The Source for Neurovascular News and Education

November 29, 2022


A prospective, multicenter study of 150 patients shows good short-term results in appropriately selected cases, researchers say.

A novel device for the treatment of wide-necked bifurcation aneurysms (WNBAs) continues to show promise, according to new findings from the WEB-IT Study.

The Woven EndoBridge (WEB) Aneurysm Embolization System (Sequent Medical), specifically designed for this condition, is a self-expanding intra-aneurysmal flow disruptor consisting of compliant braided nitinol mesh that can be deployed through a microcatheter into a saccular aneurysm. After deployment, it is retrievable and can be detached. 

“WNBAs are among the most challenging aneurysms encountered for endovascular treatment. Their treatment frequently requires craniotomy for clipping of the aneurysm or the use of one or more temporary (ie, a balloon catheter) or permanently (ie, intravascular stent) implanted adjunctive devices,” write David Fiorella, MD (State University of New York at Stony Brook), and colleagues in their paper recently published online in the Journal of NeuroInterventional Surgery. “Such complex treatment strategies are technically demanding, time intensive, require multiple catheter manipulations, and are likely to be associated with higher complication rates than more straightforward coil embolization procedures.

“Moreover, complete occlusion of WNBAs is often difficult to achieve with conventional endovascular coiling and the occlusion achieved with coils may not be durable,” they continue. “For this reason, better endovascular treatment options are needed.” 

Making the Case for a Dedicated Device

In their analysis of the WEB-IT Study, a pivotal Investigational Device Exemption study, Fiorella et al report data on 150 patients (mean age 59 years; 73.3% women) who underwent attempted endovascular treatment with the WEB system at 27 centers. Aneurysms were mainly located at the basilar apex (39.3%), followed by middle cerebral artery bifurcation (30%), anterior communicating artery (26.7%), and internal carotid artery terminus (4%). Average aneurysm size was 6.4 mm, and the mean neck size was 4.8 mm. Nine patients presented with ruptured aneurysms.

Device implantation was successful in 148 patients (98.7%); one unsuccessful case was due to anatomic tortuosity and the other to improper device size availability. Mean procedure time was 20.1 minutes, ranging from 3 to 315 minutes. The mean fluoroscopy time was 30.2 minutes, with a mean radiation dose of 2,750 mGy.

Delayed parenchymal hemorrhage 22 days after treatment was the only primary safety event (0.7%) to occur between the index procedure and 30-day follow-up. “The event was adjudicated as a major stroke, most likely related to antiplatelet medication and underlying cerebrovascular disease,” the authors note, adding that at last follow-up, the affected patient had an mRS score of 4.

Additionally, there were seven minor ischemic strokes (4.7%); five resolved without sequelae and two resulted in an mRS score of 1 at 30 days. There also were five TIAs (2.7%) and two minor subarachnoid hemorrhages (1.3%).

Among the nine patients who presented with ruptured aneurysms, seven experienced a total of 15 adverse events. Only one, an incidentally discovered spinal stenosis, was serious. All events resolved without sequelae. One case of procedural arterial thrombosis, deemed both serious and device-related, occurred. 

Based on these findings, the “WEB device can be used to treat WNBAs with a high level of procedural safety and a high degree of technical success,” the investigators conclude, reporting that data from the WEB-IT Study will be used to support a US regulatory submission.

They stress the importance of case selection, however. Without the level of experience and degree of screening involved in the WEB-IT Study, the “extremely high” rate of technical success seen here may not be achievable in clinical practice, Fiorella and colleagues advise. Also, they say, preoperative imaging and planning are essential.



Fiorella D, Molyneux A, Coon A, et al. Demographic, procedural and 30-day safety results from the WEB Intra-saccular Therapy Study (WEB-IT). J NeuroIntervent Surg. 2017;Epub ahead of print.


  • The study was funded by Sequent Medical.
  • The primary investigators for the WEB-IT trial received institutional salary support for study-related activities. Investigators in the WEB-IT trial also received payment for proctoring cases within the context of the trial.