Abdominal aneurysms and Aortic tears Flashcards
Define aneurysm
- Permanent localised dilatation
- Affecting all layers of an artery
- >50% of its normal diameter
- <50% diameter = Ectasia
Differentiate true and false aneurysms
- True aneurysm
- Pathological degeneration of all/part of the vessel wall.
- False aneurysm
- Leakage of blood out of an artery, into a cavity surrounded by connective tissue, which is expansile and pulsatile.
Name the common sites of true aneurysms
Abdominal aorta Iliac artery Popliteal artery Femoral artery
Name 4 causes of aneurysms
Atherosclerosis Vasculitis Syphilis Infection (mycotic aneurysm) Trauma Congenital (berry aneurysm) Cocaine use
List three risk factors for aneurysms
- Atherosclerosis
- Male (4:1)
- Increasing age
- Caucasian
- Smoking
- FHx of familial aneurysm
- Aortic dissection
- Connective tissue disease: Marfan, Ehlers-Danlos
Why is it important to differentiate between aortic aneurysm and aortic dissection?
Aneurysm is managed surgically
Dissection is initially managed medically
What is the commonest site of an arterial aneurysm?
Infra-renal abdominal aortic aneurysm. Occurs in 5% of elderly males.
What factors increase the risk of AAA rupture?
Larger AAA Women Smoking HTN Strong FHx
Describe the presentation of AAAs
- Majority are asymptomatic
- Occasionally distal embolisation ➔ limb ischaemia
- Inflammatory aneurysm
- Abdominal pain
- General malaise
- Weight loss
- Rupture
- Abdominal/back pain
- Pulsatile mass
- Hypotension (less 1/3rd have this triad)
What laboratory investigations should be done for non-urgent AAA?
- Abdominal USS
- CT angiogram
- Pre-op
- FBC
- Clotting
- U+E
- LFT
- G+S
- ESR and/or CRP if inflammatory aneurysm suspected
What are the indications for AAA repair?
- Asymptomatic aneurysm >5.5cm
- Balance risk of surgery vs risk of rupture
- Ruptured, rapid expansion (>1cm/yr)
- Sinister presentation e.g. abdominal pain
Outline the medical management of AAA
- Regular USS monitoring
- Treat underlying cause
- Risk factor modification
- Diet and exercise
- Smoking cessation
- BP control
- Statins
- Antiplatet therapy: primary prevention
What types of surgical management are available for AAA repair?
- Surgical (open) repair
- Endovascular repair (stent graft)
Name 3 complications of surgical (open) of AAA
- Rupture
- Haemorrhage
- Aortovenous fistula
- GI bleed due to aortoenteric fistula
- Embolisation of distal vessels ➔ limb ischaemia
- Colonic ischaemia: due to ligation of IMA
- Infected aneurysm
- Death (5-10%)
Name two advantages and disadvantages of AAA endovascular repair
Advantages
- Avoids open abdominal surgery
- Avoids aortic cross clamping
- Reduced morality in first 4 years of follow-up
Disadvantages
- Requires follow-up USS/CT
- Endograft failure
- No long-term survival benefit compared with open repair
- Significantly higher risks of reintervention and rupture
What is the association between aortic aneurysms and cardiovascular events?
People with aortic aneurysms are at increased risk of cardiovascular events, mostly unrelated to the aneurysm.
Outline AAA screening
USS abdomen in men aged 65-74
Outcome:
- Normal (<3cm) ➔ No further USS
- Small (3-4.4cm) ➔ Annual USS
- Medium (4.5-5.4cm) ➔ 3-monthly USS
- Large (>5.5cm) ➔ indication for surgery
- High-risk of rupture
- Other indications: >1cm yearly expansion; symptomatic
What are the sinister signs and symptoms of AAA?
- Abdominal pain and vomiting
- Abdominal and back pain with collapse
- Renal colic in males >55yr
Name two differential diagnoses for ruptured AAA
- MI with cardiogenic shock
- Massive PE
- Acute pancreatitis
Describe the initial management of a ruptured AAA
- A-E assessment
- Oxygen 15L/min
- IV access IV fluids
- Maintain systolic BP <100mmHg
- Catheterise
- Contact vascular surgeon ASAP
- If haemodynamically unstable ➔ immediate transfer to vascular
- If haemodynamically stable ➔ CT angiogram
- To determine if suitable for EVAR
What are endoleaks?
A complication characterised by persistent blood flow within the aneurysm sac after endovascular aneurysm repair (EVAR - Teflon material)
Why is heparin given after AAA repair?
To reduce the risk of embolisation to distal arteries
Define aortic dissection
Disruption of the intima of the aorta provoked by intramural bleeding ➔ separation of the aortic wall laters and formation of a true and false lumen
Which age group is most commonly affected by aortic dissection?
50-70
Name 3 risk factors for aortic dissection
HTN Smoking Direct blunt chest trauma Hypercholesterolaemia Pre-existing aortic disease Pre-existing aortic valve disease FHx of aortic disease Hx of cardiac surgery Connective tissue disease Familial thoracic aortic aneurysm
Outline the Stanford classification of aortic dissection?
Type A (60%): involves the ascending aorta and arch Type B (40%): commences distal to left subclavian artery
What is the importance of the Stanford classification of aortic dissection
It separates aortic dissections into those that need surgical repair (type A) and those that usually only require medical management (type B)
What sign may be elicited with a type A aortic dissection?
Aortic regurgitation (50%): occurs when the dissection involves the aortic valve
Describe the management of Type A dissections
Immediate surgical correction: Aortic graft
Describe the initial management of Type B dissections
HTN management - typically IV B-block
What are the indications for surgical management of Type B dissections?
Persistent pain Aneurysm >5cm End-organ or limb ischaemia Retrograde dissection to ascending aorta
What surgical management is available for Type B dissections?
Thoracic endovascular aortic repair (TEVAR) Open repair
How does a ruptured AAA present?
Rupture: abdominal/back pain, pulsatile mass, hypotension (less 1/3rd have this triad) Cold Sweaty NaV Tachycardia Postural hypotension Syncope
What is the association between popliteal aneurysms and abdominal aortic aneurysms?
50% of patients with popliteal aneurysms also have AAAs
