Arteriovenous malformations are not very common but they are still being studied extensively by doctors and scientists to devise new ways to diagnose them, prevent their subsequent complication in the form of hemorrhage, and minimize the signs and symptoms associated with brain and spinal AVMs. In some patients, the symptoms start to appear between the age of 10 and 40, while some patients do not experience any sign at all till the AVM ruptures and causes internal bleeding.
Clinical and laboratory research is being undertaken by doctors particularly neurologists all over the world in the context of central nervous system vascular lesions to find new treatment options, assess results of combined treatments, see if certain AVMs grow in size or remain the same throughout the lifetime, and study the effects of multiple lesions in the brain along with arteriovenous malformation. Some of the topics that have been covered in previous research and case studies include;
• Artificial embolization for the treatment of AVMs
• History of asymptomatic malformations of the brain
• A link between intracranial AVMs and dural arteries
• Connection of subarachnoid hemorrhage with AVMs
• Bleeding characteristics of cerebral arteriovenous malformations
• New grading system for AVMs
A good number of clinical studies are available in literature regarding the study of arteriovenous malformations and their several types. Some of these are described below:
– Arteriovenous malformations of the brain: natural history in unoperated patients
o In this study, a total of 217 patients with AVMs were managed without being operated on. It was found after about 10 years that the risk of hemorrhage was 42% and the risk of death was 29%. Many other complications and symptoms were also studied including epilepsy and neurological handicap.
– A proposed grading system for arteriovenous malformations
o A new grading system to grade the lesions has been proposed in this study, which would be used to predict morbidity and mortality in patients with AVMs depending on the size of the lesion, venous drainage pattern, and neurological health of the brain. According to this system, Grade I lesions are usually very small in size and are superficial in nature and Grade VI lesions are large, extremely deep, and totally inoperable.
– The natural history of symptomatic arteriovenous malformations of the brain: a 24-year follow-up
o A total of 166 patients with symptomatic AVMs (not operated on) were studied giving a follow-up period of about 24 years. It was found that the rate of rebleeding was 4% per year and the rate of mortality was found to be 1% per year. About 23% of the cases died during the study from brain hemorrhage.
– Artificial embolization of cerebral arteries: report of use in a case of arteriovenous malformation
o Vascular embolization is a treatment option available not just for patients with arteriovenous malformations but also other lesions in the brain and spinal cord. This study proposes an artificial way to achieve the objective of this procedure. It was found that certain large AVMs that are too risky to be removed by surgery can be treated with artificial embolization.
– Bleeding from cerebral arteriovenous malformations as part of their natural history
o A total of 191 patients were studied in this research having brain AVMs to see chances of a hemorrhage influenced by some other factors like age, sex, and location of the lesion. It was found that among those 191 patients, 102 experienced a single hemorrhage and 32 experienced more than one hemorrhage. There were 57 patients who did not experience any hemorrhage or bleeding because of their AVM. It was also found that size of the AVM had a great impact on the risk of hemorrhage.