Tech Corner: eCLIPs bifurcation remodeling system

December 2020

Treatment of wide-necked bifurcation aneurysms has been, and will likely continue to be, an ongoing topic of debate in the field of neurointerventional surgery. Various options for endovascular treatment of these lesions include balloon-assisted coiling, stent-assisted coiling, and flow-diversion. The eCLIPs bifurcation remodeling system (Evasc Medical Systems Corp,Vancouver, British Columbia, Canada) is a novel device in the continuous search for optimal treatment of these difficult lesions.

The device:
The eCLIPs device is a nickel-titanium, noncircumferential device. The device received CE Mark status in January 2015. The device has 2 discrete sections: an ‘anchor’ segment designed to conform to the arterial walls beside the neck of a bifurcation aneurysm, and a ‘leaf’ segment with a higher density of penetrable ribs, which allow a microcatheter to pass through for coil embolization. The leaf segment is designed to divert blood flow away from the aneurysm, thus reducing the chances of aneurysm recurrence, in a manner similar to flow-diversion. The 2^nd generation device is a self-expanding, microcatheter-delivered, fully retrievable, and self-orientating device. The porosity of the device is approximately 65% (range 58–77%) depending on vessel diameter.

Technique/Delivery:
In the literature cited below, most patients receive pre-procedural dual antiplatelet therapy, which was continued for a minimum of 3 months post-procedurally. All patients underwent a neuroendovascular procedure with a quadriaxial technique using transfemoral 6/8 Fr guide sheath, and intermediate catheter. The unique delivery system consists of a 0.014-in microwire through an eCLIPs micro-introducer which is then coaxially inserted through an eCLIPs microcatheter (i.e 4.2 F Fargo mini-catheter; Balt, Montmorency, France). The eCLIPs is unsheathed in one limb of the parent vessel, and then the microwire is used to catheterize the other limb. The eCLIPs is advanced over the wire until complete neck coverage is achieved. The device is then mechanically detached from its pusher. After detachment, the eCLIPs device can be crossed with any commercially available coil delivery microcatheter for concurrent coil embolization.

Published Results:
De Vries et. al describe the use of the eCLIPs in 24 patients with unruptured ICA and basilar terminus aneurysms with unfavorable metrics (DTN <1.6and aspect ratio <1.2) treated at 12 international centers whom were taken from a larger prospective voluntary post-marketing registry of patients.[1] The authors show that the (1) eCLIPs was successfully deployed in 23/24 (96%) patients; (2) had good radiologic outcomes (defined as modified Raymond-Roy class I-II) at follow-up in 20/21 (95%) cases; and (3) had a low retreatment (1/24, 4.2%) and mortality rate (1/24, 4.2%) that was comparable with other devices used to treat wide-necked bifurcation aneurysms.

Chiu et. al report on 33 patients treated with the eCLIPs device, from a registry covering 13 international centers.[2] Two (8%) of the 25 patients were treated for acute rupture, while 16 patients had not had any prior treatment. Twenty-five (76%) patients had successful placement of an eCLIPs device. Eight cases of nondeployment occurred during the 1st year of use, consistent with a learning curve; no failures of deployment occurred thereafter. Two periprocedural transient ischemic attacks and 2 asymptomatic thrombotic events occurred. Twenty-one (91%) of 23 patients underwent follow-up at an average of 8 months; 9 (42.9%) of these 21 patients demonstrated an improvement in Raymond-Roy grade; 17 (81.0%) patients demonstrated a Raymond-Roy class I or II. Two delayed ruptures were recorded. Two aneurysm-related late deaths were noted.

eCLIPs has some technical limitations. The device is recommended only when one of the arteries past the bifurcation measures 1.5–3.25 mm. In addition, a very acute take off angle and tortuous morphology of the post bifurcation arteries makes the placement of the device more difficult. There seems to be a steep learning curve as nearly 25% of Chiu et. al’s cases demonstrated deployment failure in the first year.

Conclusion:
De Vries et. al conclude that the safety profile of eCLIPs compares favorably with other reported treatment modalities of wide neck bifurcation aneurysms, such as Y-stenting, pCONUS and WEB, which demonstrate complication rates of 8 – 23%.  Chiu et. al conclude that the second-generation eCLIPs device appears to be a viable option for treatment of both ruptured and unruptured wide-necked bifurcation aneurysms, when appropriate case selection is made. The device’s unique design does not mandate jailing of either the parent or branch vessels. The device’s capacity to serve as flow diverter and a platform for neointimal growth over the aneurysm neck is quite novel. When compared with data for other wide neck bifurcation aneurysm devices, the occlusion rates in initial clinical data appears to be favorable.

As with any new device, greater patient numbers and longitudinal follow-up are required to directly compare the procedural safety, efficacy, and long-term outcome of this new treatment method. A multicenter, open-label, single-arm feasibility, safety, and efficacy study (the European eCLIPs Safety, Feasibility and Efficacy Study [EESIS]) is underway.

1. De Vries, J., et al., eCLIPs bifurcation remodeling system for treatment of wide neck bifurcation aneurysms with extremely low dome-to-neck and aspect ratios: a multicenter experience. J Neurointerv Surg, 2020.
2. Chiu, A.H., et al., The second-generation eCLIPs Endovascular Clip System: initial experience. J Neurosurg, 2018. 128(2): p. 482-489.