Cardio: Aneurysms Flashcards
what is an aneurysm?
an abnormal dilatation of an artery
classification of aneurysms
- true aneurysm
- false aneurysm
what is a true aneurysm?
this contains all layers of the vessel wall; appears as either a fusiform or a saccular dilatation
what is a false aneurysm?
these do not contain all layers of the arterial wall; usually involves only a collection of blood in the adventitia
causes of true aneurysm
- congenital: berry aneurysm of circle of Willis, aneursymal varices associated with AV fistula, connective tissue disorders (Marfan’s, Ehlers-Danlos), inflammatory (Takayasu’s aortitis)
- acquired: trauma (irradiation) infection (syphilis, mycotic aneurysm), degeneration (arteriosclerosis, cystic medical necrosis), atheroma
- the bigger the aneurysm, the quicker it will expand
causes of false aneurysm
trauma
common sites of aneurysm
- aorta (more commonly, infrarenal)
- iliac artery
- femoral artery
- popliteal artery
complications of an aneurysm
- rupture
- thrombosis
- distal emboli
- fistula
- pressure on other structures
types of aortic aneurysms
- thoracic
- thoracoabdominal
- abdominal
where can the aorta dilate
from the ascending aorta to the aortic bifurcation
why do aneurysms occur?
degeneration of the elastic lamellae and smooth muscle loss
from when is aorta considered to have an aneurysm?
greater than 3cm across
risk factors for aneurysms
- elastic degeneration due to increased levels of metalloproteinases
- flow dynamics
- hypertension (involved in formation and rate of expansion)
- atherosclerosis
- collagen defects
- genetic association
- smoking (associated with a more rapid expansion)
- associated with emphysema and inguinal hernias
symptoms of aneurysms
- mainly asymptomatic
- backache (pressure on the vertebral bodies)
- sign: pulsatile abdominal mass just above the umbilicus
investigation of aneurysms
- ultrasound (assess the diameter)
- CT scan
- pre-op investigations: FBC, U&E, clotting studies, ECG, CXR, lung function tests, ABGs, echo
where can aneurysm bleed into?
retroperitoneal or intraperitoneal or into the IVC (AV fistula)
management of aortic aneurysm
- depends on the size
- <5cm: monitored annually if <4.5cm or biannually if >4.5cm
- > 5cm: investigated to check whether he is fit for surgery
- only aneurysms >5.5cm (>5cm in women) are considered for surgery or if the patient is symptomatic
treatment options of aortic aneurysm
- EVAR (endovascular repair - stenting)
- open surgery
risk factors for aortic dissection
- hypertension
- smoking
- female
- strong family history
- COPD
- shape of aneurysm (saccular>cylindral)
symptoms of ruptured abdominal aortic aneurysm
- intermittent/continuous abdominal pain
- radiating to the back, iliac fossae or groins
- expansile abdominal mass
- collapse and shock
how do you know that the patient has an adequate blood pressure
conscious and talking
what happens if the aorta dissects and there is an AV fistula with the IVC
- severe heart failure
- massive lower limb oedema
investigations of dissected AAA
- should be clinically obvious
- if not, CT and US
management of dissected AAA
- emergency style
- call the vascular surgeon before doing anything else
- amylase, Hb, crossmatch, ECG
- take the patient straight to theatre
what are inflammatory aneurysms?
one where the walls become thickened and inflamed
which arteries can iliac artery aneurysms involve
- common iliac
- internal iliac
associations of iliac artery aneurysm
- associated with AAA
- rarely occur in isolation
management of iliac artery aneurysm
- open surgery using Dacron
- endovascular stenting
- in internal iliac artery, ligation if the other is still patent
symptoms and signs of femoral artery aneurysm
- asymptomatic pulsatile mass in the groin
- associated with AAA
- compression of local structures, thrombosis, ischaemia, distal emboli and rupture
causes of false aneurysms in the femoral artery
- percutaneous catheterisation for angiography; stab wounds
- previous surgery, especially with prosthetic grafts (infection)
treatment of femoral aneurysms
- small: monitor or treat if symptomatic
- if rapidly expanding, surgery
- iatrogenic false: compression therapy
signs and symptoms of popliteal aneurysm
- mass behind the knee
complications of popliteal aneurysm
- thrombosis with compromise of the distal circulation and distal embolism
- compression of local structure
treatment of popliteal aneurysm
- considered if >2cm
- open surgery is preferred
- exclusion bypass
- in-lay graft
what are the visceral artery?
- splenic artery
- hepatic artery
- superior mesenteric artery
- renal artery
signs and symptoms of visceral artery aneurysms
- abdominal/flank pain
- renal: haematuria/hypertension
how are visceral aneurysms diagnosed?
- ultrasound scanning
- arteriography
why are splenic artery aneurysms important?
- they can present at the 3rd trimester of pregnancy
- if >2.5cm, they should be treated
affects of a thoracic aortic dissection
- carotid artery: hemiplegia
- anterior spinal artery: unequal arm pulses and blood pressure, acute limb ischaemia, paraplegia
- renal arteries: anuria
complications of thoracic aortic dissection
- aortic valve incompetence
- inferior myocardial infarction
- cardiac arrest
types of thoracic aortic dissections?
type A and type B
what are type A dissection?
- ascending aorta
- consider these for surgery
what are type B dissection?
- medical management
- surgery is reserved for distal dissections that are leaking, ruptured or compromising vital organs
management of thorcic aortic dissection
- crossmatch 10U blood
- ECG & CXR
- CT/MRI or TOE
what is a false aneurysm?
- pulsating haematoma, the cavity of which is in contact with the arterial lumen
- made of a fibrous capsule made of adventitia
what happens in IVDU with false aneurysm
- infection might be present (has to be treated)
- if all of the vessels have been damaged, ligate all the vessels
- this is associated with a high rate of limb loss and disabling claudication
how would you do an open surgery?
- umbilical/paraumbilical/transverse incision
- push the omentum and bowel out of way
- put a banding around the neck of the aneurysm
- clamp any arteries found in the surroundings
- open the sac to remove the thrombus
- put a piece of graft in according to the patient’s aorta and then, suture the sac around it
how would you do an EVAR?
- small transverse cut in the groin
- pass the wire through the artery into the heart
- mount the graft onto the tube
- the graft is fixed in placed via barbs on top
- once the position is good, the spring opens and seals the graft onto the vessel
- this is monitored using CT/angiography
- the aneurysmal sac should thrombose and shrink with time
