Abdominal Aortic Aneurysm Flashcards
List the common causes for severe abdominal pain of sudden onset accompanied by the clinical signs mentioned above (fast pulse, low BP, cold/clammy hands, pale, CRT > 5s)
- Perforated viscus (i.e. perforated gastric/duodenal ulcer)
- Acute pancreatitis
- Biliary colic/acute cholangitis
- Acute mesenteric occlusion
- Ruptured/leaking abdominal aortic aneurysm
- Basal pneumonia (rare)
- Inferior MI (rare)
What are the branches of the celiac trunk?
- L gastric artery
- Splenic artery
- Common hepatic artery
Discuss the relevance of AAA clamping on patient outcome
Supra-coeliac clamping: highest stress on the heart, iscahemia to all organs below the coeliac artery with subsequent reperfusion injury.
Supra-renal clamp: high stress on the heart, ischaemia to all organs below the superior mesenteric artery with subsequent reperfusion injury.
Infra-renal clamp: relatively less stress on the heart, ischaemia to all organs below the kidneys with subsequent reperfusion injury.
What are the signs of ruptured AAA? Dissection/PVD?
Shock + bilateral limb schema
Shock + unilateral limb ischemia
What should you suspect in a male > 60y with first presentation of renal colic?
Aortic aneurysm rupture
What should you suspect in a patient with GI bleed + PMH of aortic surgery?
Aorto-enteric fistula (until proven otherwise)
What is the transfusion management of major hemorrhage?
- Reverse anticoagulation (vitamin K, prothrombin complex concentrate)
- Tranexamic acid (antifibrinolytic agent) within 1st hour
- Bloods (FBC, U&E, Ca2+, LFTs, PT, APTT, Fibrinogen, crossmatch)
- Request (Red cells, FFP, platelets)
- Request O RhD negative = extreme emergency only!
- Within 15min from sample arriving in the lab = can receive group specific (ABO + RhD compatible)
- Safest product if time allows (45-60min after arriving in lab) = Crossmatched (fully screened for antibodies)
Pack 1: 4U red cells, 4U fresh frozen plasma
Pack 2: 4U red cells, 4U FFP, 1 dose platelets, 2 packs cryoprecipitate
** Red cells don’t control coagulopathy!!
Try to keep blood results at the following ranges: Fibrinogen > 1.5g/L PT/APTT < 1.5 Hb 80-100g/L Platelets > 75 x 10^9L
How do cardiac output and blood pressure change in a patient who is losing blood?
As shown in the figure, the body is able to maintain pressure (at the expense of cardiac output and tissue blood flow) until a large volume of blood has been lost. In other words, it is only when the compensatory mechanisms are unable to cope that the blood pressure begins to fall. Therefore, any person (particularly young subjects with good physiological reflexes) who have a low blood pressure in the context of acute blood loss, is extremely ill and needs urgent medical attention.
What causes the formation of an atherosclerotic plaque?
- Smooth muscle proliferation/migration
- Inflammation
- Lipid deposit
What is the cause of chronic ischemia? Acute ischemia?
Chronic ischemia = decreased diameter of lumen due to atherosclerosis
Acute ischemia = rupture of atherosclerotic plaque
What are risk factors for PVD?
- Increased age
- Male
- Family history
- Smoking
- HTN
- Cholesterol
- Diabetes
What are the 6Ps of limb ischemia?
- Pale
- Perishingly cold
- Pulseless
(onset within 4h of acute ischemia) - Paraesthesia
- Pain
(within 6h) - Paralyzed (irreversible)
How is chronic ischemia classified?
Fontaine Classification system
I = asymptomatic II = claudication III = rest pain IV = tissue loss (i.e. ulcers, gangrene)
What is the treatment of limb ischemia?
- Stop smoking
- Antiplatelet therapy (aspirin)
- BP control
- Cholesterol control
- Exercise
- Lose weight
- Strict diabetic control
What is the cause of cerebrovascular disease?
Atheroma
- Affects the carotids
- Leads to stroke, TIA, Amaurosis fugax (transient blindness in ipsilateral eye)
What investigations are done in CVD?
- Duplex
- Angiography
- MR/CT
What are the indications for carotid surgery?
- Symptomatic patients (in last 6mo)
- > 70% stenosis of ICA
- 2yr life expectancy
- Fit for surgery (2.6% risk of stroke, 2% risk of death, 1% risk of nerve palsy - CN 9/10)
What are abdominal aneurysms? How are they treated?
> 50% of normal transverse diameter.
Ectasia = dilation of up to 50%
Either saccular or fusiform in shape
Above umbilicus = AAA
Below umbilicus = iliac aneurysm
Small AAA < 4.5cm
Large AAA > 5.5cm -> requires surgery!
EVAR: endovascular aneurysm repair
- 70% pts suitable on anatomical basis: proximal infrarenal aortic neck, iliac arteries
- Lifelong CT/duplex follow-up
- 8% chance of 2nd procedure needed -> endoleak: sac repressurization
What signs would lead you to believe there was a suspected rupture
- collapse
- hypotension
- low back/flank pain
What is an aortic dissection?
- Separation of layers in wall of aorta
- Layers of artery (adventitia, media-muscle layer, intima)
- Tear in intima, blood enters between intimacy + media = increased tearing OR exit tear allowing blood to re-enter aorta (false lumen formed) -> hypotension, shock
What are the causes of aortic dissection?
- Chronic HTN
- Connective tissue disorder (Marfan’s, Ehler-Danlos)
- Aneurysm
- Chest trauma
- Males
- Increased age (50-65y)
How are aortic dissections classified?
Stanford System
Type A: ascending aorta (surgical treatment)
Type B: Descending aorta after L subclavian artery (medical treatment)
- Most common site = 2cm above aortic root (type A)
What are the symptoms of aortic dissection?
- Severe central chest pain “tearing” to the back
- Sweating, Nausea, SOB, Syncope, Weakness
- Abdo pain (if abdominal aortic dissection)
How is an aortic dissection diagnosed?
- CT scan with contrast (GOLD STANDARD!)
- MR angiogram
- Transesophageal echocardiogram (TEE) - shows thoracic aorta + aortic valve only
What is shock?
An acute clinical syndrome initiated by ineffective perfusion and cellular hypoxia, resulting in severe dysfunction of organs vital to survival
What are the key features of shock?
- Acute tissue/organ hypo-perfusion
- Impaired delivery of oxygen to cells
- Supply inadequate to meet demand
- Generalised cellular hypoxia
- Consequences for cellular respiration
- Hemodynamic abnormalities but shock isn’t simply the presence of hypotension
- Oxygen utilization may be abnormal