Predictors of clinical outcomes for the treatment of complex intracranial aneurysms in the anterior circulation: a prospective randomised study; SCAT

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Background. Large and giant aneurysms (> 10 mm and >25 mm, respectively), wide-necked (dome / neck ratio > 1.5) and fusiform examples are challenging for both endovascular and microsurgical intervention. Currently, there is a lack of a universal approach in treating complex anterior circulatory aneurysms. Due to high morbidity and mortality rates and the absence of a common strategy, predictor analysis may have diagnostic relevance.Aim. We sought to identify predictors of unfavourable neurological outcomes for the treatment of complex intracranial aneurysms.Methods. The investigation of complex intracranial aneurysms (SCAT, NCT03269942) is a prospective randomised multicentre study. Unifactorial and multifactorial analyses of clinical outcomes were performed to identify predictors. According to our study protocol, we included 110 patients admitted to Meshalkin National Medical Research Center and the Federal Neurosurgical Center (Novosibirsk, Russian Federation) from March 2015 to June 2018, who met eligibility criteria (age > 75 years, neck size > 4 mm and dome/neck ratio <1.5). Depending on the procedure, patients were divided into two groups using sealed envelope randomisation: 1) endovascular flow diversion (55 patients) and 2) microsurgical revascularisation (55 patients). Unfavourable outcomes were thought to be neurological deterioration with two or more mRS (modified Rankin scale) scores or ≥ mRS 4 decline.Results. Data analysis revealed significatly favourable outcomes in 94.5 % of the endovascular group, and 76.4 % of the microsurgical group at 12 months follow-up (p = 0.001). Morbidity and mortality rates were 5.5 and 1.8 % for the endovascular group, and 25.4 and 3.6 % for the microsurgical group, respectively. Log-rank criteria did not reveal any differences in mortality (p = 0.32). The overall complication rates were 29.1 % for the endovascular group, and 5.4 % for the microsurgical group (p = 0.001). We identified a significant difference in the frequency of ischaemic complications (p = 0.004), but haemorrhagic complication rates were similar (p = 0.297). Unifactorial analysis revealed predictors of unfavourable clinical outcomes: gender (male, ОR = 2.475, 95% CI: 1.005–6.094, p = 0.049), microsurgical intervention (OR = 5.618, 95% CI: 1.635–19.302, p = 0.006), giant aneurysm size (OR = 3.1, 95% CI: 1.22–7.88, p = 0,017), and temporary occlusion for > 40 min (OR = 3.016, 95% CI: 1.13–8.04, p = 0.028). Giant aneurysm size is 6.1 times more increase the probability of unfavorable outcomes according multifactorial analysis.Conclusion. In spite of a high complete occlusion rate after microsurgical treatment with revascularisation, endovascular flow diversion demonstrated better clinical outcomes at short-term follow-up (12 months). Giant aneurysm size was a predictor of both ischaemic and haemorrhagic complications, with an approximate six-fold rise in unfavourable clinical outcomes. Other predictors included the microsurgical intervention itself, especially with increased temporary occlusion for > 40 min, and the male gender. Received 12 May 2020. Revised 11 November 2020. Accepted 12 November 2020. Funding: The study did not have sponsorship. Conflict of interest: Authors declare no conflict of interest. Author contributionsConception and design: K.Yu. Orlov, A.V. DubovoyData collection and analysis: R.S. KiselevStatistical analysis: R.S. KiselevDrafting the article: R.S. KiselevCritical revision of the article: D.S. Kislitsin, A.V. Gorbatykh, A.V. Dubovoy, K.Yu. Orlov, V.V. Berestov, K.S. OvsyannikovFinal approval of the version to be published: R.S. Kiselev, A.V. Dubovoy, D.S. Kislitsin, A.V. Gorbatykh, K.S. Ovsyannikov, V.V. Berestov, K.Yu. Orlov