Abstract
An acute basilar artery occlusion is not an uncommon cause of stroke. It represents 6–10% of large vessel strokes and has been associated with poor clinical outcomes. Multimodal treatments have been introduced to recanalise a basilar artery occlusion successfully. However, all mechanical thrombectomy devices are not always usable in an emergent situation. We present a case of basilar artery occlusion treated with a stent retriever assisted by a vertebral artery vasospasm. We attempted thrombectomy with a stent retriever several times. However, the captured thrombus was not pulled out and migrated to the distal basilar artery and posterior cerebral artery due to anterograde flow of the vertebral artery. We carefully advanced the catheter into the distal vertebral artery and generated a vasospasm. The vertebral artery vasospasm reduced the forward flow significantly like a balloon-guided catheter. The thrombus was pulled out with the stent.
Keywords: Basilar artery occlusion, thrombectomy, vasospasm
Introduction
Acute basilar artery (BA) occlusion is the most devastating ischaemic stroke and is associated with over 50% major morbidity and mortality, even with aggressive endovascular intervention.1 The likelihood of a good outcome without recanalisation is less than 5%.2 Stent retrievers are often used in conjunction with another device, such as an aspiration thrombectomy catheter or a balloon-guided catheter.3,4 However, these devices are not preferred for posterior circulation and all mechanical thrombectomy devices are not always usable in an emergent situation. Here, we present a case of BA occlusion treated with a stent retriever assisted by a vertebral artery vasospasm.
Case report
A 67-year-old man presented to the emergency department with loss of consciousness at 07:10 hours. The patient was last seen as normal by his grandson at 21:00 hours the previous day. The grandson found him lying on the floor at 06:30 hours. He had a brainstem syndrome at admission, with stupor, left-sided hemiplegia and ophthalmoplegia. He had a medical history of hypertension. A non-contrast brain computed tomography scan did not demonstrate haemorrhage. His respiration became ataxic, and he was intubated on the way to the magnetic resonance imaging (MRI) room. Diffusion-weighted imaging showed scattered hyperintense lesions in the right thalamus, midbrain, pons and right cerebellum. Fluid-attenuated inversion recovery imaging showed no apparent signal changes. Perfusion-weighted MRI revealed severely impaired perfusion in the brainstem and cerebellum. Magnetic resonance angiography did not reveal the BA. He was brought to the endovascular suite for intra-arterial thrombolysis. Angiography was performed via the femoral approach using a 5F sheath and a diagnostic Headhunter (Cordis, Miami Lakes, FL, USA) catheter. Angiography showed an occluding clot in the proximal BA (Figure 1(a)). Once the location of the clot had been identified, the diagnostic catheter was removed, and a 6F guide catheter (Envoy; Cordis) was placed in the cervical segment of the dominant right vertebral artery. A mixture of 2000 IU heparin and 1000 ml 0.9% normal saline was administered continuously through the guiding catheter to prevent a procedural-related thromboembolic event. A Trevo-18 microcatheter (Concentric Medical, Mountain View, California) with a 0.014 in Synchro microwire was advanced distally to the clot. The microwire was removed, a Trevo retriever 4 × 20 mm was deployed to engage and snare the clot, left in place for 5 minutes, and then retrieved. We thought that a larger stent such as 6 × 30 mm was needed. Unfortunately, Trevo retrievers 6 × 20 mm and 6 × 30 mm were not imported into our country at that time. The microcatheter and the stent were withdrawn gently together. The clot was not pulled out during two thrombectomy attempts, and migrated gradually to the distal BA and the posterior cerebral artery due to anterograde flow of the vertebral artery (Figure 1(b)). We attempted the thrombectomy again while a 50 cc syringe maintained negative pressure through the guiding catheter to aspirate the thrombus and to prevent clot migration, but the thrombectomy failed. We thought that a vertebral artery vasospasm could arrest forward flow like a balloon-guided catheter. We slowly and carefully advanced the catheter into the V3 segment of the vertebral artery. An angiographic road-mapping after injection of contrast demonstrated a vertebral artery vasospasm with contrast stasis (Figure 1(c)). The thrombus was pulled out with the stent. The guiding catheter was withdrawn immediately, and angiography showed complete recanalisation (Figure 1(d) and 1(e)). The vertebral artery vasospasm was resolved, and no vascular injury occurred. A post-procedural non-contrast computed tomography scan excluded a procedural-related intracerebral haemorrhage. At five follow-up MRIs, there was no infarct growth in the brain and the BA was patent. The National Institutes of Health stroke scale score recovered to 7, and the patient progressed to ambulation with a walker prior to dismissal for rehabilitation.
Figure 1.
(a) Initial angiogram shows occlusion of the proximal basilar artery. (b) The thrombus migrated to the distal basilar artery and posterior cerebral arteries after three attempts to retrieve the stent. (c) After a guiding catheter was advanced into the V3 segment of the vertebral artery, an angiographic road-mapping demonstrated a vertebral artery vasospasm with contrast stasis. (d) Final angiography shows complete recanalisation. (e) The thrombus was trapped by the stent.
Discussion
An acute BA occlusion is not an uncommon cause of stroke, accounting for 6–10% of large vessel strokes, and has been associated with poor clinical outcomes including death and locked-in state.5,6 The factors associated with clinical outcomes are the clinical state at presentation, the location of the occlusion, early recanalisation, and the degree of recanalization.7 Multimodal treatments have been introduced to recanalise a BA occlusion successfully. Mechanical thrombectomy devices, particularly stent retrievers, have improved recanalisation success.8 One important component of a stent retriever is the balloon-guided catheter, which is inflated to arrest anterograde flow. Nguyen et al.9 reported using a balloon-guided catheter with a Solitaire stent retriever. Thrombolysis in cerebral infarction (TICI) 3 recanalisation was seen more often in cases when a balloon-guided catheter was used (53.7% with balloon-guided catheter vs. 32.5% without; P < 0.001). They concluded that arresting anterograde flow with the balloon-guided catheter is likely to be an important element to reduce migration of the entrapped thrombus. Our case results agree with their study. We attempted thrombectomy with a stent retriever several times. However, the captured thrombus was not pulled out and migrated to the distal BA and posterior cerebral artery due to anterograde flow of the vertebral artery. Applying negative pressure through a guiding catheter was not feasible. Espinosa de Rueda et al.10 suggested that thrombectomy with balloon-guided catheter and stent retrievers was feasible in the treatment of vertebrobasilar occlusion. However, we do not prefer a balloon-guided catheter for posterior circulation. There is an increased risk of dissection of the vertebral artery (compared to anterior circulation) while manipulating the balloon to and fro. Moreover, we did not have a balloon-guided catheter at that time and needed to find an alternative method. The vertebral artery is very sensitive and it is prone to vasospasm even in a little interventional attempt or touch, so it is expected to have vasospasm with a 6F guiding catheter. Therefore, we thought that a vertebral artery vasospasm could arrest the forward flow. Advancing the catheter into the distal vertebral artery requires caution to avoid dissection. We carefully advanced the catheter into the distal vertebral artery and generated a vasospasm. During the final attempts, the captured thrombus did not migrate to the distal BA and a complete recanalisation was performed. It was not a true negative aspiration by creating a vasospasm in the right vertebral artery as the flow from the left vertebral artery still continued, but the right vertebral artery was dominant and the vertebral artery vasospasm seemed to reduce the forward flow significantly like a balloon-guided catheter. Vertebral vasospasm can lead to pain and decreases blood flow to the vertebral artery branches. The duration of the vertebral artery vasospasm should be as short as possible.
Conclusion
In conclusion, multimodal thrombectomy devices have been introduced to achieve the successful recanalisation of BA occlusions. However, devices are not always available. Creating a vertebral artery vasospasm is feasible during a thrombectomy with a stent retriever when antegrade flow disturbs retrieving the captured thrombus.
Funding
The authors received no financial support for the research, authorship, and/or publication of this article.
Conflict of interest
The authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
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