Arteriovenous malformations (AVMs) are complex vascular malformations that are often discovered incidentally during the evaluation of diseases of the central nervous system (CNS). The main problem is the risk of spontaneous cerebral hemorrhage. Here you can learn everything about the causes, risk factors, and available modern treatment options.
The goal: to completely eliminate the arteriovenous malformation. This is the only way to eliminate further bleeding risk. A precise, innovative, and low-side-effect treatment option is CyberKnife or ZAP-X therapy—both procedures we offer at ERCM.
Are you interested in a customized treatment? Our team of experts will discuss the optimal therapy approach with you in detail.
If you as a patient have been diagnosed with arteriovenous malformations, AV malformations or AVMs for short, you should be cared for by an interdisciplinary team of experienced experts in neurosurgery, neuroradiology, radiotherapy and neurology – a team of specialists who are familiar with your clinical picture and who pursue individually tailored treatment concepts [1].
The choice of treatment method must always be carefully considered on an individual basis. In some cases, a combination of different methods may be necessary and appropriate to achieve AVM closure.
Possible treatment options include the state-of-the-art, non-invasive, robot-guided precision treatment with CyberKnife therapy and ZAP-X therapy. These two innovative procedures enable the targeted destruction of malformations, while protecting the surrounding healthy tissue.
Here at ERCM, we have already treated hundreds of patients with AV malformations, in many cases in an interdisciplinary capacity with our neurosurgical and neuroradiological partners. Individual patient cases are discussed in detail and individually, for example, at our weekly Neurovascular Board conference with the Stroke Center at the Großhadern Hospital of the University of Munich (LMU).
Arteriovenous malformations are abnormal vascular malformations that are usually congenital and can occur in any region of the brain. They consist of a nidus ( Latin for nest) – a kind of vascular cluster – of supplying vessels (arteries) and draining vessels (veins). What this cluster lacks, however, is an intervening network of small capillaries, which is why arteries merge directly into veins, like a short circuit.
For this reason, among other things, blood flow is increased, which in turn results in a high cumulative risk of cerebral hemorrhage [1]. Other factors that play a role include patient age, previous bleeding, and hormonal factors, especially in women.
The incidence of this disease is 10 to 18 cases per 100,000 inhabitants [1]. Symptoms usually appear between the ages of 20 and 50 [2]. For example, about one-third of all affected individuals develop epileptic seizures [1].
In principle, a distinction is made between symptomatic and asymptomatic arteriovenous malformations. There are forms of the disease that cause symptoms such as headaches, seizure disorders, neurological deficits, or that have already triggered a cerebral hemorrhage. However, there are also asymptomatic forms that do not cause neurological deficits and have not yet caused bleeding.
Headaches, epileptic seizures, and paralysis are common. Depending on the location of the arteriovenous malformation, speech or memory impairment may also be present. Pulsatile tinnitus is rare [1].
The most common symptom, occurring in over 50% of cases, is intracerebral hemorrhage. Larger studies estimate the risk of this bleeding to be approximately 1 to 2% per year. The risk of bleeding is higher in cases of large vascular malformations that have already bled.
Arteriovenous malformations are generally considered a congenital condition. They are also the most common cause of hemorrhagic strokes in children and young adults [3].
Imaging diagnostics allow the arteriovenous malformation to be further classified based on its size, location, and hemodynamics—the dynamics of blood flow in your vessels—(Spetzler-Martin classification). This medical classification describes the extent of the vascular malformations in a total of five levels of severity. The specific treatment plan and available treatment options, which we will always discuss with you in detail, are also based on the individual severity.
Computed tomography with CT angiography (CTA) is often sufficient for the primary diagnosis [1]. CTA allows the vascular tangle – the nidus – to be defined very well.
Digital subtraction angiography (DSA) also provides a complementary visualization of the vascular architecture and flow dynamics of the blood.
Magnetic resonance imaging (MRI) is used for precise localization of the pathological vascular tangle – especially in relation to functionally relevant brain regions. MRI is therefore a prerequisite for precise treatment planning [1].
Left: Illustration of a frontal arteriovenous malformation on MRI.
Right: Precise depiction using digital subtraction angiography (DSA). It is clearly visible that in an AV malformation there is no network of tiny capillaries interposed between arteries and veins. The abnormal tangle of vessels appears as black, winding lines and dots.
The treatment decision is based on the individual clinical symptoms, the results of imaging diagnostics, the potential risk of symptomatic cerebral hemorrhage, and above all the risks of the individual treatment options [1].
For this reason, close cooperation among all treating specialists is particularly important in vascular malformations such as arteriovenous malformations and is a prerequisite for successful treatment.
This treatment focuses on the therapeutic occlusion of the feeding and draining vessels using medical adhesive or particles, as well as small coils, via a catheter that is usually inserted through the groin and advanced into the vascular malformation.
Surgical resection is an invasive therapy involving complete removal of the vascular malformation with selective occlusion of the feeding and draining vessels while preserving the surrounding cerebral vessels.
Robot-guided, non-invasive precision treatment with CyberKnife or ZAP-X therapy is an innovative and effective treatment option. This state-of-the-art method is particularly suitable for vascular malformations that are difficult to access [1, 4]. However, a combination with embolization is also conceivable, especially if the existing arteriovenous malformation is not suitable for surgery or embolization alone, or if only partial occlusion can be achieved after embolization [5].
In robot-guided high-precision treatment with CyberKnife or ZAP-X therapy, photons are highly focused in the center of the vascular malformation, causing long-term occlusion of the diseased vessels. This is done while preserving the remaining normal cerebral blood flow.
In this video, ERCM Director Prof. Alexander Muacevic, MD, explains the method, which is characterized by its high precision, minimal side effects, and non-invasive nature, resulting in a significant reduction in complications and rapid recovery for patients.
Therapy options that have become more complex also mean that your personal decision for therapy should always be made with a view to your personal life situation. We accompany you on this path and advise you comprehensively with regard to the best possible treatment concept for you individually. Contact us and use our contact form.
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An arteriovenous malformation is not a tumor in the strict sense. While tumors consist of cells that proliferate uncontrollably, arteriovenous malformations are vascular anomalies—translated: composed of congenital abnormal blood vessels.
An arteriovenous malformation is a short circuit between small arteries and veins of the cerebral blood vessels. An aneurysm is a bulging of a blood vessel at a branching point; this can also lead to cerebral hemorrhages.
The danger of vascular malformations lies in the risk of cerebral hemorrhage, which can occur in both large and small abnormal vessels. Depending on the extent and location of the bleeding, symptoms may range from mere headaches to severe neurological deficits.
Arteriovenous malformations are not malignant, as they do not contain cancer cells. However, they are abnormal and can be dangerous because they can cause cerebral hemorrhages. With such vascular malformations, the concern is always the risk of bleeding and neurological symptoms, not malignant growth.
An arteriovenous malformation can rupture if the pressure in the blood vessels becomes too high, but this happens only rarely. Vascular malformations are generally asymptomatic or cause only minor symptoms. Most affected individuals live with them without ever experiencing a hemorrhage.
In very small vascular malformations, this is theoretically possible, but extremely rare.
Yes, such vascular malformations also occur in other regions of the body, for example in the spinal cord. In principle, arteriovenous malformations can develop anywhere in the body where there is a denser blood supply.
[1] Poppert, H. et al., Zerebrale Gefäßmalformationen. S1-Leitlinie 2023, in: Deutsche Gesellschaft für Neurologie; Hrsg. Leitlinien für Diagnostik und Therapie in der Neurologie.
https://register.awmf.org/de/leitlinien/detail/030-088
[2] Diener, H. C., Steinmetz, H., Kastrup, O., Stahl, B., Staiger, A. et al., Referenz Neurologie, Print ISBN: 9783132413870; Georg Thieme Verlag KG, Stuttgart 2019.ngstreth Jr., W. T., Weber, F., Yi-Chung, L. et al., Incidental findings on brain magnetic resonance imaging: systematic review and meta-analysis. BMJ 2009;339:b3016.
https://eref.thieme.de/ebooks/cs_9846568#/ebook_cs_9846568_cs9583
[3] Tasiou, A., Tzerefos, C., Alleyne Jr., C. H., Boccardi, E., Karlsson, B. et al., Arteriovenous Malformations: Congenital or Acquired Lesions? World Neurosurg 2020;134:e799-e807.
https://www.sciencedirect.com/science/article/abs/pii/S1878875019328360?via%3Dihub
[4] Greve, T., Ehret, F., Hofmann, T., Thorsteinsdottir, J., Dorn, F. et al., Magnetic Resonance Imaging-Based Robotic Radiosurgery of Arteriovenous Malformations. Front. Oncol. 2021;Volume 10:608750.
https://www.frontiersin.org/journals/oncology/articles/10.3389/fonc.2020.608750/full
[5] Steiner, L., Lindquist, C., Cail, W., Karlsson, B., Steiner, M., Microsurgery and radiosurgery in brain arteriovenous malformations. J Neurosurg 1993;79:647-652.
https://thejns.org/view/journals/j-neurosurg/79/5/article-p647.xml