Abdominal aortic aneurysm Flashcards
Average lifetime aortic blood flow
200 million litres
Layers of arterial wall
Tunica intima: covered by endothelium
Tunica media: thick collagen
Tunica adevntita: extrnal coverings containing vasa vasorum
Windkessel function
Refers to the secondary pump quality of the aortic
Elastic nature provides pump force during diastole
–> helps to perfuse coronaries
Average aortic expansion
Men: 0.9mm per DECADE
Women: 0.7mm per DECADE
Symptoms of aortic disease
Acute deep, aching or throbbing chest or abdominal pain that can spread to the back, buttocks, groin or legs, suggestive of AD or other AAS, and best described as ‘feeling of rupture’
Cough, shortness of breath, or difficult or painful swallowing in large TAAs.
Constant or intermittent abdominal pain or discomfort, a pulsating feeling in the abdomen, or feeling of fullnessafter minimal food intake in large AAAs.
Stroke, transient ischaemic attack, or claudication secondary to aortic atherosclerosis.
Hoarseness due to left laryngeal nerve palsy in rapidly progressing lesions.
Ideal place to measure diameter of aorta
Measure diameter perpendicular to flow
Measure at set anatomical points
When in cardiac cycle to measure aortic diameter
Discussion to be had
Diastolic measurements are the most reproducible
Inter and itnra variability in measurement of diameter on CT
Inter assessor variability ~ 5mm
Intra assessor variability ~3mm
Generally changes <5mm unlikely to be significant
Ultrasound measurement of aortic diameter
Tend to under report size by 1-3mm
Measured in AP direction
Use of PET CT
18F-fluorodeoxyglucose (FDG), which is taken up with high affinity by hypermetabolic cells (e.g. inflammatory
cells), and can be used to detect vascular inflammation in large vessels.
The advantages of PET may be combined with CT imaging with good resolution.
inflammatory vascular disease (e.g. Takayasu arteritis,GCA), to detect endovascular graft infection,
and to track inflammatory activity over a given period of
treatment
Disadvantages of MRA
Cannot evaluate calcification which is important for evaluating landing zones of a graft
Availability
Difficulty in patient monitoring during scan
Time taken to perform scan
Gadolinium causes nephrogenic systemic fibrosis
Measuring aortic stiffness
Carotid -femoral pulse wave velocity
Fast velocity = stiffer aorta
> 10m/s = stiff aorta
Predictor of CV events and poor otucome
Effect of smoking on aneurysm expansion
Quicker aneurysm expansion
Smoking status associated with expansion rate of 0.4mm / YEAR
TEVAR landing zone
Diameter <40mm
Length >20mm
CT angiogram pre TEVAR
<3mm slices
From supra-aortic vessels down to femoral arteries
Asses landing zones
Asses relationship to side branches
Evaluate femoral access