Aortic dissection and aneurysm Flashcards
What is an aneurysm?
This is a permanent, localised dilatation of an artery of more than 50% of the local arterial diameter (>3cm)
What are the 2 types of aneurysm?
True aneurysm
False aneurysm
What is meant by a true aneurysm?
A dilatation of an artery in which all 3 layers of the blood vessel wall are involved
What is meant by a false aneurysm?
A dilatation of an artery in which there is a defect in the wall, meaning that only 1 layer is involved
What usually forms in the extra luminal space of an aneurysm?
A platelet rich clot, caused by collagen exposure
What is the suspected pathogenesis of abdominal aortic aneurysms?
It is thought to be caused by abnormal regulation of elastin and collagen proteins in the aortic wall by enzymatic agents
What are some risk factors of abdominal aortic aneurysm?
Age (Risk increases with age)
Sex (M:F = 6:1)
Genetics
Smoking
Hypertension
Atherosclerosis
Which region of the aorta is most susceptible to aneurysm and why?
The abdominal aorta below the T2 vertebrae, as this section loses its vasa vasorum in its tunica adventitia, and so is more susceptible to ischaemia
What percentage of AAAs are asymptomatic until rupture?
75%
What are some possible symptoms of abdominal aortic aneurysm?
Epigastric pain, radiating to the back
Hiccups due to obstruction of phrenic nerve
Dysphagia due to obstruction of oesophagus
What are some clinical signs of abdominal aortic aneurysm?
Trash feet - Throwing off clots
Tachycardia
Hypotension
Collapse
What are the 2 forms of investigation in abdominal aortic aneurysm?
Echocardiography (USS)
CT scan
What are some pharmacological managements used in aortic aneurysm, to reduce underlying causes?
Anti-hypertensives
Smoking cessation
Lipid lowering medication
When is surgical intervention indicated in AAA?
When an asymptomatic aneurysm reaches an AP (Anterior-Posterior) diameter of >5.5cm
If the AAA is symptomatic
What is meant by trash feet?
This is the dusky discolouration of the toes, caused by micro emboli moving down into the feet due to breaking apart of the clots in an aneurysm
What are the 2 forms of surgery indicated for AAA?
EVAR
Open repair
What is meant by EVAR in AAA?
Endovascular Aneurysm repair, in which a stent is inserted via percutaneous catheterisation, allowing a tube to be placed through the aneurysm, preventing the risk of rupture
This is X-ray guided
What are some possible complications of EVAR?
Stent misplacement
Endoleak
Stent migration and dislocation
What are some advantages of EVAR over open repair?
Lower mortality risk (2% vs 4%)
Faster recovery (10 days vs 8 months)
What are some advantages of open repair over EVAR?
Open repair is possible in most people, whereas 25% of people are not indicated for EVAR
What occurs in open repair of AAA?
Laparotomy is given and the aorta and iliac arteries are clamped
Dacron grafting is then performed in which a new aortic wall is stitched in place of the old wall
What are some possible complications of open repair in AAA?
MI
CVA
Pneumonia
DVT
PE
Ischaemia
Death
What are some tests required to check fitness for intervention in AAA?
Echocardiogram for EF
PFTs
Cardiopulmonary exercise test
Renal assessment
ABPI
Anaesthetic assessment
Who is placed into surveillance for AAA?
Asymptomatic patients with an aneurysm between 3 and 5.5cm in diameter
Who is screened for AAA?
All makes >65 by ultrasound scan
What are the 3 conditions that make up the acute aortic syndrome?
Penetrating Aortic Ulcer (PAU)
Intra-Mural Haematoma (IMH)
Aortic dissection
What is a penetrating aortic ulcer?
This is the formation of a small in-pouching of the tunica intima, into the wall of the aorta
What is meant by an intra-mural haematoma?
This is the rupture of a penetrating aortic ulcer, leading to bleeding into the vessel wall
What is an aortic dissection?
This is the flowing of blood between the tunica media and intima, forming a new blood track and splitting the walls of the aorta
What are some risk factors for aortic dissection?
Genetic mutations
Connective tissue disorders
Trauma
What are some genetic mutations that predispose to aortic dissection?
Fibrillin-1
Transforming growth factor ß1
What are some connective tissue disorders that can predispose to aortic dissection?
Ehlers Danlos syndrome
Marfans syndrome
Loeys dietz syndrome
Describe the pathophysiology of an aortic dissection
A tear in the tunica intima can allow blood the propagate within the medial layer, breathing a flap between true lumen and false lumen
Describe the pathophysiology of an aortic dissection
A tear in the tunica intima can allow blood the propagate within the medial layer, breathing a flap between true lumen and false lumen
Where can a tear in the tunica intima propagate to?
Aortic arch
Aortic valve
Coronary arteries
Mesenteric and renal arteries
Iliac arteries
How are aortic dissections classified?
Standford type A
Stanford type B
What is meant by a Stanford type A aortic dissection?
Proximal - Affects the aorta near the subclavian artery, involving the ascending aorta and arch
What is meant by a Stanford type B aortic dissection?
Distal - Affects anywhere from the left subclavian and down, involving the descending thoracic aorta distal to the left subclavian
What are some possible complications of aortic dissection propagation?
Aortic regurgitation
MI
Cardiac tamponade
Stroke
Ischameia
Paraplegia (Spinal cord ischaemia)
What are some symptoms of aortic dissection?
Acute excruciating pain, radiating to the back, described as tearing
Abdominal pain
Syncope
Hypotension
Ischaemia
Paraplegia
How is a diagnosis of aortic dissection made?
CT angiogram from aortic arch to femoral arteries
What are some pharmacological management strategies in aortic dissection?
IV ß-Blockers
Ca2+ channel blockers
ACEi
Sodium nitroprisside
What is the target blood pressure and heart rate in aortic dissection pharmacological management?
100-120mmHg systolic
<60bpm
What are the 2 surgical options in treatment of aortic dissection?
Thoracic Endovascular repair (TEVR)
Open repair
