Small pipes: preliminary experience with 3-mm or smaller pipeline flow-diverting stents for aneurysm repair prior to regulatory approval.

Flow diversion has become an established treatment option for challenging intracranial aneurysms. The use of small devices of ≤3-mm diameter remains unapproved by major regulatory bodies. A retrospective review of patients treated with Pipeline Embolization Devices of ≤3-mm diameter at 3 Canadian institutions was conducted. Clinical and radiologic follow-up data were collected and reported. Twelve cases were treated with ≥1 Pipeline Embolization Device of ≤3-mm diameter, including 2 with adjunctive coiling, with a median follow-up of 18 months (range, 4-42 months). One patient experienced a posttreatment minor complication (8%) due to an embolic infarct. No posttreatment hemorrhage or delayed complications such as in-stent stenosis/thrombosis were observed. Radiologic occlusion was seen in 9/12 cases (75%) and near-occlusion in 2/12 cases (17%). Intracranial aneurysm treatment with small-diameter flow-diverting stents provided safe and effective aneurysm closure in this small selected sample. These devices should be further studied and considered for regulatory approval.