Birthmarks, Vascular Malformations and Anomalies
What Are They and What Can Be Done About Them?

Vascular anomalies occur in barely 1% of all births. Yet, because of their rarity, their proper diagnosis and treatment is difficult as most physicians do not see these problems often enough to become knowledgeable about their management.

Vascular anomalies is an all-inclusive term for vascular malformations, vascular tumors and other congenital vascular defects. The more commonly used term, Congenital Vascular Malformation (CVM), implies abnormally formed blood vessels that one is born with. However, in spite of its redundancy CVM is a popular term and it will be used here. This article is intended to explain the various vascular anomalies, which mostly present in childhood, and discuss their management in lay terms.

The significance of birthmarks. The difference between a CVM and a vascular tumor or hemangioma (the medical term), both of which are commonly called "birthmarks" is very important to the child. Although they may initially appear the same, "all birthmarks are not the same." Most birthmarks represent a superficial vascular malformation, consisting of abnormal collections of small blood vessels near the skin. Typically this CVM type of "birthmark" does not go away nor does it enlarge, growing only at the same rate as the child. It thus maintains the same size and appearance indefinitely, is not a health threat, and requires no immediate treatment. Some of them, because of their location, particularly around the face and neck or on some other exposed body part, are unsightly and cosmetically disturbing. Fortunately their characteristic reddish color coincides with the range of certain lasers that can be used for their destruction. Another approach has been to cover them up by tattooing them a skin color. The other type of "birthmark" may appear the same at first but is actually a true vascular tumor or hemangioma. In contrast, this type undergoes rapid growth in the months after its discovery, but then almost miraculously it "involutes", or gets progressively smaller. The majority disappears completely in a few years, leaving a patch of shrunken elastic skin in its wake. This regression normally is completed between two and eight years of age, but not all of them completely disappear. During their growth phase these "juvenile hemangiomas" can be alarming, particularly if they grow in a critical location, such as those on the face impinging on the eye, nose or mouth, in which case they may require early treatment. However, most juvenile hemangiomas do not require treatment. Rather the best advice is to do nothing but wait it out, giving it a chance to go away by itself.

Both of these contrasting types of birthmarks, or the smaller remnants of them which remain, can be greatly improved in appearance by plastic surgery, but this is only occasionally needed and can usually be done later, after the child grows up. Are there other types of vascular malformations that can be serious? Yes, the two conditions discussed above are on the surface of the body and among the easiest to deal with. Others may be deeper, and more extensive and complex. Vascular malformations can develop from any type of blood vessel and develop in any part of the body although the majority involve the extremities. They represent defects or development problems that occurred during embryonic growth. Depending on the stage of the development at the time this occurs, the result can involve arteries, veins, lymph vessels or combinations of these. In early embryonic development, all blood vessels appear as a diffuse network of simple channels and are not identifiable as the particular type of mature blood vessel they are destined to become. At later stages this network of vessels develops central channels of flow, finally becoming arteries and veins, and the small capillaries of the microcirculation.

Arterial-Venous CVMs
During these early developmental stages, large connecting channels or shunts between future arteries and veins exist, and a defect or arrest occurring at this stage may allow these artery-to-vein connections, or a cluster of them to persist. Such connections are called arteriovenous fistulas (AVFs), or if there is a cluster of them they are called arteriovenous malformations (AVMs). These are potentially the most serious type of CVMs because, in shunting blood from arteries to veins, they bypass the small vessels that make up the normal circulation beyond that point. This not only robs or steals blood that would otherwise pass through to more distant tissues and nourish them, but doesn't allow for a gradual pressure drop from the high arterial pressure to the low pressure on the venous side. Thus these AVFs represent a high flow short-circuit, and depending on their size and location they may respectively force the heart to work harder. They may also cause poor circulation in the limb beyond the point of the AVF. In time, these AVFs tend to get bigger and have greater effect on the circulation. For example, an AVF or AVM in an extremity can "steal" (reduce) blood flow to a foot or hand as much as a blocked artery would. Fortunately, AVFs located in the legs and arms are more common than elsewhere in the body and thus easier to deal with. Those involving pelvic vessels, or vessels to vital organs or the brain can be extremely difficult to treat without injuring the organs or tissues they lie in. Clearly, although AVFs make up only one-third of all CVMs, they attract the most attention because of the more serious nature of the problems they create, and are the CVMs most likely to need interventional treatment.

Venous CVMs
CVMs composed entirely of veins, which are numerically the most common, comprising almost half of the total, are of two basic types. The more primitive ones appear as thin-walled lakes in which venous blood collects and when they develop in groups or clusters they may form a mass consisting of a collection of grape-like clusters of these venous lakes. This type usually does not affect the venous circulation which returns blood to the heart, but these masses of venous malformations can be unsightly, cumbersome or be the site of blood clots (which fortunately are not the kind that travel to the heart or lungs). They are more annoying than being a serious threat, but nevertheless may be worth treating if the mass is large and causes local problems, for example, interfering with walking.

The other type of venous defect involves the large deep or central veins and often interferes with their function. Segments of major veins may be absent or narrowed. Or segments may be greatly widened and expanded (dilated), called a venous aneurysm. Depending on how severely they affect venous return or contribute to deep venous thrombosis (DVT) determines treatment. Most of the venous malformations involve only short venous segments and do not require treatment.

Arterial CVMs
Arterial defects or malformations are the least common type of CVM, being responsible for only 1-2 percent of the total. The most common arterial defect involves a segment that did not develop. The result is that a normal arterial segment is missing and instead blood flows through a normally undeveloped side channel or collateral artery which persists rather than withers. Although this allows bypassing the blockage, the enlarged bypassing segment often becomes more vulnerable to compression and injury, developing into an aneurysm or suddenly clotting off. The most common example of this is the so called persistent sciatic artery.

How does one recognize a CVM and what are the appropriate diagnostic approaches? When located in an extremity, CVMs may show up as a birthmark, a visible or palpable mass of blood vessels, or may stimulate the development of collateral blood vessels in the form of varicose veins, or produce an enlargement of the limb or a lengthening of the limb by stimulating its bony growth centers. The localized masses may be of various sizes from small to huge and at their surface the vessels may be vulnerable to injury and bleed or may even break down and ulcerate. AVFs, by "stealing" blood from the circulation beyond them may cause "ischemic" pain, which is the medical term for the pain that results when the circulation is so restricted that the tissues, and the nerves serving them, do not get enough blood.

Years ago the only definitive way to evaluate blood vessel problems was by the injection of a contrast dye in them that would make them visible on x-ray, called an angiogram. However, since most CVMs do not need treatment, or treatment is often delayed until the child grows up and the need for treatment is more obvious, it is now rarely necessary to get angiograms as a first step. They may ultimately be needed, but only when intervention is required and even then are best obtained just before or at the time of such treatment.

Fortunately, great strides have been made in less invasive forms of vascular imaging. The localized superficial CVMs can often be initially studied more simply by a form of ultrasound imaging called a color duplex scan. Larger mass lesions can best be studied by Magnetic Resonance Imaging (MRI) which has the advantage of not only imaging the blood vessels involved by these malformations in multiple planes (view angles), but determining the anatomic extent of the malformation and importantly whether its involvement of surrounding tissues (muscles, nerves, bones and joints) might preclude or complicate surgical treatment.

When and how should these vascular anomalies be treated? As a general rule CVMs should be treated for specific indications: persistent pain, ulceration, bleeding, causing blood clots, obstructing major vessels, causing progressive limb asymmetry by overgrowth, and for cosmetic indications or because the vascular mass is cumbersome and leads to a badly misshapen limb or interferes with extremity function in a mechanical way. Since most of the patients with the worst CVMs present early in life, the timing of any intervention should be done with a mind to interfering the least with the child's growth and development. Often it is better to delay operating on very young children if possible.

In the past, the only treatment for these vascular anomalies was surgical removal. However only a minority, around 10 to 15 percent, of those CVMs that were significant enough to justify operation could be totally removed by surgery. Even then, removing even the simplest of these vascular malformations could lead to a bloody procedure with considerable blood loss and therefore significant risk.

Surgery may still be appropriate for localized, accessible lesions but in the last few decades techniques using catheters have been developed. Catheters are placed (usually through a groin vessel) and advanced into the lesions and the malformed vessels are blocked, or embolized, with a variety of injectable particles, substances or devices such as polyvinyl foam, biological glues, and absolute alcohol.

These catheter embolization techniques can be used to control these lesions without surgery. They can also shrink larger CVM's to make them more readily treatable by surgery. Laser therapy may also be effective for small localized birthmarks (port wine stains). Patients with a rare venous malformation (Klippel-Trenaunay Syndrome) of the limbs frequently benefit from elastic garments and bandages used for compression of the large veins. After careful evaluation, surgery or less invasive therapy of the enlarged superficial veins can also be helpful.

Congenital vascular malformations can be extremely complex and proper diagnosis and selective treatment at the appropriate time requires experience, skill and judgment. Management is usually best left to those major centers that specialize in treating this type of problem. Most vascular surgeons and other vascular specialists are capable of the initial evaluation and know where and when to refer these patients for interventional treatment when it is required.

About the author: Robert B. Rutherford, MD, is one of the early pioneers in vascular surgery and is the author of the textbook used to train vascular surgeons. Now retired, Dr. Rutherford is Professor Emeritus and was the Chair of the Division of Vascular Surgery of the University of Colorado Health Sciences Center for over 20 years. The Vascular Disease Foundation is privileged to have Dr. Rutherford serve as a special advisor to its Board of Directors.