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.

Blood pressure variability and prognosis in aneurysmal subarachnoid hemorrhage: a systematic review and meta-analysis

INTRODUCTION

The subarachnoid hemorrhage due to a ruptured brain aneurysm is a neurological emergency with high mobility and mortality. Hypertensive states are related to a bad prognosis and a higher risk of a ruptured aneurysm. However, the relationship between the blood pressure variability with the aneurysmal subarachnoid hemorrhage and its prognosis is quite unknown.

EVIDENCE ACQUISITION

A systematic review was performed across the databases. The following descriptors and related were used for the search: blood pressure, arterial pressure, variability, subarachnoid hemorrhage, hemorrhage, aneurysmal, aneurysmal subarachnoid hemorrhage. The following data were extracted: Glasgow Outcome Scale or Modified Rankin Scale, and blood pressure variabilities to categorize the prognosis.

EVIDENCE SYNTHESIS

Five studies were selected. The blood pressure variability and the related outcome were assessed by mean systolic blood pressure and minimum systolic blood. The meta-analysis of mean systolic blood pressure (cut-off >95.3 mmHg) showed an odds ratio of 11.23 (95% CI: 4.423 to 28.537) (P≤0.001), predicting the good outcome after the aneurysmal subarachnoid hemorrhage. The pooled analysis revealed AUC of the ROC predicting the good outcome was statistically significant (AUC: 0.85, P<0.001). The pooled data analysis of minimum systolic blood pressure revealed an odds ratio of 6.43 (95% CI: 2.834-14.589, P<0.001) and AUC of the pooled ROC 0.931 (95% CI: 0.851 to 1.000, P<0.001) to predict poor outcome. The funnel plot through Egger's test for the analysis showed different grades of asymmetry.

CONCLUSIONS

The blood pressure variability (mean and minimum systolic blood pressure) is a good predictor and parameter in the aneurysmal subarachnoid hemorrhage prognosis and outcome prediction.

Hemoglobin levels as a transfusion criterion in moderate to severe traumatic brain injury: a systematic review and meta-analysis

BACKGROUND

Several factors can influence the outcome of severe head injuries including the patient's hemoglobin levels. There has often been a dilemma regarding levels of hemoglobin at which red cell blood transfusion (RCBT) should be performed.

OBJECTIVE

To systematically review the literature to determine the usefulness of management protocols that have hemoglobin levels <10 g/dL vs <7 g/dL as an RCBT criterion.

METHODS

Following the PRISMA statement, the search was constructed using terms and descriptors of the Medical Subject Heading (MeSH), combined with Boolean operators. Full text of these articles was studied, and outcome measures at 3-6 months were considered for patients who were given a RCBT at <10 g/dL or at 7 g/dL hemoglobin levels.

RESULTS

A total of 4 articles were found suitable for inclusion in the meta-analysis. RCBT below 7 g/dL was not associated with an increased risk of mortality as compared to RCBT using the value of less than 10 g/dL. RCBT at lower levels of hemoglobin was also not associated with a poor neurological outcome (GOS 4-5) but rather RCBT at lower levels lead to better outcomes (GOS 1-3) and the association was significant.

CONCLUSION

Allogenic RCBT was associated with poorer neurological outcomes, within a wide range of reported differences in the hemoglobin threshold to decide for RCBT in TBI patients. Restrictive RCBT strategy may be useful in moderate to severe TBI cases although the risk of anemia-induced cerebral injury needs further investigation regarding the risks and complications inherent to RCBT.

Obesity and Stroke: Does the Paradox Apply for Stroke?

Historically, obesity has been identified as one of the most important risk factors for developing cardiovascular diseases including stroke; however, a theory called "The Obesity Paradox" has been recently considered. The paradoxical theory is that obese or overweight patients (according to body mass index score) can have better outcomes compared to leaner or malnourished patients. The paradox was initially discovered in patients with heart failure. The purpose of this manuscript was to investigate whether this paradox also applies to stroke patients, according to information available in the current literature.

The Prion-like Properties of Amyloid-beta Peptide and Tau: Is there Any Risk of Transmitting Alzheimer's Disease During Neurosurgical Interventions?

Recent studies have recognized similarities between the peptides involved in the neuropathology of Alzheimer's disease and prions. The Tau protein and the Amyloid β peptide represent the theoretical pillars of Alzheimer's disease development. It is probable that there is a shared mechanism for the transmission of these substances and the prion diseases development; this presumption is based on the presentation of several cases of individuals without risk factors who developed dementia decades after a neurosurgical procedure. This article aims to present the role of Aβ and Tau, which underlie the pathophysiologic mechanisms involved in the AD and their similarities with the prion diseases infective mechanisms by means of the presentation of the available evidence at molecular (in-vitro), animal, and human levels that support the controversy on whether these diseases might be transmitted in neurosurgical interventions, which may constitute a wide public health issue.

Immunomodulatory Effect of Hypertonic Saline Solution in Traumatic Brain-Injured Patients and Intracranial Hypertension

Traumatic brain injury (TBI) is often associated with an increase in the intracranial pressure (ICP). This increase in ICP can cross the physiological range and lead to a reduction in cerebral perfusion pressure (CPP) and the resultant cerebral blood flow (CBF). It is this reduction in the CBF that leads to the secondary damage to the neural parenchyma along with the physical axonal and neuronal damage caused by the mass effect. In certain cases, a surgical intervention may be required to either remove the mass lesion (hematoma of contusion evacuation) or provide more space to the insulted brain to expand (decompressive craniectomy). Whether or not a surgical intervention is performed, all these patients require some form of pharmaceutical antiedema agents to bring down the raised ICP. These agents have been broadly classified as colloids (e.g., mannitol, glycerol, urea) and crystalloids (e.g., hypertonic saline), and have been used since decades. Even though mannitol has been the workhorse for ICP reduction owing to its unique properties, crystalloids have been found to be the preferred agents, especially when long-term use is warranted. The safest and most widely used agent is hypertonic saline in various concentrations. Whatever be the concentration, hypertonic saline has created special interest among physicians owing to its additional property of immunomodulation and neuroprotection. In this review, we summarize and understand the various mechanism by which hypertonic saline exerts its immunomodulatory effects that helps in neuroprotection after TBI.

Current Status of Indications, Timing, Management, Complications, and Outcomes of Tracheostomy in Traumatic Brain Injury Patients

Tracheostomy is the commonest bedside surgical procedure performed on patients needing mechanical ventilation with traumatic brain injury (TBI). The researchers made an effort to organize a narrative review of the indications, timing, management, complications, and outcomes of tracheostomy in relation to neuronal and brain-injured patients following TBI. The study observations were collated from the published literature, namely original articles, book chapters, case series, randomized studies, systematic reviews, and review articles. Information sorting was restricted to tracheostomy and its association with TBI. Care was taken to review the correlation of tracheostomy with clinical correlates including indications, scheduling, interventions, prognosis, and complications of the patients suffering from mild, moderate and severe TBIs using Glasgow Coma Scale, Glasgow Outcome Scale, intraclass correlation coefficient, and other internationally acclaimed outcome scales. Tracheostomy is needed to overcome airway obstruction, prolonged respiratory failure and as indispensable component of mechanical ventilation due to diverse reasons in intensive care unit. Researchers are divided over early tracheostomy or late tracheostomy from days to weeks. The conventional classic surgical technique of tracheostomy has been superseded by percutaneous techniques by being less invasive with lesser complications, classified into early and late complications that may be life threatening. Additional studies have to be conducted to validate and streamline varied observations to frame evidence-based practice for successful weaning and decannulation. Tracheostomy is a safer option in critically ill TBI patients for which a universally accepted protocol for tracheostomy is needed that can help to optimize indications and outcomes.