Vascular Malformations

Vascular malformations are abnormal clusters of blood vessels that occur during fetal development. The exact cause of these malformations remains unknown.  Both males and females are equally affected by vascular anomalies.

Although these lesions are always present at birth, they may not be visible until weeks or even years after birth. These lesions will typically grow in proportion to the growth of the child, meaning they tend to grow steadily throughout life.

While they sometimes grow quite rapidly, their growth is usually gradual and steady during the first year of life. Without treatment, a vascular malformation will not diminish or disappear.

There are a number of different sub-types of vascular malformations, depending on the predominant abnormality. These include:

The severity of these malformations varies greatly both within and among these groups.

In addition to being classified by predominant abnormality, vascular malformations are categorized as either slow flow or fast flow. These terms refer to the rapidity of blood flowing through the lesion.

Fast-flow lesions can lead to high-output heart failure and may thus require specific treatments to manage the problem.

Arteriovenous malformations are fast-flow lesions.

Capillary, lymphatic, and venous malformations are considered slow-flow lesions.

Combined malformations may be either slow or fast flow.

These lesions are diagnosed by both physical examination and by using a number of imaging techniques, including magnetic resonance imaging (MRI), computed tomography (CT) and ultrasonography. In some cases, an angiogram is needed to assist in detailed treatment planning. These tests are briefly described:

  • Magnetic resonance imaging (MRI): This technique uses a magnetic field and radio waves to produce three-dimensional images of the inside of the body. Since the child must lie still for up to one hour, sedation is frequently given through an intravenous catheter (a small needle placed in the arm or foot). Some younger children may require general anesthesia.
  • Computed tomography (CT):  This imaging technique uses X-rays linked to a computer to visualize the internal anatomy of the body.  Sedation, given orally or through an intravenous catheter, is sometimes used.
  • Ultrasonography: This technique uses sound waves to take pictures of the inside of the body. Sedation is not required for this test.
  • Angiogram: This is a study of the blood vessels that uses a special X-ray machine. A dye is injected into the bloodstream through a tube, which is placed in an artery in the leg. This allows the doctor to see the blood vessels and take X-rays. An angiogram is done either with sedation or under general anesthesia.

Management of vascular malformations is dependent upon the type and location of the malformation as well as its depth.

Observation and the use of supportive treatments (e.g., compression garments and drug therapy) are sometimes recommended.

For lesions that are only superficial, laser therapy is commonly used.

Lesions that are deep may, however, require surgical removal and other therapies. While surgery is complex and was previously associated with the risk of blood loss, advances in technology now enable removal to be more safely performed.

The management of combined vascular lesions is far more complex, and usually requires evaluation and treatment by a multidisciplinary team. 


Last Updated 12/2013