Vascular malformations are abnormal clusters of blood vessels that develop while the foetus is in the womb. There are a number of different types of vascular malformations. Venous malformations are veins which have developed abnormally, and are the most common form of vascular malformations. Lymphatic malformations are sponge-like collections of abnormal growths that contain clear fluid. Venolymphatic malformations are vascular malformations that affect both veins and lymph vessels, resulting in cysts or varicose veins. Arteriovenous malformations are abnormal connections between veins and arteries.
While all forms of vascular malformation are congenital (present at birth), it may take weeks or even years for them to become noticeable.
The most common symptom is pain. Depending on the location of the vascular malformation, patients may experience other symptoms such as birthmarks and swelling of the limbs. If the patient has a lymphatic malformation, infection may cause complications. In some cases, arteriovenous malformations are stressful on the heart or cause bleeding complications. Patients with pulmonary arteriovenous malformations may experience symptoms such as low oxygen supply, shortness of breath, fatigue and coughing.
Often, vascular malformations are visible in a physical examination. If you have superficial vascular lesions, these can be evaluated with ultrasound, but for deeper lesions ultrasound is limited in the information it can provide. Ultrasound with Doppler sonography can be used to show the flow and speed of the blood.
MRI is the most useful diagnostic tool for evaluating vascular malformations. MRI can show the exact location of the core of the vascular malformation (known as the nidus), how far the malformation extends and how it is connected with the surrounding vessels. MRI can also be used to gain information on the blood flow in these lesions, and is useful for assessing the success of the treatment during follow-up.
Minimally invasive procedures include phlebography and angiography, which are performed under fluoroscopy. Contrast material is injected to aid visualisation of the vascular malformation. These techniques are usually performed before treatments such as sclerotherapy and embolisation.
Conservative treatment is a good option for patients with mild symptoms. It is not always feasible to surgically remove vascular malformations, and this treatment has a high rate of recurrence.
Minimally invasive image-guided interventions, performed by interventional radiologists, are the treatment of choice for vascular malformations. These techniques include embolisation and sclerotherapy, and are carried out under fluoroscopy. During these procedures, the interventional radiologist will guide a catheter to the vascular malformation and will then insert alcohol, glue or small beads into the surrounding vessels to block blood or lymph flow to the malformation. The aim of this is to destroy the core of the malformation, and the success of the procedure will be confirmed using angiography. Patients have a local anaesthesia for these procedures and tend to be hospitalised for one day. Patients may experience minimal discomfort for a couple of days.
1. Peripheral Vascular Diagnosis and Interventions, Peripheral Vascular Malformations: Imaging, Treatment Approaches, and Therapeutic Issues. Hideki Hyodoh, Masakazu Hori, Hidenari Akiba, Mitsuharu Tamakawa, Kazusa Hyodoh, Masato Hareyama, Rdiographics, October 2005, Volume 25, Issue suppl_1.
2. Vascular Malformations and Hemangiomas. A Practical Approach in a Multidisciplinary Clinic. L. Donnelly, D. Adams, G Bisset, American Journal of Roentgenology, March 2000, Volume 174, Number 3.