Novel stent works wonders for adults with intracranial aneurysm

Application of the modified Alpha stent, an intracranial closed-cell stent with a unique mesh design, delivers satisfactory outcomes in coil embolization of unruptured distal internal carotid artery (ICA) aneurysms, reports a study. Its recent adjustment facilitates a less complicated delivery and deployment.

“The Alpha stent is a recently developed, laser-cut, modified closed-cell stent that aims to capture the merits of both an open-cell stent and a closed-cell stent: good wall apposition and the ability to be recaptured,” said lead author Junhyung Kim, Department of Neurosurgery, Severance Hospital, Yonsei University College of Medicine, Seoul, Korea.

Kim and colleagues prospectively enrolled 35 adult patients with unruptured intracranial aneurysms in the distal ICA between January 2021 and November 2021. They assessed the efficacy of the Alpha stent by examining the magnetic resonance angiography at 6-month follow-up using the Raymond-Roy occlusion classification (RROC). For safety, they assessed the occurrence of symptomatic procedure-related neurological complications up to 6 months after the procedure.

Assessment of aneurysm occlusion postoperatively revealed RROC I in 24 aneurysms (68.6 percent), RROC II in eight aneurysms (22.9 percent), and RROC III in three aneurysms (8.5 percent). Of the patients, 34 (97.1 percent) achieved technical success with the Alpha stent. [Sci Rep 2024;14:8723]

At 6-month radiologic follow-up, findings revealed RROC I in 34 aneurysms (97.1 percent) and RROC II in one (2.9 percent).

At clinical follow-up, one patient experienced procedure-related complications after an uneventful stent-assisted coil embolization of the right ICA-paraclinoid aneurysm. Twenty-four hours after the procedure, the patient complained of mild left hemiparesis. Diffusion-weighted imaging revealed acute infarction in the right corona, with an mRS score of 1.

Haemorrhagic procedure-related complications, morbidity, and death were not observed. One patient had a device-related problem, but it was not considered a technical failure.

“The proximal end of the stent was not fully deployed during coil embolization of the ICA-paraclinoid aneurysm, although no additional procedure was necessary,” Kim said.

Structural modification

The Alpha stent went through some changes in its structure to improve its safety and manipulability. These modifications included reducing the length of the distal tip of a pusher guide wire by 25 percent, increasing the bending force of the pusher guide wire by 50 percent for better “pushability,” and changing the austenite finish temperature to prevent abrupt radian expansion during unsheathing.

“The main advantage of the Alpha stent stems from its hybrid cell design,” according to Kim and colleagues. “In our experience, stents can be successfully recaptured without much difficulty.”

Additionally, the Alpha stent exhibited “excellent wall apposition and no kinking, especially when deployed in the paraclinoid ICA involving the curve of the anterior genu.”

The new features allowed the Alpha stent to be suitable for tortuous parent arteries, given that a closed-cell stent system was shown to provide inadequate wall apposition in the tortuous parent vessels. [Am J Neuroradiol 2011;32:1714-1720; J Neurosurg JNS 2011;115:624-632]

“Our initial experience with the Alpha stent is confined to ICA aneurysms,” Kim said. “However, analysis of its application in other locations such as [the] proximal anterior cerebral artery/middle cerebral artery and the vertebrobasilar artery, as well as the utilization of the Alpha Jr stent in smaller arteries, warrants further investigation.”