A Developmental Venous Anomaly (DVA) is a common variation in the brain’s venous drainage system. While the term “anomaly” might sound concerning, these are typically benign formations. They represent a normal, albeit atypical, way for blood to drain from a specific area of the brain.
What is a Developmental Venous Anomaly?
A DVA is a collection of small veins that converge and drain into a larger central vein, often described as resembling the spokes of a wheel or a “caput medusae” due to their appearance on imaging. These formations are congenital and are considered a variant of normal venous drainage rather than a true malformation or tumor. DVAs are quite common, found in an estimated 2% to 10% of the population, making them the most frequently encountered vascular variation in the brain. They function as a normal drainage pathway for healthy brain tissue.
How DVAs Are Discovered
Most DVAs are discovered incidentally during brain imaging scans, such as MRI or CT, performed for unrelated reasons. Individuals might undergo these scans for symptoms like headaches or dizziness, or following a minor head injury. The vast majority of people with a DVA do not experience any symptoms directly caused by the DVA itself. This incidental discovery underscores their benign nature, as many individuals live their entire lives unaware of having a DVA.
Understanding Potential Risks
Isolated DVAs, those not accompanied by other vascular lesions, rarely cause problems. However, DVAs can sometimes be found alongside another type of vascular lesion called a cavernous malformation, also known as a cavernoma. It is typically the cavernous malformation, rather than the DVA itself, that can lead to symptoms such as bleeding or seizures. The association between DVAs and cavernous malformations is common, with studies indicating they can coexist in 8% to 44% of cases.
In extremely rare instances, an isolated DVA might lead to complications like a blood clot (thrombosis) or hemorrhage. Such events are uncommon and often linked to factors disrupting normal blood flow within the DVA’s drainage system. The risk of bleeding from an isolated DVA is very low, estimated to be less than 0.7% per year. These rare symptomatic cases are often attributed to issues such as venous congestion or outflow obstruction.
Living with a DVA
For most individuals diagnosed with an isolated DVA, no specific medical treatment is necessary. Since these veins are functioning drainage pathways for normal brain tissue, attempting to remove or alter them can carry significant risks. Therefore, surgical intervention is generally avoided for isolated DVAs.
Regular follow-up imaging is typically not required for asymptomatic DVAs unless there are new symptoms or specific concerns. Most DVAs remain stable throughout a person’s life and do not cause health problems. If a DVA is found in conjunction with another lesion, such as a cavernous malformation, the management approach would primarily focus on addressing the associated lesion.