Internal Carotid Artery Aneurysm: Multiple Internal Carotid Artery Aneurysms in a Patient Presenting with Subarachnoid Hemorrhage; Treatment with Flow Diverter Stents
Up to 30% of patients presenting with acute aneurysmal hemorrhage are found to have multiple aneurysms. As the determination of the source of the bleeding may not be straightforward in the cases of multiple aneurysms, the simultaneous treatment of all aneurysms is often considered. We present the case of a 41-year-old woman with an unremarkable medical history apart from chronic headaches, who presented with a left-sided basal subarachnoid hemorrhage (SAH; Hunt and Hess II, Fisher grade III). Neuroradiological examinations, including CT and CT angiography (CTA), revealed a midsized carotid ophthalmic aneurysm at the left internal carotid artery (ICA). Angiography confirmed the diagnosis of the ophthalmic aneurysm and depicted two other small aneurysms on the posterior communicating (PcomA) and anterior choroidal (AchoA) arteries. An external ventricular drain was inserted and the patient was given loading doses of aspirin and prasugrel. All three aneurysm ostia were completely covered by the implantation of two telescoping flow diverter stents in a single uneventful procedure. The ventriculostomy was removed after day 7 and the patient was discharged home after 12 days. Follow-up head CT at days 5 and 10 showed no hydrocephalus. Follow-up angiography at 3 months confirmed occlusion of all three left ICA aneurysms. Prasugrel was discontinued at month 4 and aspirin was continued indefinitely. The safety and effectiveness of flow diverter stent implantation in the management of multiple carotid aneurysms, including the less-explored situation of multiple aneurysms presenting with SAH, is the main topic of this chapter.
KeywordsInternal carotid artery Flow diverter stent Multiple aneurysms Subarachnoid hemorrhage
A 41-year-old female with chronic headache and spontaneous subarachnoid hemorrhage (SAH), graded Hunt and Hess II and Fisher III.
The primary goal of the treatment was to exclude all three left ICA aneurysms in a single endovascular procedure. The ophthalmic aneurysm was thought most likely to be the source of the SAH, mainly due to its larger size compared with the other two aneurysms. However, carotid ophthalmic aneurysms have a comparatively lower tendency to bleed compared with PcomA aneurysms. Additionally, in our patient, the shape of the carotid ophthalmic aneurysm was very regular without any visible bleb or nipple, raising the possibility that one of the other aneurysms was the source of bleeding. We transferred the patient to the operating room to place a ventriculostomy. Loading doses of aspirin and prasugrel were then administered via a nasogastric tube and the patient was transferred back to the interventional neuroradiology suite for treatment. Evaluation of antiplatelet inhibition activity was performed 1 h later and was found to be optimal. Then, with the patient still under general anesthesia, two flow diverter stents were telescopically implanted at the supraclinoid, paraclinoid, and anterior half of the left cavernous ICA, completely covering the ostia of all three carotid aneurysms. Telescoping (double-layered coverage) was intended to occur at the carotid ophthalmic aneurysm inflow zone to achieve a greater impact on intra-aneurysmal hemodynamics.
Procedure, 21.04.2015: implantation of two telescoping flow diverter stents in the left ICA
Anesthesia: general anesthesia; 4,000 U unfractionated heparin IV (80–100 IU/Kg), bolus dose, target activated clotting time (ACT) 250–320 s
Premedication: 3× 100 mg aspirin PO via a nasogastric tube (NGT), 4× 10 mg prasugrel NGT given in the OR immediately after ventriculostomy placement, which was performed 1 h before stent implantation; platelet reactivity to prasugrel was confirmed by VerifyNow (Accumetrics)
Access: right femoral artery, 6F Arrowsheath (Arrow); guide catheter: Navien A+ 058 (Medtronic); microcatheter: Excelsior XT 27 (Stryker) for flow diverter stent implantation; microguidewire: Synchro2 0.014″ 200 cm (Stryker)
Implants: 2× p64 3.5/20 mm (phenox)
Duration: 1st–22nd run: 113 min; fluoroscopy time: 32.5 min
Postmedication: 1× 100 mg aspirin PO dail continued indefinitely, and 1× 10 mg and 1× 5 mg prasugrel on alternating days for 4 months
Immediately after the endovascular procedure, the patient was transferred to the neurosurgical intensive care unit. The introducer sheath was removed 1 h later, after reevaluation of ACT. The patient was then extubated and she returned to her baseline status without pain or discomfort. She began to experience left orbital discomfort 12 h after the intervention and her pain persisted for 3 days. Regular analgesics (acetaminophen, dipirone) were given with an excellent clinical response. Head CTs performed after 12 h and 5, 7, and 11 days after the intervention were unremarkable. The ventriculostomy was removed on day 7 after the SAH. The patient was discharged home 12 days after stent implantation.
Multiple aneurysms are found in 30% of all patients with spontaneous subarachnoid hemorrhage (SAH) (Juvela 2000; Rinne et al. 1994). In these patients, it can be difficult to determine which aneurysm is most likely to have bled and, therefore, which should be prioritized for treatment. In some cases, a diagnosis can be made based on clinical and radiological findings on CT, for example, the distribution of SAH or the presence of intracerebral hematomas or by cerebral angiography, notably aneurysm location, size, and morphology (Nehls et al. 1985). However, the source of bleeding often cannot be clearly determined.
A recent pooled analysis from six prospective cohort studies found that increased age, hypertension, a previous history of SAH from another aneurysm, and aneurysm size (>7 mm) and location (vertebrobasilar, AcomA, and PcomA) were predictors of rupture (Greving et al. 2014; Nehls et al. 1985). Another study comparing the features of ruptured and unruptured aneurysms found that an irregular aneurysm shape and an aspect ratio of ≥1.3 are associated with increased risk of rupture (Backes et al. 2014). Computational fluid dynamics (CFD) has recently become a popular tool for studying intracranial aneurysm hemodynamics and assessing the likelihood of previous or future rupture (Valen-Sendstad and Steinman 2014), and contrast-enhanced MR vessel wall imaging may be helpful in identifying the site of rupture in patients with multiple aneurysms (Omodaka et al. 2018). However, neither the classical nor more recent approaches are currently accurate enough to identify the ruptured lesion in patients with multiple aneurysms, especially when they are located in close proximity.
According to previous reports, surgical clipping of multiple aneurysms can lead to poorer outcomes (Mizoi et al. 1989) and endovascular therapy of multiple aneurysms has usually been performed in staged procedures. Thus, patients with SAH and multiple intracranial aneurysms present a unique challenge to the neurosurgeon as well as to the neurointerventionalist. Unless all aneurysms can be treated during a single intervention, the physician must accurately determine which aneurysm has ruptured. Misjudgment may result in disastrous postoperative rebleeding from the untreated lesion responsible for the initial bleeding.
Our patient presented with SAH and three aneurysms, each of which could have been the origin of the hemorrhage. All supraclinoid aneurysms were treated by means of telescoping implantation of two flow diverter stents in a single intervention during the acute phase of hemorrhage. The case illustrates the management of multiple aneurysms by means of flow diverter stents and the use of these devices during the acute phase of SAH, a controversial strategy that is slowly gaining acceptance.
Stenting devices have greatly expanded the therapeutic spectrum of endovascular techniques for the management of intracranial aneurysms; however, they have largely been reserved for patients with unruptured aneurysms because of concerns regarding the use of antiplatelet therapy in cases of SAH. Several authors have nevertheless presented their experience with the use of stents in patients with ruptured aneurysms, and a systematic review of stent-assisted coiling in ruptured aneurysms concluded that the technique can be performed with a high degree of technical success, although adverse events appear more common (Bodily et al. 2011).
In recent reports, we found many variations in the strategies for managing these patients (Amenta et al. 2012; Bodily et al. 2011; Cai et al. 2017; Chalouhi et al. 2013; Chung et al. 2014; Lessne et al. 2011; Tähtinen et al. 2009). Early external ventricular drain (EVD) placement was not frequently discussed, suggesting there are no special considerations in this population. There were many approaches to antiplatelet type, dose, and timing, and assessment of the effects of antiplatelet medications was rare. Given the relatively high rates of hemorrhage, thrombotic complications, and mortality that have been reported, guidelines in these areas are urgently needed. One recent publication (Cohen et al. 2018) presented a protocol for stent-based treatment of acutely ruptured aneurysms based on a low threshold for EVD placement prior to stenting and preprocedure administration of antiplatelet agents with platelet response testing to ensure that the response falls within a safe range. This protocol aims to limit the risks of both hemorrhage and stent-related thrombus formation. In this series of 47 patients with acutely ruptured aneurysms, including 46 with aneurysmal SAH, immediate total or near-total aneurysm occlusion was achieved in 97% of patients treated with a combination of stents and coils, and there were even higher delayed occlusion rates in patients treated with flow diverter stents for the 45 surviving patients. Despite the routine administration of dual antiplatelet therapy and heparin, there were no episodes of intra- or post-procedural hemorrhage. Isolated intraprocedural thromboembolic events in 8.5% of patients were managed conservatively without long-term sequelae.
We believe this illustrative case contributes to the growing body of evidence supporting the use of flow diverter stent techniques in the management of multiple ICA aneurysms, even in acute cases, with judicious placement of pre-procedure ventriculostomy and strict adherence to a carefully designed policy for antiplatelet therapy in these patients.
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