Dr Adam S ArthurAdam S. Arthur, MD, MPH
The Woven EndoBridge (WEB) system, an FDA-approved treatment for saccular, wide neck, bifurcation intracranial aneurysms, may be an option for patients with wide-neck bifurcation aneurysms (WNBAs), with recent clinical trial data showing efficacy comparable to that of the available therapies.1

Additionally, the investigators, led by Adam S. Arthur, MD, MPH, neurosurgeon, Semmes-Murphey Neurologic and Spine Institute, noted that the WEB system was markedly safer compared to current treatments, with no primary safety end points occurring between 30 days and 1 year, and only a single end point during the study (1 of 148 patients; 0.7%), on postoperative Day 22.

“In the present study, no postprocedural device, procedure-related serious adverse events or deaths were observed between days 31 and 365,” Arthur and colleagues wrote. “This level of postprocedural safety is unparalleled for the treatment of WNBAs. Parent artery stenting has been associated with significant rates of postprocedural events, related to delayed in-stent stenosis or thrombosis, and hemorrhagic events related to dual antiplatelet therapy.”

Arthur told NeurologyLive® that this system is a stand-alone solution for WNBAs. "These aneurysms have often required either surgical clipping or stent-assistance to bridge their necks. WEB allows treatment without open surgery or the use of antiplatelet medications that are necessary when leaving metal in the parent artery, as you must do with stents," he explained.

In total, 148 patients underwent successful implantation of the WEB system. The primary end point, defined as the proportion of patients with complete aneurysm occlusion without any retreatment, recurrence of subarachnoid hemorrhage, or significant parent artery stenosis at 1 year, was achieved by 53.8% of patients (77 of 143) with angiographic follow-up. Likewise, adequate occlusion (defined as complete occlusion or residual neck) was achieved by 84.6% of patients (121 of 143).

Compared with the angiogram done immediately post-treatment, 91.5% of patients (129 of 141) were substantially improved by 6 months, while only 5% (7 of 141) and 3.5% (5 of 141) were worse or the same, respectively. When compared to the angiograms at 6 months, 11.5% (15 of 131) were worse, while 79.4% (104 of 131) remained stable and 9.2% (12 of 131) were improved at 1 year.

All told, most patients with recanalization or regrowth between the 6- and 12-month period dropped by a small number of percentage points. Of those with 100% occlusion at 6 months, 10 declined: 3 to 98%, 5 to 95%, and 2 to 90% at 12 months.

Over the course of the 12-month period, 5.6% of patients (n = 8) had planned target aneurysm retreatment, and 6 additional patients underwent electively scheduled retreatment, increasing the rate to 9.8% (n = 14).

“The final data from the Pivotal WEB-IT trial demonstrate that the WEB device, when used for the treatment of appropriately selected wide-necked bifurcation aneurysms provides an effective means of achieving durable, adequate occlusion in most (~85%) cases, and can be used with a high degree of procedural safety and with a low rate of major morbidity and mortality,” Arthur and coinvestigators wrote.

All patients included in the trial were required to have aneurysms meeting the following criteria: Be ruptured or unruptured, and saccular in shape; be located at the basilar apex (BA), middle cerebral artery (MCA) bifurcation internal carotid artery terminus, or anterior communicating artery complex; have a dome-to-neck ratio ≥1 and be a wide-neck intracranial aneurysm with neck size ≥4 mm or dome-to-neck ratio <2; and a diameter appropriate for treatment with the WEB device according to the device instructions for use.

“This device is an important tool for the treatment of WNBAs, particularly for patients in whom surgical clipping carries high risks and in patients with contraindications to antiplatelet therapies,” the investigators wrote. They added that they anticipate continued improvement in intrasaccular flow diversion technologies as a result. “It is our hope that these improvements will result in higher rates of complete aneurysm occlusion and durability,” they added.

Previous findings from Gawlitza et al. found that use of the WEB system resulted in rates of complete occlusion, neck remnant, and aneurysm remnant of 33.3%, 40.0%, and 26.7%, respectively, in 15 patients with recurrent aneurysms.2

"The safety results are surprisingly good. 150 patients participated in the trial and only one of them had a stroke or death that qualified as a safety failure. Put simply, this is the safest intervention for cerebral aneurysms that has ever been studied," Arthur said. "The WEB offers an extremely safe and effective treatment for wide neck bifurcation aneurysms without the use of stents or open surgery."
REFERENCES
1. Arthur AS, Molyneux A, Coon AL, et al. The safety and effectiveness of the Woven EndoBridge (WEB) system for the treatment of wide-necked bifurcation aneurysms: final 12-month results of the pivotal WEB Intrasaccular Therapy (WEB-IT) Study. J Neurointerv Surg. Published online April 16, 2019. Accessed April 18, 2019. doi: 10.1136/neurintsurg-2019-014815.
2. Gawlitza M, Soize S, Januel AC, et al. Treatment of recurrent aneurysms using the Woven EndoBridge (WEB): anatomical and clinical results. J Neurointerv Surg. 2018;10(7):629-633. doi: 10.1136/neurintsurg-2017-013287.