Multiple overlapping uncovered stents as an alternative flow-diverting strategy in the management of peripheral and visceral aneurysms

In this study we aimed to report on the midterm outcome of multiple overlapping uncovered stents in the treatment of peripheral and visceral aneurysms, and analyze the possible factors affecting the treatment efficacy.

Data of patients who were regularly followed up over 24 months were retrospectively reviewed. Descriptive statistics were applied to present aneurysm thrombosis process and diameter change at each follow-up point, and a comparison with the baseline level was performed. Patients were divided into a totally thrombosed (TT) group and a residual perfusion (RP) group according to the sac thrombosis ratio (thrombus volume to sac volume ratio) at 3, 6, and 12 months of follow-up. Aneurysm shrinkage in the two groups was compared to explore the effect of the initial RP on the treatment outcome. Patients were also grouped based on their aneurysm morphology (saccular/fusiform). The aneurysm sac thrombosis speed (time to thrombosis) and diameter decrease (DD) ratio (percentage of DD) were compared between the two groups to understand the influence of aneurysm shape on the treatment efficacy.

Of the 64 patients treated, the initial 37 patients (25 male; average age, 55.5 ± 13.0 years) were enrolled into this study. Technical success rate was 100%. All patients were regularly followed up. At 24 months, 94.6% aneurysms (35/37) were TT, and the maximum aneurysm diameter decreased from 36.5 ± 9.7 mm preoperatively to 23.6 ± 7.7 mm (P < .001). Overall clinical success rate (complete thrombosis and shrinkage/stabilization of the aneurysm without aneurysm-related mortality) reached 94.6% in the study cohort. Most side branches (31/33) covered by the bare stent stayed patent during follow-up. Initial sac RP at 3, 6, and 12 months might not fully affect the final aneurysm DD ratio (TT group: 0.37 ± 0.09, 0.35 ± 0.09, and 0.35 ± 0.09; compared with the RP group: 0.33 ± 0.09, 0.36 ± 0.11, and 0.36 ± 0.13; P = .153, .964, and .418, respectively). At 3 and 6 months follow-up, saccular aneurysms (n = 29) seemed to have a faster thrombosis speed compared with fusiform aneurysms (78.1 ± 26.8% and 83.9 ± 21.8% vs 47.0 ± 24.4% and 63.9 ± 22.6%; P = .004 and .013, respectively), but there was no significant difference in aneurysm shrinkage ratio at 24 months between the two groups (0.36 ± 0.10 vs 0.33 ± 0.06; P = .357).

Multiple overlapping uncovered stents could be a feasible option for the endovascular treatment of peripheral and visceral aneurysms. Neither the aneurysm shape nor the initial sac RP would affect the midterm treatment outcome. Further validation of this technique is required to substantiate these results.