Postoperative transient neurological symptoms and chronic subdural hematoma after extracranial-intracranial bypass for internal carotid/middle cerebral atherosclerotic steno-occlusive diseases: negative effect on cognitive performance

Cognitive outcomes after extracranial-intracranial bypass surgery in elderly patients diagnosed with atherosclerotic cerebral steno-occlusive artery disease

Background

The safety and clinical effectiveness of extracranial-intracranial (EC-IC) bypass surgery in elderly patients with atherosclerotic internal carotid artery and/or middle cerebral artery steno-occlusive (ACMSO) disease remain ambiguous. Here, we analyzed our experience of EC-IC bypass surgery to evaluate its clinical safety and effect on the cognitive function for elderly patients with ACMSO.

Methods

This retrospective study enrolled patients >60 years of age diagnosed with ACMSO who underwent EC-IC bypass surgery at the authors' center between January 2018 and January 2021. Indications for bypass surgery included symptomatic ACMSO defined by cerebral angiography and evidence of relative hypoperfusion in the territories of steno-occlusive arteries based on computed tomography perfusion (CTP) neuroimaging. All patients underwent the Montreal Cognitive Assessment preoperatively and 2 years after bypass surgery. Clinical data, such as the National Institute of Health Stroke Scale and cognitive function scores, and CTP parameters were retrospectively analyzed.

Results

The study cohort ultimately included data from 65 patients (60-68 years of age; median age, 66 years) who underwent 82 bypass surgeries. The patency rate of bridge arteries was 100% on intraoperative fluoroscopy and 95.0% (76/80) according to cerebral angiography at the last follow-up. The perioperative stroke rate was 1.54 % and the mortality rate was 3.08% in the 2nd year of follow-up. Compared with preoperative data, the mismatch volume of CTP was reduced (P < 0.001), and the Montreal Cognitive Assessment score significantly increased (P < 0.001) 2 years after bypass surgery. Forty patients in the cognitive improvement group had a higher educational level (P = 0.020), shorter course of disease (P = 0.041), shorter mean transit time (MTT) (P < 0.001), and shorter time to peak value (P = 0.015) on CTP, as determined by single-factor analysis before bypass, compared with those in the inactive group. Based on multivariate logistic regression analysis, a shorter preoperative MTT was an independent clinical factor for cognitive improvement after bypass (odds ratio 0.452 [95% confidence interval 0.082-0.760]; P = 0.003).

Conclusion

EC-IC bypass surgery was safe and improved cognitive function in elderly patients diagnosed with ACMSO. Reversible cerebral perfusion function is one of the better prognoses, which needs to be confirmed in future study.

Impact of Extracranial-Intracranial Bypass on Cognitive Function in a Patient with Chronic Cerebral Ischemia

Extracranial–intracranial (EC-IC) arterial bypass surgery was developed to prevent subsequent stroke by improving hemodynamics distal to the occluded intracranial artery, but its utilization has been decreasing due to the development in medical treatment. However, EC-IC bypass surgery may be effective for arresting or reversing cognitive decline in patients with cerebral ischemia. A 69-year-old man with the left internal carotid artery occlusion that manifested as scattered cerebral infarction of the left hemisphere presented with dysarthria and transient right hemiparesis. Hemodynamic condition was impaired in the left side, and therefore, EC-IC bypass surgery was performed to prevent recurrence of cerebral infarction. Neuropsychological examination at 6 months after the surgery showed marked improvement as compared to the preoperative examination and there was no recurrence of stroke in the patient. EC-IC bypass may contribute to the improvement of cognitive function as well as the prevention of recurrence of cerebral infarction in patients with hemodynamic insufficiency, but there might be a threshold of hemodynamic impairment with respect to the reversibility of cognitive performance. Investigation of the target and timing can identify cases in which the cognitive function is improved by surgery.

Preservation of spatial memory and neuroprotection by the fatty acid amide hydrolase inhibitor URB597 in a rat model of vascular dementia

Background

Chronic cerebral hypoperfusion (CCH) is a major risk factor for vascular dementia (VaD). There are currently no broadly effective prevention or treatment strategies for VaD, but recent studies have reported promising results following vascular bypass surgery and pharmacomodulation of the brain endocannabinoid system (ECS). In this study, early effects of encephalomyosynangiosis (EMS) bypass surgery and augmented endocannabinoid signaling on CCH-induced cognitive dysfunction and neuronal damage were investigated.

Methods

An animal model of VaD was established by bilateral common carotid artery occlusion (BCCAO). Cannabinoid signaling was upregulated by treatment with the fatty acid amide hydrolase inhibitor URB597 (URB). Spatial learning and memory, cerebral blood flow (CBF), revascularization, brain-derived neurotrophic factor (BDNF)-tropomyosin receptor kinase B (TrkB) signaling, and apoptosis were compared among Sham, BCCAO, BCCAO + EMS, BCCAO + URB, and BCCAO + URB + EMS groups. Spatial learning and memory were evaluated using the Morris water maze (MWM). The CBF in cortex and hippocampus was evaluated by 3-dimensional arterial spin labeling. The neovascularization was visualized by CD34 immunofluorescence staining, and BDNF-TrkB signaling protein expression levels were assessed by Western blotting.

Results

Treatment with URB597 but not EMS alone reversed the spatial learning and memory deficits induced by BCCAO. Neovascularization was enhanced after EMS surgery but not by URB597. Alternatively, there were no significant differences in CBF among treatment groups. Expression levels of BDNF and TrkB were significantly reduced by CCH compared to Sham treatment, and downregulation of both proteins was reversed by URB597 treatment but not EMS. BCCAO enhanced neuronal apoptosis, which was also reversed by URB597.

Conclusions

Augmentation of endogenous cannabinoid signaling but not EMS protects against CCH-induced neurodegeneration and preserves spatial learning and memory, possibly by activating BDNF-TrkB signaling.

Safety of Extracranial-Intracranial Arterial Bypass in the Treatment of Moyamoya Disease

OBJECTIVE

The purpose of this study is to uncover the controversial problems and review the safety of extracranial-intracranial arterial bypass (EC-IC arterial bypass) in the treatment of moyamoya disease.

METHODS

Published randomized controlled clinical trials were searched from PubMed, EMBASE, Cochrane Central Register of Controlled Trials, and Web of science without date or language limitations until September 2016. Meta-analysis was performed as recommended by the Cochrane Collaboration of trials.

RESULTS

In total 2 studies were included by strict inclusion and exclusion criteria. The result of meta-analysis showed that surgical group had a greater reduction of the primary end points (OR [0.35], 95% CI [0.15, 0.84], I = 0%) than that of the nonsurgical group.

CONCLUSION

Surgical therapy significantly lowers incidence of the primary end points (including rebleeding attack; completed stroke resulting in significant morbidity; mortality from any medical cause and requirement for bypass surgery fora nonsurgical patient as determined by a registered neurologist) compared with nonsurgical therapy. High-quality randomized controlled trials are required to confirm this conclusion.

High-flow bypass with radial artery graft followed by internal carotid artery ligation for large or giant aneurysms of cavernous or cervical portion: clinical results and cognitive performance

High-flow bypass followed by ligation of the internal carotid artery (ICA) is an effective treatment, but the impact of abrupt occlusion of the ICA is unpredictable, especially on postoperative cognitive function. The present study evaluated the clinical results as well as cognitive performances after high-flow bypass using radial artery graft (RAG) with supportive superficial temporal artery (STA)-middle cerebral artery (MCA) bypass, followed by ICA ligation. Ten consecutive patients underwent high-flow bypass surgery for large or giant ICA aneurysms of cavernous or cervical portion. Demographics, clinical information, magnetic resonance (MR) imaging, computed tomography, digital subtraction angiography (DSA), intraoperative somatosensory evoked potentials, neuropsychological examinations including the Wechsler Adult Intelligence Scale-Third Edition and the Wechsler Memory Scale-Revised (WMS-R), and follow-up data were analyzed. The aneurysm was located on the cavernous segment in eight cases and cervical segment in two cases, and mean aneurysm size was 27.9 mm. Postoperative DSA demonstrated robust bypass flow from the external carotid artery to MCA via the RAG, and no anterograde flow into the aneurysm. No patient showed new symptoms after the operation. Follow-up clinical study and MR imaging were performed in nine patients and showed no additional ischemic lesion compared with preoperative imaging. Seven patients completed neuropsychological examinations before and after surgery. All postoperative scores except WMS-R composite memory score slightly improved. High-flow bypass followed by ICA ligation can achieve good clinical outcomes. Successful high-flow bypass using RAG with supportive STA-MCA bypass and ICA ligation does not adversely affect postoperative cognitive function.