Peripheral arterial disease Flashcards
Roughly define what peripheral arterial disease is?
Is the narrowing of arteries that supply the lower limb
What are the risk factors associated with PAD?
Age Male Smoking Hypertension Obesity/Hyperlipidaemiaa/cholestrolemia Diabetes
Very briefly, explain the pathology process behind PAD
Similar to atheroma process
Development of atheroma/emboli/thrombus/plaque rupture leads to decreased diameter and hardening/blockage.
This causes increased resistance to flow and therefore, distal circulation decreased.
3 things happen:
1. Decreased tissue perfusion =ischaemia, absent pulse, pallow and dependent rubor. Alongside that, exercise leads to increased lactic acid which = claudication and transient ischaemia
- Increased blood velocity and turbulence = BRUITS
- Increased vasodilation initally but then decreased diameter.
Causes nerve/limb ischaemia and necrosis = pain at rest, ulcer, angrene, hyporeflexia
For clinical symptoms, state the 4 stages in the fontaine classification
Stage 1 = Asymptomatic Stage 2 = Mild claudication A = Pain when walking more than 200m B=Pain when walking less than 200m Stage 3=Pain at rest Stage 4= Necrosis+/or Gangrene
Describe the signs in the terms of LOOK, FEEL and AUSCULTATE in PAD
Look:
Ulcers
Pallor
Hair Loss
Feel: Temperature No pulse Capillary refill Peripheral sensation
Auscultate: doppler
Dorsalis pedis pulse
Post tibial pulse
What formula does the ankle brachial pressure index use? And what do the results mean?
Ankle pressure/brachial pressure
Results: 1-0.95 = Normal 0.95-0.5 = Intermittent claudication 0.5-0.3 = Rest pain Less than 0.2 = Gangrene and ulceration
Describe what the buergers test is
Elevate the legs at certain angles eg: 90 or 45 and observe whether pallor occurs
If occur at less that 20degrees, then severe ischamia
Then hang feet over edge and observe the return of blood.
If dark red = reactive hyperaemia
What does the investigation involve for PAD?
Duplex US - view decreased blood flow
CTA/MRA - can overestimate calcification
Ankle brachial index
Auscultation: BRUITS
Digital subtraction angiography:
visualise blood vessels
Describe the medicinal treatment usually given for PAD?
Statin + Anticoagulant
Statin - inhibits platelet, thrombosis, endothelial and inflammation activation as well as plaque rupture
Antiplatelet - reduces risk of needing revascularisation
What the risk factor controls for PAD ?
BP needs to be less than 140/85
Smoking cessation
Exercise
What are the option in revascularisation treatment?
Open surgery:
- Bypass
- Endarterectomy
Endovascular intervention
- Balloon angioplasty
- Stent placement
- Atherectomy
What does a surgical bypass involve?
It requires:
Inflow
Conduit: autologous
Outflow
Complications:
General - Bleeding, wound infection, pain, scar, DVT, PE. MI
Technique: Damage to nearby vein, artery and nerve, distal emboli, graft fail
Generally describe the difference between embolus and thrombus
Embolus: any object that travels through bloodstream and causes obstruction
Thrombus: blood clot in situ and causes obstruction
What are the possible general reasons for acute limb ischaemia?
Acute embolus = MI, AF, proximal athlerosclerosis Thrombosis Dissection Trauma Acute aneurysm thrombosis eg; popiteal
What is compartment syndrome? and what can it be caused by? How can it be identified?
When the pressure inside the muscles builds up to dangerous levels
Painful and results in muscle ischaemia which is irreversible after 6-8hours
Can be caused by inflammation, oedema and venous obstruction
Rise in creatine kinase and increased risk of renal failure
