Spontaneous Thrombosis of the Main Draining Veins Revealing an Unruptured Brain Arteriovenous Malformation
A case of AVM was presented and surgical details presented and discussed.
KeywordsAVM Thrombosis Treatment
Spontaneous venous thrombosis in unruptured AVM is rare and only seven cases have previously been published [1, 2, 3, 4, 5, 6, 7]. The revealing clinical symptoms were headache (3/7), seizure (3/7) or mild hemiplegia (1/7). Among those seven AVMs, 71% (5/7) were small (<3 cm) and 29% (2/7) were medium in size (3–6 cm). Venous drainage was superficial in 71% of the cases (5/7) and mixed in the remaining 29% (2/7). The main pathological basis of draining vein occlusion is venous thrombosis. Pathomechanisms proposed to explain spontaneous thrombosis of the draining vein are venous stagnation related to stenosis of the draining vein, alteration of the endothelium of the main draining vein, thrombophilia/acquired coagulation disorders and mass effect related to the nidus on the main draining vein [3, 4]. Based on the pathological mechanisms, the occlusion of draining vein is always permanent obliteration with a risk of bleeding . In this case, The preoperative DSA showed that there was only little cortical venous drainage without main draining veins, which suggested a high risk of bleeding, and there was severe brain edema around the lesion. The spontaneous obliteration of AVM have similar clinical manifestations with conventional subtype. The revealing symptom of this patient was left limbs numbness. DSA showed that this malformation was supplied by distal branches of right MCA, and was through small cortical venous drainage. Bulky drainage venous thrombosis was found intraoperatively, which confirmed that this case was spontaneous occlusion of cerebral AVM due to drainage vein thrombosis. Treatment of an unruptured AVM with thrombosed main draining vein is not consensual. Previous studies indicated that low venous outlet draining meant a high risk of rupture . Early interventional therapy or operation is recommended if surgical indications existed. A retrospective literature showed that four patients were managed conservatively and the other three were treated by interventional embolization.
Conflict of Interest
The authors declare that there is no conflict of interest regarding the publication of this paper.
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