Vascular

Question 1

Define aortic aneurysm

Answer 1

1. Localized dilatation of an artery > 1.5x normal diameter (3cm and larger for abdo aorta)
2. True aneurysm = involves all vessel wall layers (intimate, media, adventitia)
3. False aneurysm (pseudo aneurysm) = does not involve all layers; breach in intima/media that allows blood to collect between media and adventitia

Question 2

How are aortic aneurysms classified?

Answer 2

1. Shape
   - Fusiform = concentric, involves full circumference of vessel wall
   - Saccular = eccentric, involves only a portion of vessel wall (higher risk of rupture due to unequal distribution of pressure)
2. Location
   - TAA: ascending, transverse arch, descending
   - Thoracoabdominal
   - AAA: 90-98% are infrarenal (suprarenal = starts above renal arteries + doesn’t involve thoracic aorta; pararenal = starts at the renal arteries but superior mesenteric artery origin is not aneurysmal; juxtarenal = starts immediately distal to renal arteries; infrarenal = starts distal to renal arteries)

Question 3

Risk factors for AAA

Answer 3

1. Smoking, advanced age, male sex, white race, family history, presence of other large vessel aneurysms, HTN
2. Degenerative
3. Traumatic
4. Mycotic (salmonella, staph, usually suprarenal aneurysms)
5. Connective tissue disorder (Marfan syndrome, Loeys-Dietz syndrome, Ehlers-Danlos type 4 syndrome)
6. Vasculitis
7. Infectious (syphilis, fungal)
8. Ascending thoracic aneurysms are associated with bicuspid aortic valve
9. Aortic dissection
10. Congenital (Turner’s syndrome)

Question 4

Classic symptom triad of ruptured AAA

Answer 4

1. Hypotension/collapse
2. Back/abdo pain
3. Palpable, pulsatile abdo mass (caution in patients with raised BMI)

Question 5

Initial management for ruptured AAA

Answer 5

1. IV access with 2 peripheral large bore IVs

2. Permissive hypotension (systolic BP enough to maintain mental status)

Question 6

Clinical features of AAA

Answer 6

• 75% asymptomatic
• commonly abdo aorta
• common presentation due to acute expansion/rupture

1. Syncope
2. Pain (chest, abdo, flank, back)
3. Hypotension
4. Palpable pulsatile mass above the umbilicus
5. Airway or esophageal obstruction, hoarseness (L recurrent laryngeal nerve paralysis), hemoptysis or hematemesis (indicates thoracic AA)
6. Distal pulses may be intact

Question 7

Investigations for AAA

Answer 7

1. Bloods: FBC, U&Es, urea, creatinine, PTT, INR, blood type, crossmatch
2. Abdo USS: for screening + surveillance
3. CT with contrast: size determination + EVAR planning
4. Peripheral arterial duplex (rule out aneurysm elsewhere)

Question 8

Treatment for AAA

Answer 8

1. Conservative (for asymptomatic aneurysms that don’t meet size threshold for repair) - cardiovascular risk factor reduction
2. Surgical
   - indications = ruptured, symptomatic, AAA size > 5.5cm in men or 5cm in women
   - open surgery with graft replacement or EVAR (endovascular aneurysm repair)

Question 9

Screening for AAA

Answer 9

One time USS for:

1. men 65-80y
2. women age 65-80y with smoking history or cardiovascular disease
3. First degree relatives after age 55

Repeat USS 10yr after initial screening if aortic diameter > 2.5cm and < 3cm