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. 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 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.