Acute Aortic Dissection

Acute aortic dissection is dissection of the media of the aortic wall by a column of blood. It occurs most commonly in the thoracic aorta, and the age of onset is usually at least 50 years. A history of hypertension is usually (80%) present. Aortic dissection is rare in those younger than 40 years of age unless other predisposing conditions are present, such as Marfan's syndrome, Ehlers-Danlos syndrome, congenital heart disease, iatrogenic trauma (e.g., cardiac catheterization), bicuspid aortic valve, or pregnancy. AAD should also be considered when acute dysfunction of more than one organ system is observed.

Causes

Aortic dissection is most common in patient with High blood pressure, connective tissue disorders, congenital aortic stenosis and in those with first-degree relatives with history of thoracic dissections. These diseases affect the media of the aorta and predispose it to dissection.

• High blood pressure or pulsatile blood flow can propagate the dissection.
• Crack cocaine use may precipitate aortic dissection.
• Iatrogenic causes of aortic dissection include cardiac catheterization.
• Aortopathy may be due to the following heritable diseases:
  • Annuloaortic ectasia
  • Adult polycystic kidney disease
  • Annuloaortic ectasia
  • Metabolic disorders (eg, homocystinuria, familial etc)

Symptoms

• Chest pain is the most common symptom ++++ and is classically sudden in onset and ripping or tearing in quality.
• Anterior chest pain is more common in ascending aortic dissection ++++; back pain is more common in descending aortic dissection ++++. Coexisting anterior chest pain and back pain is seen less frequently.
• Pain may migrate as the dissection progresses and may also involve the limbs, particularly if the dissection obstructs the origin of a limb vessel.
• Neurologic deficits ++
• Syncope +
• Nausea
• Diaphoresis
• Light-headedness

Signs

• Hypertension (early)
• Hypotension (late)
• Tachycardia
• Pulse deficits in extremities +++
• Aortic insufficiency (+++ in patients with ascending aorta involvement)
• Murmur over the thoracic inlet
• Tamponade
• Acute stroke + - ++
• Hemoptysis, hematemesis, Homer's syndrome, and SVC syndrome (rare)

Treatment

Acute aortic dissection is an emergency; medical treatment should start as soon as possible. The patient is admitted in the intensive care unit and drugs to lower blood pressure and heart rate are given. In few cases emergency surgery is needed. Recently, alternative procedures, such as placing a stent inside the aorta, have been used for high-risk surgical patients.

• The Assure adequate breathing, treat shock, maintain oxygenation, and obtain useful historic information.
• In all individuals with aortic dissections, medication should be used to control high blood pressure, if present.