What are the immediate management steps for a suspected ruptured abdominal aortic aneurysm?

Signs of Ruptured Abdominal Aortic Aneurysm

Any patient with a known AAA presenting with acute abdominal, back, or flank pain should be presumed to have impending or actual rupture and requires immediate ICU admission with urgent imaging and repair. 1

Clinical Presentation

Cardinal Symptoms

• Acute onset pain in the abdomen, back, or flank is the most important presenting symptom, though sensitivity is only 61.7% for abdominal pain and 53.6% for back pain 1, 2
• Recurrent or refractory pain identifies patients at highest risk of progression to complete rupture 1
• Syncope occurs in approximately 27.8% of cases, indicating significant hemodynamic compromise 2

Physical Examination Findings

• Hypotension (systolic BP <90 mmHg or signs of shock) suggests active bleeding, though present in only 30.9% of cases 2
• Pulsatile abdominal mass is palpable in only 47.1% of patients, making its absence unreliable for ruling out rupture 2
• Hemodynamic instability with decreasing blood pressure and hematocrit strongly suggests rupture and mandates immediate operation 3

Critical caveat: Classic clinical symptoms have poor sensitivity—their absence does not rule out rupture 2. Maintain high clinical suspicion even with atypical presentations.

Imaging Findings

CT Angiography (Preferred Modality)

For hemodynamically stable patients, CT imaging is recommended to evaluate rupture and assess suitability for endovascular repair 4, 5

CT findings indicating rupture or impending rupture include:

• Contrast extravasation indicating active bleeding (complete rupture) 1
• Perivascular hematoma sealed off by retroperitoneal structures (contained rupture) 1
• Intramural hematoma visible on non-contrast phase (impending rupture) 1
• Pleural or peritoneal effusions, particularly if increasing on serial imaging 1
• Periaortic stranding or soft tissue changes 4

CTA has 91.4% sensitivity and 93.6% specificity for diagnosing rupture, though it misses some cases 2. The advantage is rapid examination defining precise location, detecting impending rupture, and guiding surgical planning 4

Point-of-Care Ultrasound

• PoCUS has 97.8% sensitivity and 97.0% specificity for detecting AAA (not rupture itself) in patients suspected of having ruptured AAA 2
• Valuable for guiding urgent transfer to vascular center when CT unavailable 2
• Cannot reliably detect rupture, only presence of aneurysm 2

Distinguishing Features from Non-Ruptured AAA

Ruptured/Symptomatic AAA:

• Fever present in ≥70% of cases (uncommon in bland atherosclerotic aneurysms) 4
• Back pain in 65-90% of cases 4
• Acute onset symptoms with hemodynamic changes 1
• Preserved aortic wall integrity on imaging despite acute pain indicates impending rupture 1

Special Considerations:

• Saccular AAAs can rupture at smaller sizes than fusiform aneurysms 1
• Women experience rupture at smaller diameters than men 1
• AAAs <5 cm rarely rupture, but it can occur, particularly with saccular morphology 6
• Symptomatic aneurysms require urgent treatment regardless of diameter 1

Immediate Management Algorithm

Hemodynamically Stable Patients:

1. Immediate ICU admission 1
2. CT angiography to confirm rupture and assess anatomy 4, 5
3. Permissive hypotension to decrease bleeding rate 4, 5
4. Urgent repair within 24-48 hours to prevent progression to free rupture 1

Hemodynamically Unstable Patients:

1. Immediate operation without preoperative imaging if blood pressure, hematocrit, or clinical findings suggest active bleeding 3
2. Aggressive resuscitation with prompt proximal control 7
3. Direct transfer to operating room for open or endovascular repair 4

Endovascular repair is preferred over open repair when anatomically suitable, reducing perioperative mortality from 29-33% to 19-23% 4, 5. Local anesthesia is preferred over general anesthesia for endovascular repair to reduce perioperative mortality 4, 5.