Introduction Flow-diverter stents (FDSs) have been used effectively to treat wide neck and complex intracranial aneurysms (IAs). However, treatment strategies vary significantly. Previously, the normalized mean aneurysm flow amplitude ratio (MAFA-R) has been described as a novel metric to quantify aneurysm flow reduction that occurs as a result of FD stenting. The aim of this study was to evaluate the performance of the MAFA-R in predicting complete occlusion for IAs treated with FDSs.
Materials and methods We included patients harboring unruptured saccular IAs, which were treated with flow diverter stents. For each patient, a 3D rotational angiogram was performed prior to implantation and two high frame rate DSA sequences were acquired respectively pre- and post- FD stenting. The aneurysmal flow reduction as indicated by the MAFA-R was calculated using dedicated software (AneurysmFlow, Philips Healthcare). The MAFA-R performance for prediction of complete aneurysm occlusion was tested against the thrombosis incidence at 3, 6, and 12 months by using the receiver operating characteristic (ROC) analysis performance test. The AUC was determined, as well as the threshold maximizing the sum of sensitivity and specificity. The analysis was carried out on the total aneurysm cohort as well as for a subgroup of aneurysms >10 mm.
Results We included 54 consecutive patients. All cases were successfully treated with a[o1] flow diverter stent. At 3 months follow-up, 11 out of 54 aneurysms were fully occluded (20%), and 43 displayed residual circulation (80%). The performance of MAFA-R test for the total cohort was: AUC = 0.60, p = 0.386 and threshold = 0.62. At 6 months 31/54 aneurysms occluded (57%), AUC = 0.657, p = 0.414, threshold = 0.93. At 12 months 39/52 aneurysms occluded (75%), AUC = 0.66, p = 0.081, threshold =0.89. For the large aneurysm subgroup, the results were: at 3 months 2/19 aneurysms occluded (11%): AUC = 0.97, p = 0.014, threshold = 0.64; at 6 months 7/19 aneurysms occluded (37%): AUC = 0.82, p < 0.0001, threshold = 0.93; and at 12 months 11/18 aneurysms occluded (61%): AUC = 0.91, p < 0.0001, threshold = 0.89.
Conclusions Aneurysm occlusion after FD stenting is determined by multiple factors including aneurysm size, morphology and the hemodynamic environment. While for the total aneurysm cohort no significance was reached, the results of this study show that for large aneurysms, the MAFA-R is an independent predictor of aneurysm occlusion at 12 months follow up (MAFA-R threshold = 0.89). This real-time functional assessment may potentially help the clinician to adapt the treatment during the procedure by adding further FDS layers or intra-saccular coils. [o1]Some cases were implanted with 2 devices, BB4-4AE2-9764-89B1B81991A1$$
Disclosures V. Mendes Pereira: 1; C; Philips, Medtronic. O. Brina: None. J. Bracken: 5; C; Philips. T. Krings: None. K. Lovblad: None. F. van Nijnatten: 5; C; Philips. D. Ruijters: 5; C; Philips. T. Grünhagen: 5; C; Philips.
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