Evaluating the safety and technical effectiveness of a newly developed intravascular 'flow isolator' stent for the treatment of intracranial aneurysms: study protocol for a first-in-human single-arm multiple-site clinical trial in Japan

Introduction: Wide-neck or large intracranial aneurysms are difficult to cure by conventional surgical or endovascular procedures. A flow diverter (FD) is an implantable, stent-like, fine-mesh medical device for the treatment of intracranial aneurysms. Although endovascular treatment with FDs is becoming a routine first-line option, a systematic review noted the heterogeneity and publication biases of the clinical studies for FDs. We have developed a new honeycomb microporous covered stent (NCVC-CS1) as a 'flow isolator' for the endovascular treatment of intracranial aneurysms.

Methods and analysis: We planned the NCVC-CS1_UAN as a first-in-human study to evaluate the safety and technical effectiveness of the NCVC-CS1, a newly developed honeycomb microporous covered stent, for the treatment of intracranial aneurysms that are difficult to cure by conventional surgical or endovascular procedures. The study is a multicentre, open-label, uncontrolled, exploratory, medical device, investigator-initiated clinical study. The primary safety endpoint of this study is any stroke or death related to the procedure within 180 days, while for efficacy, the endpoint is complete obliteration of the target aneurysm and patency of the target vessel (less than 50% stenosis) confirmed by angiography at 180 days after the procedure.

Ethics and dissemination: Full ethics approval of institutional review boards was obtained at all participating sites. A clinical trial notification as a new medical device was accepted by the Japanese regulatory agency before it started. The study should be followed by a pivotal study to obtain satisfactory data for an application for marketing approval. The main results of this study will be submitted for publication in a peer-reviewed journal. The planned subject number for this study is 12.

Trial registration number: NCT02907229.