Pearls & Oy-sters: Small but consequential: Intracerebral hemorrhage caused by lenticulostriate artery aneurysm

Cerebral hemorrhage after thrombolysis in stroke patients with unruptured intracranial aneurysms: a systemic review and meta-analysis

BACKGROUND

For ischemic stroke patients with concomitant unruptured aneurysm, intravenous thrombolysis therapy (IVT) remains a disputable decision. We hence performed a meta-analysis to identify the related brain hemorrhage rate of unruptured aneurysms and the risk ratio for their rupture comparing to stroke patients who do not have aneurysms.

METHODS

A comprehensive search was conducted to identify the studies from the online database from 2000 to September 1st, 2022. Cohort studies were included and assessed by Newcastle-Ottawa Scale (NOS) for quality. The research procedures were subjected to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Fixed-effects model was used based on the heterogeneity tests.

RESULTS

In 10 eligible studies, 7238 ischemic stroke patients were screened, a total of 302 patients with 348 aneurysms were included. 10 studies were eligible for ICH rate analysis, 8 for SAH rate analysis and 7 for risk ratio of stroke patients with unruptured aneurysms. The pooled any ICH rate was 16% (95% CI 11-21%), symptomatic ICH rate was 4% (95% CI 1-7%, I2 = 0.00%, p = 0.90), and 0% (95% CI 0-1%) for aneurysm-related ICH. Subarachnoid hemorrhage was as low as 2% (95% CI 0-5%), while 0% (95% CI 0-2%) directly related to the aneurysm rupture. The risk ratio of ICH in stroke patients with aneurysms was 1.18 (95% CI 0.79-1.77). Additionally, the hemorrhage rate difference was not evident between saccular and fusiform aneurysms due to a lack of details.

CONCLUSIONS

IVT is unlikely to induce hemorrhage of pre-existing unruptured aneurysms in stroke patients. Further randomized control studies are warranted to validate these conclusions.

Remodeling of the Neurovascular Unit Following Cerebral Ischemia and Hemorrhage

Formulated as a group effort of the stroke community, the transforming concept of the neurovascular unit (NVU) depicts the structural and functional relationship between brain cells and the vascular structure. Composed of both neural and vascular elements, the NVU forms the blood-brain barrier that regulates cerebral blood flow to meet the oxygen demand of the brain in normal physiology and maintain brain homeostasis. Conversely, the dysregulation and dysfunction of the NVU is an essential pathological feature that underlies neurological disorders spanning from chronic neurodegeneration to acute cerebrovascular events such as ischemic stroke and cerebral hemorrhage, which were the focus of this review. We also discussed how common vascular risk factors of stroke predispose the NVU to pathological changes. We synthesized existing literature and first provided an overview of the basic structure and function of NVU, followed by knowledge of how these components remodel in response to ischemic stroke and brain hemorrhage. A greater understanding of the NVU dysfunction and remodeling will enable the design of targeted therapies and provide a valuable foundation for relevant research in this area.