Nursing Care by System‎ > ‎Cardiac‎ > ‎

Aortic Dissection

An aortic dissection, also called a dissecting aneurysm, is a tear in the inner lining of the aorta. This tear allows blood to flow through the walls of the aorta rather than remaining in the central channel (lumen). The two major types of aortic dissection, type A and type B, are defined by the location of the tear.


    * Type A dissection—The tear begins in the ascending aorta and progresses throughout the vessel, often extending as far as the arteries in the leg.
    * Type B dissection—The tear is located only in the descending aorta, and may extend into the abdomen.

The distinction between the two types is important, as it guides the management of the disease. Type A is the more common and more dangerous type, and requires immediate surgery. Type B is considered a chronic condition that can be treated with medications.
Symptoms

Patients often feel as though they are having a heart attack. Specific symptoms include:

  • Sudden and severe "tearing" or "crushing" pain between the shoulder blades or behind the sternum
  • Inability to find a comfortable position
  • Profound hypertension (extremely high blood pressure)
  • Loss of consciousness
  • Shortness of breath
  • Weakness
  • Stroke

Diagnosis

Detection of aortic aneurysms can be tricky because the same symptoms occur in conjunction with many other health problems. Type B dissection is frequently misdiagnosed in the emergency room as heart attack. Prompt diagnosis is essential, however: type A dissections are surgical emergencies, with a mortality rate of 3 - 5% per hour after onset.

Diagnosis can be made by CT scan of the chest and/or a transesophageal echocardiography (TEE, or ultrasound images of the heart taken from within the esophagus).

If a type A aortic dissection is strongly suspected, the patient is transported directly from our emergency room or an outside hospital to the operating room for a confirmation of diagnosis via TEE. For those found to have a type A aortic dissection, surgical repair is begun immediately.

Complications

Type A dissection is associated with many acute and chronic complications. Emergency intervention is required to prevent death. The most lethal acute complications are:

   1. Exsanguinating hemorrhage: aortic rupture causing extreme blood loss
   2. Aortic valve incompetence: failure of the aortic valve leading to rapid heart failure
   3. Coronary artery dissection: loss of blood from the coronary arteries to the heart muscle causing a heart attack (myocardial infarction)
   4. Cardiac tamponade: accumulation of blood in the pericardium (sac surrounding the heart) leading to heart failure
   5. Carotid artery dissection: loss of blood from the carotid arteries to the brain arteries causing acute stroke

Type A or B dissection can also cause a process known as malperfusion syndrome. Because blood flows in the walls of the aorta rather than through the vessel itself, not enough blood may reach its intended destination. This condition may cause organ failure, most frequently involving the kidneys and intestines. The result may be temporary or permanent kidney failure and dead bowel, which may necessitate extensive bowel resection.
Comments