Delayed Rebleeding from Pseudoaneurysm After Mechanical Thrombectomy Using Stent Retriever Due to Small Artery Avulsion Confirmed by Open Surgery

Acute internal carotid artery occlusion due to dissection of the paraclinoid segment: Diagnostic usefulness of angiographic findings during stent retriever deployment

Intracranial artery dissection is an uncommon but possible cause of ischemic stroke, and is usually diagnosed based on imaging findings such as mural hematoma and dissection flap. However, it is challenging to recognize the underlying dissection in cases of acute large vessel occlusion. In this report, we present a case of acute internal carotid artery occlusion, in which the underlying dissection of the paraclinoid segment was found during the thrombectomy procedure. Two thrombectomy procedures failed to recanalize the acute internal carotid artery occlusion without removing any clot. Angiography performed during a Trevo stent retriever deployment in the first pass showed obscure contrast defects in the stent strut with temporary flow restoration. In the next pass, the appearance of the contrast defects changed and a parallel linear contrast appeared on the outside of the vessel wall. These angiographic findings were identified as mural hematoma and dissection flap, indicating dissection of the paraclinoid as the cause of the occlusion. During antiplatelet loading and preparation of a dedicated intracranial stent, the Trevo stent retriever was left deployed again at the occlusion site to maintain the blood flow. After permanent stenting with an Enterprise stent, angiography revealed complete recanalization. The patient recovered fully after the procedure. In the present case, stent retriever deployment revealed the hallmarks of dissection on angiography, such as mural hematoma, dissection flap, and temporal morphological changes, by restoring the blood flow temporarily. Such angiographic findings can provide useful information on the occlusion characteristics and real-time feedback for optimal treatment strategy.

Traumatic pseudoaneurysm resulting from avulsion of the falcine branch of an azygos anterior cerebral artery: a case report

Traumatic anterior cerebral artery (ACA) aneurysms are extremely rare. Traumatic anterior ACA aneurysms are thought to develop when the ACA at the pericallosal segment travel adjacent to immobile falx cerebri. As the majority of aneurysms are pseudoaneurysms, direct neck clipping is usually not possible, and it is often necessary to carry out direct or endovascular trapping in conjunction with proficient bypass techniques. The authors describe the first reported case of a traumatic ACA pseudoaneurysm resulting from avulsion of the falcine branch of an azygos ACA. In this case, the lacerated aneurysm wall was successfully sutured, without the need for a bypass. Neurosurgeons should be aware that avulsion of the falcine branch arising from the ACA can occur, and that this may cause a traumatic aneurysm on the distal ACA. Furthermore, direct suturing of a lacerated arterial wall should be considered a treatment option for this type of traumatic intracranial aneurysm.

Crossing double stent retriever technique for refractory terminal internal carotid artery occlusion

Mechanical thrombectomy is highly effective for the recovery of acute ischemic stroke with large vessel occlusion. However, refractory occlusions are still encountered despite the use of currently available devices. In this article, we present a case of refractory terminal internal carotid artery occlusion treated with the "crossing double stent retriever technique." Two thrombectomy procedures with the combined technique using a stent retriever and aspiration catheter failed to recanalize the terminal internal carotid artery occlusion that involved the dominant anterior cerebral artery. We then applied the crossing double stent retriever technique as a rescue technique. Two microcatheters were advanced across the occlusion: one to the anterior cerebral artery and the other to the middle cerebral artery. First, a Trevo NXT 4 mm stent retriever was deployed from the anterior cerebral artery. Next, an additional Trevo NXT 4 mm stent retriever was deployed from the middle cerebral artery, and full immediate restoration of flow was achieved on angiography. Intraprocedural radiological images showed that the 2 microcatheters traversed different pathways, and the 2 stent retrievers completely covered the entire vessel with apparent in-stent clot sign. Both stent retrievers were then pulled back together, and a hard clot was retrieved. Subsequent angiography revealed complete recanalization. The crossing double stent retriever technique seems an effective rescue technique for treating refractory terminal internal carotid artery occlusion, especially with the anatomical feature of branching of the dominant anterior cerebral artery. This technique can facilitate the device-clot-vessel interaction by engaging the clot via 2 different device pathways.

Delayed Rupture of an Anterior Communicating Artery Pseudoaneurysm Caused by Distal Occlusion Thrombectomy Using a Stent Retriever: A Case Report and Mechanism of Injury

We report a case of delayed rupture of an anterior communicating artery (Acom) pseudoaneurysm following mechanical thrombectomy (MT) of a distal artery occlusion using a stent retriever. An elderly patient with right hemiparesis showed left proximal internal cerebral artery and middle cerebral artery occlusions. During MT, a fragmented thrombus moved to the anterior cerebral artery (ACA). A stent retriever was deployed to the occluded ACA, and the Acom and proximal ACA segment were significantly straightened. Additionally, we attempted a blind exchange mini-pinning (BEMP) technique, but a subarachnoid hemorrhage (SAH) occurred. Bleeding was almost entirely absorbed 9 days after the procedure, but the SAH recurred at 20 days, and computed tomography angiography revealed a new pseudoaneurysm formation in the Acom. We suggest that the proposed mechanism of pseudoaneurysm formation was likely due to the dislocation and avulsion of the Acom perforators when the ipsilateral ACA was pushed and pulled during MT.

Iatrogenic intracranial vessel dissection during mechanical thrombectomy rescued by emergent stenting: 2 case reports

Intracranial vessel dissection is a procedural complication associated with endovascular treatment. However, there have been few reports on its potential causes and management during mechanical thrombectomy. In approximately 250 cases of mechanical thrombectomy over the past 5 years at our institution, iatrogenic intracranial dissection occurred in 2 patients (0.8%). In this report, we described these 2 cases that were rescued through emergent stenting. Mechanical thrombectomy, using both a stent retriever and an aspiration catheter, was performed for acute middle cerebral artery M2 occlusion in Patient 1 (a 69-year-old man) and for distal M1 occlusion in Patient 2 (an 83-year-old woman). In both cases, recanalization was achieved with the procedure, but irregular stenosis developed at the initially nonoccluded, but mildly arteriosclerotic, M1, after recanalization. During the thrombectomy procedure, the aspiration catheter sifted up to the arteriosclerotic M1. In both cases, the lesions were considered vessel dissection, due to a shift of the aspiration catheter tip into the arteriosclerotic vessel wall. Repeated percutaneous angiography with antithrombotic therapy failed to improve the lesions and to maintain the antegrade blood flow. Finally, lesions in each patient were successfully rescued through the use of emergent stenting. A drug-eluting stent for coronary use was deployed in Patient 1, and an Enterprise stent was applied in Patient 2. Inadvertent shift of the aspiration catheter into arteriosclerotic vessels can cause a serious intracranial vessel dissection. When performing mechanical thrombectomy, intracranial stents need to be available as rescue treatment devices to manage refractory iatrogenic intracranial vessel dissection.

Sylvian Hematoma Removal after the Stent-Retriever Thrombectomy Accompanied by Arteriole Avulsion: Case Report

Objective

We describe an instructive case of post-thrombectomy subarachnoid hemorrhage (PTSAH) by sylvian hematoma removal.

Case Presentations

An 83-year-old female presented with an acute cardiogenic right M1 occlusion. After the thrombectomy with combined stent retriever and aspiration technique with total five passes, TICI 2b reperfusion was achieved; however, CT imaging displayed subarachnoid hematoma (SAH) along the right sylvian fissure. Throughout the approach, contrast extravasation was not confirmed. The SAH grew up to become the sylvian hematoma; therefore, removal of the sylvian hematoma was conducted. An abrupt arteriole tear around the distal M2 of parietal artery was confirmed as bleeding point and those teared arteriole's stumps were electrically coagulated not to re-bleed.

Conclusion

We suggest that the PTSAH is possible even in invisible-extravasation cases and the sylvian hematoma removal is effective to elucidate the etiology of the PTSAH, and is a reliable method to prevent the re-bleeding and is anticipated to improve the prognosis. Craniotomy is required for medically resistant PTSAH after thrombectomy, and avulsion of the pial artery can be the cause.

Intracranial Pseudoaneurysms: Evaluation and Management

Intracranial pseudoaneurysms account for about 1% of intracranial aneurysms with a high mortality. The natural history of intracranial pseudoaneurysm is not well-understood, and its management remains controversial. This review provides an overview of the etiology, pathophysiology, clinical presentation, imaging, and management of intracranial pseudoaneurysms. Especially, this article emphasizes the factors that should be considered for the most appropriate management strategy based on the risks and benefits of each treatment option.

Impact of introducing endovascular treatment on acute ischemic stroke outcomes: A shift from an era of medical management to thrombectomy in Japan

Background

Endovascular treatment (EVT) has increasingly become the standard treatment of acute cerebral large vessel occlusion (LVO). We evaluated the impact of introducing EVT on LVO therapy in a single center where intravenous thrombolysis (IVT) had been the only recanalization therapy.

Materials and methods

Between April 2013 and March 2017, 354 consecutive patients with LVO admitted to our institution were analyzed. We compared outcomes between two chronological groups before (Pre-EVT group) and after (Post-EVT group) introducing EVT in April 2015. We assessed prognostic factors for favorable outcomes (modified Rankin scale score ≤2 at 90 days).

Results

In the Pre-EVT group, all 140 patients were treated medically, including 30 patients (21%) undergoing IVT. In the Post-EVT group, 118 patients (55%) underwent EVT, and the remaining 96 patients treated medically, including six patients (3%) undergoing IVT. The proportion undergoing recanalization therapy with IVT or EVT significantly increased after introducing EVT (21% versus 58%, p < 0.001). The rate of patients achieving favorable outcomes also significantly increased (14% versus 31%, p < 0.001). In multivariate regression analysis, introducing EVT was an independent predictive factor after adjusting for age, stroke severity and extent, and time (p = 0.005). The arrival time in patients with helicopter transport was significantly shorter than that with ground ambulance for a distance of more than 10 km (p < 0.001).

Conclusions

This study demonstrated that the introduction of EVT improved outcomes of acute LVO patients, increasing the opportunity to receive recanalization therapy. Further efforts to establish medical systems to provide EVT are required throughout the country.