Re-treatment of an unruptured anterior communicating artery aneurysm using the new pCONus 2 device: Description of a case

Abstract

Endovascular approach represents today the first option in treatment of ruptured and unruptured cerebral aneurysms. Nevertheless, wide-neck bifurcation aneurysms still represent a technical challenge for endovascular treatment due to the need to protect vessels arising next to the aneurysmal neck. A variety of devices have been implemented to ensure adequate assistance for coiling of these lesions. Among these devices, the new pCONus 2 represents an evolution of the well-known pCONus; compared to the previous one in fact, it allows a degree of articulation and flexibility between the shaft and the distal part (crown), making it more suitable for treatment of aneurysms presenting an angle between the longitudinal axis of the dome and parent vessel. We report our first case using pCONus 2 in the re-treatment of an unruptured anterior communicating artery aneurysm in a 57-year-old man, showing evident recanalization two years after coiling.

Introduction

Endovascular coiling and surgical clipping are widely accepted strategies in the treatment of cerebral aneurysms. In case of aneurysms presenting unfavourable dome-to-neck ratio (<2), endovascular treatment is often challenging because of possibility of coils protruding into parent artery. Therefore, many devices have been implemented in order to expand indications for endovascular treatment, according to assisted coiling technique or providing different endovascular approaches such as flow-diverters and intrasaccular flow-disruptors. However, wide-neck intracranial aneurysms involving bifurcations still represent an issue for the need to protect patency of efferent vessels. In recent years, Y/X-stenting and waffle-cone technique have been developed to achieve adequate coiling of these lesions.¹ Y/X-stenting technique requires deployment of two different stents in efferent vessels, getting patient more prone to thromboembolic complications, while, alternatively, waffle-cone technique proved to be promising in some cases, even if it showed examples of recanalization.^2,3

Following the concept of waffle-cone technique, an intra-extra-aneurysm stent device (pCONus) has been realized in recent years.^4,5

We present our first experience with the new pCONus 2 device, in the elective treatment of a recurrent, unruptured anterior communicating artery aneurysm.

Case report

This study was carried out according to the Declaration of Helsinki principles and approved by our institutional review board. The patient gave informed consent to publish this work and to report individual data.

A 57-year-old man arrived in our Department in September 2015 to perform an endovascular embolization of an unruptured wide-neck anterior communicating aneurysm. The aneurysm measured 8 × 4 mm latero-lateral x cranio-caudally (LL × CC), and it presented a neck of about 3.7 mm with oriented medially fundus (Figure 1(a)). Both A2 segments originated next to the neck, with hypoplastic appearance of right A1 segment. The aneurysm was treated with simple coiling, obtaining complete obliteration of the dome with a good coverage of the neck (Figure 1(b)); a slight opacification of central part of the neck was present (Class I-II Raymond-Roy classification).

Figure 1.

(a) Unruptured anterior communicating artery aneurysm in a 57-year-old man. (b) Immediate angiographic result showing slight opacification of the neck.

The patient was awakened without any neurological deficit and subsequently discharged after 5 days with normal neurological examination.

The six-month follow-up cerebral angiogram showed no increase in the slight neck residual, confirming subtotal exclusion of the aneurysm (Figure 2(a)).

Figure 2.

(a) Six-month angiographic follow-up showing the minimal neck residual is stable. (b) Angiographic follow-up after two years showing significant recanalization.

In October 2017 the patient underwent angiographic examination showing recanalization of the aneurysm with a remnant measuring 4.5 × 3.5 mm (CC × LL) (Figure 2(b)).

A multidisciplinary team composed of interventional neuroradiologists and neurosurgeons agreed to re-treat the aneurysm with endovascular approach.

PCONus 2 was preferred over similar devices for assisted coiling, (e.g. PulseRider) at the discretion of the senior neurointerventionalist, following a positive three-year experience in our center with pCONus device since 2014; moreover, its less than 5% metal-to-artery surface coverage, promotes fast endothelialization.

The procedure was performed one month later using a biplane digital subtraction angiography unit (Artis Zee Siemens, Germany).

Premedication consisted of 75 mg clopidogrel and 100 mg aspirin daily 3 days before procedure; adequate inhibition of platelet function was checked before the procedure with the VerifyNow test (Accriva, USA).

A 7F Arrow-Flex® introducer sheath was placed in left distal common carotid artery and subsequently a 6F FargoMax guiding catheter (Balt, France) was advanced coaxially in intracranial internal carotid artery.

A Vasco+21 micro-catheter (Balt, France) was advanced over a 0.014-inches Synchro micro-guidewire (Stryker, USA) until the proximal part of the aneurysm and a pCONus 2 stent (Phenox, Germany) was then inserted inside the micro-catheter.

PCONus 2 is shaped like a blossoming flower with six petals in the distal part, positioned inside the dome just over the neck and a stem-like portion proximally, positioned in left A1 segment.

The petals of pCONus 2 were opened inside the dome and then the device was gently pulled back aiming to obtain a complete coverage of the neck (Figure 3).

Figure 3.

(a) and (b) Radiopaque markers of petals (distally) and articulation zone (proximally) are well evident in unsubtracted images. Petals are positioned with the aim of completely covering the neck. (c) Shaft, crown and petals of pCONus 2 device.

A Vasco+10 micro-catheter (Balt, France) was subsequently advanced in parallel over a Synchro 0.014-inches micro-guidewire inside the aneurysm, passing through the device.

Two Cashmere® micro-coils (Micrus, USA) 4 mm × 8 cm and 3 mm × 6 cm were released inside the aneurysm, achieving complete filling of the dome.

Finally, micro-catheter for coiling was withdrawn and pCONus 2 was electrolytically detached.

Angiographic check-up showed exclusion of the lesion with regular patency of bifurcation vessels (Figure 4).

Figure 4.

Anterior communicating artery aneurysm before (a) and after (b) re-treatment.

During the procedure 7500 I.U. of heparin were intravenously administrated.

Patient was then awakened without neurological deficits and discharged after five days.

Double antiplatelet therapy, consisting of 75 mg clopidogrel and 100 mg aspirin, was prescribed for three months after procedure, before switching to single antiplatelet therapy with aspirin for at least one year; a six-month angiographic follow-up has been scheduled.

Computed tomography scan performed 2 days after procedure did not show ischemic or hemorrhagic complications.

Discussion

The pCONus 2 endoluminal device represents a further development of pCONus, available for clinical use in Italy since November 2017.

It is a bifurcation aneurysm implant, specifically intended to treat intracranial, wide-neck, bifurcated aneurysms, consisting of a proximal part (shaft) and a distal part (crown).

The shaft is a self-expanding laser-cut stent structure, intended for implant in parent vessels.

Unlike the pCONus, the pCONus 2 presents six petals instead of four in the distal end, each with a radiopaque marker reaching up to the distal end of the device; there are no polyamide fibres crossing between petals.

Two additional radiopaque markers are in the “articulation zone” between the proximal part of the crown and the shaft and in the very proximal part of the shaft, where the detachment zone is located.

The device is carried into a 0.021 in (0.5334 mm) micro-catheter together with an insertion wire and is released by slowly withdrawing the micro-catheter while advancing the insertion wire; the final target is to release the crown inside the aneurysm, near to the base, and the shaft in the parent vessel, in order to provide support for coiling.

The device needs to be recrossed with a coiling micro-catheter and, according to the company producing the device, this can easily be done before or after its detachment.

Even after fully released, pCONus 2 can be completely withdrawn and retrieved for repositioning; lastly the device is electrolytically detached.

PCONus 2 is available in a range of petals with a diameter from 5 to 15 mm; the shaft has a diameter of 4 mm, intended for parent vessels ranging from 2.5 to 3.7 mm.

When selecting the size of the device, the manufacturer company recommends a slight oversizing of the crown diameter, in order to ensure complete coverage of the neck.

The so-called ‘articulation zone’ between the crown and the distal shaft, is intended to allow improved flexibility than pCONus,⁶ making pCONus 2 more suitable for aneurysms presenting an angle between the longitudinal axis of the dome and the longitudinal axis of parent vessel.

Thanks to radiopaque markers in each petal, the device should be easier to see under fluoroscopic guidance.

In our experience, the device was repositioned three times before obtaining a satisfactory position; stent deployment was not technically challenging and we did not experience significant frictions on the delivery system.

We decided to place the coiling catheter in the dome navigating through the stent and this was unproblematic.

The device was finally detached once coiling was judged to be stable.

In this preliminary experience, pCONus 2 proved to be an effective and safe device in re-treatment of wide-neck bifurcation aneurysms, showing similar trackability and pushability than pCONus.

Nevertheless, the slightly higher visibility and stability of pCONus 2 that we experienced, together with a smaller amount of metal, made it preferable than pCONus.

Moreover, the articulation zone could provide significant advantages in the treatment of morphologically complex aneurysms than pCONus, but this concept still needs to be demonstrated.

However, a larger sample size and long-term follow-up data are required to confirm the aforementioned features.

A potential role of pCONus 2 in emergency treatment of ruptured aneurysms, following the promising results obtained with pCONus,⁷ has still to be proven, even if management of antiplatelet therapy could still represent an issue.

Declaration of conflicting interests

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

Funding

The authors received no financial support for the research, authorship, and/or publication of this article.