The Use of Flow Diversion in Vessels ≤2.5 mm in Diametere-A Single-Center Experience

BACKGROUND: Flow diversion has become an accepted treatment strategy for aneurysms; however, there are limited data on the use of these devices in small vessels <= 2.5 mm in diameter. METHODS: We performed a retrospective review of our prospectively maintained database to identify all patients treated with flow diversion between September 2009 and January 2018. We identified all patients in whom the average parent artery was <= 2.5 mm in diameter. Ruptured aneurysms were excluded from the analysis as were patients who had adjunctive coiling at the time of flow diversion. RESULTS: We identified 29 patients (22 female, 76%) with average age 56.2 +/- 15.9 years (range, 21-83 years). Most aneurysms were classified as saccular (n = 21, 72.4%), with 7 fusiform aneurysms (24.2%) and 1 presumed dissecting aneurysm (3.4%). The average parent artery diameter was 2.1 +/- 0.37 mm (range, 1.3-2.5 mm). Delayed angiographic follow-up was available for 18 patients at an average of 19.4 months after treatment. Fifteen patients showed Raymond-Roy classification grade 1 occlusion (94%) and 1 patient with complete filling showed Raymond-Roy classification grade 3 (6%). Four patients (13.7%) underwent repeat treatment with implantation of another flow-diverting stent in a telescoping manner. At 90 days, 2 patients had a modified Rankin Scale (mRS) score of 6, 1 from an unrelated cause and 1 from the enlarging compressive dissecting aneurysm and intraparenchymal hemorrhage. All the remaining patients had an mRS score <= 2 at 90 days, with 24 patients (83%) with an mRS score of 0. CONCLUSIONS: Flow diverters can be implanted into small vessels with a high rate of technical success and good rates of aneurysm occlusion. Dedicated devices to target these vessels should be developed.