Patient outcomes following subarachnoid hemorrhage between the medical center and regional hospital: whether all patients should be transferred to medical centers

Effects of case volume and comprehensive stroke center capabilities on patient outcomes of clipping and coiling for subarachnoid hemorrhage

OBJECTIVE

Improved outcomes in patients with subarachnoid hemorrhage (SAH) treated at high-volume centers have been reported. The authors sought to examine whether hospital case volume and comprehensive stroke center (CSC) capabilities affect outcomes in patients treated with clipping or coiling for SAH.

METHODS

The authors conducted a nationwide retrospective cohort study in 27,490 SAH patients who underwent clipping or coiling in 621 institutions between 2010 and 2015 and whose data were collected from the Japanese nationwide J-ASPECT Diagnosis Procedure Combination database. The CSC capabilities of each hospital were assessed by use of a validated scoring system based on answers to a previously reported 25-item questionnaire (CSC score 1-25 points). Hospitals were classified into quartiles based on CSC scores and case volumes of clipping or coiling for SAH.

RESULTS

Overall, the absolute risk reductions associated with high versus low case volumes and high versus low CSC scores were relatively small. Nevertheless, in patients who underwent clipping, a high case volume (> 14 cases/yr) was significantly associated with reduced in-hospital mortality (Q1 as control, Q4 OR 0.71, 95% CI 0.55-0.90) but not with short-term poor outcome. In patients who underwent coiling, a high case volume (> 9 cases/yr) was associated with reduced in-hospital mortality (Q4 OR 0.69, 95% CI 0.53-0.90) and short-term poor outcomes (Q3 [> 5 cases/yr] OR 0.75, 95% CI 0.59-0.96 vs Q4 OR 0.65, 95% CI 0.51-0.82). A high CSC score (> 19 points) was significantly associated with reduced in-hospital mortality for clipping (OR 0.68, 95% CI 0.54-0.86) but not coiling treatment. There was no association between CSC capabilities and short-term poor outcomes.

CONCLUSIONS

The effects of case volume and CSC capabilities on in-hospital mortality and short-term functional outcomes in SAH patients differed between patients undergoing clipping and those undergoing coiling. In the modern endovascular era, better outcomes of clipping may be achieved in facilities with high CSC capabilities.

Hippocampal Atrophy Following Subarachnoid Hemorrhage Correlates with Disruption of Astrocyte Morphology and Capillary Coverage by AQP4

Despite successful management of ruptured intracranial aneurysm following subarachnoid hemorrhage (SAH), delayed cerebral ischemia (DCI) remains the main cause of high mortality and morbidity in patients who survive the initial bleeding. Astrocytes play a key role in neurovascular coupling. Therefore, changes in the neurovascular unit including astrocytes following SAH may contribute to the development of DCI and long-term complications. In this study, we characterized morphological changes in hippocampal astrocytes following experimental SAH, with special emphasis on glia-vascular cross-talk and hippocampal volume changes. Four days after induction of SAH or sham-operation in mice, their hippocampal volumes were determined by magnetic resonance imaging (MRI) and histological/stereological methods. Glial fibrillary acid protein (GFAP) immunostained hippocampal sections were examined by stereological techniques to detect differences in astrocyte morphology, and global spatial sampling method was used to quantify the length density of Aquaporin-4 (AQP4) positive capillaries. Our results indicated that hippocampal volume, as measured both by MRI and by histological approaches, was significantly lower in SAH animals than in the sham-operated group. Accordingly, in this animal model of SAH, hippocampal atrophy existed already at the time of DCI onset in humans. SAH induced retraction of GFAP positive astrocyte processes, accompanied by a significant reduction in the length density of AQP4 positive capillaries as well as narrowing of hippocampal capillaries. Meanwhile, astrocyte volume was higher in SAH mice compared with the sham-operated group. Morphological changes in hippocampal astrocytes seemingly disrupt glia-vascular interactions early after SAH and may contribute to hippocampal atrophy. We speculate that astrocytes and astrocyte-capillary interactions may provide targets for the development of therapies to improve the prognosis of SAH.