What is the diagnostic approach for suspected ruptured aortic aneurysm?

Diagnosing Ruptured Aortic Aneurysm

For hemodynamically stable patients with suspected ruptured aortic aneurysm, CT angiography is the diagnostic test of choice, while unstable patients require immediate surgical intervention without imaging delay. 1, 2

Clinical Presentation

The diagnosis begins with recognizing the cardinal symptom: acute onset of severe pain. 3

• Thoracic aortic rupture: Sudden, severe chest and/or back pain, often described as tearing or interscapular 1, 3
• Abdominal aortic rupture: Acute abdominal, back, or flank pain occurring in 65-90% of cases 3, 4
• Recurrent or refractory pain identifies patients at highest risk of progression from contained to free rupture 2, 3

Critical Hemodynamic Assessment

Hypotension or shock is the most critical prognostic indicator and mandates immediate intervention. 4 Blood pressure can fluctuate dramatically as rupture transitions from contained to free. 4 Hemodynamic data suggesting decreased blood volume (hypotension, dropping hematocrit) dictate immediate operation without imaging. 5

Contained rupture patients remain hemodynamically stable because hemorrhage is sealed by surrounding structures (pleura, pericardium, retroperitoneum). 1, 3 In contrast, free rupture causes hemorrhagic shock and rapid death. 3

Diagnostic Imaging Algorithm

For Hemodynamically Stable Patients

CT angiography is the gold standard imaging modality with 91.4% sensitivity and 93.6% specificity for diagnosing rupture. 2, 3

CT Protocol and Findings

The protocol should include both non-contrast and contrast-enhanced phases. 1

Non-contrast CT findings indicating rupture or impending rupture: 1, 2, 3

• Intramural hematoma (critical sign of impending rupture)
• Displaced aortic calcifications (94% sensitive for acute aortic syndrome)
• Periaortic stranding or soft tissue changes
• Abnormal aortic wall contour

Contrast-enhanced CTA findings confirming rupture: 2, 3

• Contrast extravasation (active bleeding, complete rupture)
• Perivascular hematoma sealed by retroperitoneal structures (contained rupture)
• Pleural or peritoneal effusions, especially if increasing on serial imaging
• Preserved aortic wall integrity despite acute pain (impending rupture)

For Hemodynamically Unstable Patients

Do not delay for imaging—proceed directly to operating room. 5 The mortality for ruptured AAA is 54% at 6 hours and 76% at 24 hours, making time critical. 1, 4

Alternative Imaging Modalities

Chest radiography may show suggestive findings but is neither sensitive nor specific: 1

• Mediastinal widening
• Disruption of aortic knob contour
• "Calcium sign" (intimal calcification >5mm from aortic wall)
• Tracheal deviation to the right

Transesophageal echocardiography (TEE) can provide rapid bedside diagnosis in unstable patients, particularly for thoracic aortic rupture, though it has blind spots in the aortic arch. 1 TEE is excellent for ascending and descending aortic assessment but limited for arch pathology. 1

Transthoracic echocardiography (TTE) is less invasive but limited by body habitus, chest wall abnormalities, and inability to visualize the entire thoracic aorta. 1

Key Diagnostic Pitfalls

Do not assume preserved wall integrity on imaging excludes rupture—contained rupture presents with intact wall on imaging but acute pain and intramural changes. 1, 2

Fever occurs in ≥70% of ruptured AAA cases due to inflammatory response to retroperitoneal blood, which can mislead clinicians toward infectious etiologies. 2, 4

Any patient with known aneurysm presenting with acute pain should be presumed to have impending rupture regardless of imaging findings, requiring immediate ICU admission and urgent repair within 24-48 hours. 2

CT angiography misses some ruptures despite high sensitivity—clinical judgment supersedes negative imaging when suspicion is high. 2

Immediate Management Priorities

Once rupture is diagnosed or strongly suspected:

• Immediate ICU admission 2
• Permissive hypotension (target systolic 70-90 mmHg to prevent clot disruption) 4
• Urgent vascular surgery consultation for repair within 24-48 hours 2, 4
• Endovascular repair preferred when anatomically suitable, reducing perioperative mortality from 29-33% to 19-23% compared to open repair 2, 4