Flashcards in AAA Deck (30):
What are the Hx features of AAA?
-Patients invariably smoker (ex or current)
-FHx atherosclerotic disease
-Previous Hx IHD, PVD, CVA, CT disorders.
Symptoms: pain begins in centre of abdomen, radiates to back +/- groin along course of genitofemoral nerve.
Examination features of AAA on inspection?
Abdomen often distended; if pt thin ==> large central pulsating mass in epigastrium or umbilical region.
Long standing rupture: Cullen's or Grey Turner's sign.
What is Cullen's sign?
bruising around the umbilicus indicative of long standing rupture.
What is Grey Turner's sign?
Bruising in the flank indicative of long standing rupture.
Examination features of AAA on palpation?
Expansile pulsatile mass; usually tender.
Consists of aneurysm and surrounding haematoma. Define upper and lower limits of aneurysm.
What is the first test to order in suspected AAA?
Ultrasound: aortic dilation >1.5 x that expected.
What is an AAA?
Permanent pathological dilation of the aorta with a diameter >1.5 times the expected AP diameter of that segment (based on gender and size of pt).
In whom are AAAs most common?
Men 4-6x more likely than women.
Risk increases with age.
What is the aetiology of AAAs?
Historically thought to be atherosclerosis alone --> does usually accompany AAA.
Altered tissue metalloproteinases may diminish integrity of arterial wall.
What is the pathophysiology of AAA formation?
-Obliteration of collagen and elastin in media and adventitia,
-smooth muscle cell loss with resulting tapering of the medial wall,
-infiltration of lymphocytes and macrophages, inflammation with matrix proteins and metal-proteinases
How can AAAs be classified?
-Congenital: medial degeneration occurs with age but is accelerated in pts with bicuspid aortic valves and Marfan's syndrome.
-Infectious: infection of aortic wall rare aetiology (Staph, Salmonella).
-Inflammatory: controversial. Accumulation of M0 and cytokines.
How should AAAs be screened for?
Recommended U/S for males >65 years. Rescreen if >3.5cm.
What tests (other than U/S) could be considered in AAA workup?
FBE: leukocytosis, anemia.
Once confirmed on U/S: CT/MRI for anatomical mapping.
What are the standard resuscitation measures for AAA rupture?
+: urgent surgical repair
+: perioperative antibiotic therapy
ABC and straight to theatre; crossmatch 10u PRBCs.
-Airway: O2 and endotracheal intubation
-Insertion of arterial catheter and urinary catheter
-Target systolic BP of 50-70mmHg
-Withold fluids preoperatively (dilutional coagulopathy, clot displacement etc)
What is the surgical method of AAA repair?
EVAR (endovascualr AAA repair). or traditional open repair (mortality 48%).
Ruptured AAA triad?
1) Pain (sudden abdo/back)
2) Hypotension / fx of hypovolemia
3) Pulsatile Abdominal Mass
True vs false aneurysm?
-True: involves all layers (intima, media, adventitia)
-False: disruption of aortic wall or anastomotic site between vessel and graft with containment of blood by fibrous capsule of surrounding tissue
Conservative Mx AAA?
-CV RFx reduction (HTN / DM / smoking cessation)
-Watchful waiting (rpt US 6/12)
When should surgical Mx AAA be pursued?
-Indications: rupture, mycotic, symptomatic, Type A dissection / complicated Type B dissection
-Rupture risk > surgical risk (>5.5cm)
-Rupture risk depends on size, rate of enlargement, symptoms, comorbidities
Contraindications to surgical Mx of AAA?
Surgical options for AAA repair
-Open (laparotomy) with graft replacement
-EVAR with graft replacement
Possible complications of open AAA repair?
-EARLY: AKI, spinal cord injury, impotence, arterial thrombosis, anastomotic rupture/bleeding, peripheral emboli.
-LATE: infection/thrombosis, aortoenteric fistula, anastomotic aneurysm
Complications of EVAR?
-EARLY: conversion to open, groin haematoma, arterial thrombosis, iliac artery rupture, thromboemboli
-LATE: endoleak, severe graft kinking, migration, thrombosis, rupture of aneurysm.
What is an aneurysm
Focal arterial dilation
1.25-1.5x greater diameter than adjacent normal artery
Natural Hx aneurysm?
Continued expansion and eventual rupture
Common sites of arterial aneurysm?
-Common iliac arteries
How is risk of aneurysm rupture determined?
Risk of aneurysm rupture related to diameter:
-8cm 25% annual risk of rupture
Aneurysm primary prevention?
Aneurysm secondary prevention?
Screen and treat aneurysms >5-5.5cm