How is ABPI calculated
Foot artery occlusion pressure / brachial systolic pressure
ABPI >1.1 indicates
Calcified or incompressible vessels e.g. diabetes and renal failure
ABPI 0.7-0.9 indicates
Mild ischaemia
ABPI 0.4-0.7 indicates
Moderate ischaemia
ABPI <0.4 indicates
Critical ischaemia
What is the most accurate investigation for imaging the arterial system
Intra-arterial digital subtraction angiography (IADSA)
What is the investigation of choice for imaging the lymphatic system
Lymphoscintigraphy
How is lymphoscintigraphy performed
Radiolabelled colloid is injected into the webspace between the 2nd and 3rd toes and images obtained with a gamma camera
What are the 3 histological layers of an artery
What are the 2 types of artery
2. Muscular distributing arteries
Describe the tunica intima
- Single layer of endothelial cells orientated in the direction of flow
Describe the tunica media
- Composed of elastin and collagen fibres with vascular smooth muscle cells
Describe the tunica adventitia
- Connective tissue
What are the histological differences between the thoracic and abdominal aorta
Thoracic aorta has >30% elastin compared to <20% in the abdominal section
What crosses the abdominal aorta anteriorly
What lies immediately to the right of the abdominal aorta
What lies immediately to the left of the abdominal aorta
- Left ureter
Define an aneurysm
Pathological dilatation of an artery to >1.5x its normal diameter
What is the diameter of the aorta
2cm
Define a true aneurysm
Dilatation of an artery involving all layers of the arterial wall
Define a false aneurysm
Pulsatile, expansile swelling due to a defect in an arterial wall, with blood outside of the lumen, surrounded by a capsule of fibrous tissue or compressed surrounding tissue
List the causes of aneurysms
Where is the most common site of atherosclerotic AAA
Infrarenal
Mortality rate for elective AAA repair
5%