to pain
Reduced blood flow to limbs
At rest, perfusion is adequate to meet O2 demands of the tissue
During exercise, perfusion is not adequate enough to meet increased O2 demands of the tissue
Classical features of intermittent claudication
Gripping, tight, cramp-like pain (typically in calves)
Induced by exercise
Typically relieved by rest
Predominates in one leg usually
Reproducible
Difference in presentations between arterial insufficiency and cauda equina
arterial insufficiency- Fixed claudication distance
Pain exacerbated by walking uphill, better downhill
Pain disappears after 1-2 mins of rest typically
Examination findings: Absent peripheral pulses and reduced ABPI but no evidence of neurological findings
Cauda equina
Variable claudication distance
Pain often better when walking uphill but worse downhill
Pain disappears after 15-30 mins typically
Examination findings: LMN findings such as reduced reflexes but pulses present as normal
What is the progression of symptoms of peripheral arterial disease
Intermittent claudication
- Claudication distance reducing
- Ischaemic rest pain (worse at night because of reduced nocturnal BP dye to reduced CO and loss of gravity)–> Patients may report improvement of symptoms with legs hanging out of bed or sleeping in chair
- Gangrene
Clinical signs of pts with peripheral arterial disease
Pale, cold hairless legs
- Reduced CRT
- Arterial ulcerations (deep, punched out, painful, small, present over toe joints, heel and lateral aspect of leg)
Arterial bruits
Weak of absent pulses
two main symptoms of critical limb ischaemia
Rest pain due to insufficient blood supply (burning pain)
Tissue loss- Development of necrotic tissue which if infected becomes gangrene
–>Can lead to osteomyelitis so urgent treatment required
Bedside Investigations for peripheral arterial disease
Obs
ECG
Blood investigations for peripheral arterial disease
FBCs ESR (erythrocyte sedimentation rate)- secondary causes such as vasculitis Thrombophilia screen Lipid levels Blood glucose
Scans for peripheral arterial disease
ABPI (ankle brachial pressure index)
Non invasive- Duplex USS (to determine the site of the disease and indicate the degree of stenosis and length of occlusion)
Non invasive- MRI/CT angiography (prior to revascularisation via angioplasty or reconstructive surgery)
What is ABPI (ankle brachial pressure Index)
Method of quantifying severity of arterial disease in legs
Uses a dopplerto measure the blood pressure in the brachial artery and the two arteries in the foot
As arterial disease progresses in the legs, we get reduced flow through the arteries and hence the blood pressure falls
This is commonly measured in patients with ulcers to help differentiate the type of ulcer
