Keywords► intracranial arteriovenous malformations ► arteriovenous fistula ► cerebral hemorrhage ► natural history of diseases
AbstractBrain arteriovenous malformations (AVMs) are relatively rare lesions with irreversible consequences in the context of hemorrhage. They are characterized by direct connections between arteries and veins without an intervening capillary network. The natural history of brain AVMs is controversial in the literature, with low evidence level gathered in the papers published, and with large divergence of results among them. A detailed understanding of the natural history is critical for treatment decision.The risk of development of deleterious outcomes such as hemorrhage or brain infarction should always be considered when submitting a patient to the risks of treatment. Several factors related to the patient and to the AVMs are determinants in the natural history of this disease. The topography, size, morphology and angioarchitecture of AVMs determine the risk of rupture. Large AVMs, those located in the posterior fossa and with deep venous drainage, have higher risk of rupture. Due to divergence in the literature regarding the natural history of AVMs, the choice of treatment should also consider experiences acquired over the years from reference centers with a high number of AVMs treated per year. We determined 7 variables that should be considered during the decision to treat an AVM: 1) previous hemorrhage; 2) aneurysm associated to the AVM; 3) direct arteriovenous fistula; 4) factors related to the nidus; 5) age and habits (smoking, sedentary lifestyle, diet quality); 6) the functional performance of the patient; 7) psychological factors.
ResumoMalformações arteriovenosas (MAVs) são lesões caracterizadas por conexões diretas entre artérias e veias sem rede capilar. São relativamente raras e com consequências muitas vezes irreversíveis no contexto de hemorragia. A história natural das MAVs é controversa na literatura, com pouca evidência extraída dos artigos publicados, além de alta divergência entre resultados. Um entendimento detalhado da história natural da doença é determinante para a decisão do tratamento. O risco de desenvolver
Atrial myxomas are the most common primary cardiac tumors and may manifest with neurological symptoms in ∼ 30% of cases. Cerebral ischemia, aneurysmal formation, and extravascular metastases are mechanisms that lead to these neurological manifestations. Perilesional changes on computed tomography (CT) and magnetic resonance imaging (MRI) may help in the diagnosis of myxomatous aneurysms, which are usually located in the distal middle cerebral artery (MCA) and in the posterior cerebral artery (PCA) circulation territories. Careful resection of the cardiac lesion is essential for preventing embolism. However, treatment of myxomatous aneurysms is controversial due to the limited understanding of the natural history of this condition. Treatment may include clinical observation in asymptomatic patients, surgical resection, endovascular approaches, adjuvant chemotherapy, and low-dose radiation therapy. We present one case of a female patient with myxomatous aneurysm secondary to an atrial myxoma who presented with neurological symptoms and another case of a female patient who developed neurological symptoms after initial surgical treatment of the primary lesion. Lesion growth rate, topography, morphology, and the patient's clinical condition must be considered when choosing a therapeutical method. Further clinical studies are needed to achieve a better understanding and treatment of this disease.
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