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Tomohiro Aoki, Masaki Nishimura, Ryota Ishibashi, Hiroharu Kataoka, Yasushi Takagi and Nobuo Hashimoto

Object

The pathophysiological origin of cerebral aneurysms is closely associated with chronic inflammation in arterial walls. Recently, the authors identified nuclear factor–kappa B (NF-κB) as a key mediator of cerebral aneurysm formation and progression. Because Toll-like receptor 4 (TLR4) stimulates NF-κB activation in arterial walls in atherosclerosis, the authors hypothesize that TLR4 expresses in cerebral aneurysms and contributes to the activation of NF-κB in cerebral aneurysm walls.

Methods

Cerebral aneurysms were induced in male Sprague-Dawley rats. Expression of TLRs in cerebral aneurysm walls was assessed using reverse transcriptase polymerase chain reaction (RT-PCR). The expression of TLR4 was examined using RT-PCR, immunohistochemical studies, and Western blotting. To assess TLR4 dependency on NF-κB activation, double immunostaining and a study using NF-κB–deficient mice were done. Finally, TLR4 expression in human cerebral aneurysm walls was assessed using immunohistochemical studies.

Results

In cerebral aneurysm walls, TLR1, -4, -5, -6, -10, and -11 were expressed. Among them, TLR4 and TLR10 expression changed during cerebral aneurysm formation. Expression of TLR4 was predominantly in the endothelial cell layer of cerebral aneurysm walls, and was transitionally upregulated at the early stage of cerebral aneurysm formation. The TLR4 expression coincided well with NF-κB activation. In human cerebral aneurysms, TLR4 was also expressed in the endothelial cell layer, as it was in rats.

Conclusions

Toll-like receptor 4 was expressed in cerebral aneurysm walls both in rats and humans. This receptor may play a crucial role in cerebral aneurysm formation through NF-κB activation in endothelial cells. The results of the present study will shed new light on the pathogenesis of cerebral aneurysm formation.

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Hidehisa Nishi, Akira Ishii, Ichiro Nakahara, Shoji Matsumoto, Nobutake Sadamasa, Yasutoshi Kai, Ryota Ishibashi, Michio Yamamoto, Satoshi Morita and Izumi Nagata

OBJECTIVE

The clinical outcomes of a direct aspiration first-pass technique (ADAPT) and stent retriever (SR) have been reported to be similar in several observational studies. In this study, procedural and clinical outcomes with ADAPT and SR for the treatment of acute ischemic stroke with large artery occlusion were compared in different time periods.

METHODS

In each specific time period, SR and ADAPT were used as the first-line treatment approach for acute ischemic stroke patients with large artery occlusion at the authors’ institution. Baseline characteristics, procedural variables, and functional outcome at 90 days were compared between patients treated with SR and those treated with ADAPT. These 2 groups were divided into 3 sequential subgroups to assess the learning curve effects of the endovascular team and individual operators on the procedural variables of each treatment strategy.

RESULTS

Overall, 89 patients were treated. In the SR group, the recanalization rate was higher (84% vs 65%; p = 0.01) and the procedure time was shorter than in the ADAPT group (median 42 minutes vs 76 minutes, p = 0.04). On the subgroup analysis of the learning curve, the SR group showed more rapid improvement in procedure time than the ADAPT group (p = 0.01 for the team; p < 0.01 for individual operators).

CONCLUSIONS

In this initial experience, a higher recanalization rate and shorter procedure time were achieved with SR than with ADAPT. A high recanalization rate with SR was possible with relatively less clinical experience, whereas procedure time dramatically decreased with experience. These observed effects on the learning curve might be useful when choosing the method for initial endovascular treatment of acute ischemic stroke at relatively small stroke centers.

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Masaomi Koyanagi, Hitoshi Fukuda, Masaaki Saiki, Yoshihito Tsuji, Benjamin Lo, Toshinari Kawasaki, Yoshihiko Ioroi, Ryu Fukumitsu, Ryota Ishibashi, Masashi Oda, Osamu Narumi, Masaki Chin, Sen Yamagata and Susumu Miyamoto

OBJECTIVE

Shunt-dependent hydrocephalus (SDHC) may arise after aneurysmal subarachnoid hemorrhage (aSAH) as CSF resorptive mechanisms are disrupted. Using propensity score analysis, the authors aimed to investigate which treatment modality, surgical clipping or endovascular treatment, is superior in reducing rates of SDHC after aSAH.

METHODS

The authors’ multicenter SAH database, comprising 3 stroke centers affiliated with Kyoto University, Japan, was used to identify patients treated between January 2009 and July 2016. Univariate and multivariate analyses were performed to characterize risk factors for SDHC after aSAH. A propensity score model was generated for both treatment groups, incorporating relevant patient covariates to detect any superiority for prevention of SDHC after aSAH.

RESULTS

A total of 566 patients were enrolled in this study. SDHC developed in 127 patients (22%). On multivariate analysis, age older than 53 years, the presence of intraventricular hematoma, and surgical clipping as opposed to endovascular coiling were independently associated with SDHC after aSAH. After propensity score matching, 136 patients treated with surgical clipping and 136 with endovascular treatment were matched. Propensity score–matched cohorts exhibited a significantly lower incidence of SDHC after endovascular treatment than after surgical clipping (16% vs 30%, p = 0.009; OR 2.2, 95% CI 1.2–4.2). SDHC was independently associated with poor neurological outcomes (modified Rankin Scale score 3–6) at discharge (OR 4.3, 95% CI 2.6–7.3; p < 0.001).

CONCLUSIONS

SDHC after aSAH occurred significantly more frequently in patients who underwent surgical clipping. Strategies for treatment of ruptured aneurysms should be used to mitigate SDHC and minimize poor outcomes.