Cerebral Perfusion Pressure and Delayed Cerebral Ischemia After Aneurysmal Subarachnoid Hemorrhage

An update of predictors of cerebral infarction after aneurysmal subarachnoid hemorrhage: systematic review and meta-analysis

INTRODUCTION

Evidence about predictors of poor outcomes such as cerebral infarction (CI) after aneurysmal subarachnoid hemorrhage (aSAH) has not been fully elucidated.

EVIDENCE ACQUISITION

We performed a systematic review and meta-analysis on studies with adults with aSAH considering RCT and non-RCT, prospective, and retrospective cohort studies describing clinical, imaging as well as angiographic studies in patients with aSAH.

EVIDENCE SYNTHESIS

After reviewing the complete text, 11 studies were considered eligible, out of which four were ruled out. Degree of clinical severity was the most predictive factor with a higher degree at the presentation on different severity scales being associated with a statistically significant increasing the risk of suffering a CI following aSAH (OR 2.49 [95% CI 1.38-4.49] P=0.0003). Aneurysm size increased the risk of CI (OR 1.49 [95% CI 1.20-1.85] P=0.0003; I²=4%). In six studies analyzed, it was found that an important factor for the subsequent development of CI is vasospasm (OR 7.62 [2.19, 26.54], P=0.0001).

CONCLUSIONS

The development of vasospasm is a risk factor for CI development after aSAH. In our review, three factors were associated with an increased risk of CI: clinical severity at presentation, vasospasm, and aneurysm size. The major limitation of this meta-analysis is that included studies were conducted retrospectively or were post hoc analyses of a prospective trial.

Aneurysmal subarachnoid hemorrhage survivors show long-term deficits in spatial reference memory in a pilot study of a virtual water maze paradigm

BACKGROUND

Limited data exists on the long-term effects of aneurysmal subarachnoid hemorrhage (SAH) on spatial memory. Herein, we used a computerized virtual water maze to evaluate the feasibility of spatial memory testing in pilot cohort of ten patients who survived previous SAH.

METHODS

Ten SAH survivors (5.8 ± 5.1 years after initial hemorrhage) and 7 age-matched controls underwent testing in a virtual water maze computer program. Additional subgroup analyses were performed to evaluate spatial reference memory correlation for ventricular size on admission, placement of an external ventricular drain and placement of a shunt.

RESULTS

With respect to the spatial memory acquisition phase, there was no significant difference of pathway length traveled to reach the platform between SAH survivors and control subjects. During the probe trial, control subjects spent significantly longer time in target quadrants compared to SAH survivors (F_{(3, 24)} = 10.32, p = 0.0001; Target vs. Right: Mean percent difference 0.16 [0-0.32], p = 0.045; Target vs. Across: Mean percent difference 0.35 [0.19-0.51], p < 0.0001; Target vs. Left: Mean percent difference 0.21 [0.05-0.37], p = 0.0094). Furthermore, patients who initially presented with smaller ventricles performed worse that those patients who had ventriculomegaly and/or required surgical management of hydrocephalus.

CONCLUSIONS

Our data demonstrate that SAH survivors have persistent spatial reference memory deficits years after the hemorrhage. Hydrocephalus at presentation and external ventricular drainage were not found to be associated with poor spatial memory outcomes in this pilot cohort. Therefore, other causes such as global cerebral edema or magnitude of initial ICP spike, need to be considered to be examined as root cause as well in subsequent studies. The protocol described in this manuscript is able to demonstrate a spatial reference memory deficit and can be used to study risk factors for spatial memory impairment on a larger scale.

Cerebral Microdialysis in Aneurismal Subarachnoid Hemorrhage Patient Reveals a Detrimental Shift in Brain Energy Metabolism, Despite Normal Perfusion Pressure

The present case study concerns a patient admitted to our neuro-intensive care unit with a severe aneurismal subarachnoid hemorrhage rebleeding. The patient was equipped with multimodal neuromonitoring, including cerebral microdialysis. During the neuro-intensive care unit, there was a gradual decrease in cerebral perfusion pressure, which was within normally accepted levels, correlated to a detrimental shift in cerebral metabolism, from mitochondrial dysfunction to an ischemic pattern. Subsequently, the clinical and paraclinical status of the patient worsened. The present case highlights how the dynamic assessment of cerebral metabolic patterns and the concept of mitochondrial dysfunction can be relevant in the day-to-day clinical setting, to evaluate and optimize basic, well-known physiological parameters, such as cerebral perfusion pressure.

Functions of resolvin D1-ALX/FPR2 receptor interaction in the hemoglobin-induced microglial inflammatory response and neuronal injury

Background

Early brain injury (EBI) has been thought to be a key factor affecting the prognosis of subarachnoid hemorrhage (SAH). Many pathologies are involved in EBI, with inflammation and neuronal death being crucial to this process. Resolvin D1 (RvD1) has shown superior anti-inflammatory properties by interacting with lipoxin A4 receptor/formyl peptide receptor 2 (ALX/FPR2) in various diseases. However, it remains not well described about its role in the central nervous system (CNS). Thus, the goal of the present study was to elucidate the potential functions of the RvD1-ALX/FPR2 interaction in the brain after SAH.

Methods

We used an in vivo model of endovascular perforation and an in vitro model of hemoglobin (Hb) exposure as SAH models in the current study. RvD1 was used at a concentration of 25 nM in our experiments. Western blotting, quantitative polymerase chain reaction (qPCR), immunofluorescence, and other chemical-based assays were performed to assess the cellular localizations and time course fluctuations in ALX/FPR2 expression, evaluate the effects of RvD1 on Hb-induced primary microglial activation and neuronal damage, and confirm the role of ALX/FPR2 in the function of RvD1.

Results

ALX/FPR2 was expressed on both microglia and neurons, but not astrocytes. RvD1 exerted a good inhibitory effect in the microglial pro-inflammatory response induced by Hb, possibly by regulating the IRAK1/TRAF6/NF-κB or MAPK signaling pathways. RvD1 could also potentially attenuate Hb-induced neuronal oxidative damage and apoptosis. Finally, the mRNA expression of IRAK1/TRAF6 in microglia and GPx1/bcl-xL in neurons was reversed by the ALX/FPR2-specific antagonist Trp-Arg-Trp-Trp-Trp-Trp-NH2 (WRW4), indicating that ALX/FPR2 could mediate the neuroprotective effects of RvD1.

Conclusions

The results of the present study indicated that the RvD1-ALX/FPR2 interaction could potentially play dual roles in the CNS, as inhibiting Hb promoted microglial pro-inflammatory polarization and ameliorating Hb induced neuronal oxidant damage and death. These results shed light on a good therapeutic target (ALX/FPR2) and a potential effective drug (RvD1) for the treatment of SAH and other inflammation-associated brain diseases.

Vasopressor Infusion After Subarachnoid Hemorrhage Does Not Increase Regional Cerebral Tissue Oxygenation

INTRODUCTION

Vasopressors are commonly used after aneurysmal subarachnoid hemorrhage (aSAH) to sustain cerebral pressure gradients. Yet, the relationship between vasopressors and the degree of cerebral microcirculatory support achieved remains unclear. This study aimed to explore the changes in cerebral and peripheral regional tissue oxygen saturation (rSO2) as well as blood pressure (BP) before and after vasopressor infusion in patients with aSAH.

METHODS

Continuous noninvasive cerebral and peripheral rSO2 was obtained using near-infrared spectroscopy for up to 14 days after aSAH. Within-subject differences in rSO2 before and after the commencement of vasopressor infusion were analyzed controlling for Hunt and Hess grade and vasospasm.

RESULTS

Of 45 patients with continuous rSO2 monitoring, 19 (42%) received vasopressor infusion (all 19 on norepinephrine, plus epinephrine in 2 patients, phenylephrine in 4 patients, and vasopressin in 2 patients). In these 19 patients, their vasopressor infusion times were associated with higher BP (systolic [b = 15.1], diastolic [b = 7.3], and mean [b = 10.1]; P = .001) but lower cerebral rSO2 (left cerebral rSO2 decreased by 4.4% [b = -4.4, P < .0001]; right cerebral rSO2 decreased by 5.5% [b = -5.5, P = .0002]).

CONCLUSIONS

Despite elevation in systemic BP during vasopressor infusion times, cerebral rSO2 was concurrently diminished. These findings warrant further investigation for the effect of induced hypertension on cerebral microcirculation.

Effect of Intracranial Pressure Control on Improvement of Cerebral Perfusion After Acute Subarachnoid Hemorrhage: A Comparative Angiography Study Based on Temporal Changes of Intracranial Pressure and Systemic Pressure

OBJECTIVE

Increased intracranial pressure (ICP) is a well-known complication after aneurysmal subarachnoid hemorrhage (aSAH). This study focused on the different temporal changes in ICP, mean arterial pressure, and cerebral perfusion pressure at the early stage of aSAH, throughout aneurysm embolization, and their effects on improvement in angiographic perfusion patterns.

METHODS

Twenty-seven patients with aSAH were evaluated who underwent coiling and cerebrospinal fluid (CSF) drainage. Diagnostic angiography was performed to confirm the presence and location of the vascular lesion. The transit time of the capillary filling phase was defined as a surrogate of cerebral perfusion. Capillary filling transit times were compared before and after CSF drainage. Univariate and multivariate analyses were performed to identify associations between different physical parameters and capillary filling transit times.

RESULTS

By univariate analysis, average capillary transit time before CSF drainage had a significant correlation with initial ICP (P = 0.0004; R² = 0.398) but not systemic pressure (mean arterial pressure or cerebral perfusion pressure). Improvement in capillary filling pattern (i.e., a decrease in angiographic capillary transit time after CSF drainage) was seen in patients with high initial ICP and correlated with ICP difference after ventricular drainage (P = 0.0001 and P < 0.0001, respectively). Using multivariate regression analysis, improved control in postprocedural ICP levels significantly correlated with angiographic evidence of improved cerebral perfusion (P = 0.0243).

CONCLUSIONS

Decreasing ICP by CSF drainage strongly correlated with improved cerebral microcirculation after aSAH. Further development of ICP control protocols that can provide better ICP management of patients with aSAH is warranted.

Application values of clinical nursing pathway in patients with acute cerebral hemorrhage

Acute cerebral hemorrhage accounts for approximately 25% of strokes for elderly patients. Consequently, treatments to improve prognosis should be identified. The aim of the present study was to examine the clinical values of the application of clinical nursing pathway for patients with acute cerebral hemorrhage. Between January 2013 and January 2015, 92 patients diagnosed with acute intracerebral hemorrhage were enrolled in the study based on the guidelines recommended for providing appropriate surgical or conservative treatment and the sequence of admission. The 92 patients were randomly divided into the control and observation groups. Patients in the control group underwent routine nursing mode prior to and after admission, and underwent clinical nursing path model (hierarchical partitioning prior to admission to hospital plus general professional program of nursing in hospital) was applied to the observation group. Barthel index scores for the observation group were significantly higher than that of the control group. The length of hospital stay for patients in the observation group was significantly lower while the average score for patients' satisfaction on nursing care while in hospital was significantly higher than that of the control group, with statistically significant differences (P<0.05). The incidence of complications such as fever, infection, bedsore, gastrointestinal function, electrolyte disturbances, and malnutrition, in the observation group was significantly lower, with statistically significant differences (P<0.05). The functional independence measure (FIM) and Fugl-Meyer scores after 6 months for the observation group were significantly higher, with statistically significant differences (P<0.05). In conclusion, application of the clinical nursing pathway for patients with acute cerebral hemorrhage significantly improved the clinical effects and nursing satisfaction, reduced adverse reactions, and had a greater clinical application value.