Effects of Increased Intracranial Pressure Gradient on Cerebral Venous Infarction in Rabbits

Factors associated with the initial intracranial hemorrhage occurrence in patients with cerebral venous thrombosis

OBJECTIVES

Studies focusing on intracranial hemorrhage (ICH) in patients with cerebral venous thrombosis (CVT) are limited; thus, we aimed to identify factors associated with the occurrence of ICH in Thai patients with CVT.

METHODS

This retrospective cohort study recruited patients with CVT admitted to a tertiary university-based hospital between 2002 and 2022. The baseline characteristics, clinical presentations, radiographic findings, and etiologies were compared between the ICH and non-ICH groups. The factors with p < 0.2 in the univariate analysis were further analyzed using multivariable logistic regression analysis to identify independent factors associated with ICH in patients with CVT.

RESULTS

Of 228 screenings, 202 patients were eligible. The incidence rate of ICH was 36.63%. The ICH group showed a higher prevalence of focal neurological deficits (63.51% vs. 26.56%, p < 0.001), seizures (68.92% vs. 21.88%, p < 0.001), dependency status at admission (60.81% vs. 39.84%, p = 0.004), superior sagittal sinus thrombosis (71.62% vs. 39.07%, p < 0.001), superficial cortical vein thrombosis (36.49% vs. 10.16%, p < 0.001), and hormonal use (17.57% vs. 7.03%, p = 0.021) than the non-ICH group. In contrast, the ICH group showed a lower prevalence of isolated increased intracranial pressure (10.81% vs. 21.88%, p = 0.048) than the non-ICH group. Seizures (adjusted odds ratio [aOR], 4.537; 95% confidence interval [CI], 2.085-9.874; p < 0.001), focal neurological deficits (aOR, 2.431; 95% CI, 1.057-5.593; p = 0.037), and superior sagittal sinus thrombosis (aOR, 1.922; 95% CI, 1.913-4.045; p = 0.045) were independently associated with ICH in the multivariable logistic regression analysis.

CONCLUSIONS

Seizures, focal neurological deficits, and superior sagittal sinus thrombosis are associated with ICH in patients with CVT.

Cerebral venous hemodynamic responses in a mouse model of traumatic brain injury

Traumatic brain injury (TBI) is a serious public health problem that endangers human health and is divided into primary and secondary injuries. Previous work has confirmed that changes in cerebral blood flow (CBF) are related to the progression of secondary injury, although clinical studies have shown that CBF monitoring cannot fully and accurately evaluate disease progression. These studies have almost ignored the monitoring of venous blood flow; however, as an outflow channel of the cerebral circulation, it warrants discussion. To explore the regulation of venous blood flow after TBI, the present study established TBI mouse models of different severities, observed changes in cerebral venous blood flow by laser speckle flow imaging, and recorded intracranial pressure (ICP) after brain injury to evaluate the correlation between venous blood flow and ICP. Behavioral and histopathological assessments were performed after the intervention. The results showed that there was a significant negative correlation between ICP and venous blood flow (r = -0.795, P < 0.01), and both recovered to varying degrees in the later stages of observation. The blood flow changes in regional microvessels were similar to those in venous, and the expression of angiogenesis proteins around the impact area was significantly increased. In conclusion, this study based on the TBI mouse model, recorded the changes in venous blood flow and ICP and revealed that venous blood flow can be used as an indicator of the progression of secondary brain injury.

The characteristics of brain injury following cerebral venous infarction induced by surgical interruption of the cortical bridging vein in mice

Cerebral venous infarction (CVI) caused by the injury of cortical bridging veins (CBVs), is one of the most serious complications following neurosurgical craniotomy. Different from cerebral artery infarction, this CVI pathological process is more complicated, accompanied by acute venous hypertension, brain edema, cerebral ischemia and hemorrhage in the veins bridged brain area. Therefore, a reliable and stable small animal model is particularly important for the pathological study of CVI induced by surgical CBV interruption (CBVi). A mouse model established by cutting off the right CBVs from bregma to lambda with microsurgical technique is used for the assessment of the pathological process. Adult male mice underwent craniotomy after transection of the parietal skin under anesthesia. The right CBVs were exposed by removing the right skull along the right lateral edge of the sagittal sinus (forming a 4 mm × 3 mm bone window from bregma to lambda) with a drill under the operating microscope. Following the final inspection of the cerebral veins, the CBVs (30% one, 60% two, 10% none) were sacrificed using bipolar coagulation technique. Intracranial pressure (ICP) monitoring, motor function examination, brain edema assessment and brain histopathological observation after perfusion were performed at different time points (6 h, 12 h, 24 h, and 48 h) in the postoperative mice. Cerebral hemisphere swelling, midline shift and subcortical petechial hemorrhage were found on histological sections 6 h after CBVs dissection. The change of ICP was consistent with cerebral edema and peaked at 12 h after surgery, as well as the disruption of the blood-brain barrier assessed by Evans Blue staining. Tissue necrosis, nerve cell loss and monocytes infiltration were also dynamically increased in the postoperative hemispheric cortex. Behavioral tests showed obvious somato- and forelimb-motor dysfunction, and severe somatosensory disorder on the operative mice at 12 h, which were substantially recovered at 48 h. Our study provided a novel mouse model of CVI caused by surgical CBVi that was close to clinical practice, and preliminarily confirmed its pathological process. This model might become an important tool to study the clinical pathology and the molecular mechanism of nerve injury following CVI.

Restrictive cerebral cortical venopathy: A new clinicopathological entity

We present a case of a novel restrictive cerebral venopathy in a child, consisting of a bilateral network of small to medium cortical veins without evidence of arteriovenous shunting, absence of the deep venous system, venous ischemia, elevated intracranial pressure, and intracranial calcifications. The condition is unlike other diseases characterized by networks of small veins, including cerebral proliferative angiopathy, Sturge-Weber syndrome, or developmental venous anomaly. While this case may be the result of an anatomic variation leading to the congenital absence of or early occlusion of the deep venous system, the insidious nature over many years argues against this. The absence of large cortical veins suggests a congenital abnormality of the venous structure. The child's presentation with a seizure-like event followed by protracted hemiparesis is consistent with venous ischemia. We propose that this is likely to represent a new clinicopathological entity.

Multimodal Regional Brain Monitoring of Tissue Ischemia in Severe Cerebral Venous Sinus Thrombosis

BACKGROUND

Comatose critically ill patients with severe diffuse cerebral venous thrombosis (CVT) are at high risk of secondary hypoxic/ischemic insults, which may considerably worsen neurological recovery. Multimodal brain monitoring (MBM) may therefore improve patient care in this setting, yet no data are available in the literature.

METHODS

We report two patients with coma following severe diffuse CVT who underwent emergent invasive MBM with intracranial pressure (ICP), brain tissue oximetry (PbtO₂), and cerebral microdialysis (CMD). Therapy of CVT consisted of intravenous unfractionated heparin (UFH), followed by endovascular mechanical thrombectomy (EMT). EMT efficacy was assessed continuously at the bedside using MBM.

RESULTS

Despite effective therapeutic UFH (aPTT two times baseline levels in the two subjects), average CMD levels of lactate and glucose in the 6 h prior to EMT displayed evidence of regional brain ischemia. The EMT procedure was associated with a rapid (within 6 h) improvement in both CMD lactate (6.42 ± 0.61 4.89 ± 0.55 mmol/L, p = 0.02) and glucose (0.49 ± 0.17 vs. 0.96 ± 0.32 mmol/L, p = 0.0005). EMT was also associated with a significant increase in PbtO₂ (22.9 ± 7.5 vs. 30.1 ± 3.6 mmHg, p = 0.0003) and a decrease in CMD glutamate (12.69 ± 1.06 vs. 5.73 ± 1.76 μmol/L, p = 0.017) and intracranial pressure (ICP) (13 ± 4 vs. 11 ± 4 mmHg (p = 004). Patients did not require surgical decompression, regained consciousness, and were discharged from the hospital with a good neurological outcome (modified Rankin score 3 and 4).

CONCLUSIONS

This study illustrates the potential utility of continuous bedside MBM in patients with coma after severe brain injury, irrespective of the primary acute cerebral condition. Despite adequate ICP and PbtO₂ control, the presence of CMD signs of regional brain cell ischemia triggered emergent EMT to treat CVT, which was associated with a significant and clinically relevant improvement of intracerebral physiology.