Acute Aortic Syndrome: A Life-Threatening Cause of Sudden Chest Pain

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Acute Aortic Syndrome: A Life-Threatening Cause of Sudden Chest Pain 

Author: Scholargen Inc Medical Imaging Team
Category: Vascular Emergencies | Radiology | CTA Interpretation

Introduction: When Chest Pain Demands Urgency

Chest pain is one of the most frequent complaints in the emergency department. While acute coronary syndrome is often suspected first, Acute Aortic Syndrome (AAS) must not be overlooked, especially in elderly patients with hypertension and a history of cardiovascular procedures. AAS encompasses a group of potentially fatal aortic pathologies requiring immediate recognition and intervention.

In this case review, we present a 67-year-old woman with sudden, tearing chest pain, whose ECG-gated CT angiography (CTA) revealed Stanford type A aortic dissection with associated intramural hematoma (IMH) and intramural blood pooling. This article highlights the imaging features, pathophysiology, differential diagnosis, and management strategies for AAS.

Case Summary: Sudden Chest Pain in a High-Risk Patient

  • Patient: 67-year-old female

  • Chief Complaint: Sudden-onset chest pain radiating to the back

  • Past Medical History:

    • Poorly controlled hypertension

    • Prior ischemic stroke

    • Percutaneous coronary intervention (PCI)

    • Transcatheter aortic valve replacement (TAVR)

 Imaging Findings (ECG-gated Chest CTA):


  • Stanford Type A Aortic Dissection originating distal to the aortic valve prosthesis, extending into the aortic arch

  • Intramural Hematoma (IMH) along the distal arch and proximal descending aorta

  • Intramural Blood Pooling (IBP) was detected near the IMH, suggestive of disease progression

Quiz:

1. In a patient with suspected Acute Aortic Syndrome (AAS), which of the following CT findings is most specific for aortic dissection?

A. Crescent-shaped hyperdense thickening of the aortic wall on non-contrast CT
B. Ulcer-like outpouching penetrating the aortic wall
C. Intimal flap dividing the true and false lumens
D. Focal calcification of the intima without enhancement

Explanation:

  • The presence of an intimal flap on contrast-enhanced CTA is the hallmark of aortic dissection, separating the true lumen from the false lumen.

  • Choice A describes intramural hematoma (IMH).

  • Choice B represents penetrating atherosclerotic ulcer (PAU).

  • Choice D is a nonspecific finding and not diagnostic for AAS.


2. Which of the following is the most appropriate initial treatment strategy for a patient diagnosed with uncomplicated Stanford Type B aortic dissection?

A. Immediate surgical repair
B. Endovascular stent-graft placement (TEVAR) in all cases
C. Strict medical management with blood pressure and heart rate control
D. Observation only without medication

Explanation:

  • In uncomplicated Stanford Type B dissection, the cornerstone of treatment is medical therapy, including beta-blockers and vasodilators to reduce shear stress on the aortic wall.

  • TEVAR is reserved for patients with complications (e.g., rupture, organ malperfusion, persistent pain).

  • Immediate surgery (A) is indicated only for Stanford Type A.

  • Observation without treatment (D) is inappropriate due to the high risk of progression.


What Is Acute Aortic Syndrome?

Definition

Acute Aortic Syndrome is a collective term for three major acute aortic pathologies:

SubtypePathophysiologyClinical Implication
Aortic Dissection (AD)Intimal tear allows blood to enter the media, forming true and false lumensImmediate surgical emergency if Type A
Intramural Hematoma (IMH)Hemorrhage within the aortic wall without an intimal tearMay evolve into classic dissection
Penetrating Atherosclerotic Ulcer (PAU)Atherosclerotic plaque ulcerates through the intima into the mediaMay lead to IMH, rupture, or dissection

Epidemiology & Risk Factors

  • Incidence: ~3–4 cases per 100,000 persons/year

  • Typical Patient: Males over 60 years with hypertension

  • Risk Factors:

    • Hypertension (most common)

    • Atherosclerosis

    • Connective tissue disorders (Marfan, Ehlers-Danlos)

    • Bicuspid aortic valve

    • Prior cardiac surgery or catheterization

Imaging Diagnosis: Key Findings on CTA


CTA is the modality of choice for diagnosing AAS. Here’s what to look for:
DiseaseCTA FindingsNotes
DissectionIntimal flap, dual lumens (true/false), differential contrast opacificationThe false lumen is often larger and may be thrombosed
IMHCrescentic hyperdense area within the aortic wall on non-contrast images (60–70 HU)No intimal flap
PAUUlcer-like outpouching filled with contrast penetrating into the mediaMay resemble a pseudoaneurysm or focal dissection

Stanford Classification & Management Strategy

Stanford Type A

  • Involves: Ascending aorta (± arch, descending aorta)

  • Treatment: Emergency surgery required

Stanford Type B

  • Involves: Descending thoracic aorta only

  • Treatment: Medical management is first-line; TEVAR if complications arise

In this case, the patient had a Type A dissection — an immediate surgical indication.

Time Is Life: Mortality Rises Hourly

  • Untreated Type A dissections increase in mortality by 1% per hour

  • 48-hour mortality approaches 50%

  • Early recognition and rapid surgical referral are critical for survival

Differential Diagnosis: Mimickers of AAS

AAS can clinically resemble other life-threatening conditions:

  • Acute coronary syndrome (ACS)

  • Pulmonary embolism (PE)

  • Pericarditis

  • Myocardial infarction

  • Spontaneous mediastinal hemorrhage

CTA is invaluable for differentiating these entities in one scan.

Initial Management: Stabilization Is Key

  1. Blood Pressure Control

    • Target SBP: 100–120 mmHg

    • β-blockers (e.g., esmolol) as first-line

    • Vasodilators (e.g., nitroprusside) if needed

  2. Heart Rate Control

    • Target HR: <60 bpm

  3. Definitive Therapy

    • Type A: Emergent surgery

    • Type B: Medical ± TEVAR (Thoracic Endovascular Aortic Repair)

Prognosis & Long-Term Follow-Up

ConditionPrognosisKey Notes
Type A DissectionPoor without surgeryRequires immediate repair
Type B DissectionFavorable if uncomplicatedMonitor for rupture or ischemia
IMHA variable may progress to dissectionClose monitoring critical
PAUThe poor elderly with comorbiditiesTEVAR or surgical repair is often needed

Long-Term Strategies

  • Strict BP control

  • Serial imaging follow-up

  • Genetic screening in connective tissue disorders

  • Patient education for symptom recurrence

Expert Takeaways

  • High suspicion is vital: AAS often masquerades as other conditions

  • CTA is the diagnostic gold standard: Do not delay imaging in unstable patients

  • Stanford classification dictates management: Know your Type A from Type B

  • Hypertension control saves lives, both in acute and chronic phases

References

  1. Hiratzka LF, et al. Guidelines for the Diagnosis and Management of Thoracic Aortic Disease. Circulation. 2010.

  2. Evangelista A, et al. Insights From the International Registry of Acute Aortic Dissection. Circulation. 2018.

  3. Nienaber CA, et al. Management of Aortic Dissection: New Perspectives. Lancet. 2023.

  4. Erbel R, et al. 2014 ESC Guidelines on Aortic Diseases. Eur Heart J. 2014.

Conclusion: Recognize and Respond

Acute Aortic Syndrome is a diagnostic and therapeutic emergency. The subtle differences between dissection, IMH, and PAU have major implications for treatment. As radiologists and clinicians, our role is to act fast, interpret imaging accurately, and coordinate care across disciplines. Every minute counts.

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