- Clinical science
An aortic dissection is a tear in the inner layer of the aorta that leads to a progressively growing hematoma in the intima-media space. Risk factors for aortic dissection include age and hypertension. Patients typically present with sudden onset severe pain radiating into the chest, back, or abdomen. A widened mediastinum on chest x-ray is characteristic of the diagnosis. The diagnosis is usually confirmed with CT angiogram in stable patients and transesophageal echocardiography (TEE) in unstable patients. Treatment options range from conservative measures (e.g., blood pressure optimization) to surgery (aortic stent graft), depending on the localization and severity of the dissection. Complete occlusion of branching vessels and aortic rupture are common complications. Even with treatment, mortality rates associated with aortic dissection are high.
- Incidence: 40–80 years of age
- Sex: ♂ > ♀ (3:1)
Epidemiological data refers to the US, unless otherwise specified.
- Hypertension (most common risk factor)
- Trauma; (e.g., deceleration injury in a motor vehicle accident, or iatrogenic injury during valve replacements or graft surgery)
- Vasculitis with aortic involvement (e.g., syphilis)
- Use of amphetamines and cocaine
- Third-trimester pregnancy (or early postpartum period)
There are two classifications of aortic dissection to help direct management. Stanford classification groups dissections by whether the ascending or descending aorta is involved. DeBakey classification categorizes dissections according to their origin and extent.
- Stanford type A aortic dissection: any dissection involving the ascending aorta (defined as proximal to the brachiocephalic artery), regardless of origin
- Stanford type B aortic dissection: any dissection not involving the ascending aorta
DeBakey classification (rarely used) 
Type I: Dissections originate in the ascending aorta and continue to at least the aortic arch but typically as far as the descending aorta.
- Generally requires surgery
Type II: Dissections originate in, and are restricted to, the ascending aorta.
- Generally requires surgery
Type III: Dissections originate in the descending aorta and most often extend distally.
- Most cases can be managed by medical therapy.
- Can be further subdivided into:
- Type IIIa: limited to the descending thoracic aorta above the level of the diaphragm
- Type IIIb: extends below the diaphragm
- Common anatomic sites of origin
Transverse tear in the aortic intima (“entry”) → blood enters the media of the aorta and forms a false lumen in the intima-media space → hematoma forms and propagates longitudinally downwards
- Rising pressure within the aortic wall → rupture
- Occlusion of every single branching vessel (e.g., coronary arteries, arteries supplying the brain, renal arteries, arteries supplying the lower limbs) → ischemia in the affected areas (see “Complications” below)
- A second intimal tear may result in a “reentry” into the primary aortic lumen.
- Sudden and severe tearing/ripping pain
- Hypertension or hypotension
- Asymmetrical blood pressure and pulse readings between limbs
- Syncope, diaphoresis, confusion or agitation
- A heart murmur (an aortic regurgitation in a proximal dissection)
- Assess the risk of acute aortic dissection using the aortic dissection detection risk score (ADD-RS).
- Check ECG in all patients to exclude other causes of severe chest pain.
- Consider which imaging modality is indicated
- CXR: low to moderate-risk patients
- Definitive imaging (e.g., CTA, MRA): high-risk patients, unexplained hypotension, abnormal CXR, no alternative diagnosis
|Aortic dissection detection risk score (ADD-RS)|
|Risk categories||Features||Score if any feature present|
|Pain characteristics|| ||1|
Should be ordered for all patients. Findings are variable and include:
- Normal findings
- Signs of left ventricular hypertrophy
- Nonspecific changes, such as ST depression and T-wave changes
- ST elevation due to coronary artery occlusion 
- D-dimer: elevated levels 
- Evaluate for signs of end-organ damage: troponin, BMP, lactate
- Pre-operative labs: CBC, type and screen, BMP, coagulation panel
Initial imaging in low to moderate risk patients 
Chest x-ray (AP view)
- Characteristic findings
- Additional findings that may be present
Normal chest x-ray findings do not rule out aortic dissection. If clinical suspicion for acute aortic dissection persists, perform a second imaging study!
Definitive imaging 
Definitive imaging is used to determine the type of lumen, location, and extent of the dissecting membrane. The identification of a false lumen is highly suggestive of aortic dissection.
CT angiography of the chest, abdomen, and pelvis 
- Indications: stable patients, surgical planning
- Advantages: very high sensitivity and specificity (considered to be the gold standard) 
- Suggestive findings
Magnetic resonance angiography (MRA) of the chest, abdomen, and pelvis
- Indications: stable patients, contraindications to CTA
- Contraindications: renal insufficiency, claustrophobia, metallic implants, pacemakers
- Not widely available on an emergency basis
- Suggestive findings: similar to CT angiography
Transesophageal echocardiography (TEE)
- Unstable patients
- Intraoperative visualization
- Renal insufficiency or contrast allergy
- Rapid; can be performed at the bedside
- Quick differentiation between thoracic aortic aneurysm and thoracic aortic dissection
- Disadvantages: dissection flap can be difficult to distinguish from artifact
- Findings may include:
- Other: catheter angiography, ultrasound 
- See .
The differential diagnoses listed here are not exhaustive.
- Urgent cardiothoracic surgical consult for all patients with suspected or confirmed dissection, regardless of location. 
- Blood pressure control is essential in all patients to prevent progression of the dissection
- Supportive care
- Admission to surgical ICU with close monitoring and surveillance imaging
Surgical therapy 
- Open surgery with the replacement of the dissection with a polyester graft implantation 
- Endovascular treatment with aortic stent implantation (only in type B dissections and if the open operative risk is too high) 
Ascending aortic dissection is a surgical emergency!
Hypotensive patients 
- Hemodynamic support: target MAP of 70 mm Hg or euvolemia 
- Identify and treat any comorbidities that may be contributing
- Expedite operative management.
Avoid inotropes as they can worsen aortic wall stress.
Hypertensive patients 
- Control hypertension and heart rate: target SBP 100–120 mm Hg and HR ≤ 60 beats per minute 
- Patients with dissection of the descending aorta who remain stable on IV treatment can be transitioned to oral medications and discharged with outpatient imaging surveillance.
- Patients may require sedation
- Analgesia (e.g., morphine)
- Identify and treat any complications (e.g., mesenteric ischemia, acute kidney injury)
Avoid thrombolytic therapy in patients with suspected aortic dissection.
- Urgent cardiothoracic/vascular surgery consult
- Check ECG
- Check labs
- Assess risk and consider definitive imaging (see aortic dissection detection risk score)
- Consider indications for surgical repair (e.g., all type A dissection, type B dissection with complications)
- Blood pressure control: goal MAP 70
- In hypotensive patients: fluids, vasopressors
- In hypertensive patients: goal SBP < 120 mm Hg and HR < 60/min
- Supportive care: Pain management
- Continuous telemetry and pulse oximetry
- Frequently monitor blood pressure.
- Monitor urine output.
- Transfer to the ICU or OR.
- Monitor for complications.
- Aortic rupture and acute blood loss: acute back and flank pain (tearing pain); , symptoms of shock → indication for emergency surgery
- Complications of Stanford type A dissections
- Complications of both Stanford type A dissection and Stanford type B dissections
- Bleeding into the thorax, mediastinum, and abdomen
- Arterial occlusion followed by ischemia of the:
We list the most important complications. The selection is not exhaustive.
- In-hospital mortality due to aortic dissection ranges from 9 to 39%, depending on the type of dissection and treatment modality. 
- Blood pressure control
- Smoking cessation 
- Screening and repair of rapidly expanding aneurysms (also see “Therapy” and “Prevention” sections in s)