Vascular disease in the lower limb Flashcards
What is the process of atherosclerosis? 9
1) Endothelial damage
2) Damaged endothelium expresses adhesion molecules which attract monocytes which infiltrate the endothelium and differentiate into macrophages
3) Damages endothelium attracts platelets which adhere to the endothelium and release pro-inflammatory mediators
4) Smooth muscle cells grow
5) Circulating LDL is rapidly oxidised forming ox-LDL which is scavenged by the macrophages - these accumulate lipid and become foam cells
6) When foam cells die they release the lipid into the plaque
7) Plaques may then remain stable for some time if inflammation is resolved
8) They may partially occlude an arterial lumen and cause symptoms
9) If inflammation continues in a plaque, they become unstable and are liable to rupture
What are the benefits of statins?
1) Lipid lowering
2) Antiplatelet activity
3) Stabilise plaques
How does plaque rupture lead to thrombosis? 2
1) Plaque ruptures and the contents of the core are exposed to the blood in the circulation
2) This material is highly thrombogenic and platelet aggregation rapidly occurs and the coagulation cascade is triggered
Chronic limb ischaemia occurs due to what disease process?
Atherosclerosis
Patients with chronic limb ischaemia often have symptoms of what other disease?
Other manifestations of vascular disease eg. heart disease, previous stroke or TIA
What process occurs in chronic limb ischaemia which means the affected limb remains perfused (poorly though)?
Collateral circulation develops over time
The symptoms of chronic limb ischaemia develop slowly over time, what will eventually happen to the limb?
It will become critically ischaemic if a plaque suddenly ruptures and occludes a vessel and the patient will have ACUTE ON CHRONIC limb ischaemia, however the signs of this acute event will be less marked than in someone who doesn’t have a background of chronic ischaemia
What are the 4 Fontaine classifications of limb ischaemia?
1) Asymptomatic
2) Intermittent claudication
3) Ischaemic rest pain
4) Ulceration/ gangrene = critical ischaemia
What 3 symptoms signify critical limb ischaemia?
1) Pain at rest
2) Ulceration
3) Gangrene
What kind of gangrene often occurs in critical limb ischaemia and why?
Dry gangrene (tissue necrosis without infection) It often occurs in chronic ischaemia as there is minimal blood supply (hence glucose and glucose) to drive bacterial infection
What is the most important thing to remember about acute limb ischaemia?
It is a surgical emergency - once recognised this should be referred urgently to the on call vascular surgery team
There is significant mortality associated with acute limb ischaemia
What are the 3 causes of acute limb ischemia?
1) Rupture of an atherosclerotic plaque
2) Emboli from elsewhere
3) Could be trauma
Patients who have undergone recent angioplasty or grafting of an occlusion may also present with chronic limb ischemia
What are the 6P’s of an acute ischaemic limb?
1) Painful
2) Pulseless
3) Perishingly cold
4) Pallor
5) Parasthesia
6) Paralysis
What are the 2 exceptions to the 6Ps of an acute ischemic limb?
1) Acute on chronic ischemia - especially is bilateral chronic ischemia the affected leg may not look as different as expected, may also not have as marked symptoms if they have had chronic ischemia for a long amount of time
2) An acute ischemic limb may appear red if it is dependent
What are the 5 investigations which can be carried out in chronic limb ischemia?
1) Blood test: FBC, inflammatory markers, lipid profile, U&E
2) ECG
3) Clotting, G&s
4) Ankle-brachial pressure index
5) Vascular imaging
