• Clinical science
  • Physician

Aortic dissection

Summary

An aortic dissection is a tear in the inner layer of the aorta which leads to a progressively growing hematoma between in the intima-media space. Hypertensive males between the 4th and 6th decade have the highest incidence of aortic dissection. Patients complain of a sudden onset and severe pain radiating into the thorax, back, or abdomen. Initial chest x-ray shows a widened mediastinum. The diagnosis is confirmed with a contrast-enhanced CT in stable patients and transesophageal echocardiography in unstable patients. Treatment options range from conservative measures (e.g., blood pressure optimization) to surgery (aortic prosthesis), 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.

Epidemiology

References:[1][2][3]

Epidemiological data refers to the US, unless otherwise specified.

Etiology

References:[4][3]

Classification

Stanford classification

Stanford A = Affects ascending aorta; Stanford B = Begins beyond brachiocephalic vessels.

References:[5]

Pathophysiology

  • Anatomic site 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.

References:[1][6]

Clinical features

References:[4]

Diagnostics

  • Initial imaging: Chest x-ray (AP view) showing a widened mediastinum (> 8 cm)
  • Definitive diagnostic tests (determine the type of lumen, location, and extent of the dissecting membrane)
    • In stable patients → Contrast-enhanced CT angiography (gold standard) High sensitivity and specificity.
    • In unstable patients, renal insufficiency, contrast allergyTransesophageal echocardiography (TEE)
    • If contrast-enhanced CT is contraindicated in stable patients → Magnetic resonance angiography (MRA)
  • ECG: in all patients, although normal or signs of left ventricular hypertrophy

References:[4][7][8][9]

Differential diagnoses

The differential diagnoses listed here are not exhaustive.

Treatment

Stanford A dissections; (involvement of the ascending aorta) require immediate surgery; , while Stanford B dissections are generally treated conservatively unless complications (e.g., rupture or occlusion) occur.

Conservative treatment

Surgery

  • Open surgery with a polyester graft implantation
  • Possibly, endovascular treatment: aortic stent implantation (only in type B dissections and if the operative risk is too high)

Avoid thrombolytic therapy in patients with suspected aortic dissection!
References:[4]

Acute management checklist

All aortic dissection [10]

Ascending (type A) aortic dissection

  • Consult cardiothoracic surgery immediately.
  • Obtain preoperative labs (e.g., type and screen, CBC, coags, BMP, troponin).

Descending (type B) aortic dissection:

  • Consult cardiothoracic surgery for consideration of endovascular repair.

Ascending aortic dissection is a surgical emergency! Descending aortic dissection can often be managed medically.

Complications

References:[4]e.g.,

We list the most important complications. The selection is not exhaustive.

Prognosis

References:[4]

Prevention

  • Blood pressure control
  • Smoking cessation
  • Screening and repair of rapidly expanding aneurysms (also see “Therapy” and “Prevention” sections in aortic aneurysms)
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  • 4. Khan AN, Cho KJ. Aortic Dissection Imaging. In: Aortic Dissection Imaging. New York, NY: WebMD. http://emedicine.medscape.com/article/416776-overview#showall. Updated May 13, 2016. Accessed December 4, 2016.
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  • 9. Khan AN, Cho KJ. Aortic Dissection Imaging. In: Aortic Dissection Imaging. New York, NY: WebMD. http://emedicine.medscape.com/article/416776-overview#a6. Updated May 13, 2016. Accessed May 13, 2016.
  • 10. Hiratzka LF, Bakris GL, Beckman JA, et al. 2010 ACCF/AHA/AATS/ACR/ASA/SCA/SCAI/SIR/STS/SVM Guidelines for the Diagnosis and Management of Patients With Thoracic Aortic Disease. Circulation. 2010; 121(13): pp. e266–369. doi: 10.1161/CIR.0b013e3181d4739e.
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last updated 01/23/2020
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