Pipeline embolisation device with shield technology for the treatment of ruptured intracranial aneurysm

Abstract

Flow diverters have emerged as a safe and effective treatment option for patients with complex unruptured cerebral aneurysms. Their utilisation in patients with ruptured aneurysms poses significant challenges, most notably the need for periprocedural dual antiplatelet medication. We describe the use of the pipeline embolisation device with shield technology in an 88-year-old patient with a complex ruptured posterior communicating artery aneurysm not amenable to microsurgical clipping or coiling alone. The pipeline embolisation device with shield technology utilises a phosphorylcholine coating to decrease thrombotic risk. We describe our antithrombotic protocol and technique to decrease the risk of acute re-rupture. The case highlights the option of using a flow diversion device with antithrombotic coatings in patients with complex ruptured cerebral aneurysms not amenable to coiling or microsurgical clipping.

Introduction

The management of ruptured intracranial aneurysms has changed considerably since the publication of the International Subarachnoid Trial (ISAT), and the majority of ruptured cerebral aneurysms are now managed endovascularly.^1,2 Aneurysmal embolisation with flow diversion has emerged as a safe and effective treatment option for patients with complex unruptured cerebral aneurysms that would otherwise be difficult to coil or clip microsurgically.^3,4 The use of flow diverters for patients with ruptured aneurysms poses significant challenges including the requirement for dual antiplatelet medication, the risk of acute re-rupture due to incomplete occlusion and the management of ventricular drains or subsequent shunting while on antiplatelet medication.⁵

In this report, we describe the use of the pipeline embolisation device with shield technology (PED-SHIELD) in a patient with a complex ruptured posterior communicating artery (PComm) aneurysm not amenable to surgical clipping or coiling alone. The PED-SHIELD utilises phosphorylcholine, making the device less thrombogenic. To our knowledge, this is the first case of PED-SHIELD utilised for ruptured intracranial aneurysms managed solely with single antiplatelet therapy, with confirmed follow-up stent patency. In addressing the risks associated with treating ruptured aneurysms using flow diverters, we describe our antithrombotic protocol and technique to mitigate the risk of acute re-rupture. The case highlights the option of flow diversion devices with antithrombotic coatings in patients with ruptured aneurysms not amenable to coiling or microsurgical clipping.

Case report

An 88-year-old previously independent woman with hypertension presented to a peripheral hospital after sudden onset headache, vomiting and decreased level of consciousness requiring airway protection. Computed tomography angiography (CTA) showed modified fished grade 4 subarachnoid haemorrhage (SAH) secondary to ruptured right PComm artery aneurysm with acute hydrocephalus (Figure 1). On arrival an emergent external ventricular drain was placed, with postoperative Glasgow coma scale E1V1TM5 (GCS 7T) localising on the right side. She was initially World Federation of Neurological Societies grade 4, but the following day she started having eye opening and spontaneous movement. After a long discussion with her family regarding the prognosis, the decision was made to treat the aneurysm. The distal internal carotid artery (ICA) was dilated, leading to fusiform dilatation of the PComm with a saccular dome that was likely the rupture point. Given her age, clinical status, aneurysmal morphology and consultation with our cerebrovascular surgeon, we decided to treat with endovascular embolisation using a flow-diverting stent. We obtained Health Canada approval for special access use of the PED-SHIELD (Medtronic, Minneapolis, MN, USA) to attempt managing the patient with postoperative single antiplatelet therapy.

Figure 1.

Computed tomography and computed tomography angiography (CTA) showing acute subarachnoid haemorrhage (SAH) secondary to a ruptured right posterior communicating artery (PComm) aneurysm. (a) Modified Fisher grade 4 acute SAH with hydrocephalus. (b) Axial CTA showing the saccular/fusiform aneurysm of the right PComm. (c) Sagittal CTA demonstrating the right PComm aneurysm. (d) Three dimensional reconstruction of the aneurysm showing the internal carotid artery (ICA), middle cerebral artery (MCA) and saccular component (white arrow) of the fusiform aneurysm.

The patient was loaded with aspirin (ASA) 325 mg PR 2 hours before the procedure. The first step was coiling of the saccular rupture point of the aneurysm (Figure 2). Next, one 4.75 mm × 16 mm and one 4.50 mm × 16 mm PED-SHIELD stents were deployed from the distal ICA into the proximal middle cerebral artery. The final angiographic run showed an O’Kelly–Marotta score of A3 (Figure 3). Postoperatively the patient was maintained on ASA 81 mg daily. A target activated clotting time of 300 was achieved during stent deployment and heparin was not reversed at the end of the procedure. The patient underwent daily transcranial Doppler, magnetic resonance imaging (MRI), and repeat CTA showed the stent was patent with no re-rupture on postoperative day 18.

Figure 2.

Illustration of endovascular coiling and deployment of flow-diverting stent for treatment of a complex fusiform aneurysm. The first part of the procedure was placing coils in the saccular portion of the aneurysm. This was done via the right internal carotid artery. The coils were packed enough such that only the dome was coiled. Next, two flow-diverting stents were placed from the distal internal carotid to proximal middle cerebral arteries.

Figure 3.

Angiographic display of endovascular coiling and placement of the pipeline embolisation device with shield technology (PED-SHIELD). (a) Cerebral angiogram demonstrating the right saccular/fusiform posterior communicating artery aneurysm. (b) The first coils were placed into the dome of the aneurysm (yellow arrow). (c) Placement of two PED-SHIELD stents proximally in the internal carotid artery and distally in the middle cerebral artery (yellow arrows). (d) Final angiogram showing O’Kelly–Marotta score A3.

Discussion

The role of pipeline embolisation devices (PEDs) for aneurysmal embolisation in the setting of acute SAH is controversial, due to the requirement for dual antiplatelets. McAuliffe and Wenderoth treated 11 patients with acute SAH with PEDs and reported two patients dying from ruptures.⁶ The patients were loaded with ASA and clopidogrel and maintained on dual antiplatelets for a minimum of 6 months. The authors suggested that ancillary coiling of the sac may be warranted in the setting of acute rupture, using the PED as a scaffold.

After it was initially shown that the phosphorylcholine component of the erythrocyte wall was non-thrombogenic, phosphorylcholine has been used to coat drug-eluting stents. The PED-SHIELD utilises phosphorylcholine as a coating on the device. The PFLEX study was the first prospective study utilising the PED-SHIELD in patients with unruptured intracranial aneurysms.⁷ They noted no major strokes or deaths in the 30-day perioperative period and their one-year angiographic follow-up showed complete occlusion in 82% of cases.⁸ Of note, all patients received dual antiplatelets after the procedure, and all aneurysms were unruptured.

Several animal and human in vitro studies have shown that the PED-SHIELD is associated with less thrombus formation over the surface of the stent and faster endothelial growth over the stent.^9–11 Chiu et al. were the first to report using the PED-SHIELD in the treatment of a ruptured aneurysm.¹² The authors managed a ruptured vertebral artery aneurysm with a loading dose of ASA 300 mg 2 hours prior to the procedure and 20 mg of abciximab intravenously during the procedure. The patient was maintained on heparin infusion with an activated partial thromboplastin time of 40–50 for 5 days and ASA daily. MRI at 6 weeks showed the aneurysm was occluded and the stent was patent. Orlov et al. reported a case of a patient with impaired gut absorption with effectively minimal antiplatelet activity for 16 days after PED-SHIELD implantation with no in-stent thrombosis.¹³ Hanel et al. were the first to report the use of the PED-SHIELD in the United States.¹⁴ The authors treated a patient with a ruptured fusiform aneurysm in the right vertebral artery with two PED-SHIELD stents. The patient received ASA 325 mg preoperatively and was maintained on ASA 81 mg postoperatively. On postoperative day 10, the stent was shown to be thrombosed. The authors hypothesised among other things that active patient malignancy, borderline ASA resistance and placing two stents may lead to an increased risk of thrombosis.

We report on the first Canadian use of the PED-SHIELD in a patient with a ruptured PComm aneurysm. The decision to use a stent with phosphorylcholine technology was made due to the high risk of dual antiplatelets in the setting of acute SAH. Furthermore, as described by McAuliffe and Wenderoth, we decided to coil the likely rupture point in the saccular portion of the fusiform aneurysm before deploying two PED-SHIELD stents to reduce the risk of re-rupture.⁶ We maintained the patient on a single antiplatelet agent only, with no evidence of stent thrombosis or re-rupture 18 days after treatment. Our patient did not have ASA resistance or active malignancy, as described by Hanel et al. as risk factors for stent thrombosis.¹⁴ This case highlights the possibility of using the PED-SHIELD with a single antiplatelet agent in the setting of ruptured aneurysms; however, caution must be exercised given only three cases reported in the literature.

Author contribution

Study concept and design: Pasarikovski, Waggass, Cardinell, Howard, da Costa and Yang. Procedure completion: Pasarikovski, Waggass, Howard, da Costa and Yang. Acquisition of data, analysis, or interpretation of data: Pasarikovski, Waggass, Cardinell, Howard, da Costa and Yang. Drafting the article: Pasarikovski, Waggass, Howard, da Costa and Yang. Study supervision: Yang.

Conflict of interest

The authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Funding

This research did not receive any specific grant from funding agency in the public, commercial, or not-for-profit sectors.

Research ethics approval

Health Canada special access was granted for the use of this device in our patient.