Periprocedural bleeding complications of brain AVM embolization with Onyx

Abstract

The advent of Onyx has provided a new method for neurointerventional therapists to treat brain AVMs. Although some retrospective studies have reported complications for AVM embolization with Onyx, periprocedural bleeding complications with Onyx embolization have not yet been described in detail. The aim of this retrospective study was to analyze the factors of Onyx-related bleeding complications and to find a way to avoid and manage these complications.From January 2003, patients with AVMs recruited in our institution started to be treated by Onyx embolization. From January 2007 to July 2009, 143 consecutive interventions were performed in 126 patients using flow-independent microcatheters and Onyx as embolic agents. Seven patients encountered bleeding complications (5.4% per patients and 4.7% per procedures) during or after the endovascular procedures. Among them, five bleeding episodes occurred during procedures, the other two after procedures. Details of the seven patients' clinical presentations, imaging presentations, speculative reasons and management of these complications were recorded. Follow-up data, including postoperative course, clinical symptoms and duration of follow-up were documented. The five active bleedings discovered in procedures were managed in time, and the patients recovered without any new neurological symptoms compared with preoperation. However, of the two bleeding episodes that occurred after interventional procedures, one was detected half an hour later: the patient was remained comatose two months later after resection of right occipital hematoma; the other who encountered intraventricular and midbrain hemorrhage was treated conservatively and suffered Parinaud syndrome and hemianesthesia.

Conclusion: Periprocedural bleeding of AVMs embolization is considered a severe and devastating complication. The clinical course and prognosis of bleeding mostly depends on prompt detection and management. Interventional embolization is an effective method to manage bleeding during procedures, and the detection of risk factors and imaging signs of bleeding is extremely important.

Figure 1

Case 1. A) Angiogram before embolization. B) Angiogram after catheter retrieval. C) Contrast medium in the central sulcus could be seen during fluoroscopy (arrow). D) The whole vessel was occluded, only the stump of the vessel could be seen (arrow). E) CT scan immediately after embolization. F) CT scan the day after embolization shows the contrast agent was absorbed very quickly. G) MRI 3 months later.

Figure 2

Case 2. A) Angiogram before embolization. B) Contrast agent extravasation after occluding 1 feeding pedicle. C) The draining vein cannot be seen even in venous phase, and the contrast agent stagnation in the hematoma confirms draining vein occlusion. D) Contrast agent stagnation during fluoroscopy. E) CT scan immediately after embolization. F) CT scan when the patient was discharged. G) Follow-up angiography six months later, shows completely occlusion of the AVM.

Figure 3

Case 3. A) Angiogram from the carotid artery before embolization: note a hemodynamic-related aneurysm and the draining vein. We embolized the AVM and the aneurysm through RICA-AcomA-LICA. B,C) The angiogram and fluoroscopy after embolization through LACA, internal carotid artery injection showed the AVM was no longer filled, and the aneurysm was embolized as well, but we can see contrast agent in the lateral ventricle and the hematoma (arrow). D) The venous phase of the vertebral injection before embolization through the cortical branch of the PCA no longer shows the draining vein, but there was an AVM remnant. E) Vertebral injection after embolization through the medial posterior choroidal artery. F,G) CT scan postprocedure before discharge.

Figure 4

Case 4. A) A-P position carotid angiogram before embolization shows intranidal aneurysms. B) Superselective angiogram before Onyx injection displays contrast medium extravasation. C) The contrast medium diffused into the subarachnoid space during fluoroscopy. D) Angiogram after the procedure, the intranidal aneuryms disappeared. E) CT scan immediately after embolization appears to show severe SAH, but the patient did not have any symptoms.

Figure 5

Case 5. A) Vertebral angiogram before embolization. B) Angiogram after embolization shows the contrast agent diffused into the lateral ventricle. C) A-P angiogram after embolization: the arrow shows the contrast in the lateral ventricle. D) CT scan immediately after embolization appears to show severe IVH so we gave the patient extraventricular drainage post procedure. E) Angiogram follow-up six months later.

Figure 6

Case 6. A) Lateral position vertebral injection before embolization, both the two main draining veins can be seen. B) Vertebral injection, venous phase, contrast medium is stagnant in a small intranidal aneurysm. This was not noted during the procedure. C) The patient experienced a sudden coma two days after the procedure, CT scan showed midbrain hematoma and IVH. The patient suffered Parinaud syndrome and hemianesthesia, the Parinaud syndrome gradually recovered 2 months later, but the hemianesthesia was not remarkably improved.

Figure 7

Case 7. A) Vertebral injection before embolization. B) Vertebral injection after embolization showing the AVM was partially embolized; the draining vein was well protected. C) The patient complained of a sudden severe headache half an hour later, then became comatose. The CT scan showed a large hematoma in the right occipital lobe.