Vascular malformations are abnormal clusters of blood vessels that occur during fetal development.
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. While they sometimes grow quite rapidly, their growth is usually gradual and steady during the first year of life.
There are a number of different sub-types of vascular malformations, depending on the predominant channel abnormality. These include:
The severity of these malformations varies greatly both within and among these clinical groups.
In addition to being classified by predominant channel 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.
Without treatment, a vascular malformation will not diminish or disappear.
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 such as sclerotherapy. 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 multi-disciplinary team.