Acute aortic syndrome

Overview

Acute aortic syndrome (AAS) is a life-threatening group of conditions that involve sudden injury or disruption of the aortic wall. It is a medical emergency and includes three main entities: aortic dissection, intramural hematoma, and penetrating atherosclerotic ulcer. These conditions share similar clinical presentations and require prompt diagnosis and treatment to prevent catastrophic outcomes such as aortic rupture, cardiac tamponade, or death. AAS most commonly affects the thoracic aorta and is typically seen in older adults with cardiovascular risk factors.

Causes

Acute aortic syndrome results from structural weakening or damage to the aortic wall, which may be spontaneous or triggered by underlying conditions. Common causes and risk factors include:

• Chronic hypertension: The most significant risk factor, contributing to mechanical stress on the aorta

• Atherosclerosis: Weakens the aortic wall and can lead to ulceration

• Connective tissue disorders: Such as Marfan syndrome, Ehlers–Danlos syndrome

• Preexisting aortic aneurysm

• Trauma: Blunt chest trauma may precipitate an aortic injury

• Iatrogenic injury: During catheterization or cardiac surgery

Symptoms

Symptoms of acute aortic syndrome are often sudden and severe, resembling other cardiac emergencies like myocardial infarction. Key symptoms include:

• Severe chest or back pain: Described as sharp, tearing, or ripping

• Pain that migrates: Especially with aortic dissection, as the tear propagates

• Shortness of breath

• Syncope (fainting)

• Pulse deficits: Weakened or absent pulses in one limb

• Neurologic symptoms: Stroke or paraplegia, if blood flow to the brain or spinal cord is compromised

• Shock or hypotension: Suggesting rupture or pericardial tamponade

Diagnosis

Prompt diagnosis is critical for survival. Diagnostic steps include:

• Electrocardiogram (ECG): To rule out myocardial infarction

• Chest X-ray: May show widened mediastinum or abnormal aortic contour

• CT angiography (CTA): Gold standard imaging to identify dissection, hematoma, or ulcer

• Transesophageal echocardiography (TEE): Useful in unstable patients or when CTA is not available

• Magnetic resonance angiography (MRA): Another alternative imaging modality

• D-dimer test: May be elevated in AAS, though not specific

Classification systems (e.g., Stanford type A and B) help guide treatment based on the location of the aortic involvement.

Treatment

Treatment depends on the type and severity of the acute aortic syndrome:

Stanford Type A (involving ascending aorta):

• Emergency surgery: Aortic repair or graft placement to prevent rupture or tamponade

Stanford Type B (descending aorta only):

• Medical management: Blood pressure and heart rate control (typically with beta-blockers)

• Endovascular repair (TEVAR): Considered in complicated cases or progressive disease

General supportive measures:

• ICU-level monitoring

• Intravenous antihypertensives (e.g., labetalol, esmolol)

• Pain control with opioids

Prognosis

The prognosis for acute aortic syndrome depends on rapid recognition and intervention. Without treatment, mortality is extremely high, particularly for type A aortic dissection, which has a mortality rate of up to 1–2% per hour in the first 24 hours. With prompt surgical or medical treatment, survival improves significantly.

Long-term prognosis depends on the extent of the initial injury, success of treatment, and continued control of blood pressure and cardiovascular risk factors. Lifelong follow-up with imaging is recommended to monitor for recurrence or complications such as aneurysm formation.