A ruptured abdominal aortic aneurysm is a collapse with abdominal or back pain in an older patient, and at the CST management and clinical station the answer is recognition, an immediate bedside aortic ultrasound, and an immediate call to the regional vascular service. According to NICE NG156, published 19 March 2020, you should think about ruptured AAA in anyone with new abdominal or back pain, cardiovascular collapse or loss of consciousness, and you should not chase a normal blood pressure while you arrange transfer.
Key takeaways
- NICE NG156 says to think about ruptured AAA in new abdominal and/or back pain, cardiovascular collapse or loss of consciousness, and that rupture is more likely with a known AAA, age over 60, smoking history or hypertension
- Offer an immediate bedside aortic ultrasound, and discuss immediately with a regional vascular service if it shows an AAA, is unavailable or is non-diagnostic
- NG156 recommends a restrictive approach to volume resuscitation, permissive hypotension, during emergency transfer
- For a ruptured infrarenal AAA, EVAR provides more benefit than open repair for most people, especially men over 70 and women of any age; open repair is likely better in men under 70
- Elective repair is offered for a symptomatic AAA, an AAA 5.5 cm or larger, or one over 4.0 cm that has grown by more than 1 cm in a year
- A confirmed rupture with cardiac arrest and/or persistent loss of consciousness has a negligible chance of surviving repair
How do I recognise a ruptured AAA in a collapsed patient?
Recognise a ruptured AAA by thinking of it first: NG156 says to consider it in anyone with new abdominal and/or back pain, cardiovascular collapse or loss of consciousness.
The guideline adds that rupture is more likely with an existing diagnosis of AAA, age over 60, current or previous smoking, or a history of hypertension, and that AAAs are more likely to rupture in women than in men.
The trap is the mimic. Renal colic, pancreatitis and a musculoskeletal back are all commoner, and the ruptured AAA that is misdiagnosed as one of them is the case the panel has in mind.
How do I assess and resuscitate a suspected ruptured AAA?
Assess a suspected ruptured AAA with the CCrISP immediate stage: airway, high-flow oxygen, two large-bore cannulae, bloods with a crossmatch, and a call for senior help before the full assessment.
The difference from every other shocked patient is the fluid. NG156 recommends a restrictive approach to volume resuscitation, known as permissive hypotension, for a suspected ruptured or symptomatic AAA during emergency transfer to a regional vascular service.
Say why: a normal blood pressure lifts the clot off the rupture and restarts the bleed. Give fluid for a falling conscious level or profound hypotension, not to reach a target, and activate the major haemorrhage protocol early.
Which investigation confirms a ruptured AAA?
An immediate bedside aortic ultrasound is the first investigation, and NG156 says to offer it to anyone in whom a symptomatic or ruptured AAA is being considered.
If the ultrasound shows an AAA, or is not immediately available, or is non-diagnostic while an AAA is still suspected, the guideline instructs an immediate discussion with the regional vascular service. Ultrasound confirms the aneurysm; it does not reliably show the rupture.
NG156 says to consider thin-slice contrast-enhanced arterial-phase CT angiography for a suspected rupture in a patient being evaluated for repair. The CT is for planning the repair, and it must not delay the call.
When and how is a ruptured AAA transferred?
A ruptured AAA is transferred to the regional vascular service after an immediate telephone discussion, with permissive hypotension maintained, a senior escort, and the blood products travelling with the patient.
NG156 states there is no evidence that any single symptom, sign or risk tool can be used to decide who should be transferred, so the decision is made with the vascular team on the phone rather than by a score.
That said, the guideline is explicit that a confirmed rupture with cardiac arrest and/or persistent loss of consciousness has a negligible chance of surviving repair, and it points to the NICE guideline on care in the last days of life for those patients.
What is the definitive management of a ruptured AAA?
The definitive management of a ruptured infrarenal AAA is either endovascular aneurysm repair or open surgical repair, and NG156 tells you which the balance favours.
According to NG156, EVAR provides more benefit than open surgical repair for most people, especially men over 70 and women of any age, whereas open surgical repair is likely to give a better balance of benefits and harms in men under 70.
Open repair is considered if standard EVAR is unsuitable, complex EVAR is not offered outside a trial when open repair is suitable, and the guideline says to consider local infiltrative anaesthesia alone for EVAR of a rupture.
What complications follow repair of a ruptured AAA?
The complication NG156 singles out after repair of a ruptured AAA is abdominal compartment syndrome, which can follow either EVAR or open repair.
The guideline says to assess for abdominal compartment syndrome if the patient's condition does not improve as expected, so on the ward that means a tense abdomen, falling urine output and rising airway pressures after repair.
Alongside it, name the physiology of massive transfusion, acute kidney injury, limb and bowel ischaemia, and the endoleak surveillance that EVAR commits the patient to under section 1.7 of the guideline.
What are the thresholds for elective AAA repair and surveillance?
NG156 says to consider elective repair for an unruptured AAA that is symptomatic, that is asymptomatic and 5.5 cm or larger, or that is asymptomatic, larger than 4.0 cm and has grown by more than 1 cm in one year.
Diameters are the inner-to-inner maximum anterior-posterior measurement on ultrasound, in line with the NHS AAA screening programme, which invites men at 66. Surveillance uses the same frequency as that programme.
For referral, an AAA of 5.5 cm or larger should be seen by a regional vascular service within 2 weeks of diagnosis, and one of 3.0 cm to 5.4 cm within 12 weeks.
Who do I escalate a ruptured AAA to, and what do I say?
Escalate a suspected ruptured AAA to the on-call surgical registrar and consultant at once, and make the immediate call to the regional vascular service yourself if the ultrasound shows an aneurysm or cannot be done.
Your SBAR should carry the age, the pain, the blood pressure trend, the ultrasound finding, the anticoagulants, and what you have already done: access, crossmatch, major haemorrhage call, permissive hypotension.
Involve anaesthetics and critical care in parallel, because whether the patient stays for open repair or travels for EVAR, they will need an anaesthetist within minutes.
How this comes up at the CST interview
The ruptured AAA scenario is typically a 72-year-old smoker who collapses in the emergency department with back pain, and the panel wants the diagnosis named in your first sentence.
Follow-up questions probe permissive hypotension, what you do when the nearest vascular centre is 40 miles away, and whether you would still transfer a patient who has had a cardiac arrest.
The coresurgeryinterview bank has a scored ruptured AAA scenario with AI-marked spoken practice, so the structure above can be rehearsed out loud: /Question-Bank/Sample-Questions.