Flow-diverter reconstruction of an intracranial internal carotid artery dissection during thrombectomy for acute ischaemic stroke

Abstract

Intracranial carotid artery dissections are challenging, as there are no specific guidelines for their treatment, and most research suggests solutions for treating those involving extracranial vessels. We describe a patient with an acute ischaemic stroke within the territory of the right internal carotid artery, who was found to have intracranial carotid artery dissection during the thrombectomy procedure. The dissected lumen was successfully reconstructed via deployment of a Derivo flow-diverter stent. A balloon-assisted ‘jacking’ manoeuvre, in which a balloon is partially inflated at the beginning of the dissection to serve as leverage, was used to overcome the challenge of navigating the microcatheter tip through the stenosis proximal to the dissection. This case demonstrates the feasibly and safety of stenting with a flow diverter in a patient with internal carotid artery dissection; however, further studies are needed to confirm this finding.

Background

Intracranial carotid artery dissections are challenging, with no specific guidelines for their treatment.¹ Most observational studies, mainly of extracranial artery dissections, have reported the use of endovascular treatment.² Some authors have reviewed their experience performing stenting in cases of intracranial dissections using early devices with positive outcome.^{3 4} Interestingly, in two cases involving the supraclinoid carotid artery segment, the authors were unable to place the stent because of technical limitations.³

No study has evaluated the feasibility of flow-diverter stents in restoring vessel patency in the case of intracranial dissection with stenosis of the lumen without pseudoaneurysm. We report a patient with an acute ischaemic stroke in which the intracranial dissected arterial lumen was successfully reconstructed through the deployment of a Derivo flow-diverter stent, using a balloon-assisted jacking manoeuvre to aid in microcatheter navigation through the stenosis.

Case presentation

A 63-year-old man, previously asymptomatic, presented with a wake-up stroke with pronator drift in the left arm, motor drift in the left leg, left sensation loss, complete unilateral face paralysis, left hemianopsia, partial gaze palsy and moderate dysarthria, with National Institutes of Health Stroke Scale (NIHSS) score of 11. A head CT revealed fragmented infarction of the deep right internal carotid territory (internal capsule, lenticular nucleus, caudate and insula), and CT angiography showed irregular lumen of the lacerum, cavernous and supraclinoid portion of the intracranial carotid artery (ICA), suspected to be an intracranial dissection (figure 1A–C), along with right bulb ICA stenosis. On CT angiography, a ‘double lumen sign’ was identified, referring to the presence of an intimal tear that permits contrast material within both the real and false lumen. This sign was present at the level of the intracranial carotid artery near the anterior clinoid of the sphenoid sinus (figure 1B) and increased our suspicion of intracranial artery disease. The patient was taken to the interventional radiology suite after informed consent to perform an endovascular procedure.

Figure 1.

Diagnostic imaging (A) basal non-contrast CT showing infarcts at right basal ganglia level. (B) CT angiography showing a ‘double lumen sign’ in the right arterial carotid artery near the anterior clinoid of the sphenoid sinus. (C) Mask-subtracted volume rendering reconstruction of the CT angiography performed after basal CT, showing irregular narrowing of the ICA at the level of the lacerum, petrous and supraclinoid segment. (D) Anteroposterior dynamic-subtracted angiography of the right ICA, after the first stenting attempt, confirming an irregular tapering from the cavernous to supraclinoid segment consistent with a dissection.

Treatment

Thrombectomy procedure

A Neuron MAX 088 guide catheter (Penumbra, Alameda, CA) was navigated through an 8-French short sheath to the right common carotid artery. The first angiogram confirmed the irregular filling defect, indicative of a possible dissection affecting the intracranial extradural petrous, lacerum and cavernous ICA segments, and the intracranial intradural supraclinoid segment (figure 1D) along with right bulb ICA stenosis. Moreover, intracranial diagnostic digital subtraction angiography (DSA) demonstrated the presence of a string sign, a thin string of intravenous contrast material distal to the stenotic focus, which has been described in case of intracranial dissections. The stenotic focus was located in the carotid segment distal to the origin of the posterior communicating artery, arching slightly posteriorly and superiorly, completing the anterior ICA genu. This is referred as the ophthalmic segment and is the most proximal intradural portion of the supraclinoid ICA.⁵

Because of the acute presentation, the double lumen sign on CT angiography, and the irregular narrowing of the artery with the string sign ad DSA angiography, we believed this was an acute symptomatic dissection and we decided to perform stenting of the intracranial dissected vessel. We were aware that an intracranial stent would require long-term antiplatelet therapy to prevent thrombotic complications. We considered this reasonable since the dissection was at high risk for subsequent haemodynamic failure and the patient was symptomatic for acute ischaemic stroke.

We decided to perform a staged approach: First, to perform stenting to scaffold and stabilise the lesion. Second, during follow-up, to perform postdilation to enhance stent expansion, considering that stent under expansion is an important predictor of stent restenosis and thrombosis.⁶

Because of the self-expanding nature of the flow diverter that reduces the risk for thromboembolism in the first scaffolding, and their easier navigability that facilitates secondary postdilatation along with their feasibility to be deployed in cases of unfavourable vessel anatomy, we used a flow-diverting stent.

The patient was placed under general anaesthesia and acute antiplatelet therapy with inyespirin aspirin (900 mg, intravenous) and tirofiban (48 mL/h, intravenous) was administered. A Phenom 0.027 microcatheter (Medtronic, Irvine, CA) with a microwire Synchro 0.14 (Striker Neurovascular, Fremont, CA) was used to navigate the dissected segment of the ICA. Initially, it was infeasible to navigate the microcatheter through the cavernous segment because the dissection narrowed the lumen and the vessel tortuosity hindered the passage. Therefore, we decided to perform a balloon-assisted ‘jacking’ procedure. In this procedure, a balloon remodelling Sceptre XC (Microvention, Aliso Viejo, CA) was partially inflated and placed immediately before the dissected artery to lift the distal tip of the Phenom 0.027 microcatheter directing it to the true lumen (figure 2). In this way, the balloon catheter served as leverage to orient the tip of the microcatheter towards the true lumen (figure 3). The microcatheter was successfully navigated to the clinoid segment, and a 4×20 flow-diverter stent (Derivo, Acandis, Pforzheim, Germany) was deployed from the cavernous segment to the clinoid segment (figure 4).

Figure 2.

Jacking manoeuvre—procedure (A) the Sceptre XC balloon catheter was navigated into the cavernous segment and partially inflated immediately before the beginning of the dissection in order to facilitate the bypassing of the critical stenosis with the microcatheter. (B) The Phenom 0.027 microcatheter was then successfully navigated towards the clinoid segment and C) surpassed the stenosis.

Figure 3.

Jacking manoeuvre—cartoon demonstrating the balloon guide catheter serving as leverage to orient the tip of the microcatheter towards the true lumen (with permission from Jessica Shull).

Figure 4.

Stent placement postprocedure angiography demonstrating successful deployment of the Derivo flow-diverter stent into the clinoid and ophthalmic segment of the ICA. This figure shows how the stent was purposefully and partially deployed in the clinoid segment, which was dissected, to avoid the risk of thromboembolism.

Postprocedure, the patient showed evident improvement of motor function in the left arm and persisting leg motor drift and complete unilateral paralysis with no partial gaze palsy (NIHSS 9). At the end of the procedure, we purposefully decided not to fully pull the stent over the dissected vessel to avoid the risk of fragmenting the mural thrombus and thromboembolism. Since the flow over the stent was satisfactory, we decided to maintain a more conservative approach and a 50% stenosis was left in the acute phase. We decided to perform an angioplasty with postdilatation during follow-up to open the stent up to 30%. Postprocedure, a modified treatment in cerebral infarction score of 3 was achieved, with a complete restoration of blood flow to the affected territory.⁷ Twenty-four hours postprocedure, we started the patient on aspirin (100 mg) and clopidogrel (75 mg) for 3 months.

Outcome and follow-up

A 3-month follow-up, cerebral angiogram showed 60%–70% right bulb ICA stenosis and greater than 70% stent stenosis of the flow diverter, that was slightly increased. The right bulb ICA stenosis was successfully treated by a carotid stent, and the in-stent stenosis was treated with balloon angioplasty (Gateway, Stryker), achieving good expansion with residual in-stent stenosis of less than 30% (figure 5). MRI confirmed small infarcts in the lenticular nucleus, caudate and insula observed in the CT on admission. At 3 months, modified Rankin Scale score was 2, as the patient was able to walk without assistance, but required help to carry out some previous activities.

Figure 5.

Postprocedural DSA demonstrating improved luminal patency after deployment of the stent.

Discussion

We have reported a case of intracranial ICA dissection treated successfully with a flow-diverting stent in conjunction with a thrombectomy procedure for acute ischaemic stroke. To our knowledge, this is the first case that demonstrates the feasibility of using a flow-diverting stent to reconstruct an intracranial internal carotid artery dissection. Moreover, we describe a ‘jacking’ manoeuvre strategy to improve the navigation with a microcatheter of heavily stenosed arteries in the setting of tortuous vessel anatomy using a partially inflated balloon catheter as leverage.

Our patient presented with NIHSS 11 and stenosis located at the beginning of the carotid siphon with presence of small fragmented infarcts in the deep right internal carotid territory, suggesting the presence of hypoperfused parenchyma and the urgency of restoring vessel lumen integrity. Moreover, the patient did not show radiographical and clinical signs of additional distal embolism in the distal middle or anterior cerebral artery. These findings support our consideration that symptoms were the result of occlusion of direct penetrators of the Circle of Willis due to the dissection rather than additional distal embolism.

Observational studies have reported the use of endovascular treatment for patients with arterial dissection experiencing recurrent ischaemic symptoms despite receiving optimal medical treatment,⁸ and if the dissected artery presents with a pseudoaneurysm dilation.⁹ However, these studies involve extracranial artery dissections. Patients with intracranial artery dissection may experience symptoms of brain ischaemia due to occlusion of the vessel, such as in our case.

In this case, we performed a stenting procedure since the patient was symptomatic for acute ischaemic stroke and there were CT and angiographic signs of acute haematoma presenting in the vessel wall narrowing the artery suggesting intracranial dissection.

In cases of complex vessel anatomy, postdilatations are frequently required following stenting to allow optimum wall apposition. However, in cases where plaque tissue protrudes through the strut, postdilatations are contraindicated as they can increase the risk of thromboembolism.⁵ Therefore, we decided to perform a staged approach: First to perform stenting to scaffold and stabilise the dissections to favour re-endothelialization, and second to perform successive postdilatation after stabilisation of the plaque.

Our decision of which stent to select was based on the fact that a self-expanding flow diverter presents limited inflation pressure during stent deployment and scaffolding of the lesion, even in the presence of fragile vessels, reducing the risk of thromboembolism and allowing for stabilisation of the lesion. Moreover, the metal coverage facilitates precise manipulation of microcatheters inside the stent and facilitate successive postdilatation during angioplasty, even if the stent is incompletely deployed and the arterial lumen remains relatively narrow.

In this case, the stenosis was located in an anatomically challenging position that compromised the curvature of the clinoid segment. In this situation, a conventional stent confers a technical limitation due to the lack of flexibility and larger deployment catheters. On the contrary, because of their braided metallic design,¹⁰ flow-diverter stents are more easily deployed in unfavourable vessel anatomy. Finally, the greater metal coverage of flow diverters favours re-endothelialisation of the vessels in which they are deployed,¹⁰ rendering them useful in the case of an intracranial dissection.

The most critical step of stenting with a flow diverter for a dissected artery is navigating a relatively large 0.027 catheter into the true lumen. This may be particularly challenging in the acute setting and in the presence of unfavourable vessel anatomy. For those cases, we propose utilising the balloon-assisted ‘jacking’ manoeuvre to help overcome this challenge. With this technique, a balloon is partially inflated at the beginning of the dissection to serve as leverage and overcome the challenge of navigating the microcatheter tip through the stenosis (figure 3).

In summary, we suggest that flow diverting stents may be considered in well-selected cases of internal carotid dissection, in patients who are clinically symptomatic and the anatomical location of the dissection is technically challenging. Importantly, these findings should be confirmed in larger trials with longer follow-up to test the possibility of intracranial dissection as an indication for flow-diverter stents.

Learning points.

• Intracranial carotid artery dissections are challenging to treat.

• In the acute setting of intracranial dissection, it is important to preserve the patency of the vessel since the reduction of distal flow may cause symptoms of brain ischaemia.

• Flow-diverting stents are feasible to reconstruct intracranial internal carotid artery dissection because of their expanded manageability.

• A balloon-assisted ‘jacking’ manoeuvre may aid navigation through difficult vascular anatomy.