Retinal Hemorrhage After Internal Carotid Artery Aneurysm Flow Diversion with Pipeline Vantage: A Case Report

Abstract

Brain aneurysms can be treated with flow diversion embolization. We describe a case of an internal carotid artery aneurysm treated with the Pipeline Vantage flow diverter device, who developed a post-procedural retinal hemorrhage, presenting as an acutely- presenting, painless “floater” in the visual field. Outpatient evaluation by a retinal specialist yielded a recommendation to observe the hemorrhage, with the option to intervene with retinal surgery if the hemorrhage worsens or does not resolve. Within one month, there was substantial improvement in his visual symptoms without need for further intervention, and follow-up imaging demonstrated that the aneurysm was successfully treated.

1 Introduction

Brain aneurysms are marked by dilated segments of weakened blood vessel walls, which may grow in size and/or bleed from loss of vascular wall integrity. If an aneurysm were to rupture, life-threatening complications may arise, leading to significant impairment of brain function [1–4]. The Pipeline embolization device (PED) (Medtronic, Minneapolis, Minnesota) has been used to treat aneurysms. The original PED design is comprised of a cylindrical mesh composed of 48 strands of cobalt-chromium and platinum- tungsten wires; newer generation of PEDs have modifications to the surface design to promote endothelialization and flow diverter properties [5–9]. When applied endovascularly, the mesh alters the mechanics of blood flow, reducing the amount of blood entering the aneurysmal sac and inducing eventual thrombosis [10].

Although PEDs have been generally successful in leading to aneurysm occlusion, intraprocedural complications include stroke, dissection, and ‘vessel dropout’ from the PED covering or causing thromboembolic occlusion of off-target branches (i.e., perforators or side branches) [7, 11]. Postprocedurally, patients may face the risk of device failure, ischemic stroke, hyperacute thrombosis of the flow diverter construct, and delayed aneurysm rupture [12, 13]. In real-world experience, there have been reports of clinical consequences depending on location of the aneurysm and subsequent PED placement, such as visual issues and intraocular hemorrhage after PED was used for an ophthalmic segment aneurysm. [14]

In this report, we present a patient who was treated for a left internal carotid artery aneurysm with a PED, subsequently developed a retinal hemorrhage, and our clinical management.

2 Case report

A 57-year-old male with a past medical history significant for hypertension, coronary artery disease, and hyperlipidemia presented to the emergency department complaining of the ‘worst headache of his life’. Computed tomography angiography revealed a left clinoid internal carotid artery aneurysm and middle cerebral artery stenosis (Figure 1A–B). Otherwise, he had a negative subarachnoid hemorrhage work-up. Approximately one month after initial detection, the patient underwent outpatient digital subtraction angiography (DSA) for further characterization of the aneurysm, which demonstrated an irregularly-shaped aneurysm of the left internal carotid wall measuring 4.8 mm (height) × 5.0 mm (length) × 7.3 mm (width) (Figure 1C). Due to concern for future aneurysm rupture due to high-risk morphology, an elective pipeline embolization procedure was pursued. The aneurysm was treated with a Pipeline Vantage flow diverter device inserted across the neck of the blood vessel (Figure 1D–G). The Pipeline Vantage system is an updated version of the original Pipeline Embolization Device that has greater mesh flexibility and conformability, allowing it to be used in a wider variety of vessel anatomies apart from large and wide-neck aneurysms that the original device is commonly used for. The patient was anticoagulated with dual antiplatelet therapy (75 mg clopidogrel and 81 mg aspirin) and had a P2Y12 reaction unit (PRU) of 62. His weight at the time of the procedure was 210 lbs. Intraoperatively, he was given 7000 units of heparin, his activated clotting time (ACT) was 300, and vitals monitoring was unchanged throughout the procedure.

Figure 1

(A) Coronal and (B) axial views of CTA of the head and neck prior to procedure. Contrast extravasation is visualized adjacent to the left ICA. (C) AP view of the ICA on cerebral angiogram demonstrating aneurysm (arrow). (D–E) 3D tumble of the left ICA aneurysm (arrow) in two views from rotational angiography. (F) Flow of contrast after Pipeline placement. (G) Lateral view of plain radiograph during angiography procedure showing Pipeline (arrow).

The patient regained consciousness immediately following completion of the procedure without any neurological symptoms. Two hours postoperatively, the patient experienced cognitive difficulties, mild dysarthria, and left- monocular vision loss. A non-contrast computed tomography scan ruled out a hemorrhage, and electroencephalogram ruled out seizure. Patient’s cognitive and speech symptoms were quickly self-resolved. However, the patient also reported a floater in his central vision that is red and becomes purple when contrasted to a white surface; peripheral vision was normal. A dilated eye exam of the left posterior eye revealed a round, multilayered intraretinal and subretinal hemorrhage. Outpatient follow-up with a retinal specialist was recommended.

After discharge from the hospital, he additionally reported diffuse muscle and chest pain, prompting evaluation in the emergency department. Acute cardiac and pulmonary workup ruled out acute coronary syndromes and pulmonary embolism. After two weeks, the patient continued to report diffuse muscle and chest pain and had not experienced any improvements in vision. With concern for potential statin-induced myalgia, rosuvastatin use was reduced, but there was minimal change in symptoms. Since starting clopidogrel corresponded to the onset of these musculoskeletal symptoms, and thus may be a potential source, the patient was switched from clopidogrel to 90 mg ticagrelor to continue dual antiplatelet therapy.

A retinal specialist re-evaluated the hemorrhage, and recommended observation, with option for surgical interventions (e.g., vitrectomy, laser membranotomy) if continued lack of improvement or clinical worsening.

By one month after the procedure, the diffuse musculoskeletal symptoms were resolved after changing the dual antiplatelet therapy regimen. The patient only reported residual, intermittent muscle pain localized the right side of the body, and that it felt like a ‘bolt of electricity’. This pain was present prior to flow diversion, potentially associated with a previous spinal surgery.

Furthermore, the patient reported substantial improvement in vision. On follow-up computed tomography angiography, the aneurysm was absent from the left internal carotid artery.

3 Discussion

In this case, a patient with a left internal carotid artery aneurysm who underwent treatment with a Pipeline Vantage flow diverter experienced a left retinal hemorrhage immediately following the operation.

There are several potential underlying causes for the PED-related retinal hemorrhage. Antiplatelet therapy has long been thought to play a role in intraparenchymal hemorrhage following PED placement. Skukalek et al. [15] reported transient and symptomatic intracranial hemorrhage, either subarachnoid or intraparenchymal, after PED placement in 4.7% of patients who are placed on high-dose aspirin for 6 months or less. Brinjikji et al. found a strong statistical correlation between multiple PEDs and hemorrhagic events, hypothesizing it may be due to factors including prolonged procedural time, increased platelet activation, and possible hemodynamic alterations from the placement of flow diverters [16, 17]. Consequently, factors, such as high-dose anticoagulation and altered cerebral hemodynamics after flow diversion placement, may have contributed to the occurrence of a post-procedural symptomatic retinal hemorrhage.

Intraocular hemorrhage following PED placement has been reported previously. Adeeb et al. [14] described visual disturbances due to retinal hemorrhage that developed one day after flow diversion of an aneurysm on an ophthalmic branch segment. While the aneurysm was not within an ophthalmic branch segment in our patient, any aberrant blood flow in this branch was accounted for due to the aneurysm being in the internal carotid artery wall at the same level. This illustrates the possibility that altered hemodynamics in relatively proximal branches caused changes in the flow patterns in subsequent distal branches, thus predisposing occurrence of hemodynamic-related complications, like intraocular hemorrhage [10]. This example underscores the importance of careful evaluation, including for ophthalmic complications, after flow diversion at or proximal to the blood supply of the eye [18].

Although the retinal hemorrhage was eventually self-resolving in this case, close monitoring with a retinal specialist and continued follow-up by the neurointerventionalist was crucial to ensure the complication did not worsen and facilitating developing a long-term plan of potential treatment approaches to address post-procedural complications.

4 Conclusion

PEDs have been proven to be a robust method of treatment for complex brain aneurysms. Our case report provides insight into a lesser-known side-effect of this technique, and underscores the importance of careful post-procedural evaluation of organs supplied by peripheral cerebrovascular branches that also experience changes in hemodynamic flow caused by flow diversion of the target aneurysm.