Patency of Posterior Circulation Branches Covered by Flow Diverter Device: A Hemodynamic Study

Abstract

Objective: Flow diverter devices are increasingly used in the treatment of posterior circulation aneurysms, sometimes necessarily involving ostia of side branches and perforators. The aim of this study was to identify the hemodynamic influence of flow diverters on side branches and perforators of the posterior circulation. Methods: We performed a retrospective study of consecutive patients treated by a flow diverter device for posterior circulation aneurysms with anterior inferior cerebellar artery (AICA) or posterior inferior cerebellar artery (PICA) involvement. Computational fluid dynamics (CFD) were used to discern hemodynamic changes of branches after deployment of the flow diverter. Results: We studied 18 branches from 17 patients (mean age, 50.72 ± 8.17 years). No branches were occluded on immediate angiography and later follow-up. Average flow velocity in aneurysms decreased from 0.077 ± 0.065 m/s to 0.025 ± 0.025 m/s ( p < 0.01). Average flow velocity in branch ostia decreased from 0.29 ± 0.14 m/s to 0.27 ± 0.16 m/s ( p = 0.189). The difference in flow velocity reduction ratio between aneurysms and branches was statistically significant (68.8 vs. 9.5%; p < 0.001). The mean pressure in branch ostia increased from 10,717.4 ± 489.0 to 10,859.0 ± 643.4 Pa ( p < 0.01). Conclusion: While a flow diverter device is capable of slowing down aneurysmal inflow, it is unable to block the flow into branches and perforators when used in the treatment of posterior circulation aneurysms; flow velocity in branches even increased in some cases. With a low branch occlusion ratio, it may be acceptable to cover posterior circulation branches and perforators if unavoidable.

Treatment of Unruptured Vertebral Artery Aneurysm Involving Posterior Inferior Cerebellar Artery With Pipeline Embolization Device

“…Levitt et al ( 18 ) reported that all the PICA maintained patency in six cases with vertebral artery aneurysms involving PICA treated by flow diverting stent. Similar results were reported by Adeeb et al ( 19 ) and Wu et al ( 20 ). These data suggested that the PICA can be effectively and safely preserved when using PED in treatment of these lesions.…”

Efficacy and safety of flow diverters in posterior circulation aneurysms and comparison with their efficacy in anterior circulation aneurysms: A systematic review and meta-analysis

“…A recent meta-analysis by Liang et al that investigated the PED in posterior circulation aneurysms included 12 studies with 358 patients with 365 aneurysms. 35 They reported a pooled long-term aneurysmal occlusion rate of 82% (95% CI, 73-90) and pooled procedure-related complication rate of 18% (95% CI, [14][15][16][17][18][19][20][21][22]. Despite differences in inclusion criteria, the aneurysmal occlusion rates in these studies are in line with our findings.…”

“…13 Moreover, their safety has not been well-defined and many studies have shown that posterior circulation aneurysms are associated with a higher rate of ischemic complications due to occlusion of perforators. 14 We performed this systematic literature review to assess the efficacy and safety of FDs in the management of posterior circulation cerebral aneurysms and compare their efficacy between anterior and posterior circulation aneurysms.…”

Pipeline Embolization Device With Adjunctive Coils for the Treatment of Unruptured Large or Giant Vertebrobasilar Aneurysms: A Single-Center Experience

“…Five of these LGVBA patients received coil-assisted embolization and all had favorable outcomes. Our results here are similar; 19 (90%) of the 21 LGVBA patients achieved favorable outcomes, nine patients in the PED with adjunctive coils group (100%) all had favorable outcomes, 10 patients in PED group (83%) had favorable outcomes. Although there was no statistical difference between the two groups in clinical and imaging follow-up, our results indicated that PED combined with coils did not increase perioperative or longterm complications.…”