Abdominal Aortic Aneurysm (AAA) Flashcards
What is an Abdominal Aortic Aneurysm (AAA) ?
Refers to the dilation of the abdominal aorta, with a diameter of more than 3cm
When does the patient usually realise they have an AAA?
when it ruptures
causing life-threatening bleeding into the abdominal cavity
mortality of a ruptured AAA is around 80%
Risk factors of AAA?
Men are affected significantly more often and at a younger age than women
Increased age
Smoking
Hypertension
Family history
CVD
Screening for AAA?
All men in England are offered a screening ultrasound scan at age 65 to detect asymptomatic AAA. Early detection of an AAA means preventative measures can stop it from expanding further or rupturing.
Women are not routinely offered screening, as they are at much lower risk. The NICE guidelines (2020) say a routine ultrasound can be considered in women aged over 70 with risk factors such as existing cardiovascular disease, COPD, family history, hypertension, hyperlipidaemia or smoking.
Patients with an aorta diameter above 3cm are referred to a vascular team (urgently if more than 5.5cm).
Clinical presentation of AAA?
Most patients with an AAA are asymptomatic. It may be discovered on routine screening or when it ruptures.
Other ways it can present include:
Non-specific abdominal pain
Pulsatile and expansile mass in the abdomen when palpated with both hands
As an incidental finding on an abdominal x-ray, ultrasound or CT scan
Diagnosis of AAA?
Ultrasound is the usual initial investigation for establishing the diagnosis.
CT angiogram gives a more detailed picture of the aneurysm and helps guide elective surgery to repair the aneurysm.
Classification of AAAs?
The severity of the aortic aneurysm depends on the size:
Normal: less than 3cm
Small aneurysm: 3 – 4.4cm
Medium aneurysm: 4.5 – 5.4cm
Large aneurysm: above 5.5cm
The risk of progression of an AAA can be reduced by treating reversible risk factors:
Stop smoking
Healthy diet and exercise
Optimising the management of hypertension, diabetes and hyperlipidaemia
The Public Health England (updated 2017) screening and surveillance programme recommends follow up scans:
Yearly for patients with aneurysms 3-4.4cm
3 monthly for patients with aneurysms 4.5-5.4cm
The NICE guidelines (2020) recommend elective repair for patients with any of:
Symptomatic aneurysm
Diameter growing more than 1cm per year
Diameter above 5.5cm
Elective surgical repair involves inserting an artificial “graft” into the section of the aorta affected by the aneurysm. There are two methods for inserting the graft:
Open repair via a laparotomy
Endovascular aneurysm repair (EVAR) using a stent inserted via the femoral arteries
A ruptured aortic aneurysm presents with:
Severe abdominal pain that may radiate to the back or groin
Haemodynamic instability (hypotension and tachycardia)
Pulsatile and expansile mass in the abdomen
Collapse
Loss of consciousness
Permissive hypotension refers to?
the strategy of aiming for a lower than normal blood pressure when performing fluid resuscitation. The theory is that increasing the blood pressure may increase blood loss.
what imaging can be used to diagnose or exclude ruptured AAA in haemodynamically stable patients?
CT angiogram
