Clinical and Angiographic Outcomes of Endovascular Treatment for Acute Intracranial Vertebral Artery Dissecting Aneurysms Using Double-Overlapping Stents : Low-Profile Visualized Intraluminal Support within Enterprise Stents.

Objective: The use of reconstructive treatment with a double-overlapping stents has proven to be effective and safe in the current treatment of intracranial vertebral artery dissecting aneurysms (VADAs). We employed a combination of overlapping stents, using low-profile visualized intraluminal support (LVIS) within the Enterprise stent. This combination was chosen to minimize the outward bulging of the inner LVIS by overlapping it with the Enterprise stent while maintaining flow diversion and stability. This study aimed to evaluate the clinical and angiographic outcomes following the use of double-overlapping stents with LVIS within the Enterprise stent for the treatment of VADAs. Methods: From March 2016 to January 2022, total 28 patients with unruptured VADAs were treated with the double-overlapping stent technique using LVIS within an Enterprise stent in our institute. The Enterprise stent was deployed first, followed by the LVIS stent. Patient clinical and angiographic characteristics, procedural complications, and follow-up outcomes were retrospectively reviewed. Results: All 28 patients (18 males and 10 females) were successfully treated with double-overlapping stent deployment. There were no procedural complications or new neurological deficits in any patient. Of the 28 patients, four VADAs had posterior inferior cerebellar artery involvement. Procedure-related parent artery occlusion did not occur during the angiographic follow-up conducted 6 to 12 months after the procedure. Out of 28 patients, 24 showed complete healing, three had focal residual stenosis or dilatation with residual sac and only one had a residual dissecting flap with aneurysm. All patients, including the four patients, did not require any additional procedures. The postoperative modified Rankin Scale (mRS) scores were 0-1 for all patients. Conclusion: A double-overlapping stent, with a flow-diversion effect, is a safe and effective treatment for patients with VADAs. In particular, when using the LVIS stent within an Enterprise stent, it minimizes the bulging of the inner LVIS stent while maintaining flow diversion and stability. Therefore, both can be effectively utilized as overlapping stents.

Neurogenic pulmonary edema and Takotsubo cardiomyopathy in aneurysmal subarachnoid hemorrhage.

PURPOSE: Neurogenic pulmonary edema (NPE) combined with Takotsubo cardiomyopathy (TCM) is a rare condition associated with aneurysmal subarachnoid hemorrhage (aSAH). Although several mechanisms have been proposed, the pathophysiology and management strategies are not yet fully established. We aimed to determine the radiological and clinical outcomes of patients with NPE and with TCM after aSAH to propose management strategies. METHODS: We analyzed the data of 564 patients with aSAH recorded at a single medical center from February 2015 to July 2022. This study retrospectively investigated the incidence and demographics of SAH combined with both NPE and TCM and the clinical outcomes of the patients. Correlating factors, independently associated with NPE-TCM, were also investigated. RESULTS: During the 7 years, 11 (2.0%) of 564 patients had NPE complicated with TCM after aSAH. Seven of 11 (63.6%) patients had poor-grade SAH (Hunt-Hess Grade 4 to 5). Three of 11 patients had a posterior circulation in the NPE-TCM group. The most prevalent treatment option was endovascular coil embolization, except for one case of clip. Long-term outcomes were favorable in 6 of 11 patients, and there was one case of mortality. Age, troponin I level, and alveolar-arterial oxygen gradient were correlating factors of NPE-TCM. CONCLUSION: Although NPE-TCM represents a rare complication associated with aSAH, achieving active resolution of underlying neurological causes through early and appropriate treatment may contribute to a favorable prognosis. Considering the limited incidence of SAH complicated with NPE-TCM, a multi-center study may be needed.

Feasibility of Gamma Knife Radiosurgery for Brain Arteriovenous Malformations According to Nidus Type.

Objective: Gamma Knife Radiosurgery (GKRS) is an effective and noninvasive treatment for high-risk arteriovenous malformations (AVMs). Since differences in GKRS outcomes by nidus type are unknown, this study evaluated GKRS feasibility and safety in patients with brain AVMs. Methods: This single-center retrospective study included patients with AVM who underwent GKRS between 2008 and 2021. Patients were divided into compact- and diffuse-type groups according to nidus characteristics. We excluded patients who performed GKRS and did not follow-up evaluation with MRI or DSA within 36 months from the study. We used univariate and multivariate analyses to characterize associations of nidus type with obliteration rate and GKRS-related complications. Results: We enrolled 154 patients (mean age, 32.14±17.17 years; mean post-GKRS follow-up, 52.10±33.67 months) of whom 131 (85.1%) had compact- and 23 (14.9%) diffuse-type nidus AVMs. Of all AVMs, 89 (57.8%) were unruptured, and 65 (42.2%) had ruptured. The mean Spetzler-Martin AVM grades were 2.03±0.95 and 3.39±1.23 for the compact- and diffuse-type groups, respectively (p<0.001). During the follow-up period, AVM-related hemorrhages occurred in four individuals (2.6%), three of whom had compact nidi. Substantial radiation-induced changes and cyst formation were observed in 21 (13.6%) and 1 (0.6%) patients, respectively. The AVM complete obliteration rate was 46.1% across both groups. Post-GKRS complication and complete obliteration rates were not significantly different between nidus types. For diffuse-type nidus AVMs, larger AVM size and volume (p<0.001), lower radiation dose (p<0.001), eloquent area location (p=0.015), and higher Spetzler-Martin grade (p<0.001) were observed. Conclusion: GKRS is a safe and feasible treatment for brain AVMs characterized by both diffuse- and compact-type nidi.

High-peak-power efficient edge-emitting photonic crystal nanocavity lasers.

Record-high edge-emitted peak power was collected from L3 and finite-waveguide two-dimensional photonic crystal nanocavity quantum well membrane lasers at room temperature under single-mode operations. Peak power levels of 230 microW and 540 microW were collected from L3 and finite-waveguide edge-emitters, and their quantum differential efficiencies are 11% and 27%, respectively, limited by their collection efficiencies in free space.

Double-heterostructure photonic crystal lasers with lower thresholds and higher slope efficiencies obtained by quantum well intermixing.

In order to reduce the optical absorption loss, an array of double-heterostructure photonic crystal microcavity lasers was fabricated in which much of the photonic crystal mirror region was disordered by quantum well intermixing. In characterizing these devices, we obtained more than a factor of two increase in slope efficiencies and more than 20% reduction in threshold pump powers compared to devices that were not intermixed.