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Updated: Jul 12, 2025

Double Direct Injection of Blood into the Cisterna Magna as a Model of Subarachnoid Hemorrhage
Published on: August 30, 2020
Analysis of aneurysmal subarachnoid hemorrhage as a multistep process
Ynte M Ruigrok1, Gabriel J E Rinkel1, Han-Sol Chang2
1Department of Neurology, University Medical Center Utrecht Brain Center, University Medical Center Utrecht, Utrecht, The Netherlands.
Background And Purpose:
Aneurysmal subarachnoid hemorrhage (ASAH) is a complex disease with higher incidence in women compared to men and in Japan compared to other countries. It was hypothesized that ASAH is consistent with a multistep model of disease. The following assessments were made: (1) the number of steps needed for the disease to occur and (2) whether this number may be different in female versus male and in Japanese versus non-Japanese patients.
Methods:
Incidence data were generated from a meta-analysis on ASAH incidence until 2017, which was supplemented with a literature search from 2017 to April 2023. Age- and sex-adjusted incidences per 10-year age groups were calculated and the logarithm of age-specific incidence against the logarithm of age was regressed with least-squares regression.
Results:
In 2317 ASAH patients a linear relationship between logarithm of incidence and logarithm of age was found with a slope estimate of 3.13 (95% confidence interval 2.60-3.65), consistent with a four-step process. Similar estimates were found for female, male, Japanese and non-Japanese patients.
Conclusions:
Our results suggest that ASAH is a four-step process, also in subgroups with higher ASAH incidence. Elucidation of the exact nature of these steps can provide important clues for identification of disease mechanisms underlying ASAH.
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