Introduction: Flow diversion is increasingly used for off-label flow diversion treatments of distal circulation aneurysms. Reports of use in sub-2.0mm vessels are scant.
Methods: A prospectively-collected, IRB-approved cerebral aneurysm database was reviewed to identify patients who underwent flow diversion with a 2.5 mm diameter PED.
Results: A total of 66 aneurysms were treated in 66 procedures (100% successful, single device) in 56 patients. Average age was 56 years and 61% were female. Aneurysm location was: 51(77%) ACA, 13(20%) MCA, and 2(3%) PCA. Aneurysm size was 4.1+/-3.0 mm (1-20 mm). Safety outcomes included 3 major strokes(4.5%) resulting in permanent neurological deficit (mRS 6,4,4), including one mortality(1.5%). One was a previously-ruptured, recurrent anterior communicating artery aneurysm (minimum parent vessel diameter 12mm); one was an unruptured 13mm MCA aneurysm treated by pipeline with adjunctive coiling (min12mm); and one was a previously-ruptured and coiled, recurrent A2-A3 aneurysm (min13mm). In each case, there was acute stent thrombosis observed intra-procedurally or within 24 hours. There were 2 small-volume (<10cc, 40cc) dependent ICH(3.0%) that resolved without permanent neurological deficit. For effectiveness, 71% of patients underwent follow-up angiography. Complete occlusion was achieved by 88% at 6-months, 86% at 12 months, and 89% at last follow-up. There was a slight decrease in vessel diameter post-embolization, which was statistically significant at the proximal (p=0.003) but not distal (p=0.290) end of the device. Pre-operative average parent vessel diameter was 1.9mm proximally (range 1.1-2.6mm) and 1.7mm distally (1.0-2.3mm) of the PED. At follow-up, average parent vessel diameter was 1.7mm proximally (0.7-2.4mm) and 1.6mm distally (0.6-2.1mm). There were 0 cases of asymptomatic vessel occlusion.
Conclusions: Flow diversion can be effective for aneurysms originating from parent vessels <2.0mm in diameter. The risk of ischemic issues appears greatest in the initial 24 hours post-embolization.
Patient Care: This study further characterizes the efficacy of the endovascular management of distal circulation aneurysms with the 2.5mm Pipeline Embolization Device.
Learning Objectives: By the conclusion of this session, participants should be able to 1) describe the aneurysm occlusion rates observed in this study, 2) compare pre-operative and follow-up parent vessel diameters at the distal and proximal ends of the device, 3) identify when ischemic complications most often occurred in relation to the procedure.