Aortic Intramural Hematoma

The aorta is the largest artery in the body. It rises from the heart's left ventricle (the major chamber that pumps blood out of the heart) and is filled with oxygen-rich blood that travels throughout the body.

Aortic intramural hematoma (IMH) is a condition characterized by blood leaking through the innermost layer of the aortic wall and flowing between the inner and outer walls. This leakage does not occur due to a tear in the aortic wall and, because of this, the condition has been difficult to diagnose until recently. Although the condition is similar to, and was once thought to be a type of aortic dissection, the medical community now considers aortic IMH to be a distinct condition because there is no tear in the aortic wall when the condition occurs.

Aortic IMH may cause additional conditions, such as poor blood supply to other organs, and it may occur anywhere within the aorta.

Symptoms

Symptoms of aortic IMH are often very similar to those experienced with aortic dissection. The symptoms typically occur suddenly and can vary from one patient to the next. Symptoms generally include:

  • Severe chest pain
  • Severe back pain
  • Severe abdominal pain
  • Shortness of breath
  • Pain in the arms or legs
  • Weakness
  • Loss of consciousness
  • Rapid, weak pulse
  • Heavy sweating
  • Anxiety
  • Pale skin
  • Nausea


Causes and Risk Factors

Aortic IMH is rare and is most frequently diagnosed in men between the ages of 60 and 80 years of age. However, women and younger patients can develop the condition. It occurs in an area of the aorta that has been weakened, which can be due to:

Diagnosis

Diagnosis of aortic IMH generally begins with the physician taking a medical history and performing a physical examination. During the physical exam the physician will listen to the patient's heart, lungs and abdomen using a stethoscope to see if there is any abnormal rhythm in the heartbeat.

It is important for the physician to distinguish between aortic dissection and aortic IMH. To do this, the physician will use one or more imaging diagnostic tools to see if there is a tear in the aorta. One of these tools, transesophageal echocardiography, uses an ultrasound probe inserted through the esophagus. Other imaging tests — such as a magnetic resonance angiogram (MRA), a CT scan or an aortic angiogram — may be used to view the aorta to determine whether a tear is present. Some of the diagnostic imaging tests require a special dye to be injected into the vein so that it shows up more clearly on the images.

Other laboratory tests, such as blood tests, are often performed to rule out other conditions such as a heart attack.

Treatments

Because aortic IMH is a life-threatening condition, treatment is usually needed immediately. Treatment usually involves surgery or medication. If the condition occurs in the area of the aorta that is descending into the abdomen, medication may be used to treat it. Medication may also be used to stabilize a patient's condition before surgery.

Surgery will focus on removing the damaged portion of the aorta and placing a graft in place of the removed portion in order to prevent blood from running into the aortic wall. The graft is generally a tube made of synthetic material that helps restore function to the damaged area. In some cases, the aortic IMH may have damaged the aortic valve. If this occurs, the valve will often be replaced during the same surgery.

Medications do not correct an aortic IMH located in the portion of the aorta coming out of the heart. However, they may be used to stabilize the patient before surgery or to treat aortic IMH located in the portion of the aorta descending into the abdomen. These medications are often used to help control blood pressure and generally include beta blockers.

The knowledgeable and highly trained staff at the Cedars-Sinai Heart Institute will work with each patient to determine the best treatment option.