Vascular Surgery Flashcards
Definition of AAA
Abnormal dilaiton of abdominal aortia (1.5>2 x normal) forming a true aneurysm
Name the branches of the descending abdominal aorta?
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- Phrenic [inferior]
- Celiac
- Superior mesenteric
- Suprarenal [middle]
- Renal
- Testicular [“in men” only]
- Lumbars
- Inferior mesenteric
- Sacral
Aetiology of AAA
- atherosclerotic -95%
- inflammatory - 5%
Prevalence
- older males, positive family history, hypertension, tobacco smoking
- 5% of all adults >65
- Male to female ratio is 6:1
Common site
- 85% - Infra-renal artery (below levels of the renal arterys
- 15%- Extends down to involve the origins of the common iliac arterys
- associated with other operipheral aneurysm
Symptoms of AAA
May be
- Asymptomatic (60%) - detected on routine physical examination, plain x-ray or most commonly, abdominal ultrasound scan conducted for another reason
-
Symptomatic (10%)
- pain in the central abdomen, back, loin, illiac fossa
- becomes inflamed and compresses surrounding structures (ureter, inferior vena cava)
- distal embolisation
-
Rupture (30%)
- AAA may rupture in to the retroperitoneum
Signs of AAA
- hypotension
- palpable mass felt at/above umbillicus
- bounding femoral pulses
- distal pulses inact
Investigations of AAA
- Physical exam
- ultrasound (confirm AAA with initially)
- CT scan (accurate visualisation, size, positioning, and involvement of surrounding structures )
- Angiography
Complications of AAA
- free rupture
- collpase
- hypotension
- tachycardia
- retroperitoneal rupture - abck pain, nausea, vomitting, hypotension
- distal embolisation - thrombus from the sac may disperse distally and block the small vessels in the foot and lower leg causing acute ischaemia
- aorto-caval fistula - plethora
- aorto-duodenal fistula - haematemsis, melaena
- aortic occlusion
Screening of AAA
- All men > 65 years are invited to attend screening
- screen using ultrasound scan
Treatment of AAA
- Blood pressure control and stop smoking
- incidental asymptomatic small AAA
- repair is deferred until the theortical risk of rupture exceeds the estimated risk of operative mortality - until AAA reaches 5.5cm
- ultrasound is only accurate to 0.5cm and will therfore underestimate AA.
- Perform CT once 5.0cm is reached
- Symptomatic
- if the patient is having pain concurrent with their abdominal aortic aneurysms they should always be considered for surgery as pain often preceds rupture
- surgical repair - synthetic graft
- endovascular graft
Two types of AAA surgical repair
- Open repair
- Endovascular aneuryms repair (EVAR)
Open repair process, adv and disadvantages
- involves replacing the anuerysmal segment with a prosthetic graft
- the graft is straight forward if the aneuryms is confined to the aorta or bifurcated
- If there are common iliac anuerysms as well the aorta must be clamped off during surgery
Advantages
- increased durability and long term mortality
Disadvantages
- Recovery period is 7-10 days
- return to preoperative functional status is 4-6 months
EVAR process, advantages and disadvantages
A guidewire is passed through the right common femoral artery. A catheter containing the main body of the stent graft is passed over the guidance wire and placed in position inside the aneurysms. Deployment of main body and right limb of stent graft. Deployment of short leg or stent fraft over second wire guide. Requires two incisions
Advantages
- performed under regional or local anaesthesia
- patient is fit to go home with 48 hours
- rapid return to preoperative functional status
- decreased immediate mortality
Disadvantges
- decreased durability
- expensive
- large amount of AAA not suitable
- life-long surveillance
- no long term survival rates beneft over open repair
- high re-intervention rate
Leading cause of postoperative death in a patient undergoing elective AAA treatment>
Myocardial infarction (MI)
Normal abdominal aortic diameter
2cm
Possible operative complications
- MI
- atheroembolism
- declamping hypotension
- acute renal failure (especially if the anerysm involves the renal arteries)
- uretar injury
- haemorrhage
- colonic ischaemia
Emergency management of rutured AAA
resuscitation
- call for senior surgical assistance
- transfer to theatre
- permissive hypotension- dont worry if not normal BP after fluids as may worsen the rupture
- If patient is critically hypotensive, consider calling a peri-arrest cardiac emergency
- IV access via two large bore cannulae, catheterize, cross match blood, order FFP and plateles
- high flow O2 via a non-rebreather mask
- give modest doses of analgesia
- alert anaesthesit, theatres, ITU
- Witnesses verbal consent for surgery may be the only practical way and is accectable here
Prognosis of ruputerd AAA
- risk of rupture relates to maximum AP diameters
- <0.5cm per year, <4.0cm
- once percent per year–>4-4.5cm
- over 3% –> >5.5cm
- less than 50% of patient with a ruptured AAA may reach hospital alive and the overall mortality of the condition may be as high as 75-95%
Label the arteries of the leg
- abdominal aortia
- ilternal iliac (hypogastric)
- external iliac artery
- common femoral artery
- Deep femoral artery
- Superficial femoral artery
- popliteal artery
- Trifercation
- anterior tibial artery
- peroneal artery
- posterior tibial
- dorsalis pedis artery
LAMP
- lateral anterior tibial
- Medial posterior tibial
Acute limb ischaemia features
6 P’s
- Pain
- parasethesia
- pulseless
- pallor
- perishingly cold
- paralysis
Sudden onset of a painful cold lum. Parasthesia indicates severe ischaemia. There is no history or signs of previous vascular insuffiency then an embolus is suspected.
Management of acute ischaemia
- Anticoagulation – IV heparin
- Urgent embolectomy/thrombectomy/bypass
- Thrombolysis
- If above fails or delay in diagnosis leading to dead tissue amputation may be required
Causes/ risk factors of PVD
- smoking
- diabetes
- hypertension
- hyperlipidaemia
- Old age
Stages of chronic limb ischaemia
-
Intermittent claudication:
- Cramp like pain in the legs, thigh or buttock relived by rest after walking for a given distance
- relieved by rest .
- Pain develops distal to the obstruction.
- femoral disease causes calf pain, but blockage of the iliacs causes buttock pain
-
Critical ischaemia
- Rest pain -
- Implies that the ischaemia is critical and the viability of the leg is threatened. The pain is severe and requires opioid analgesia.
- Gangrene and ulceration – in dry gangrene, ischaemia results in death of tissue
- foot pain at rest- eg burning pain at night relieved by hanging legs over side of bed