Thoracic aortic aneurysm

My DDU point form notes on thoracic aortic aneurysm…

The rest of my DDU notes are here.

definition

permanent dilation ≥ 1.5 x expected diameter

no universally accepted definition

aetiology

cystic medial necrosis

commonly ascending

in young, associated with

connective tissue disease

Marfan, Ehlers-Danlos

bicuspid AV

familial

in older

hypertension

atherosclerosis

commonly descending

rarities

syphilis, infective

?where does aortaannular ectasia fit

morphology

fusiform

full circumference involved

saccular

part of circumference

epidemiology

commonest ascending, then descending, then arch or thoracoabdominal
1 year survival with thoracic aortic aneurysm is < 60%
usually asymptomatic
commonly disease elsewhere

eg. AAA

role of echo

TTE

AV and prox ascending aorta

PLAX, RPLAX long axis good for aortic root diameter, especially RPLAX

PSAX, ± A5C, A3C

aortic arch

suprasternal

more difficult with emphysema or short wide neck

descending aorta

PLAX, A4C, A2C + tilt, SC

TOE assessment

good views of aorta to coeliac trunk except blind spot

distal ascending + part of arch

excellent sensitivity and accuracy for aneurysms
often reverberations from posterior wall of aorta / RPA
difficult to document distances, use depth from incisors
upper oesophageal LAX and SAX

Aorta structure and TOE imaging tips

Ascending aorta assessment

TOE assessment of ascending aorta

LAX view of aortic valve and measurement tips

Descending aorta assessment

distances

measure on 2D
vary with BSA and age

cf BMI poor correlation

correlation with BSA gets worse as you get older

BSA strongly correlates with annular and sinus dimensions

age strongly correlates with STJ and ascending aorta dimensions

Roman et al

Roman MJ, Devereux RB, Kramer-Fox R, O’Loughlin J. Two-dimensional echocardiographic aortic root dimensions in normal children and adults. Am J Cardiol 1989;64:507–12
emphasised not using 2D values with M-mode nomograms because 2D measurements were greater and will falsely diagnose aortic dilatation in 19% of adults
used leading edge technique (like M-mode) even though 2D – however some do inner to inner now despite using her normative data because of the advent of harmonics – more accurate imaging
98% specificity for aortic dilatation with ascending aorta ULN of 2.1 cm/m²

pitfalls

obtaining oblique sections in tortuous aorta

Cover image: “CTRupturedTA” by James Heilman, MD – Own work.