Abstract
Objective: Whether partial embolization could facilitate the post-stereotactic radiosurgery (SRS) obliteration for brain arteriovenous malformations (bAVMs) remains controversial. We performed this study to compare the outcomes of SRS with and without prior embolization for bAVMs.Methods: We retrospectively reviewed the Beijing Tiantan AVMs prospective registration research database from September 2011 to October 2014. Patients were categorized into two groups, combined upfront embolization and SRS (Em+SRS group) and SRS alone (SRS group), and we performed a propensity score matching analysis based on pre-embolization baseline characteristics; the matched groups each comprised 76 patients.Results: The obliteration rate was similar between SRS and Em+SRS (44.7 vs. 31.6%; OR, 1.754; 95% CI, 0.905–3.401; p = 0.096). However, the SRS group was superior to the Em+SRS group in terms of cumulative obliteration rate at a follow-up of 5 years (HR,1.778; 95% CI, 1.017–3.110; p = 0.033). The secondary outcomes, including functional state, post-SRS hemorrhage, all-cause mortality, and edema or cyst formation were similar between the matched cohorts. In the ruptured subgroup, the SRS group could achieve higher obliteration rate than Em+SRS group (56.5 vs. 31.9%; OR, 2.773; 95% CI, 1.190–6.464; p = 0.018). The cumulative obliteration rate at 5 years was also higher in the SRS group (64.5 vs. 41.3%; HR, 2.012; 95% CI, 1.037–3.903; p = 0.038), and the secondary outcomes were also similar between the matched cohorts.Conclusion: Although there was no significant difference in the overall obliteration rate between the two strategies, this study suggested that pre-SRS embolization may have a negative effect on post-SRS obliteration. Furthermore, the obliteration rates of the SRS only strategy was significantly higher than that of the Em+SRS strategy in the ruptured cohort, while no such phenomenon was found in the unruptured cohort.
Highlights
Stereotactic radiosurgery (SRS) has become one standard treatment strategy of brain arteriovenous malformation, especially those located in deep or eloquent regions with high surgical risks, and mounting studies suggested that SRS can achieve a satisfactory obliteration rate [1]
After propensity score matching (PSM), there were no statistical differences in baseline characteristics between the SRS group and Em+SRS group
We noticed that niduses in the Em+SRS group had higher SM grades and more complicated angioarchitectures when data derived from post-embolization characteristics, rather than pre-embolization lesions, were used as baseline characteristics
Summary
Stereotactic radiosurgery (SRS) has become one standard treatment strategy of brain arteriovenous malformation (bAVM), especially those located in deep or eloquent regions with high surgical risks, and mounting studies suggested that SRS can achieve a satisfactory obliteration rate [1]. Partial embolization was generally used to reduce the volume of large bAVMs to facilitate the complete obliteration after the following SRS [3], and the targeted embolization for the comorbid aneurysms and arteriovenous fistulas may be beneficial in reducing the rupture risk after SRS [4, 5]. Many recent studies implied a negative effect of partial nidus embolization on obliteration rates after SRS [1]. Those previous studies had some nonnegligible limitations, such as the combination strategy applied post-embolization characteristics in the comparison of baseline, and the combination strategy tended to be used in larger bAVMs [1], which resulted in a more severe condition in the combination group. We performed a propensity score matching (PSM) analysis based on pre-embolization baseline characteristics to compare the outcomes of SRS with and without prior embolization for bAVMs
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