Preliminary clinical experience with the pipeline vantage 21 flow diverter for embolization of aneurysms in small diameter parent vessels.

BACKGROUND

The Pipeline Vantage 21 flow diverter is a 4th generation 48-braid stent recently introduced in the United States that is intended for small parent vessel diameter (<3.5 mm) wide-necked aneurysm treatment. We report our clinical and angiographic outcomes in an initial case series.

METHODS

Twenty patients with 22 aneurysms (6 pericallosal, 13 anterior communicating, 2 V4, and 1 middle cerebral) underwent Vantage 21 treatment using 22 stents between April 2024 and January 2026. All procedures were performed via transfemoral triaxial access with platelet function testing on day of procedure. Mean aneurysm size was 3.7±1.5 mm. Aneurysm occlusion status was reported by modified Raymond Roy classification (mRRC).

RESULTS

Vantage 21 deployed successfully in all cases with excellent vessel wall apposition. Median clinical follow-up at 12 months (patients, n = 20) revealed one symptomatic stroke and two asymptomatic strokes. Median 4-month follow-up angiography for 20/22 stents revealed complete occlusion (mRRC 1) in 16/20 evaluated aneurysms (80%), accompanied by in-stent luminal stenosis (ISS) in 10/20 stents (50%), exceeding ≥ 50% (severe) in 7/20 stents (35%). All 10 cases of ISS had intimal hyperplasia, and two cases had fishmouth braid deformity with concurrent intimal hyperplasia. Of a total 38 arterial branches covered by Vantage 21 stents with DSA follow-up, 6 progressed to occlusion, and 21/38 (55.3%) demonstrated significant caliber reduction on cone-beam computer tomography angiography with maintained antegrade patency, resulting in two asymptomatic caudate infarcts on follow-up MRI with evidence of narrowed or occluded ipsilateral artery of Heubner.

CONCLUSIONS

This early US-based single-center series noted rapid aneurysm involution rates for the Pipeline Vantage 21 flow diverting stent. However, this is accompanied by a robust intimal hyperplastic vascular response in small parent vessels leading to frequent ISS and side-branch attenuation warranting longer-term clinical follow-up and caution if considering coverage of critical branch vessels. Larger samples with longer term follow-up are needed to validate these findings.