1. Vascular (Aortic pathology)

Question 1

Acute aortic syndrome - types (3)

Answer 1

Aortic dissection,
Intramural haematoma,
Penetrating Ulcer

Question 2

Aortic dissection - trivia (2)

Answer 2

Commonest cause of acute aortic syndrome (70%),
Most commonly caused by hypertension (70%)

Question 3

Aortic dissection - types (4)

Answer 3

Acute (<2 weeks) or chronic.
Location:
Stanford A (75%) - involve ascending aorta and arch proximal to left subclavian. Needs surgical Rx.
Stanford B - Distal to left subclavian. Treated medically unless complications (e.g. organ ischaemia)

Question 4

Aortic dissection - causes (6)

Answer 4

Hypertension is most common.
Marfans,
Turners (aortic valve defects),
Infection,
Pregnancy,
Cocaine use.

Question 5

Aortic dissection - imaging (4)

Answer 5

Non-contrast: Displacement of intimal calcifications.
Contrast:
- Intimal flap seen in 70%
- 2 lumens will spiral around each other.
- Thrombus will be seen in false lumen

Question 6

Aortic dissection - true vs false lumen (9)

Answer 6

True lumen:
- has continuity with undissected portion of aorta,
- has smaller cross section with higher velocity of blood,
- surrounded by calcifications if present,
- Usually contains origins of Coeliac trunk, SMA and right renal artery
False lumen
- Cobweb sign, slender linear areas of low attenuation
- Larger cross section, slower blood flow,
- Beak sign
- Usually contains left renl artery origin
- Surrounds true lumen in type A

Question 7

Intimo-intimal dissection - features (2)

Answer 7

Rare type of dissection, circumferencial dissection of intimal layer, which then invaginates.
Intimal tear usually starts near coronary orifices.

Question 8

Floating viscera sign (3)

Answer 8

Abdominal aortic dissection.
Opacification of abdominal aortic branch vessels during angiography (catheter in true lumen), with branch vessels (SMA, coeliac axis, renal arteries) arising out of nowhere.
Appear to be floating, with no or little antegrade opacification of the true lumen.

Question 9

Aneurysm with thrombus vs dissection with thrombus in false lumen (3)

Answer 9

Dissection is spiral shape, thrombus tends to be circumferencial.
Dissection has smooth border, Mural thrombus has irregular border.
Dissection will have displaced calcification

Question 10

Intramural haematoma - features (3)

Answer 10

Seen on old hypertensives, like dissection.
Spontaneous haemorrage caused by rupture of vaso vasorum in the media, without intimal tear.
Can proceed to classic dissection.

Question 11

Intramural haematoma - trivia (4)

Answer 11

Still classified as type A or B.
Increased mortality if:
- Ascending aorta >5cm (strongest predictor of dissection)
- IMH >2cm,
- Pericardial effusion.

Question 12

Intramural haematoma - imaging (3)

Answer 12

Unenhanced CT shows crescent of high attenuation.
Intimal calcifications may be displaced.
MRI: T2 bright blood acutely, T1 and T2 bright blood in subacute phase

Question 13

Penetrating ulcer - features (4)

Answer 13

Ulceration of atheromatous plaque that has eroded the inner elastic layer of aortic wall.
Produced a haematoma when it reaches the media.
Occurs in older people with underlying severe atherosclerosis.
Can lead to saccular aneurysm.

Question 14

Penetrating ulcer - trivia (3)

Answer 14

Still A and B classification w/corresponding surgical or medical Rx.
Mortality predictors:
- Ascending aorta >5cm (strongest predictor of dissection),
- IMH >2cm,
- Pericardial effusion.

Question 15

Aneurysm vs pseudo-aneyrusm (5)

Answer 15

True aneurysm = enlargement of lumen to 1.5x normal.
True = all 3 layers INTACT, false is essentially a contained rupture (carries higher risk of true aneurysm).
Generally: Fusiform aneurysms are true, saccular might be false.
Doppler: Yin-yang sign (to and fro on pulsed doppler in pseudo-aneurysm, can also occur with true, saccular aneurysms).
To and fro within aneurysm neck, plus clinical Hx is bestt way to tell apart.

Question 16

Causes of pseudo-aneurysm. (5)

Answer 16

Trauma,
Iatrogenic (groin access),
Infection (mycotic),
pancreatitis,
some vasculitides.

Question 17

SVC syndrome - aetiology (3)

Answer 17

Secondary to complete or near complete obstruction in SVC, caused by:
- external compression (lymphoma, lung Ca) or
- intravascular obstruction (Central venous catheter, pacemaker wire with thrombus)
- fibrosing mediastinitis (think histoplasmosis).

Question 18

SVC syndrome - clinical (3)

Answer 18

Face, neck, bilateral arm swelling.

Question 19

Traumatic psuedoaneurysm - trivia (3)

Answer 19

Most commonly in aortic isthmus (90%). Result of tethering from ligamentum arteriosum.
2nd & 3rd commonest are ascending aorta and diaphragmatic hiatus.

Question 20

Traumatic pseudoaneurysm - imaging (4)

Answer 20

CXR:
- wide mediastinum,
- deviated NG tube to right,
- depressed left main bronchs
- left apical cap

Question 21

Ascending aortic calcifications - causes/significance (3)

Answer 21

Takayasu and syphillis.
Atherosclerosis tends to spare ascending aorta.
Significance: clamping the ascending aorta may be difficult during CABG.

Question 22

Aortic aneurysm - definition (3)

Answer 22

1.5x normal lumen diameter
- >4cm asceding and transverse,
- >3.5cm descending aorta
- >3cm abdominal aorta

Question 23

Aortic aneurysm - cause (3)

Answer 23

Medial degeneration is commonest cause in ascending aorta.
Connective tissue diseases (Marfans, Ehlers Danlos) tends to affect aortic root. (Cystic medial necrosis = Marfans).
Can develop in any segment of aorta, commonest in infrarenal aorta.

Question 24

Aortic aneurysm Rx (3)

Answer 24

Surgical repair if:
>6cm in chest (>5.5cm if connective tissue disease)
>5cm in abdomen

Question 25

Sinus of valsalva aneurysm - trivia (6)

Answer 25

Rare, more common in Asian men
Typically involve right sinus.
Congenital or acquired (infection).
Associated with VSD.
Can lead to cardiac tamponade.
Repair surgically with Bentall procedure.

Question 26

Aortic endoleak - types (5)

Answer 26

Type 1:
- leak at top (1A) or bottom (1B) of the graft.
- High pressure, will keep growing without intervention.
Type 2:
- Most common type. Usually seen after AAA repair.
- Filling of sac via feeding artery, IMA or a lumbar artery.
- Treat if sac is growing, most spontaneously resolve.
Type 3:
- Defect/fracture in the graft, usually because the pieces don’t overlap.
Type 4:
- Porosity of the graft (4 = pore), doesn’t happen with modern grafts.
Type 5:
- Endotension. Not true leak, may be due to pulsation of graft wall.

Question 27

Impending rupture - warning signs (6)

Answer 27

Peri-aortic stranding.
Rapid enlargement (10mm/year).
Pain.
Draped aorta sign (posterior aota draped over vertebral column.
Focal discontinuity in circumferencial wall calcifications.
Hyperdense crescent sign
Enlargement of patent lumen suggests lysis of thrombus, can predispose to rupture.

Question 28

AAA rupture - commonest sign

Answer 28

Retroperitoeal haematoma adjacent to AAA.

Question 29

Protective signs against AAA rupture

Answer 29

Thick, circumferencial mural thrombus.

Question 30

Mycotic aneurysm - Cause

Answer 30

Most often occur due to haematogenous seeding from septicaemia (endocarditis), but can occur due to direct seeding from psoas abscess or vertebral osteomyelitis.

Question 31

Mycotic aneurysm - features (7)

Answer 31

Most often saccular and most often pseudoaneurysms.
Prone to rupture.
Findings:
- Saccular shape
- Peri-aortic inflammation
- Abscess
- Peri-aortic gas
Expand faster than atherosclerotic aneurysms

Question 32

Saccular aneurysm of aorta, think…

Answer 32

Infection (mycotic aneurysm).

Question 33

NF1 - vascular findings (3)

Answer 33

Aneurysms and stenosis seen in aorta and larger arteries.
Dysplastic features in smaller vessels.
Renal artery stenosis –> renovascular HTN (5%). Classically renal artery stenosis with HTN in child/teen. Due to dysplasia of arterial wall itself.

Question 34

Marfan syndrome - cause

Answer 34

mutation of fibrillin gene.

Question 35

Marfan syndrome - vascular findings (3)

Answer 35

Aneurysms,
Dissection,
- Recurrent dissections common.
- Triple barrel dissections can be seen (false lumen either side of true)
Pulmonary artery enlargement
- Favours the root, just like aortic aneurysm/dilatation

Question 36

Marfan syndrome - aneurysms (4)

Answer 36

Classically “Annuloaortic ectasia”, with root dilatation.
Beginns with aortic sinuses, progresses to sinotubular junction, ultimately involved annulus.
Root dilatation leads to aortic valve insufficiency (aortic regurg), which can progress to dissection or rupture.
Buzzword “Tulip Bulb” ascending aorta aneurysm.

Question 37

Loeys Dietz syndrome - features (4)

Answer 37

Ban form of Marfan syndrome.
Poor prognosis, commonly rupture aorta.
Very tortuous vessels.
Very wide eyes (hypertelorism)

Question 38

Ehlers Danlos - features (4)

Answer 38

Stretchy skin, hypermobile joints, fragile blood vessels.
Invasive angiography should be avoided due to risk of arterial dissection.
Imaging of aneurysms resembles marfans.
Abdominal visceral artery aneurysms are also common.

Question 39

Syphilitis (leutic) aneurysm - (5)

Answer 39

Rare, seen in untreated, tertiary syphillis.
Saccular, involved ascending aorta and arch.
“Saccular, asymmetric aortic aneurysm with involvement of aortic root branches”
Often heavily calcified “tree bark” intimal calcifications.
Coronary artery narrowing (at ostium) and aortic regurg are common.

Question 40

Aorto-enteric fistula - cause (2)

Answer 40

Primary
- Rare, without history of instrumentation.
- Seen in aneurysm and atherosclerosis.
Secondary
- Seen after surgery, with or without stent graft placement.

Question 41

Aorto-enteric fistula - trivia (6)

Answer 41

Usually 3rd and 4th part of duodenum involved.
Fistula vs perigraft infection: Fistula will show aortic contrast in affected bowel.
- Both will:
- have ectopic perigraft gas >4 weeks post op,
- perigraft fluid and oedema,
- lose fat plane between bowel and
- aorta, form pseudoaneurysm

Question 42

Inflammatory aneurysms - trivia (5)

Answer 42

Common in young men.
Most are symptomatic.
Increased risk of rupture, regardless of size.
Associated with elevated ESR.
Associated with smoking. Cessation is first step in Rx.

Question 43

Inflammatory aneurysms - features & imaging (4)

Answer 43

Inflammatory process usually involved ureters, 1/3 present with hydronephrosis or renal failure.
Imaging:
- Thickened wall
- Inflammatory or fibrotic changes in peri-aortic regions.
- Asymmetric thickening of aortic wall, sparing posterior wall (differentiates it from vasculitis)

Question 44

Leriche syndrome - triad (3)

Answer 44

Buttock claudication,
Absent/decreased femoral pulses
Impotence.

Question 45

Leriche syndrome (3)

Answer 45

Complete occlusion of the aorta, distal to renal arteries (most often at bifurcation).
Often secondary to atherosclerosis.
Usually features large collaterals.

Question 46

Mid aortic syndrome - features (4)

Answer 46

Progressive narrowing of the abdominal aorta and major branches.
Higher and longer in segment than Leriche.
Tends to affect children or young adults.
Possibly due to intra-uterine insult with fragmentation of the elastic media.

Question 47

Mid aortic syndrome - triad (3)

Answer 47

HTN (most common presenting symptom),
Claudication,
Renal failure

Question 48

Aortic coarctation - types (2)

Answer 48

Infantile (preductile)
- Can get pulmonary oedema.
- Typically long segment.
- Blood supply to descending aorta is via PDA.
Adult (ductile)
- Asymptomatic until later in childhood.
- Differential arm/leg BP,
- Typically short segment

Question 49

Aortic coarctation - trivia (5)

Answer 49

Strong association with Turners syndrome (15-20%).
Bicuspid aortic valve is commonest associated defect (80%).
More likely to have erry aneurysms.
Figure 3 sign on CXR.
Rib notching (most often 4-8th rib, spares 1st-2nd ribs)

Question 50

Pseudocoarctation - features (5)

Answer 50

Elongation with narrowing and kinking of the aorta.
Looks like coarctation, but without:
- Pressure gradient,
- Collateral formation,
- Rib notching
Area of aneurysmal dilatation may occur distal to narrowing. These may become progressively dilated, should be followed.